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1.  The neural mechanisms for the recognition of face identity in humans 
Every day we encounter dozens of people, and in order to interact with them appropriately we need to recognize their identity. The face is a crucial source of information to recognize a person’s identity. However, recognizing the identity of a face is challenging because it requires distinguishing between very similar images (e.g., the front views of two different faces) while categorizing very different images (e.g., a front view and a profile) as the same person. Neuroimaging has the whole-brain coverage needed to investigate where representations of face identity are encoded, but it is limited in terms of spatial and temporal resolution. In this article, we review recent neuroimaging research that attempted to investigate the representation of face identity, the challenges it faces, and the proposed solutions, to conclude that given the current state of the evidence the right anterior temporal lobe is the most promising candidate region for the representation of face identity.
doi:10.3389/fpsyg.2014.00672
PMCID: PMC4072087  PMID: 25018745
faces; identity; fMRI; object recognition; invariance
2.  Left occipitotemporal cortex contributes to the discrimination of tool-associated hand actions: fMRI and TMS evidence 
Functional neuroimaging studies have implicated the left lateral occipitotemporal cortex (LOTC) in both tool and hand perception but the functional role of this region is not fully known. Here, by using a task manipulation, we tested whether tool-/hand-selective LOTC contributes to the discrimination of tool-associated hand actions. Participants viewed briefly presented pictures of kitchen and garage tools while they performed one of two tasks: in the action task, they judged whether the tool is associated with a hand rotation action (e.g., screwdriver) or a hand squeeze action (e.g., garlic press), while in the location task they judged whether the tool is typically found in the kitchen (e.g., garlic press) or in the garage (e.g., screwdriver). Both tasks were performed on the same stimulus set and were matched for difficulty. Contrasting fMRI responses between these tasks showed stronger activity during the action task than the location task in both tool- and hand-selective LOTC regions, which closely overlapped. No differences were found in nearby object- and motion-selective control regions. Importantly, these findings were confirmed by a TMS study, which showed that effective TMS over the tool-/hand-selective LOTC region significantly slowed responses for tool action discriminations relative to tool location discriminations, with no