If neuroimaging is the answer, what
is the question?
Philos Trans R Soc Lond B Biol Sci. 1999
"It is unclear that we will come to a better
understanding of mental processes simply by observing which neural loci are activated
while subjects perform a task. Rather, I suggest here that it is better to come
armed with a question that directs one to design tasks in ways that take advantage
of the strengths of neuroimaging techniques (particularly positron emission tomography
and functional magnetic resonance imaging). Here I develop a taxonomy of types
of questions that can be easily addressed by such techniques. The first class
of questions focuses on how information processing is implemented in the brain;
these questions can be posed at a very coarse scale, focusing on the entire system
that confers a particular ability, or at increasingly more specific scales, ultimately
focusing on individual structures or processes. The second class of questions
focuses on specifying when particular processes and structures are invoked; these
questions focus on how one can use patterns of activation to infer that specific
processes and structures were invoked, and on how processing changes in different
circumstances. The use of neuroimaging to address these questions is illustrated
with results from experiments on visual cognition, and caveats regarding the logic
of inference in each case are noted. Finally, the necessary interplay between
neuroimaging and behavioural studies is stressed." [Abstract]
Jung-Beeman M, Bowden EM, Haberman J, Frymiare JL,
Arambel-Liu S, et al.
Neural Activity When People Solve Verbal Problems
PLoS Biol 2(4): e97 DOI:10.1371/journal.pbio.0020097.
"People sometimes solve problems with a unique process called insight,
accompanied by an Aha! experience. It has long been unclear whether
different cognitive and neural processes lead to insight versus noninsight solutions,
or if solutions differ only in subsequent subjective feeling. Recent behavioral
studies indicate distinct patterns of performance and suggest differential hemispheric
involvement for insight and noninsight solutions. Subjects solved verbal problems,
and after each correct solution indicated whether they solved with or without
insight. We observed two objective neural correlates of insight. Functional magnetic
resonance imaging (Experiment 1) revealed increased activity in the right hemisphere
anterior superior temporal gyrus for insight relative to noninsight solutions.
The same region was active during initial solving efforts. Scalp electroencephalogram
recordings (Experiment 2) revealed a sudden burst of high-frequency (gamma-band)
neural activity in the same area beginning 0.3 s prior to insight solutions. This
right anterior temporal area is associated with making connections across distantly
related information during comprehension. Although all problem solving relies
on a largely shared cortical network, the sudden flash of insight occurs when
solvers engage distinct neural and cognitive processes that allow them to see
connections that previously eluded them." [Full
Parsons, Lawrence M., Osherson, Daniel
Evidence for Distinct Right and Left Brain Systems for Deductive versus Probabilistic
Cereb. Cortex 2001 11: 954-965
and probabilistic reasoning are central to cognition but the functional neuroanatomy
underlying them is poorly understood. The present study contrasted these two kinds
of reasoning via positron emission tomography. Relying on changes in instruction
and psychological set, deductive versus probabilistic reasoning was
induced using identical stimuli. The stimuli were arguments in propositional calculus
not readily solved via mental diagrams. Probabilistic reasoning activated mostly
left brain areas whereas deductive activated mostly right. Deduction activated
areas near right brain homologues of left language areas in middle temporal lobe,
inferior frontal cortex and basal ganglia, as well as right amygdala, but not
spatialvisual areas. Right hemisphere activations in the deduction task
cannot be explained by spill-over from overtaxed, left language areas. Probabilistic
reasoning was mostly associated with left hemispheric areas in inferior frontal,
posterior cingulate, parahippocampal, medial temporal, and superior and medial
prefrontal cortices. The foregoing regions are implicated in recalling and evaluating
a range of world knowledge, operations required during probabilistic thought.
The findings confirm that deduction and induction are distinct processes, consistent
with psychological theories enforcing their partial separation. The results also
suggest that, except for statement decoding, deduction is largely independent
of language, and that some forms of logical thinking are non-diagrammatic."
V, Dolan RJ.
Differential involvement of left prefrontal cortexin
inductive and deductive reasoning.
Cognition. 2004 Oct;93(3):B109-21.
inductive and deductive reasoning are considered distinct logical and psychological
processes, little is known about their respective neural basis. To address this
issue we scanned 16 subjects with fMRI, using an event-related design, while they
engaged in inductive and deductive reasoning tasks. Both types of reasoning were
characterized by activation of left lateral prefrontal and bilateral dorsal frontal,
parietal, and occipital cortices. Neural responses unique to each type of reasoning
determined from the Reasoning Type (deduction and induction) by Task (reasoning
and baseline) interaction indicated greater involvement of left inferior frontal
gyrus (BA 44) in deduction than induction, while left dorsolateral (BA 8/9) prefrontal
gyrus showed greater activity during induction than deduction. This pattern suggests
a dissociation within prefrontal cortex for deductive and inductive reasoning."
M, Fangmeier T, Ruff CC, Johnson-Laird PN.
Reasoning, models, and
images: behavioral measures and cortical activity.
Neurosci. 2003 May 15;15(4):559-73.
"The goal of this study was to investigate
the neurocognitive processes of mental imagery in deductive reasoning. Behavioral
studies yielded four sorts of verbal relations: (1) visuospatial relations that
are easy to envisage both visually and spatially; (2) visual relations that are
easy to envisage visually but hard to envisage spatially; (3) spatial relations
that are hard to envisage visually but easy to envisage spatially; and (4) control
relations that are hard to envisage both visually and spatially. In three experiments,
visual relations slowed the process of reasoning in comparison with control relations,
whereas visuospatial and spatial relations yielded inferences comparable to those
of control relations. An experiment using functional magnetic resonance imaging
showed that in the absence of any correlated visual input (problems were presented
acoustically via headphones), all types of reasoning problems evoked activity
in the left middle temporal gyrus, in the right superior parietal cortex, and
bilaterally in the precuneus. In the prefrontal cortex, increased activity was
found in the middle and inferior frontal gyri. However, only the problems based
on visual relations also activated areas of the visual association cortex corresponding
to V2. The results indicate that cortical activity during reasoning depends on
the nature of verbal relations. All relations elicit mental models that underlie
reasoning, but visual relations in addition elicit visual images. This account
resolves inconsistencies in the previous literature." [Abstract]
Knauff M, Mulack T, Kassubek J, Salih HR, Greenlee
Spatial imagery in deductive reasoning: a functional MRI study.
Res Cogn Brain Res. 2002 Apr;13(2):203-12.
"Various cognitive theories
aim to explain human deductive reasoning: (1) mental logic theories claim syntactic
language-based proofs of derivation, (2) the mental model theory proposes cognitive
processes of constructing and manipulating spatially organized mental models,
and (3) imagery theories postulate that such abilities are based on visual mental
images. To explore the neural substrates of human deductive reasoning, we examined
BOLD (blood oxygen level dependent) contrasts of twelve healthy participants during
relational and conditional reasoning with whole-brain functional magnetic resonance
imaging (fMRI). The results indicate that, in the absence of any correlated visual
input, reasoning activated an occipitoparietal-frontal network, including parts
of the prefrontal cortex (Brodmann's area, BA, 6, 9) and the cingulate gyrus (BA
32), the superior and inferior parietal cortex (BA 7, 40), the precuneus (BA 7),
and the visual association cortex (BA 19). In the discussion, we first focus on
the activated occipito-parietal pathway that is well known to be involved in spatial
perception and spatial working memory. Second, we briefly relate the activation
in the prefrontal cortical areas and in the anterior cingulate gyrus to other
imaging studies on higher cognitive functions. Finally, we draw some general conclusions
and argue that reasoners envisage and inspect spatially organized mental models
to solve deductive inference problems." [Abstract]
Zacks JM, Ollinger JM, Sheridan MA, Tversky B.
parametric study of mental spatial transformations of bodies.
"TWO CLASSES OF MENTAL SPATIAL TRANSFORMATION CAN
BE DISTINGUISHED: Object-based spatial transformations are imagined movements
of objects; and egocentric perspective transformations are imagined movements
of one's point of view. The hypothesis that multiple neural systems contribute
to these mental imagery operations was tested with functional MRI. Participants
made spatial judgments about pictures of human bodies, and brain activity was
analyzed as a function of the judgment required and the time taken to respond.
Areas in right temporal, occipital and parietal cortex and the medial superior
cerebellum appear to be differentially involved in object-based spatial transformations.
Additionally, midline structures and lateral parietal cortex were found to decrease
in activity during the spatial reasoning tasks, independently of the judgment
required or of the latency of response. The results are discussed in terms of
a model of spatial reasoning that postulates specialized subsystems for performing
object-based and egocentric perspective image transformations." [Abstract]
V, Gold B, Kapur S, Houle S.
Neuroanatomical correlates of human
J Cogn Neurosci. 1998 May;10(3):293-302.
of the important questions cognitive theories of reasoning must address is whether
logical reasoning is inherently sentential or spatial. A sentential model would
exploit nonspatial (linguistic) properties of representations whereas a spatial
model would exploit spatial properties of representations. In general terms, the
linguistic hypothesis predicts that the language processing regions underwrite
human reasoning processes, and the spatial hypothesis suggests that the neural
structures for perception and motor control contribute the basic representational
building blocks used for high-level logical and linguistic reasoning. We carried
out a [(15)O] H(2)O PET imaging study to address this issue. Twelve normal volunteers
performed three types of deductive reasoning tasks (categorical syllogisms, three-term
spatial relational items, and three-term nonspatial relational items) while their
regional cerebral blood flow pattern was recorded using [(15)O] H(2)O PET imaging.
In the control condition subjects semantically comprehended sets of three sentences.
In the deductive reasoning conditions subjects determined whether the third sentence
was entailed by the first two sentences. The areas of activation in each reasoning
condition were confined to the left hemisphere and were similar to each other
and to activation reported in previous studies. They included the left inferior
frontal gyrus (Brodmann area 45, 47), a portion of the left middle frontal gyrus
(Brodmann area 46), the left middle temporal gyrus (Brodmann areas 21, 22), a
region of the left lateral inferior temporal gyrus and superior temporal gyrus
(Brodmann areas 22, 37), and a portion of the left cingulate gyrus (Brodmann areas
32, 24). There was no significant right-hemisphere or parietal activation. These
results are consistent with previous neuroimaging studies and raise questions
about the level of involvement of classic spatial regions in reasoning about linguistically
presented spatial relations." [Abstract]
Goel V, Dolan RJ.
of three-term relational reasoning.
a recent study we demonstrated that reasoning with categorical syllogisms engages
two dissociable mechanisms. Reasoning involving concrete sentences engaged a left
hemisphere linguistic system while formally identical arguments, involving abstract
sentences, recruited a parietal spatial network. The involvement of a parietal
visuo-spatial system in abstract syllogism reasoning raised the question whether
argument forms involving explicit spatial relations (or relations that can be
easily mapped onto spatial relations) are sufficient to engage the parietal system?
We addressed this question in an event-related fMRI study of three-term relational
reasoning, using sentences with concrete and abstract content. Our findings indicate
that both concrete and abstract three-term relational arguments activate a similar
bilateral occipital-parietal-frontal network. However, the abstract reasoning
condition engendered greater parietal activation than the concrete reasoning condition.
We conclude that arguments involving relations that can be easily mapped onto
explicit spatial relations engage a visuo-spatial system, irrespective of concrete
or abstract content." [Abstract]
Cognitive Neuroscience of
In Cambridge Handbook of Thinking
& Reasoning, Eds. K. Holyoak & R. Morrison. Cambridge UniversityPress.
V, Dolan RJ.
Anatomical segregation of component processes in an
inductive inference task.
J Cogn Neurosci. 2000 Jan;12(1):110-9.
inference underlies much of human cognition. The essential component of induction
is hypothesis selection based on some criterion of relevance. The purpose of this
study was to determine the neural substrate of inductive inference, particularly
hypothesis selection, using fMRI. Ten volunteers were shown stimuli consisting
of novel animals under two task conditions, and asked to judge whether all the
animals in the set were the same type of animal. In one condition, subjects were
given a rule that specified the criteria for "same type of animal".
In the other condition, subjects had to infer the rule without instruction. The
two conditions were further factored into easy and difficult components. Rule
inference was specifically associated with bilateral hippocampal activation while
the task by difficulty interaction was associated with activation in right lateral
orbital prefrontal cortex. We interpret the former in terms of semantic encoding
of novel stimuli and the latter in terms of hypothesis selection. Thus, we show
an anatomical dissociation between task implementation and task difficulty that
may correspond to a critical psychological distinction in the processes necessary
for inductive inference." [Abstract]
V, Gold B, Kapur S, Houle S.
The seats of reason? An imaging study
of deductive and inductive reasoning.
"We carried out a neuroimaging study to test the
neurophysiological predictions made by different cognitive models of reasoning.
Ten normal volunteers performed deductive and inductive reasoning tasks while
their regional cerebral blood flow pattern was recorded using [15O]H2O PET imaging.
In the control condition subjects semantically comprehended sets of three sentences.
In the deductive reasoning condition subjects determined whether the third sentence
was entailed by the first two sentences. In the inductive reasoning condition
subjects reported whether the third sentence was plausible given the first two
sentences. The deduction condition resulted in activation of the left inferior
frontal gyrus (Brodmann areas 45, 47). The induction condition resulted in activation
of a large area comprised of the left medial frontal gyrus, the left cingulate
gyrus, and the left superior frontal gyrus (Brodmann areas 8, 9, 24, 32). Induction
was distinguished from deduction by the involvement of the medial aspect of the
left superior frontal gyrus (Brodmann areas 8, 9). These results are consistent
with cognitive models of reasoning that postulate different mechanisms for inductive
and deductive reasoning and view deduction as a formal rule-based process."
Acuna BD, Eliassen JC, Donoghue JP, Sanes JN.
and parietal lobe activation during transitive inference in humans.
Cortex. 2002 Dec;12(12):1312-21.
"Cortical areas engaged in knowledge
manipulation during reasoning were identified with functional magnetic resonance
imaging (MRI) while participants performed transitive inference (TI) on an ordered
list of 11 items (e.g. if A < B and B < C, then A < C). Initially, participants
learned a list of arbitrarily ordered visual shapes. Learning occurred by exposure
to pairs of list items that were adjacent in the sequence. Subsequently, functional
MR images were acquired as participants performed TI on non-adjacent sequence
items. Control tasks consisted of height comparisons (HT) and passive viewing
(VIS). Comparison of the TI task with the HT task identified activation resulting
from TI, termed 'reasoning', while controlling for rule application, decision
processes, perception, and movement, collectively termed 'support processes'.
The HT-VIS comparison revealed activation related to support processes. The TI
reasoning network included bilateral prefrontal cortex (PFC), pre-supplementary
motor area (preSMA), premotor area (PMA), insula, precuneus, and lateral posterior
parietal cortex. By contrast, cortical regions activated by support processes
included the bilateral supplementary motor area (SMA), primary motor cortex (M1),
somatic sensory cortices, and right PMA. These results emphasize the role of a
prefrontal-parietal network in manipulating information to form new knowledge
based on familiar facts. The findings also demonstrate PFC activation beyond short-term
memory to include mental operations associated with reasoning." [Abstract]
Wharton CM, Grafman J, Flitman SS, Hansen EK, Brauner
J, Marks A, Honda M.
Toward neuroanatomical models of analogy: a
positron emission tomography study of analogical mapping.
Psychol. 2000 May;40(3):173-97.
"Several brain regions associated with
analogical mapping were identified using (15)O-positron emission tomography with
12 normal, high intelligence adults. Each trial presented during scanning consisted
of a source picture of colored geometric shapes, a brief delay, and a target picture
of colored geometric shapes. Analogous pictures did not share similar geometric
shapes but did share the same system of abstract visuospatial relations. Participants
judged whether each source-target pairing was analogous (analogy condition) or
identical (literal condition). The results of the analogy-literal comparison showed
activation in the dorsomedial frontal cortex and in the left hemisphere; the inferior,
middle, and medial frontal cortices; the parietal cortex; and the superior occipital
cortex. Based on these results as well as evidence from relevant cognitive neuroscience
studies of reasoning and of executive working memory, we hypothesize that analogical
mapping is mediated by the left prefrontal and inferior parietal cortices."
Q, Perry C, Peng D, Jin Z, Xu D, Ding G, Xu S.
The neural substrate
of analogical reasoning: an fMRI study.
Brain Res Cogn Brain
Res. 2003 Oct;17(3):527-34.
"This study investigated the anatomical substrate
of analogical reasoning using functional magnetic resonance imaging. In the study,
subjects performed a verbal analogy task (e.g., soldier is to army as drummer
is to band) and, to control for activation caused by purely semantic access, a
semantic judgment task. Significant activation differences between the verbal
analogy and the semantic judgment task were found bilaterally in the prefrontal
cortex (right BA 11/BA 47 and left BA45), the fusiform gyrus, and the basal ganglia;
left lateralized in the postero-superior temporal gyrus (BA 22) and the (para)
hippocampal region; and right lateralized in the anterior cingulate. The role
of these areas in analogical reasoning is discussed." [Abstract]
Ruff CC, Knauff M, Fangmeier T, Spreer J.
and working memory: common and distinct neuronal processes.
"The neuronal processes underlying reasoning and the
related working memory subsystems were examined with functional magnetic resonance
imaging (fMRI). Twelve volunteers solved relational reasoning problems which either
supported a single (determinate) or several alternative solutions (indeterminate).
In a second condition, participants maintained the identical premises of these
problems in working memory without making inferences. Although problems were presented
in auditory format, activity was detected for both reasoning and maintenance in
a network comprising bilaterally the secondary visual cortex, the posterior cingulate
cortex, and the medial anterior frontal cortex. In direct comparisons, reasoning
was associated with stronger dorsolateral and medial prefrontal activation than
maintenance, whereas maintenance led to stronger lateral parietal activation than
reasoning. Participants' visuo-spatial abilities ("Block Design" score)
covaried positively with behavioral performance and negatively with activity of
the precuneus for reasoning, but not for maintenance. These results support the
notion that relational reasoning is based on visuo-spatial mental models, and
they help to distinguish the neuronal processes related to reasoning itself versus
to the maintenance of problem information in working memory." [Abstract]
M, Domahs F, Bartha L, Brenneis C, Lochy A, Trieb T, Benke T.
complex arithmetic-an fMRI study.
Brain Res Cogn Brain Res.
"Aim of the present functional magnet resonance
imaging (fMRI) study was to detect modifications of cerebral activation patterns
related to learning arithmetic. Thirteen right-handed subjects were extensively
trained on a set of 18 complex multiplication problems. In the following fMRI
session, trained and untrained problems (closely matched for difficulty) were
presented in blocked order alternating with a number matching task and a fact
retrieval task. Importantly, left hemispheric activations were dominant in the
two contrasts between untrained and trained condition, suggesting that learning
processes in arithmetic are predominantly supported by the left hemisphere. Contrasting
untrained versus trained condition, the left intraparietal sulcus showed significant
activations, as well as the inferior parietal lobule. A further significant activation
was found in the left inferior frontal gyrus. This activation may be accounted
for by higher working memory demands in the untrained as compared to the trained
condition. Contrasting trained versus untrained condition a significant focus
of activation was found in the left angular gyrus. Following the triple-code model
[Science 284 (1999) 970], the shift of activation within the parietal lobe from
the intraparietal sulcus to the left angular gyrus suggests a modification from
quantity-based processing to more automatic retrieval. The present study shows
that the left angular gyrus is not only involved in arithmetic tasks requiring
simple fact retrieval, but may show significant activations as a result of relatively
short training of complex calculation." [Abstract]
V, Mackenzie K, Rivera SM, Reiss AL.
Prefrontal cortex involvement
in processing incorrect arithmetic equations: evidence from event-related fMRI.
Brain Mapp. 2002 Jun;16(2):119-30.
"The main aim of this study was to
investigate the differential processing of correct and incorrect equations to
gain further insight into the neural processes involved in arithmetic reasoning.
Electrophysiological studies in humans have demonstrated that processing incorrect
arithmetic equations (e.g., 2 + 2 = 5) elicits a prominent event-related potential
(ERP) compared to processing correct equations (e.g., 2 + 2 = 4). In the present
study, we investigated the neural substrates of this process using event-related
functional magnetic resonance imaging (fMRI). Subjects were presented with arithmetic
equations and asked to indicate whether the solution displayed was correct or
incorrect. We found greater activation to incorrect, compared to correct equations,
in the left dorsolateral prefrontal cortex (DLPFC, BA 46) and the left ventrolateral
prefrontal cortex (VLPFC, BA 47). Our results provide the first brain imaging
evidence for differential processing of incorrect vs. correct equations. The prefrontal
cortex activation observed in processing incorrect equations overlaps with brain
areas known to be involved in working memory and interference processing. The
DLPFC region differentially activated by incorrect equations was also involved
in overall arithmetic processing, whereas the VLPFC was activated only during
the differential processing of incorrect equations. Differential response to correct
and incorrect arithmetic equations was not observed in parietal cortex regions
such as the angular gyrus and intra-parietal sulcus, which are known to play a
specific role in performing arithmetic computations. The pattern of brain response
observed is consistent with the hypothesis that processing incorrect equations
involves detection of an incorrect answer and resolution of the interference between
the internally computed and externally presented incorrect answer. More specifically,
greater activation during processing of incorrect equations appears to reflect
additional operations involved in maintaining the results in working memory, while
subjects attempt to resolve the conflict and select a response. These findings
allow us to further delineate and dissociate the contributions of prefrontal and
parietal cortices to arithmetic reasoning." [Abstract]
V, Rypma B, Gabrieli JD.
Neural substrates of mathematical reasoning:
a functional magnetic resonance imaging study of neocortical activation during
performance of the necessary arithmetic operations test.
"Brain activation was examined using functional
magnetic resonance imaging during mathematical problem solving in 7 young healthy
participants. Problems were selected from the Necessary Arithmetic Operations
Test (NAOT; R. B. Ekstrom, J. W. French, H. H. Harman, & D. Dermen, 1976).
Participants solved 3 types of problems: 2-operation problems requiring mathematical
reasoning and text processing, 1-operation problems requiring text processing
but minimal mathematical reasoning, and 0-operation problems requiring minimal
text processing and controlling sensorimotor demands of the NAOT problems. Two-operation
problems yielded major activations in bilateral frontal regions similar to those
found in other problem-solving tasks, indicating that the processes mediated by
these regions subserve many forms of reasoning. Findings suggest a dissociation
in mathematical problem solving between reasoning, mediated by frontal cortex,
and text processing, mediated by temporal cortex." [Abstract]
N. Wood & Jordan Grafman
HUMAN PREFRONTAL CORTEX: PROCESSING
AND REPRESENTATIONAL PERSPECTIVES
Nature Reviews Neuroscience
4, 139 -147 (2003); doi:10.1038/nrn1033
"Through evolution, humans have
acquired 'higher' cognitive skills such as language, reasoning and planning
and complex social behaviour. Evidence from neuropsychological and neuroimaging
research indicates that the prefrontal cortex (PFC) underlies much of this higher
cognition. A number of theories have been proposed for how the PFC might achieve
this. Although many of these theories focus on the types of 'process' that the
PFC carries out, we argue for the validity of a representational approach to understanding
PFC function." [Abstract]
CE, D'Esposito M.
Persistent activity in the prefrontal cortex during
Trends Cogn Sci. 2003 Sep;7(9):415-423.
dorsolateral prefrontal cortex (DLPFC) plays a crucial role in working memory.
Notably, persistent activity in the DLPFC is often observed during the retention
interval of delayed response tasks. The code carried by the persistent activity
remains unclear, however. We critically evaluate how well recent findings from
functional magnetic resonance imaging studies are compatible with current models
of the role of the DLFPC in working memory. These new findings suggest that the
DLPFC aids in the maintenance of information by directing attention to internal
representations of sensory stimuli and motor plans that are stored in more posterior
H, Bretschneider V, Gron G, Zurowski B, Wunderlich AP, Tomczak R, Spitzer M.
for quantitative domain dominance for verbal and spatial working memory in frontal
and parietal cortex.
Cortex. 2003 Sep-Dec;39(4-5):897-911.
studies in humans have shown that different working memory (WM) tasks recruit
a common bilateral fronto-parietal cortical network. Animal studies as well as
neuroimaging studies in humans have suggested that this network, in particular
the prefrontal cortex, is preferentially recruited when material from different
domains (e.g. spatial information or verbal/object information) has to be memorized.
Early imaging studies have suggested qualitative dissociations in the prefrontal
cortex for spatial and object/verbal WM, either in a left-right or a ventral-dorsal
dimension. However, results from different studies are inconsistent. Moreover,
recent fMRI studies have failed to find evidence for domain dependent dissociations
of WM-related activity in prefrontal cortex. Here we present evidence from two
independent fMRI studies using physically identical stimuli in a verbal and spatial
WM task showing that domain dominance for WM does indeed exist, although only
in the form of quantitative differences in activation and not in the form of a
dissociation with different prefrontal regions showing mutually exclusive activation
in different domains. Our results support a mixed dimension model of domain dominance
for WM within the prefrontal cortex, with left ventral prefrontal cortex (PFC)
supporting preferentially verbal WM and right dorsal PFC supporting preferentially
spatial WM. The concept of domain dominance is discussed in the light of recent
theories of prefrontal cortex function." [Abstract]
Reichle ED, Carpenter PA, Just MA.
neural bases of strategy and skill in sentence-picture verification.
Psychol. 2000 Jun;40(4):261-95.
"This experiment used functional Magnetic
Resonance Imaging to examine the relation between individual differences in cognitive
skill and the amount of cortical activation engendered by two strategies (linguistic
vs. visual-spatial) in a sentence-picture verification task. The verbal strategy
produced more activation in language-related cortical regions (e.g., Broca's area),
whereas the visual-spatial strategy produced more activation in regions that have
been implicated in visual-spatial reasoning (e.g., parietal cortex). These relations
were also modulated by individual differences in cognitive skill: Individuals
with better verbal skills (as measured by the reading span test) had less activation
in Broca's area when they used the verbal strategy. Similarly, individuals with
better visual-spatial skills (as measured by the Vandenberg, 1971, mental rotation
test) had less activation in the left parietal cortex when they used the visual-spatial
strategy. These results indicate that language and visual-spatial processing are
supported by partially separable networks of cortical regions and suggests one
basis for strategy selection: the minimization of cognitive workload." [Abstract]
F. Ramsey, J. M. Jansma, G. Jager, T. Van Raalten, and R. S. Kahn
factors in human information processing capacity
Advance Access published on March 1, 2004, DOI 10.1093/brain/awh060.
"What determines how well an individual can manage the complexity
of information processing demands when several tasks have to be executed simultaneously?
Various theoretical frameworks address the mechanisms of information processing
and the changes that take place when processes become automated, and brain regions
involved in various types of information processing have been identified, as well
as sequences of events in the brain. The neurophysiological substrate of human
information processing capacity, i.e. the amount that can be processed simultaneously,
is, however, unresolved, as is the basis of inter-individual variability in capacity.
Automatization of cognitive functions is known to increase capacity to process
additional tasks, but behavioural indices of automatization are poor predictors
of processing capacity in individuals. Automatization also leads to a decline
of brain activity in the working memory system. In this study, we test the hypothesis
that processing capacity is closely related to the way that the brain adjusts
to practice of a single cognitive task, i.e. to the changes in neuronal activity
that accompany automatization as measured with functional MRI (fMRI). Using a
task that taxes the working memory system, and is sensitive to automatization,
performance improved while activity in the network declined, as expected. The
key finding is that the magnitude of automatization-induced reduction of activity
in this system was a strong predictor for the ability to perform two different
working memory tasks simultaneously (after scanning). It explained 60% of the
variation in information processing capacity across individuals. In contrast,
the behavioural measures of automatization did not predict this. We postulate
that automatization involves at least two partially independent neurophysiological
mechanisms, i.e. (i) streamlining of neuronal communication which improves performance
on a single task; and (ii) functional trimming of neuronal ensembles which enhances
the capacity to accommodate processing of additional tasks, potentially by facilitating
rapid switching of instruction sets or contexts. Finally, this study shows that
fMRI can provide information that predicts behavioural output, which is not provided
by overt behavioural measures." [Abstract]
N, Osaka M, Kondo H, Morishita M, Fukuyama H, Shibasaki H.
basis of executive function in working memory: an fMRI study based on individual
Neuroimage. 2004 Feb;21(2):623-31.
fMRI, neural substrates of the executive system were investigated with respect
to differences in working memory capacity. To explore the executive control processes,
reading span test (RST) and read conditions were performed. Two subject groups
were selected: those with large working memory capacities, labeled high-span subjects
(HSS) according to the reading span test, and those with small working memory
capacities, labeled low-span subjects (LSS). Significant activation was found
mainly in three regions in comparison with the control: anterior cingulate cortex
(ACC), left inferior frontal gyrus (IFG), visual association cortex (VAC) and
superior parietal lobule (SPL). For both groups, the fMRI signal intensity increased
in ACC and IFG during the RST condition compared to that under the read condition.
A group difference was also found in the ACC and IFG region, specifically a significant
increase in signal intensity was observed only for the HSS group but not for the
LSS group. Behavioral data also showed that the performance was better in HSS
than in LSS. Moreover, the cross correlation of signal change between ACC and
IFG was higher in HSS than in LSS, indicating that the network system between
ACC and IFG was more activated in HSS compared to that of LSS. These results suggest
that executive function, that is, working attention controlling system is more
active in HSS than in LSS. Moreover, the results confirmed our hypothesis that
there is a general neural basis for the central executive function in both RST
and previous LST (listening span test) tasks despite differences in modality-specific
JR, Chabris CF, Braver TS.
Neural mechanisms of general fluid intelligence.
Neurosci. 2003 Mar;6(3):316-22.
"We used an individual-differences approach
to test whether general fluid intelligence (gF) is mediated by brain regions that
support attentional (executive) control, including subregions of the prefrontal
cortex. Forty-eight participants first completed a standard measure of gF (Raven's
Advanced Progressive Matrices). They then performed verbal and nonverbal versions
of a challenging working-memory task (three-back) while their brain activity was
measured using functional magnetic resonance imaging (fMRI). Trials within the
three-back task varied greatly in the demand for attentional control because of
differences in trial-to-trial interference. On high-interference trials specifically,
participants with higher gF were more accurate and had greater event-related neural
activity in several brain regions. Multiple regression analyses indicated that
lateral prefrontal and parietal regions may mediate the relation between ability
(gF) and performance (accuracy despite interference), providing constraints on
the neural mechanisms that support gF." [Abstract]
Duncan, John, Seitz, Rudiger J., Kolodny, Jonathan,
Bor, Daniel, Herzog, Hans, Ahmed, Ayesha, Newell, Fiona N., Emslie, Hazel
Neural Basis for General Intelligence
Science 2000 289:
"Universal positive correlations between different cognitive tests
motivate the concept of "general intelligence" or Spearman's g. Here
the neural basis for g is investigated by means of positron emission tomography.
Spatial, verbal, and perceptuo-motor tasks with high-g involvement are compared
with matched low-g control tasks. In contrast to the common view that g reflects
a broad sample of major cognitive functions, high-g tasks do not show diffuse
recruitment of multiple brain regions. Instead they are associated with selective
recruitment of lateral frontal cortex in one or both hemispheres. Despite very
different task content in the three high-g-low-g contrasts, lateral frontal recruitment
is markedly similar in each case. Many previous experiments have shown these same
frontal regions to be recruited by a broad range of different cognitive demands.
The results suggest that "general intelligence" derives from a specific
frontal system important in the control of diverse forms of behavior." [Full
Prabhakaran V, Smith JA, Desmond JE, Glover
GH, Gabrieli JD.
Neural substrates of fluid reasoning: an fMRI study
of neocortical activation during performance of the Raven's Progressive Matrices
Cognit Psychol. 1997 Jun;33(1):43-63.
examined brain activation, as measured by functional magnetic resonance imaging,
during problem solving in seven young, healthy participants. Participants solved
problems selected from the Raven's Progressive Matrices Test, a test known to
predict performance on a wide range of reasoning tasks. In three conditions, participants
solved problems requiring (1) analytic reasoning; (2) figural or visuospatial
reasoning; or (3) simple pattern matching that served as a perceptual-motor control.
Right frontal and bilateral parietal regions were activated more by figural than
control problems. Bilateral frontal and left parietal, occipital, and temporal
regions were activated more by analytic than figural problems. All of these regions
were activated more by analytic than match problems. Many of these activations
occurred in regions associated with working memory. Figural reasoning activated
areas involved in spatial and object working memory. Analytic reasoning activated
additional areas involved in verbal working memory and domain-independent associative
and executive processes. These results suggest that fluid reasoning is mediated
by a composite of working memory systems." [Abstract]
Cabeza R, Dolcos F, Graham R, Nyberg L.
and differences in the neural correlates of episodic memory retrieval and working
Neuroimage. 2002 Jun;16(2):317-30.
neuroimaging studies have shown that different cognitive functions activate overlapping
brain regions. An activation overlap may occur because a region is involved in
operations tapped by different cognitive functions or because the activated area
comprises subregions differentially involved in each of the functions. To investigate
these issues, we directly compared brain activity during episodic retrieval (ER)
and working memory (WM) using event-related functional MRI (fMRI). ER was investigated
with a word recognition test, and WM was investigated with a word delayed-response
test. Two-phase trials distinguished between retrieval mode and cue-specific aspects
of ER, as well as between encoding/maintenance and retrieval aspects of WM. The
results revealed a common fronto-parieto-cerebellar network for ER and WM, as
well as subregions differentially involved in each function. Specifically, there
were two main findings. First, the results differentiated common and specific
subregions within the prefrontal cortex: (i) left dorsolateral areas were recruited
by both functions, possibly reflecting monitoring operations; (ii) bilateral anterior
and ventrolateral areas were more activated during ER than during WM, possibly
reflecting retrieval mode and cue-specific ER operations, respectively; and (iii)
left posterior/ventral (Broca's area) and bilateral posterior/dorsal areas were
more activated during WM than during ER, possibly reflecting phonological and
generic WM operations, respectively. Second, hippocampal and parahippocampal regions
were activated not only for ER but also for WM. This result suggests that indexing
operations mediated by the medial temporal lobes apply to both long-term and short-term
memory traces. Overall, our results show that direct cross-function comparisons
are critical to understand the role of different brain regions in various cognitive
Rypma, Bart, Berger, Jeffrey S., D'Esposito, Mark
Influence of Working-Memory Demand and Subject Performance on Prefrontal Cortical
J. Cogn. Neurosci. 2002 14: 721-731
imaging and behavioral studies of working memory (WM) converge to suggest that
the ventrolateral prefrontal cortex (PFC) mediates a capacity-limited storage
buffer and that the dorsolateral PFC mediates memory organization processes that
support supracapacity memory storage. Previous research from our laboratory has
shown that the extent to which such memory organization processes are required
depends on both task factors (i.e., memory load) and subject factors (i.e., response
speed). Task factors exert their effects mainly during WM encoding while subject
factors exert their effects mainly during WM retrieval. In this study, we sought
to test the generalizability of these phenomena under more difficult memory-demand
conditions than have been used previously. During scanning, subjects performed
a WM task in which they were required to maintain between 1 and 8 letters over
a brief delay. Neural activity was measured during encoding, maintenance, and
retrieval task periods using event-related functional magnetic resonance imaging.
With increasing memory load, there were reaction time increases and accuracy rate
decreases, ventrolateral PFC activation decreases during encoding, and dorsolateral
PFC activation increases during maintenance and retrieval. These results suggest
that the ventrolateral PFC mediates WM storage and that the dorsolateral PFC mediates
strategic memory organization processes that facilitate supracapacity WM storage.
Additionally, high-performing subjects showed overall less activation than low-performing
subjects, but activation increases with increasing memory load in the lateral
PFC during maintenance and retrieval. Low-performing subjects showed overall more
activation than high-performing subjects, but minimal activation increases in
the dorsolateral PFC with increasing memory load. These results suggest that individual
differences in both neural efficiency and cognitive strategy underlie individual
differences in the quality of subjects' WM performance." [Abstract]
A. Bunge, Itamar Kahn, Jonathan D. Wallis, Earl K. Miller, and Anthony D. Wagner
Neural Circuits Subserving the Retrieval and Maintenance of Abstract
J Neurophysiol 90: 3419-3428, 2003. First published
"Behavior is often governed by abstract rules or
instructions for behavior that can be abstracted from one context and applied
to another. Prefrontal cortex (PFC) is thought to be important for representing
rules, although the contributions of ventrolateral (VLPFC) and dorsolateral (DLPFC)
regions remain under-specified. In the present study, event-related fMRI was used
to examine abstract rule representation in humans. Prior to scanning, subjects
learned to associate unfamiliar shapes and nonwords with particular rules. During
each fMRI trial, presentation of one of these cues was followed by a delay and
then by sample and probe stimuli. Match and non-match rules required subjects
to indicate whether or not the sample and probe matched; go rules required subjects
to make a response that was not contingent on the sample/probe relation. Left
VLPFC, parietal cortex, and pre-SMA exhibited sensitivity to rule type during
the cue and delay periods. Delay-period activation in these regions, but not DLPFC,
was greater when subjects had to maintain response contingencies (match, non-match)
relative to when the cue signaled a specific response (go). In contrast, left
middle temporal cortex exhibited rule sensitivity during the cue but not delay
period. These results support the hypothesis that VLPFC interacts with temporal
cortex to retrieve semantic information associated with a cue and with parietal
cortex to retrieve and maintain relevant response contingencies across delays.
Future investigations of cross-regional interactions will enable full assessment
of this account. Collectively, these results demonstrate that multiple, neurally
separable processes are recruited during abstract rule representation." [Abstract]
M, Pandya DN.
Comparative cytoarchitectonic analysis of the human
and the macaque ventrolateral prefrontal cortex and corticocortical connection
patterns in the monkey.
Eur J Neurosci. 2002 Jul;16(2):291-310.
comparison of the cytoarchitecture of the human and the macaque monkey ventrolateral
prefrontal cortex demonstrated a region in the monkey that exhibits the architectonic
characteristic of area 45 in the human brain. This region occupies the dorsal
part of the ventrolateral prefrontal convexity just below area 9/46v. Rostroventral
to area 45 in the human brain lies a large cortical region labelled as area 47
by Brodmann. The ventrolateral component of this region extending as far as the
lateral orbital sulcus has architectonic characteristics similar to those of the
ventrolateral prefrontal region labelled by Walker as area 12 in the macaque monkey.
We designated this region in both the human and the monkey ventrolateral prefrontal
cortex as area 47/12. Thus, area 47/12 designates the specific part of the zone
previously labelled as area 47 in the human brain that has the same overall architectonic
pattern as that of Walker's area 12 in the macaque monkey brain. The cortical
connections of these two areas were examined in the monkey by injecting fluorescent
retrograde tracers. Although both area 45 and area 47/12 as defined here had complex
multimodal input, they could be differentiated in terms of some of their inputs.
Retrograde tracers restricted to area 47/12 resulted in heavy labelling of neurons
in the rostral inferotemporal visual association cortex and in temporal limbic
areas (i.e. perirhinal and parahippocampal cortex). In contrast, injections of
tracers into dorsally adjacent area 45 demonstrated strong labelling in the superior
temporal gyrus (i.e. the auditory association cortex) and the multimodal cortex
in the upper bank of the superior temporal sulcus." [Abstract]
JD, Anderson KC, Miller EK.
Single neurons in prefrontal cortex encode
Nature. 2001 Jun 21;411(6840):953-6.
ability to abstract principles or rules from direct experience allows behaviour
to extend beyond specific circumstances to general situations. For example, we
learn the 'rules' for restaurant dining from specific experiences and can then
apply them in new restaurants. The use of such rules is thought to depend on the
prefrontal cortex (PFC) because its damage often results in difficulty in following
rules. Here we explore its neural basis by recording from single neurons in the
PFC of monkeys trained to use two abstract rules. They were required to indicate
whether two successively presented pictures were the same or different depending
on which rule was currently in effect. The monkeys performed this task with new
pictures, thus showing that they had learned two general principles that could
be applied to stimuli that they had not yet experienced. The most prevalent neuronal
activity observed in the PFC reflected the coding of these abstract rules."
M. Fincham, Cameron S. Carter, Vincent van Veen, V. Andrew Stenger, and John R.
Neural mechanisms of planning: A computational analysis
using event-related fMRI
PNAS 99: 3346-3351. 2002.
investigate the neural mechanisms of planning, we used a novel adaptation of the
Tower of Hanoi (TOH) task and event-related functional MRI. Participants were
trained in applying a specific strategy to an isomorph of the five-disk TOH task.
After training, participants solved novel problems during event-related functional
MRI. A computational cognitive model of the task was used to generate a reference
time series representing the expected blood oxygen level-dependent response in
brain areas involved in the manipulation and planning of goals. This time series
was used as one term within a general linear modeling framework to identify brain
areas in which the time course of activity varied as a function of goal-processing
events. Two distinct time courses of activation were identified, one in which
activation varied parametrically with goal-processing operations, and the other
in which activation became pronounced only during goal-processing intensive trials.
Regions showing the parametric relationship comprised a frontoparietal system
and include right dorsolateral prefrontal cortex [Brodmann's area (BA 9)], bilateral
parietal (BA 40/7), and bilateral premotor (BA 6) areas. Regions preferentially
engaged only during goal-intensive processing include left inferior frontal gyrus
(BA 44). The implications of these results for the current model, as well as for
our understanding of the neural mechanisms of planning and functional specialization
of the prefrontal cortex, are discussed." [Full
Newman SD, Carpenter PA, Varma S, Just
Frontal and parietal participation in problem solving in the
Tower of London: fMRI and computational modeling of planning and high-level perception.
"This study triangulates executive planning and visuo-spatial
reasoning in the context of the Tower of London (TOL) task by using a variety
of methodological approaches. These approaches include functional magnetic resonance
imaging (fMRI), functional connectivity analysis, individual difference analysis,
and computational modeling. A graded fMRI paradigm compared the brain activation
during the solution of problems with varying path lengths: easy (1 and 2 moves),
moderate (3 and 4 moves) and difficult (5 and 6 moves). There were three central
findings regarding the prefrontal cortex: (1) while both the left and right prefrontal
cortices were equally involved during the solution of moderate and difficult problems,
the activation on the right was differentially attenuated during the solution
of the easy problems; (2) the activation observed in the right prefrontal cortex
was highly correlated with individual differences in working memory (measured
independently by the reading span task); and (3) different patterns of functional
connectivity were observed in the left and right prefrontal cortices. Results
obtained from the superior parietal region also revealed left/right differences;
only the left superior parietal region revealed an effect of difficulty. These
fMRI results converged upon two hypotheses: (1) the right prefrontal area may
be more involved in the generation of a plan, whereas the left prefrontal area
may be more involved in plan execution; and (2) the right superior parietal region
is more involved in attention processes while the left homologue is more of a
visuo-spatial workspace. A 4CAPS computational model of the cognitive processes
and brain activation in the TOL task integrated these hypothesized mechanisms,
and provided a reasonably good fit to the observed behavioral and brain activation
data. The multiple research approaches presented here converge on a deepening
understanding of the combination of perceptual and conceptual processes in this
type of visual problem solving." [Abstract]
CY, Wager TD, Lacey SC, Hernandez L, Nichols TE, Smith EE, Jonides J.
attention and resolving interference: fMRI measures of executive functions.
"Is there a single executive process or are there multiple
executive processes that work together towards the same goal in some task? In
these experiments, we use counter switching and response inhibition tasks to examine
the neural underpinnings of two cognitive processes that have often been identified
as potential executive processes: the switching of attention between tasks, and
the resolution of interference between competing task responses. Using functional
magnetic resonance imaging (fMRI), for both event-related and blocked design tasks,
we find evidence for common neural areas across both tasks in bilateral parietal
cortex (BA 40), left dorsolateral prefrontal cortex (DLPFC; BA 9), premotor cortex
(BA 6) and medial frontal cortex (BA 6/32). However, we also find areas preferentially
involved in the switching of attention between mental counts (BA 7, BA 18) and
the inhibition of a prepotent motor response (BA 6, BA 10), respectively. These
findings provide evidence for the separability of cognitive processes underlying
executive control." [Abstract]
Konishi S, Uchida I, Okuaki T, Machida T,
Shirouzu I, Miyashita Y.
Neural correlates of recency judgment.
Neurosci. 2002 Nov 1;22(21):9549-55.
"The prefrontal cortex plays a critical
role in recollecting the temporal context of past events. The present study used
event-related functional magnetic resonance imaging (fMRI) and explored the neural
correlates of temporal-order retrieval during a recency judgment paradigm. In
this paradigm, after study of a list of words presented sequentially, subjects
were presented with two of the studied words simultaneously and were asked which
of the two words was studied more recently. Two types of such retrieval trials
with varied (high and low) levels of demand for temporal-order retrieval were
intermixed and compared using event-related fMRI. The intraparadigm comparison
of high versus low demand trials revealed brain regions with activation that was
modulated on the basis of demand for temporal-order retrieval. Multiple lateral
prefrontal regions including the middle and inferior lateral prefrontal cortex
were prominently activated. Activation was also observed in the anterior prefrontal
cortex and the medial temporal cortex, regions well documented to be related to
memory retrieval in general. The modulation of brain activity in these regions
suggests a detailed pathway that is engaged during recency judgment." [Full
Hideaki Kawabata, and Semir Zeki
Correlates of Beauty
J Neurophysiol 91: 1699-1705, 2004.
"We have used the technique of functional MRI to
address the question of whether there are brain areas that are specifically engaged
when subjects view paintings that they consider to be beautiful, regardless of
the category of painting (that is whether it is a portrait, a landscape, a still
life, or an abstract composition). Prior to scanning, each subject viewed a large
number of paintings and classified them into beautiful, neutral, or ugly. They
then viewed the same paintings in the scanner. The results show that the perception
of different categories of paintings are associated with distinct and specialized
visual areas of the brain, that the orbito-frontal cortex is differentially engaged
during the perception of beautiful and ugly stimuli, regardless of the category
of painting, and that the perception of stimuli as beautiful or ugly mobilizes
the motor cortex differentially." [Abstract]
JM, Wig GS, Adams RB Jr, Janata P, Kelley WM.
Neural correlates of
humor detection and appreciation.
Neuroimage. 2004 Mar;21(3):1055-60.
is a uniquely human quality whose neural substrates remain enigmatic. The present
report combined dynamic, real-life content and event-related functional magnetic
resonance imaging (fMRI) to dissociate humor detection ("getting the joke")
from humor appreciation (the affective experience of mirth). During scanning,
subjects viewed full-length episodes of the television sitcoms Seinfeld or The
Simpsons. Brain activity time-locked to humor detection moments revealed increases
in left inferior frontal and posterior temporal cortices, whereas brain activity
time-locked to moments of humor appreciation revealed increases in bilateral regions
of insular cortex and the amygdala. These findings provide evidence that humor
depends critically upon extant neural systems important for resolving incongruities
(humor detection) and for the expression of affect (humor appreciation)."
VS, Berman KF, Ostrem JL, Esposito G, Van Horn JD, Bigelow LB, Weinberger DR.
enhances "neural network-specific" physiological signals: a positron-emission
tomography rCBF study.
J Neurosci. 1996 Aug 1;16(15):4816-22.
studies in animals and humans suggest that monoamines enhance behavior-evoked
neural activity relative to nonspecific background activity (i.e., increase signal-to-noise
ratio). We studied the effects of dextroamphetamine, an indirect monoaminergic
agonist, on cognitively evoked neural activity in eight healthy subjects using
positron-emission tomography and the O15 water intravenous bolus method to measure
regional cerebral blood flow (rCBF). Dextroamphetamine (0.25 mg/kg) or placebo
was administered in a double-blind, counterbalanced design 2 hr before the rCBF
study in sessions separated by 1-2 weeks. rCBF was measured while subjects performed
four different tasks: two abstract reasoning tasks--the Wisconsin Card Sorting
Task (WCST), a neuropsychological test linked to a cortical network involving
dorsolateral prefrontal cortex and other association cortices, and Ravens Progressive
Matrices (RPM), a nonverbal intelligence test linked to posterior cortical systems--and
two corresponding sensorimotor control tasks. There were no significant drug or
task effects on pCO2 or on global blood flow. However, the effect of dextroamphetamine
(i.e., dextroamphetamine vs placebo) on task-dependent rCBF activation (i.e.,
task - control task) showed double dissociations with respect to task and region
in the very brain areas that most distinctly differentiate the tasks. In the superior
portion of the left inferior frontal gyrus, dextroamphetamine increased rCBF during
WCST but decreased it during RPM (ANOVA F (1,7) = 16.72, p < 0.0046). In right
hippocampus, blood flow decreased during WCST but increased during RPM (ANOVA
F(1,7) = 18.7, p < 0.0035). These findings illustrate that dextroamphetamine
tends to "focus" neural activity, to highlight the neural network that
is specific for a particular cognitive task. This capacity of dextroamphetamine
to induce cognitively specific signal augmentation may provide a neurobiological
explanation for improved cognitive efficiency with dextroamphetamine." [Abstract]
Mazoyer B, Zago L, Mellet E, Bricogne S, Etard O, Houde
O, Crivello F, Joliot M, Petit L, Tzourio-Mazoyer N.
for working memory and executive functions sustain the conscious resting state
Brain Res Bull. 2001 Feb;54(3):287-98.
cortical anatomy of the conscious resting state (REST) was investigated using
a meta-analysis of nine positron emission tomography (PET) activation protocols
that dealt with different cognitive tasks but shared REST as a common control
state. During REST, subjects were in darkness and silence, and were instructed
to relax, refrain from moving, and avoid systematic thoughts. Each protocol contrasted
REST to a different cognitive task consisting either of language, mental imagery,
mental calculation, reasoning, finger movement, or spatial working memory, using
either auditory, visual or no stimulus delivery, and requiring either vocal, motor
or no output. A total of 63 subjects and 370 spatially normalized PET scans were
entered in the meta-analysis. Conjunction analysis revealed a network of brain
areas jointly activated during conscious REST as compared to the nine cognitive
tasks, including the bilateral angular gyrus, the left anterior precuneus and
posterior cingulate cortex, the left medial frontal and anterior cingulate cortex,
the left superior and medial frontal sulcus, and the left inferior frontal cortex.
These results suggest that brain activity during conscious REST is sustained by
a large scale network of heteromodal associative parietal and frontal cortical
areas, that can be further hierarchically organized in an episodic working memory
parieto-frontal network, driven in part by emotions, working under the supervision
of an executive left prefrontal network." [Abstract]
What's so special about human tool use?
2003 Jul 17;39(2):201-4.
"Evidence suggests homologies in parietofrontal
circuits involved in object prehension among humans and monkeys. Likewise, tool
use is known to induce functional reorganization of their visuotactile limb representations.
Yet, humans are the only species for whom tool use is a defining and universal
characteristic. Why? Comparative studies of chimpanzee tool use indicate that
critical differences are likely to be found in mechanisms involved in causal reasoning
rather than those implementing sensorimotor transformations. Available evidence
implicates higher-level perceptual areas in these processes." [Abstract]
V, Dolan RJ.
Reciprocal neural response within lateral and ventral
medial prefrontal cortex during hot and cold reasoning.
"Logic is widely considered the basis of rationality.
Logical choices, however, are often influenced by emotional responses, sometimes
to our detriment, sometimes to our advantage. To understand the neural basis of
emotionally neutral ("cold") and emotionally salient ("hot")
reasoning we studied 19 volunteers using event-related fMRI, as they made logical
judgments about arguments that varied in emotional saliency. Despite identical
logical form and content categories across "hot" and "cold"
reasoning conditions, lateral and ventral medial prefrontal cortex showed reciprocal
response patterns as a function of emotional saliency of content. "Cold"
reasoning trials resulted in enhanced activity in lateral/dorsal lateral prefrontal
cortex (L/DLPFC) and suppression of activity in ventral medial prefrontal cortex
(VMPFC). By contrast, "hot" reasoning trials resulted in enhanced activation
in VMPFC and suppression of activation in L/DLPFC. This reciprocal engagement
of L/DLPFC and VMPFC provides evidence for a dynamic neural system for reasoning,
the configuration of which is strongly influenced by emotional saliency."
Houde O, Zago L, Crivello F, Moutier S, Pineau A, Mazoyer
B, Tzourio-Mazoyer N.
Access to deductive logic depends on a right
ventromedial prefrontal area devoted to emotion and feeling: evidence from a training
Neuroimage. 2001 Dec;14(6):1486-92.
the human capacity for access to deductive logic depend on emotion and feeling?
With positron emission tomography, we compared the brain networks recruited by
two groups of subjects who were either able or not able to shift from errors to
logical responses in a deductive reasoning task. They were scanned twice while
performing the same task, before and after a training session. The error-to-logical
shift occurred in a group that underwent logicoemotional training but not in the
other group, trained in logic only-a "cold" kind of training. The intergroup
comparison pointed out that access to deductive logic involved a right ventromedial
prefrontal area known to be devoted to emotion and feeling." [Abstract]
Goel V, Dolan RJ.
of reasoning by belief.
Cognition. 2003 Feb;87(1):B11-22.
deductive reasoning is a closed system, one's beliefs about the world can influence
validity judgements. To understand the associated functional neuroanatomy of this
belief-bias we studied 14 volunteers using event-related fMRI, as they performed
reasoning tasks under neutral, facilitatory and inhibitory belief conditions.
We found evidence for the engagement of a left temporal lobe system during belief-based
reasoning and a bilateral parietal lobe system during belief-neutral reasoning.
Activation of right lateral prefrontal cortex was evident when subjects inhibited
a prepotent response associated with belief-bias and correctly completed a logical
task, a finding consistent with its putative role in cognitive monitoring. By
contrast, when logical reasoning was overcome by belief-bias, there was engagement
of ventral medial prefrontal cortex, a region implicated in affective processing.
This latter involvement suggests that belief-bias effects in reasoning may be
mediated through an influence of emotional processes on reasoning." [Abstract]
V, Buchel C, Frith C, Dolan RJ.
Dissociation of mechanisms underlying
Neuroimage. 2000 Nov;12(5):504-14.
key question for cognitive theories of reasoning is whether logical reasoning
is inherently a sentential linguistic process or a process requiring spatial manipulation
and search. We addressed this question in an event-related fMRI study of syllogistic
reasoning, using sentences with and without semantic content. Our findings indicate
involvement of two dissociable networks in deductive reasoning. During content-based
reasoning a left hemisphere temporal system was recruited. By contrast, a formally
identical reasoning task, which lacked semantic content, activated a parietal
system. The two systems share common components in bilateral basal ganglia nuclei,
right cerebellum, bilateral fusiform gyri, and left prefrontal cortex. We conclude
that syllogistic reasoning is implemented in two distinct systems whose engagement
is primarily a function of the presence or absence of semantic content. Furthermore,
when a logical argument results in a belief-logic conflict, the nature of the
reasoning process is changed by recruitment of the right prefrontal cortex."
R. Gray, Todd S. Braver, and Marcus E. Raichle
Integration of emotion
and cognition in the lateral prefrontal cortex
"We used functional MRI to test the hypothesis that emotional
states can selectively influence cognition-related neural activity in lateral
prefrontal cortex (PFC), as evidence for an integration of emotion and cognition.
Participants (n = 14) watched short videos intended to induce emotional states
(pleasant/approach related, unpleasant/withdrawal related, or neutral). After
each video, the participants were scanned while performing a 3-back working memory
task having either words or faces as stimuli. Task-related neural activity in
bilateral PFC showed a predicted pattern: an Emotion × Stimulus crossover
interaction, with no main effects, with activity predicting task performance.
This highly specific result indicates that emotion and higher cognition can be
truly integrated, i.e., at some point of processing, functional specialization
is lost, and emotion and cognition conjointly and equally contribute to the control
of thought and behavior. Other regions in lateral PFC showed hemispheric specialization
for emotion and for stimuli separately, consistent with a hierarchical and hemisphere-based
mechanism of integration." [Full
Phan KL, Taylor SF, Welsh RC, Ho SH, Britton
JC, Liberzon I.
Neural correlates of individual ratings of emotional
salience: a trial-related fMRI study.
Neuroimage. 2004 Feb;21(2):768-80.
appraisal of meaningful environmental signals involves the interpretation of salient
information for their intrinsic emotional value and personal relevance. We examined
the neural basis for these components of endogenous salience during such appraisals
using trial-related functional magnetic resonance imaging (fMRI). Subjects viewed
affective pictures and assessed either the emotional intensity or extent of self-relatedness
of the content of those pictures. In a parametric factorial design, individualized
subjective ratings of these two dimensions were correlated with brain activity.
The nucleus accumbens (NAcc) responded to both increasing emotional intensity
and self-relatedness. Activity in the amygdala was specifically related to affective
judgments and emotional intensity. The volitional act of appraising the extent
of personal association specifically engaged the ventral medial prefrontal cortex
(MPFC), and additionally recruited dorsal medial frontal regions and insula as
the extent of self-relatedness increased. The findings highlight both overlapping
and segregated neural representations of intrinsic value and personal relevance
during the appraisal of emotional stimuli." [Abstract]
KL, Wager T, Taylor SF, Liberzon I.
Functional neuroanatomy of emotion:
a meta-analysis of emotion activation studies in PET and fMRI.
"Neuroimagingstudies with positron emission tomography
(PET) and functional magnetic resonance imaging (fMRI) have begun to describe
the functional neuroanatomy of emotion. Taken separately, specific studies vary
in task dimensions and in type(s) of emotion studied and are limited by statistical
power and sensitivity. By examining findings across studies, we sought to determine
if common or segregated patterns of activations exist across various emotional
tasks. We reviewed 55 PET and fMRI activation studies (yielding 761 individual
peaks) which investigated emotion in healthy subjects. Peak activation coordinates
were transformed into a standard space and plotted onto canonical 3-D brain renderings.
We divided the brain into 20 nonoverlapping regions, and characterized each region
by its responsiveness across individual emotions (positive, negative, happiness,
fear, anger, sadness, disgust), to different induction methods (visual, auditory,
recall/imagery), and in emotional tasks with and without cognitive demand. Our
review yielded the following summary observations: (1) The medial prefrontal cortex
had a general role in emotional processing; (2) fear specifically engaged the
amygdala; (3) sadness was associated with activity in the subcallosal cingulate;
(4) emotional induction by visual stimuli activated the occipital cortex and the
amygdala; (5) induction by emotional recall/imagery recruited the anterior cingulate
and insula; (6) emotional tasks with cognitive demand also involved the anterior
cingulate and insula. This review provides a critical comparison of findings across
individual studies and suggests that separate brain regions are involved in different
aspects of emotion." [Abstract]
Zysset S, Huber O, Ferstl E, von Cramon DY.
anterior frontomedian cortex and evaluative judgment: an fMRI study.
"This study investigated the neuronal basis of
evaluative judgment. Judgments can be defined as the assessment of an external
or internal stimulus on an internal scale and they are fundamental for decision-making
and other cognitive processes. Evaluative judgments (I like George W. Bush: yes/no)
are a special type of judgment, in which the internal scale is related to the
person's value system (preferences, norms, aesthetic values, etc.). We used functional
magnetic resonance imaging to examine brain activation during the performance
of evaluative judgments as opposed to episodic and semantic memory retrieval.
Evaluative judgment produced significant activation in the anterior frontomedian
cortex (BA 10/9), the inferior precuneus (BA 23/31), and the left inferior prefrontal
cortex (BA 45/47). The results show a functional dissociation between the activations
in the anterior frontomedian cortex and in the inferior precuneus. The latter
was mainly activated by episodic retrieval processes, supporting its function
as a multimodal association area that integrates the different aspects of retrieved
and newly presented information. In contrast, the anterior frontomedian cortex
was mainly involved in evaluative judgments, supporting its role in self-referential
processes and in the self-initiation of cognitive processes." [Abstract]
Volz KG, Schubotz RI, Von Cramon DY.
am I unsure? Internal and external attributions of uncertainty dissociated by
Neuroimage. 2004 Mar;21(3):848-57.
evidence suggests that the perceived reason of uncertainty causes different coping
strategies to be implemented, particularly frequency ratings with externally attributed
uncertainty and memory search with internally attributed uncertainty. We used
functional magnetic resonance imaging (fMRI) to investigate whether processes
related to these different attributions of uncertainty differ also in their neural
substrates. Participants had to predict events that were uncertain due to internal
factors, that is, insufficient knowledge. Data were compared with a preceding
study in which event prediction was uncertain due to external factors, that is,
event probabilities. Parametric analyses revealed the posterior frontomedian cortex,
that is, mesial Brodmann Area 8 (BA 8) as the common cortical substrate mediating
processes related to uncertainty no matter what the cause of uncertainty. However,
processes related to the two differently attributed types of uncertainty differed
significantly in relation to the brain network that was coactivated. Only processes
related to internally attributed uncertainty elicited activation within the mid-dorsolateral
and posterior parietal areas known to underlie working memory (WM) functions.
Together, findings from both experiments suggest that there is a common cerebral
correlate for uncertain predictions but different correlates for coping strategies
of uncertainty. Concluding, BA 8 reflects that we are uncertain, coactivated networks
what we do to resolve uncertainty." [Abstract]
Zerssen GC, Mecklinger A, Opitz B, von Cramon DY.
and illusory recognition: an event-related fMRI study.
J Neurosci. 2001 Jun;13(11):2148-56.
"In this event-related functional
magnetic resonance imaging (fMRI) study we examined the neuronal correlates of
the subprocesses underlying recognition memory. In an explicit memory task, participants
had to discriminate studied ('old') words from semantically related and unrelated
'new' (unstudied) words. We examined whether the correct rejection of semantically
related words which were similar to old words, which had elicited correct responses,
was based on conscious recollection of study phase information. In this task,
false-positive responses to semantically related new words can be assumed to result
from the assessment of the semantic similarity between test words and studied
words with minimal recollection. For correct identification of old words and correct
rejection of new related words we found common activation in a variety of brain
areas that have been shown to be involved in conscious recollection, among them
the left middle frontal gyrus, the precuneus, the retrosplenial cortex, the left
parahippocampal gyrus and the thalamus. For correct responses to old words, the
frontomedian wall, the posterior cingulate cortex and the nucleus accumbens were
additionally activated, suggesting an emotional contribution to these judgements.
Correct rejections of related new words were associated with additional activation
of the right middle frontal gyrus, suggesting higher monitoring demands for these
more difficult recognition judgements. False-positive responses to semantically
related new words were associated with enhanced activation in the frontomedian
wall. The results point to an important role of the prefrontal cortex as well
as medial temporal and medial parietal regions of the brain in successful memory
retrieval and conscious recollection." [Abstract]
EC, von Cramon DY.
What does the frontomedian cortex contribute to
language processing: coherence or theory of mind?
"The frontomedian cortex (FMC) has been shown
to be important for coherence processes in language comprehension, i.e., for establishing
the pragmatic connection between successively presented sentences. The same brain
region has a role during theory-of-mind processes, i.e., during the attribution
of other people's actions to their motivations, beliefs, or emotions. In this
study, we used event-related functional magnetic resonance imaging at 3 T to disentangle
the relative contributions of the FMC to theory-of-mind (ToM) and coherence processes,
respectively. The BOLD response of nine participants was recorded while they listened
to pragmatically coherent or unrelated sentence pairs. Using a logic instruction
for inanimate sentence pairs, ToM processing was discouraged during the first
part of the experiment. Using explicit ToM instructions for sentence pairs mentioning
human protagonists, ToM processing was induced during the second part. In three
of the resulting four conditions a significant increase in the BOLD response was
observed in FMC: when ToM instructions were given, both coherent and incoherent
trials elicited frontomedian activation, in replication of previous results showing
involvement of the FMC during ToM tasks. When logic instructions were given, the
coherent trials, but not the incoherent trials, activated the FMC. These results
clearly show that the FMC plays a role in coherence processes even in the absence
of concomitant ToM processes. The findings support the view of this cortex having
a domain-independent functionality related to volitional aspects of the initiation
and maintenance of nonautomatic cognitive processes." [Abstract]
Ferstl EC, von Cramon DY.
The role of
coherence and cohesion in text comprehension: an event-related fMRI study.
Res Cogn Brain Res. 2001 Jun;11(3):325-40.
"Text processing requires inferences
for establishing coherence between successive sentences. In neuropsychological
studies and brain imaging studies, these coherence-building processes have been
ascribed to the right hemisphere. On the other hand, there is evidence for prefrontal
brain damage causing non-aphasic language disorders, in which text level processes
are impaired. In this study, we used an event-related, whole-head fMRI methodology
to evaluate the contributions of prefrontal areas and the right hemisphere to
coherence building. We scanned 12 participants while they read 120 sentence pairs
and judged their coherence. Four conditions were used, resulting from crossing
coherence and cohesion (i.e. the presence of a lexical connection). A behavioral
pretest confirmed that cohesion aided establishing coherence, whereas it hindered
the detection of coherence breaks. In the fMRI study, all language conditions
yielded activation in left frontolateral and temporolateral regions, when compared
to a physical control task. The differences due to coherence of the sentence pairs
were most evident in larger activation for coherent as compared to incoherent
sentence pairs in the left frontomedian wall, but also in posterior cingulate
and precuneal regions. Finally, a left inferior prefrontal area was sensitive
to the difficulty of the task, and in particular to the increase in processing
costs when cohesion falsely indicated coherence. These results could not provide
evidence for a special involvement of the right hemisphere during inferencing.
Rather, they suggest that the left frontomedian cortex plays an important role
in coherence building." [Abstract]
R, Rees G, Dolan RJ.
Ventromedial prefrontal cortex mediates guessing.
"Guessing is an important component of everyday
cognition. The present study examined the neural substrates of guessing using
a simple card-playing task in conjunction with functional magnetic resonance imaging
(fMRI). Subjects were scanned under four conditions. In two, they were shown images
of the back of a playing card and had to guess either the colour or the suit of
the card. In the other two they were shown the face of a card and had to report
either the colour or the suit. Guessing compared to reporting was associated with
significant activations in lateral prefrontal cortex (right more than left), right
orbitofrontal cortex, anterior cingulate, bilateral inferior parietal cortex and
right thalamus. Increasing the guessing demands by manipulating the number of
alternative outcomes was associated with activation of the left lateral and medial
orbitofrontal cortex. These data suggest that while simple two choice guessing
depends on an extensive neural system including regions of the right lateral prefrontal
cortex, activation of orbitofrontal cortex increases as the probabilistic contingencies
become more complex. Guessing thus involves not only systems implicated in working
memory processes but also depends upon orbitofrontal cortex. This region is not
typically activated in working memory tasks and its activation may reflect additional
requirements of dealing with uncertainty." [Abstract]
Marian, Harries, Clare, Garcia-Monco, Juan Carlos, Ballus, Emma, Grafman, Jordan
with Right Frontal Lesions are Unable to Assess and Use Advice to Make Predictive
J. Cogn. Neurosci. 2004 16: 74-89
lobe damage impairs decision-making. Most studies have employed gambling and probabilistic
tasks, which have an emotional (rewardpunishment) component and found that
patients with ventromedial sector lesions have exceptional difficulty performing
normally on these tasks. We have recently presented an economic decision-making
task to patients and normal volunteers that required them to not only forecast
an economic outcome but also to weigh advice from four advisors about the possible
outcome across 40 trials. We studied 20 patients with right frontal lobe lesions
and 9 patients with parietal lobe lesions and compared their performance to 20
matched controls. Frontal lobe lesion patients were inconsistent at using advice
and their forecasts were poor. Patients with dorsolateral but not orbito-frontal
lesions showed some ability to assess advice. Patients with parietal lobe lesions
were good at assessing advice but were slow at doing so; they were consistent
but poor at using advice and their use of advice was unrelated to their forecasting.
All three patient groups were overconfident in their own performance. In contrast,
controls could both use and assess advice, their ability to use advice was mediated
by their ability to assess it, and they were not overconfident. Group differences
on an overall measure of accuracy on this task were associated with an ability
to accurately plan. Differences in ability to assess and forecast were associated
with planning and working memory performance. These findings indicate that patients
with both right dorsolateral and orbito-frontal lesions may be impaired when required
to make complex decisions related to forecasting and judgment. Our findings enlarge
the scope of decision-making deficits seen in patients with frontal lobe lesions
and indicate additional circumstances in which patients with frontal lobe lesions
will have difficulty in deciding." [Full
Sanfey, Alan G., Rilling, James K., Aronson,
Jessica A., Nystrom, Leigh E., Cohen, Jonathan D.
The Neural Basis
of Economic Decision-Making in the Ultimatum Game
2003 300: 1755-1758
"The nascent field of neuroeconomics seeks to ground
economic decisionmaking in the biological substrate of the brain. We used functional
magnetic resonance imaging of Ultimatum Game players to investigate neural substrates
of cognitive and emotional processes involved in economic decision-making. In
this game, two players split a sum of money;one player proposes a division and
the other can accept or reject this. We scanned players as they responded to fair
and unfair proposals. Unfair offers elicited activity in brain areas related to
both emotion (anterior insula) and cognition (dorsolateral prefrontal cortex).
Further, significantly heightened activity in anterior insula for rejected unfair
offers suggests an important role for emotions in decision-making." [Full
Camerer, Colin F.
AND ECONOMICS: Enhanced: Strategizing in the Brain
2003 300: 1673-1675 [Full
Shimoyama H, Aihara M, Fukuyama H, Hashikawa
K, Aoyagi K, Goldberg E, Nakazawa S.
in a cognitive bias task Part II. SPECT activation study.
Dev. 2004 Jan;26(1):37-42.
"A cognitive bias task (CBT) delineates two
different cognitive selection mechanisms in the prefrontal cortex. To identify
functional anatomy of context-dependent reasoning, we used technetium-99mhexamethyl-
propyleneamine oxime (99mTc HM-PAO) single photon emission computed tomography
(SPECT) and statistical parametric mapping. Twelve right-handed men 20-24 years
old were instructed to look at a target card and then select the choice card (among
two) that they preferred (modified CBT; mCBT). They also selected a choice card
2 weeks later without prior presentation of a target card (control task). In both
tasks, 99mTc HM-PAO was injected intravenously about 15 s after initiation of
the mCBT or control task. Brain images were obtained using a gamma camera and
reconstructed by a UNIX-based workstation. Statistical analysis compared all activated
images to control images. Results associated with P values of less than 0.01 (Z
score > 2.36) were depicted on T1-weighted magnetic resonance images. All subjects
preferred choices more similar to the target. SPECT activation occurred bilaterally
in the dorsolateral prefrontal cortices and middle temporal gyri during performance
of the CBT. Additionally, the left inferior prefrontal cortex and left fusiform
gyrus showed significant activation compared with the control task. A neural network
linking the temporal and prefrontal cortices prominently seen in the left hemisphere
participates in context-dependent reasoning. Knowledge of such neural systems
is essential for understanding prefrontal lobe function and dysfunction."
Ramnani & Adrian M. Owen
ANTERIOR PREFRONTAL CORTEX: INSIGHTS
INTO FUNCTION FROM ANATOMY AND NEUROIMAGING
Neuroscience 5, 184 -194 (2004); doi:10.1038/nrn1343
The anterior prefrontal
cortex (aPFC), or Brodmann area 10, is one of the least well understood regions
of the human brain. Work with non-human primates has provided almost no indications
as to the function of this area. In recent years, investigators have attempted
to integrate findings from functional neuroimaging studies in humans to generate
models that might describe the contribution that this area makes to cognition.
In all cases, however, such explanations are either too tied to a given task to
be plausible or too general to be theoretically useful. Here, we use an account
that is consistent with the connectional and cellular anatomy of the aPFC to explain
the key features of existing models within a common theoretical framework. The
results indicate a specific role for this region in integrating the outcomes of
two or more separate cognitive operations in the pursuit of a higher behavioural
K, Ream JM, Geddes LP, Gabrieli JD.
Evaluating self-generated information:
anterior prefrontal contributions to human cognition.
Neurosci. 2003 Dec;117(6):1161-8.
"The anterior or rostrolateral prefrontal
cortex (RLPFC) is frequently recruited during complex cognitive tasks across a
wide range of domains, including reasoning, long-term memory retrieval, and working
memory. The authors report an event-related functional MRI study, indicating that
the RLPFC is specifically involved in the evaluation of internally generated information--or
information that cannot be readily perceived from the external environment but
has to be inferred or self-generated. The findings are consistent with a hierarchical
model of lateral prefrontal organization, with RLPFC contributing only at the
highest orders of cognitive transformations. This characterization of RLPFC function
may help explain seemingly disparate findings across multiple cognitive domains
and could provide a unified account of this region's contribution to human cognition."
K, Prabhakaran V, Dorfman J, Zhao Z, Kroger JK, Holyoak KJ, Gabrieli JD.
prefrontal cortex involvement in relational integration during reasoning.
"Patient and neuroimaging studies indicate that
complex reasoning tasks are associated with the prefrontal cortex (PFC). In this
study, we tested the hypothesis that the process of relational integration, or
considering multiple relations simultaneously, is a component process of complex
reasoning that selectively recruits PFC. We used fMRI to examine brain activation
during 0-relational, 1-relational, and 2-relational problems adapted from the
Raven's Progressive Matrices and hypothesized that PFC would be preferentially
recruited by the 2-relational problem type. Event-related responses were modeled
by convolving a canonical hemodynamic response function with the response time
(RT) associated with each trial. The results across different analyses revealed
the same pattern: PFC activation was specific to the comparison between 2- and
1-relational problems and was not observed in the comparison between 1- and 0-relational
problems. Furthermore, the process of relational integration was specifically
associated with bilateral rostrolateral PFC (RLPFC; lateral area 10) and right
dorsolateral PFC (areas 9 and 46). Left RLPFC showed the greatest specificity
by remaining preferentially recruited during 2-relational problems even after
comparisons were restricted to trials matched for RT and accuracy. The link between
RLPFC and the process of relational integration may be due to the associated process
of manipulating self-generated information, a process that may characterize RLPFC
Kroger JK, Sabb FW, Fales CL, Bookheimer SY, Cohen
MS, Holyoak KJ.
Recruitment of anterior dorsolateral prefrontal
cortex in human reasoning: a parametric study of relational complexity.
Cortex. 2002 May;12(5):477-85.
"Reasoning and problem solving depend on
the ability to represent and integrate complex relationships among stimuli. For
example, deciding whether an animal is dangerous requires integrating information
about the type of animal, its size, its distance from oneself, and one's proximity
to shelter. Relational complexity increases with the number of such interdependent
elements that must be simultaneously considered to solve a problem. We used functional
magnetic resonance imaging to identify brain regions that respond selectively
in processing high levels of relational complexity. Performance on nonverbal reasoning
problems in which relational complexity was varied parametrically was compared
with performance on control problems in which relational complexity was held constant
while difficulty was manipulated by adding distractor forms to the problems. Increasing
complexity and adding distractors both led to increased activation in parietal
and in dorsolateral prefrontal cortex, with high levels of relational complexity
selectively activating anterior left prefrontal cortex. Our data provide evidence
that brain regions specific to integrating complex relations among stimuli are
distinct from those involved in coping with general task difficulty and with working-memory
B.A., Henson, R.N.A., Friston, K.J., Dolan, R.J.
Cortex Mediates Rule Learning in Humans
Cereb. Cortex 2001
"Despite a need for rule learning in everyday life, the
brain regions involved in explicit rule induction remain undetermined. Here we
use event-related functional magnetic resonance imaging to measure learning-dependent
neuronal responses during an explicit categor- ization task. Subjects made category
decisions, with feedback, to exemplar letter strings for which the rule governing
category membership was periodically changed. Bilateral fronto-polar prefrontal
cortices were selectively engaged following rule change. This activation pattern
declined with improving task performance reflecting rule acquisition. The vocabulary
of letters comprising the exemplars was also periodically changed, independently
of rule changes. This exemplar change modulated activation in left anterior hippocampus.
Our finding that fronto-polar cortex mediates rule learning supports a functional
contribution of this region to generic reasoning and problem-solving behaviours."
TS, Bongiolatti SR.
The role of frontopolar cortex in subgoal processing
during working memory.
Neuroimage. 2002 Mar;15(3):523-36.
studies have implicated the anterior-most or frontopolar regions of prefrontal
cortex (FP-PFC, e.g., Brodmann's Area 10) as playing a central role in higher
cognitive functions such as planning, problem solving, reasoning, and episodic
memory retrieval. The current functional magnetic resonance imaging (fMRI) study
tested the hypothesis that FP-PFC subserves processes related to the monitoring
and management of subgoals, while maintaining information in working memory (WM).
Subjects were scanned while performing two variants of a simple delayed response
WM task. In the control WM condition, subjects monitored for the presence of a
specific concrete probe word (LIME) occurring following a specific abstract cue
word (FATE). In the subgoal WM condition, subjects monitored for the presence
of any concrete probe word immediately following any abstract cue word. Thus,
the task required semantic classification of the probe word (the subgoal task),
while the cue was simultaneously maintained in WM, so that both pieces of information
could be integrated into a target determination. In a second control condition,
subjects performed abstract/concrete semantic classification without WM demands.
A region within right FP-PFC was identified which showed significant activation
during the subgoal WM condition, but no activity in either of the two control
conditions. However, this FP-PFC region was not modulated by direct manipulation
of active maintenance demands. In contrast, left dorsolateral PFC was affected
by active maintenance demands, but the effect did not interact with the presence
of a subgoal task. Finally, left ventral PFC regions showed activation in response
to semantic classification, but were not affected by WM demands. These results
suggest a triple dissociation of function within PFC regions, and further indicate
that FP-PFC is selectively engaged by the requirement to monitor and integrate
subgoals during WM tasks." [Abstract]
E, Basso G, Pietrini P, Panzer S, Grafman J.
The role of the anterior
prefrontal cortex in human cognition.
Nature. 1999 May 13;399(6732):148-51.
problem-solving and planning involve the most anterior part of the frontal lobes
including the fronto-polar prefrontal cortex (FPPC), which is especially well
developed in humans compared with other primates. The specific role of this region
in human cognition, however, is poorly understood. Here we show, using functional
magnetic resonance imaging, that bilateral regions in the FPPC alone are selectively
activated when subjects have to keep in mind a main goal while performing concurrent
(sub)goals. Neither keeping in mind a goal over time (working memory) nor successively
allocating attentional resources between alternative goals (dual-task performance)
could by themselves activate these regions. Our results indicate that the FPPC
selectively mediates the human ability to hold in mind goals while exploring and
processing secondary goals, a process generally required in planning and reasoning."
O, Zago L, Mellet E, Moutier S, Pineau A, Mazoyer B, Tzourio-Mazoyer N.
from the perceptual brain to the logical brain: the neural impact of cognitive
J Cogn Neurosci. 2000 Sep;12(5):721-8.
happens in the human brain when the mind has to inhibit a perceptual process in
order to activate a logical reasoning process? Here, we use functional imaging
to show the networks of brain areas involved in a deductive logic task performed
twice by the same subjects, first with a perceptual bias and then with a logical
response following bias-inhibition training. The main finding is a striking shift
in the cortical anatomy of reasoning from the posterior part of the brain (the
ventral and dorsal pathways) to a left-prefrontal network including the middle-frontal
gyrus, Broca's area, the anterior insula, and the pre-SMA. This result indicates
that such brain shifting is an essential element for human access to logical thinking."
A. C., Coull, J. T., Maquet, P., Frith, C. D., Vandenberghe, R., Mesulam, M. M.
Attention to Locations in Perceptual Versus Mental Representations
Cogn. Neurosci. 2004 16: 363-373
"Extensive clinical and imaging research
has characterized the neural networks mediating the adaptive distribution of spatial
attention. In everyday behavior, the distribution of attention is guided not only
by extrapersonal targets but also by mental representations of their spatial layout.
We used event-related functional magnetic resonance imaging to identify the neural
system involved in directing attention to locations in arrays held as mental representations,
and to compare it with the system for directing spatial attention to locations
in the external world. We found that these two crucial aspects of spatial cognition
are subserved by extensively overlapping networks. However, we also found that
a region of right parietal cortex selectively participated in orienting attention
to the extrapersonal space, whereas several frontal lobe regions selectively participated
in orienting attention within on-line mental representations." [Abstract]
Konishi, Koji Jimura, Tomoki Asari, and Yasushi Miyashita
Activation of Superior Prefrontal Cortex during Inhibition of Cognitive Set
Neurosci. 23: 7776-7782. 2003.
"The prefrontal cortex implements a set-shifting
function that includes inhibition of a previously acquired cognitive set. The
impairment of the inhibitory function results in perseverative behavior that forms
one characteristic feature of frontal lobe dysfunction. Previous neuroimaging
studies have revealed inhibitory mechanisms in the inferior prefrontal cortex.
The present functional magnetic resonance imaging study devised "dual-match"
stimuli in a set-shifting paradigm that allowed us to temporally isolate the inhibitory
processes recruited during exposure to a previously acquired set. Transient activation
time-locked to the isolated inhibition was revealed in the left middle frontal
gyrus near the superior frontal sulcus. In a control experiment conducted after
subjects had been informed and made aware of the exposure, however, the superior
prefrontal activation disappeared, and prominent activation was revealed in a
set of brain regions that included the left posterior inferior frontal sulcus.
These double dissociation results indicate inhibitory mechanisms in the superior
prefrontal cortex, alternative to the inferior prefrontal ones, that are activated
depending on the subjects' strategy for inhibition of cognitive set." [Abstract]
Atherton M, Zhuang J, Bart WM, Hu X, He S.
functional MRI study of high-level cognition. I. The game of chess.
Res Cogn Brain Res. 2003 Mar;16(1):26-31.
"Chess is a game that involves
many aspects of high level cognition and requires sophisticated problem solving
skills. However, there is little understanding of the neural basis of chess cognition.
This study employed functional magnetic resonance imaging (fMRI) to identify cortical
areas that are active during the analysis of chess positions compared with a spatial
task with matched visual stimuli. Bilateral activation was revealed in the superior
frontal lobes, the parietal lobes, and occipital lobes. Some small areas of activation
were observed unilaterally in the left hemisphere. The left hemisphere showed
more activation than the right. Results are discussed in relation to a similar
brain imaging study on the game Go." [Abstract]
Cary R. Savage, Thilo Deckersbach, Stephan Heckers, Anthony
D. Wagner, Daniel L. Schacter, Nathaniel M. Alpert, Alan J. Fischman, and Scott
Prefrontal regions supporting spontaneous and directed
application of verbal learning strategies: Evidence from PET
"The prefrontal cortex has been implicated in strategic
memory processes, including the ability to use semantic organizational strategies
to facilitate episodic learning. An important feature of these strategies is the
way they are applied in novel or ambiguous situations-failure to initiate effective
strategies spontaneously in unstructured settings is a central cognitive deficit
in patients with frontal lobe disorders. The current study examined strategic
memory with PET and a verbal encoding paradigm that manipulated semantic organization
in three encoding conditions: spontaneous, directed and unrelated. During the
spontaneous condition, subjects heard 24 words that were related in four categories
but presented in mixed order, and they were not informed of this structure beforehand.
Any semantic reorganization was, therefore, initiated spontaneously by the subject.
In the directed condition, subjects were given a different list of 24 related
words and explicitly instructed to notice relationships and mentally group related
words together to improve memory. The unrelated list consisted of 24 unrelated
words. Behavioural measures included semantic clustering, which assessed active
regrouping of words into semantic categories during free recall. In graded PET
contrasts (directed > spontaneous > unrelated), two distinct activations
were found in left inferior prefrontal cortex (inferior frontal gyrus) and left
dorsolateral prefrontal cortex (middle frontal gyrus), corresponding to levels
of semantic clustering observed in the behavioural data. Additional covariate
analyses in the first spontaneous condition indicated that blood flow in orbitofrontal
cortex (OFC) was strongly correlated with semantic clustering scores during immediate
free recall. Thus, blood flow in OFC during encoding predicted which subjects
would spontaneously initiate effective strategies during free recall. Our findings
indicate that OFC performs an important, and previously unappreciated, role in
strategic memory by supporting the early mobilization of effective behavioural
strategies in novel or ambiguous situations. Once initiated, lateral regions of
left prefrontal cortex control verbal semantic organization." [Full
Grossman M, Smith EE, Koenig P, Glosser
G, DeVita C, Moore P, McMillan C.
The neural basis for categorization
in semantic memory.
Neuroimage. 2002 Nov;17(3):1549-61.
asked young adults to categorize written object descriptions into one of two categories,
based on a rule or on overall similarity, while we monitored regional brain activity
with functional magnetic resonance imaging (fMRI). We found significantly greater
recruitment of left dorsolateral prefrontal cortex for rule-based categorization
in direct comparison with similarity-based categorization. Recruitment of right
ventral frontal cortex and thalamus was uniquely associated with rule-based categorization
as well. These observations lend support to the claim that executive functions
such as working memory, inhibitory control, and selective attention contribute
to rule-based categorization. Right inferior parietal activation was uniquely
associated with similarity-based categorization. This region may play an important
role in overall feature configuration that is important for this form of categorization.
We found other brain regions recruited for both rule-based and similarity-based
categorization: Anterior cingulate cortex may support the implementation of executive
functions during situations with competing response alternatives; and left inferior
parietal cortex may be related to the integration of feature knowledge about objects
represented in modality-specific association cortices. We also administered a
degraded-similarity condition where the task of categorizing a written object
description was made more difficult by perceptually degrading the stimulus materials.
The degraded condition and the rule-based condition, but not the similarity-based
condition, were associated with caudate activation. The caudate may support resource
demands that are not specific for a particular categorization process. These findings
associate partially distinct large-scale neural networks with different forms
of categorization in semantic memory." [Abstract]
Caplan R, Dapretto M.
Making sense during
conversation: an fMRI study.
Neuroreport. 2001 Nov 16;12(16):3625-32.
language is thought of as a left hemisphere function, there is increasing evidence
that the right hemisphere contributes to language processing by identifying the
theme of spoken and written language. Using fMRI, we examined the role played
by the right and left hemispheres in making sense of a conversation. When this
process involves implicit appraisal of changes in the conversation's topic, the
neural network has a right hemisphere bias and includes Broca's and Wernicke's
areas, their right hemisphere homologues, right dorsolateral prefrontal cortex,
and the cerebellum. When making sense of conversation involves appraisal of the
conversation's reasoning, however, the network includes Broca's and Wernicke's
areas. Thus, right and left hemisphere systems contribute uniquely to the linguistic
skills involved in making sense of a conversation." [Abstract]
SD, Just MA, Carpenter PA.
The synchronization of the human cortical
working memory network.
Neuroimage. 2002 Apr;15(4):810-22.
verbal reasoning problem at the intersection of verbal working memory, problem-solving,
and language comprehension was examined using event-related fMRI to distinguish
differences in the differential timing of the response of the various cortical
regions that compose the working memory network. Problems were developed such
that the process demand as well as the timing of the manipulation of the contents
of working memory (i.e., a demanding computation) was varied. Activation was observed
in several regions including the dorsolateral prefrontal cortex, the inferior
frontal gyrus, and the parietal lobe. Examination of the MR amplitude response
revealed that the regions do not all activate simultaneously; instead, their activation
time courses reveal differential responses that correspond to their theoretical
processing role in the problem-solving task. The coordination of cortical area
responses reveals how the various cortical regions synchronize and collaborate
in order to accomplish a given cognitive function." [Abstract]
Demonet JF, Thierry G, Cardebat D.
Renewal of the neurophysiology of language: functional neuroimaging.
Physiol Rev. 2005 Jan;85(1):49-95.
Functional neuroimaging methods have reached maturity. It is now possible to start to build the foundations of a physiology of language. The remarkable number of neuroimaging studies performed so far illustrates the potential of this approach, which complements the classical knowledge accumulated on aphasia. Here we attempt to characterize the impact of the functional neuroimaging revolution on our understanding of language. Although today considered as neuroimaging techniques, we refer less to electroencephalography and magnetoencephalography studies than to positron emission tomography and functional magnetic resonance imaging studies, which deal more directly with the question of localization and functional neuroanatomy. This review is structured in three parts. 1) Because of their rapid evolution, we address technical and methodological issues to provide an overview of current procedures and sketch out future perspectives. 2) We review a set of significant results acquired in normal adults (the core of functional imaging studies) to provide an overview of language mechanisms in the "standard" brain. Single-word processing is considered in relation to input modalities (visual and auditory input), output modalities (speech and written output), and the involvement of "central" semantic processes before sentence processing and nonstandard language (illiteracy, multilingualism, and sensory deficits) are addressed. 3) We address the influence of plasticity on physiological functions in relation to its main contexts of appearance, i.e., development and brain lesions, to show how functional imaging can allow fine-grained approaches to adaptation, the fundamental property of the brain. In closing, we consider future developments for language research using functional imaging. [Full Text]
Mason RA, Just MA.
How the brain processes
causal inferences in text.
Psychol Sci. 2004 Jan;15(1):1-7.
models of text processing, such as the construction-integration framework, pose
fundamental questions about causal inference making that are not easily addressed
by behavioral studies. In particular, a common result is that causal relatedness
has a different effect on text reading times than on memory for the text: Whereas
reading times increase linearly as causal relatedness decreases, memory for the
text is best for events that are related by a moderate degree of causal relatedness
and is poorer for events with low and high relatedness. Our functional magnetic
resonance imaging study of the processing of two-sentence passages that varied
in their degree of causal relatedness suggests that the inference process can
be analyzed into two components, generation and integration, that are subserved
by two large-scale cortical networks (a reasoning system in dorsolateral prefrontal
cortex and the right-hemisphere language areas). These two cortical networks,
which are distinguishable from the classical left-hemisphere language areas, approximately
correspond to the two functional relations observed in the behavioral results."
SP, Brown GG, Salamat JS.
Brain regions involved in simple and complex
2003 Jun 11;14(8):1117-22.
"Grammatical transformation is a verbal reasoning
task requiring judging the veracity of statements describing the spatial order
of letter sets. We studied 18 adults with FMRI while they performed grammatical
transformations of varying complexity levels (2-letter, 3-letter, and 4-letter
sentences). Brain regions activated by 2-letter sentences included the visuospatial
processing regions of the bilateral parietal lobes and the frontal operculum.
A linear increase in sentence complexity engaged dorsolateral and ventrolateral
prefrontal cortex as well as significantly increased activation within 2LTR areas.
These data provide evidence that grammatical transformation reasoning relies primarily
on the posterior visuospatial working memory system and need not necessarily engage
the prefrontal cortex. Increasing the complexity of grammatical transformation,
though, activates prefrontal cortex." [Abstract]
F, Hashimoto R, Nakajima K, Miyashita Y, Sakai KL.
to sentence comprehension: the convergence of auditory and visual information
of language in the left inferior frontal cortex.
"We used functional magnetic resonance imaging
(fMRI) to characterize cortical activation associated with sentence processing,
thereby elucidating where in the brain auditory and visual inputs of words converge
during sentence comprehension. Within one scanning session, subjects performed
three types of tasks with different linguistic components from perception to sentence
comprehension: nonword (N(AV); auditory and visual), phrase (P; either auditory
or visual), and sentence (S; either auditory or visual) tasks. In a comparison
of the P and N(AV) tasks, the angular and supramarginal gyri showed bilateral
activation, whereas the inferior and middle frontal gyri showed left-lateralized
activation. A comparison of the S and P tasks, together with a conjunction analysis,
revealed a ventral region of the left inferior frontal gyrus (F3t/F3O), which
was sentence-processing selective and modality-independent. These results unequivocally
demonstrated that the left F3t/F3O is involved in the selection and integration
of semantic information that are separable from lexico-semantic processing."
Carpenter PA, Just MA, Keller TA, Eddy WF, Thulborn
Time course of fMRI-activation in language and spatial networks
during sentence comprehension.
Neuroimage. 1999 Aug;10(2):216-24.
neuroimaging previously has been considered to provide inadequate temporal resolution
to study changes of brain states as a function of cognitive computations; however,
we have obtained evidence of differential amounts of brain activity related to
high-level cognition (sentence processing) within 1.5 s of stimulus onset. The
study used an event-related paradigm with high-speed echoplanar functional magnetic
resonance imaging (fMRI) to trace the time course of the brain activation in the
temporal and parietal regions as participants comprehended single sentences describing
a spatial configuration. Within the first set of images, on average 1 s from when
the participant begins to read a sentence, there was significant activation in
a key cortical area involved in language comprehension (the left posterior temporal
gyrus) and visuospatial processing (the left and right parietal regions). In all
three areas, the amount of activation during sentence comprehension was higher
for negative sentences than for their affirmative counterparts, which are linguistically
less complex. The effect of negation indicates that the activation in these areas
is modulated by the difficulty of the linguistic processing. These results suggest
a relatively rapid coactivation in both linguistic and spatial cortical regions
to support the integration of information from multiple processing streams."
Evelyne, Keysers, Christian, Umilta, M. Alessandra, Fogassi, Leonardo, Gallese,
Vittorio, Rizzolatti, Giacomo
Hearing Sounds, Understanding Actions:
Action Representation in Mirror Neurons
Science 2002 297:
"Many object-related actions can be recognized by their sound.
We found neurons in monkey premotor cortex that discharge when the animal performs
a specific action and when it hears the related sound. Most of the neurons also
discharge when the monkey observes the same action. These audiovisual mirror neurons
code actions independently of whether these actions are performed, heard, or seen.
This discovery in the monkey homolog of Broca's area might shed light on the origin
of language: audiovisual mirror neurons code abstract contents-the meaning of
actions-and have the auditory access typical of human language to these contents."
F, Rijntjes M, Dettmers C, Glauche V, Weiller C, Buchel C.
action recognition system and its relationship to Broca's area: an fMRI study.
"Primate studies have identified populations of
neurons that are capable of action recognition. These "mirror neurons"
show spiking activity both when the monkey executes or observes a grasping movement.
These neurons are located in the ventral premotor cortex, possibly the homologue
of "Broca's area" in human. This led to the speculation that action
recognition and language production share a common system [Trends Neurosci. 21
(1998), 188]. To test this hypothesis, we combined an action recognition with
a language production (VERB) and a grasping movement task (MOVE) by using functional
magnetic resonance imaging. Action recognition-related activation was observed
in the left inferior frontal gyrus and on the border between the inferior frontal
gyrus and precentral gyrus (defined as IFG/PG), the ventral occipitotemporal junction,
the superior and inferior parietal cortex, and in the intraparietal sulcus in
the left hemisphere. An overlap of activations due to the language production,
movement execution, and action recognition was found in the parietal cortex, the
left inferior frontal gyrus, and the IFG-PG border (IFG/PG). The activation peaks
of action recognition and verb generation were always different in single subjects,
but no consistent spatial relationship was detected, in accord with the hypothesis
that action recognition and language production share a common functional architecture."
Connecting mirror neurons and forward models.
2003 Dec 2;14(17):2135-7.
"SUMMARY: Two recent developments in motor neuroscience
are promising the extension of theoretical concepts from motor control towards
cognitive processes, including human social interactions and understanding the
intentions of others. The first of these is the discovery of what are now called
mirror neurons, which code for both observed and executed actions. The second
is the concept of internal models, and in particular recent proposals that forward
and inverse models operate in paired modules. These two ideas will be briefly
introduced, and a recent suggestion linking between the two processes of mirroring
and modelling will be described which may underlie our abilities for imitating
actions, for cooperation between two actors, and possibly for communication via
gesture and language." [Abstract]
From mouth to hand: gesture,
speech, and the evolution of right-handedness.
Sci. 2003 Apr;26(2):199-208; discussion 208-60.
"The strong predominance
of right-handedness appears to be a uniquely human characteristic, whereas the
left-cerebral dominance for vocalization occurs in many species, including frogs,
birds, and mammals. Right-handedness may have arisen because of an association
between manual gestures and vocalization in the evolution of language. I argue
that language evolved from manual gestures, gradually incorporating vocal elements.
The transition may be traced through changes in the function of Broca's area.
Its homologue in monkeys has nothing to do with vocal control, but contains the
so-called "mirror neurons," the code for both the production of manual
reaching movements and the perception of the same movements performed by others.
This system is bilateral in monkeys, but predominantly left-hemispheric in humans,
and in humans is involved with vocalization as well as manual actions. There is
evidence that Broca's area is enlarged on the left side in Homo habilis, suggesting
that a link between gesture and vocalization may go back at least two million
years, although other evidence suggests that speech may not have become fully
autonomous until Homo sapiens appeared some 170,000 years ago, or perhaps even
later. The removal of manual gesture as a necessary component of language may
explain the rapid advance of technology, allowing late migrations of Homo sapiens
from Africa to replace all other hominids in other parts of the world, including
the Neanderthals in Europe and Homo erectus in Asia. Nevertheless, the long association
of vocalization with manual gesture left us a legacy of right-handedness."
Leslie KR, Johnson-Frey SH, Grafton ST.
imaging of face and hand imitation: towards a motor theory of empathy.
"Empathy requires the ability to map the feelings
of others onto our own nervous system. Until recently, there was no plausible
mechanism to explain how such a mapping might occur. The discovery of mirror neurons,
however, suggests that the nervous system is capable of mapping the observed actions
of others onto the premotor cortex of the self, at least for reaching and grasping
movements. Is there a mirroring system for emotive actions, such as facial expression?
Subjects (N = 15; all right-handed; eight men, seven women) watched movies of
facial expressions (smile or frown) and hand movements (move index or middle finger)
while brain activity was imaged using functional magnetic resonance imaging (fMRI).
Subjects watched the movies under three different conditions: passive viewing,
active imitation, and an active motor control. Subjects also performed a verb
generation task to functionally identify language-processing areas. We found evidence
for a common cortical imitation circuit for both face and hand imitation, consisting
of Broca's area, bilateral dorsal and ventral premotor areas, right superior temporal
gyrus (STG), supplementary motor area, posterior temporo-occipital cortex, and
cerebellar areas. For faces, passive viewing led to significant activation in
the right ventral premotor area, whereas imitation produced bilateral activation.
This result is consistent with evidence for right hemisphere (RH) dominance for
emotional processing, and suggests that there may be a right hemisphere mirroring
system that could provide a neural substrate for empathy." [Abstract]
Tai YF, Scherfler C, Brooks DJ, Sawamoto N, Castiello
The human premotor cortex is 'mirror' only for biological actions.
Biol. 2004 Jan 20;14(2):117-20.
"Previous work has shown that both human
adults and children attend to grasping actions performed by another person but
not necessarily to those made by a mechanical device. According to recent neurophysiological
data, the monkey premotor cortex contains "mirror" neurons that discharge
both when the monkey performs specific manual grasping actions and when it observes
another individual performing the same or similar actions. However, when a human
model uses tools to perform grasping actions, the mirror neurons are not activated.
A similar "mirror" system has been described in humans, but whether
or not it is also tuned specifically to biological actions has never been tested.
Here we show that when subjects observed manual grasping actions performed by
a human model a significant neural response was elicited in the left premotor
cortex. This activation was not evident for the observation of grasping actions
performed by a robot model commanded by an experimenter. This result indicates
for the first time that in humans the mirror system is biologically tuned. This
system appears to be the neural substrate for biological preference during action
Mason MF, Banfield JF, Macrae CN.
about actions: the neural substrates of person knowledge.
Cortex. 2004 Feb;14(2):209-14.
"Despite an extensive literature on the
neural substrates of semantic knowledge, how person-related information is represented
in the brain has yet to be elucidated. Accordingly, in the present study we used
functional magnetic resonance imaging (fMRI) to investigate the neural correlates
of person knowledge. Focusing on the neural substrates of action knowledge, participants
reported whether or not a common set of behaviors could be performed by people
or dogs. While dogs and people are capable of performing many of the same actions
(e.g. run, sit, bite), we surmised that the representation of this knowledge would
be associated with distinct patterns of neural activity. Specifically, person
judgments were expected to activate cortical areas associated with theory of mind
(ToM) reasoning. The results supported this prediction. Whereas action-related
judgments about dogs were associated with activity in various regions, including
the occipital and parahippocampal gyri; identical judgments about people yielded
activity in areas of prefrontal cortex, notably the right middle and medial frontal
gyri. These findings suggest that person knowledge may be functionally dissociable
from comparable information about other animals, with action-related judgments
about people recruiting neural activity that is indicative of ToM reasoning."
J, Frith CD, Passingham RE.
Inferring false beliefs from the actions
of oneself and others: an fMRI study.
Neuroimage. 2004 Feb;21(2):744-50.
ability to make judgments about mental states is critical to social interactions.
Simulation theory suggests that the observer covertly mimics the activity of the
observed person, leading to shared states of mind between the observer and the
person observed. We tested this hypothesis by investigating the neural networks
activated while subjects watched videos of themselves and of others lifting a
box, and judged the beliefs of the actors about the weight of the box. A parietal
premotor circuit was recruited during action perception, and the activity started
earlier when making judgments about one's own actions as opposed to those of others.
This earlier activity in action-related structures can be explained by simulation
theory on the basis that when one observes one's own actions, there is a closer
match between the simulated and perceived action than there is when one observes
the actions of others. When the observers judged the actions to reflect a false
belief, there was activation in the superior temporal sulcus, orbitofrontal, paracingulate
cortex and cerebellum. We suggest that this reflects a mismatch between the perceived
action and the predicted action's outcomes derived from simulation." [Abstract]
R, Kanwisher N.
People thinking about thinking people. The role of
the temporo-parietal junction in "theory of mind".
"Humans powerfully and flexibly interpret the
behaviour of other people based on an understanding of their minds: that is, we
use a "theory of mind." In this study we distinguish theory of mind,
which represents another person's mental states, from a representation of the
simple presence of another person per se. The studies reported here establish
for the first time that a region in the human temporo-parietal junction (here
called the TPJ-M) is involved specifically in reasoning about the contents of
another person's mind. First, the TPJ-M was doubly dissociated from the nearby
extrastriate body area (EBA; Downing et al., 2001). Second, the TPJ-M does not
respond to false representations in non-social control stories. Third, the BOLD
response in the TPJ-M bilaterally was higher when subjects read stories about
a character's mental states, compared with stories that described people in physical
detail, which did not differ from stories about nonhuman objects. Thus, the role
of the TPJ-M in understanding other people appears to be specific to reasoning
about the content of mental states." [Abstract]
Donald T. Stuss, Gordon G. Gallup, Jr, and Michael
The frontal lobes are necessary for `theory of mind'
Brain 124: 279-286. 2001.
"Patients with limited
focal frontal and nonfrontal lesions were tested for visual perspective taking
and detecting deception. Frontal lobe lesions impaired the ability to infer mental
states in others, with dissociation of performance within the frontal lobes. Lesions
throughout the frontal lobe, with some suggestion of a more important role for
the right frontal lobe, were associated with impaired visual perspective taking.
Medial frontal lesions, particularly right ventral, impaired detection of deception.
The former may require cognitive processes of the lateral and superior medial
frontal regions, the latter affective connections of the ventral medial frontal
with amygdala and other limbic regions." [Full
Stone VE, Cosmides L, Tooby J, Kroll
N, Knight RT.
Selective impairment of reasoning about social exchange
in a patient with bilateral limbic system damage.
Acad Sci U S A. 2002 Aug 20;99(17):11531-6. Epub 2002 Aug 12.
exchange is a pervasive feature of human social life. Models in evolutionary biology
predict that for social exchange to evolve in a species, individuals must be able
to detect cheaters (nonreciprocators). Previous research suggests that humans
have a cognitive mechanism specialized for detecting cheaters. Here we provide
neurological evidence indicating that social exchange reasoning can be selectively
impaired while reasoning about other domains is left intact. The patient, R.M.,
had extensive bilateral limbic system damage, affecting orbitofrontal cortex,
temporal pole, and amygdala. We compared his performance on two types of reasoning
problem that were closely matched in form and equally difficult for control subjects:
social contract rules (of the form, "If you take the benefit, then you must
satisfy the requirement") and precaution rules (of the form, "If you
engage in hazardous activity X, then you must take precaution Y"). R.M. performed
significantly worse in social contract reasoning than in precaution reasoning,
when compared both with normal controls and with other brain-damaged subjects.
This dissociation in reasoning performance provides evidence that reasoning about
social exchange is a specialized and separable component of human social intelligence,
and is consistent with other research indicating that the brain processes information
about the social world differently from other types of information." [Full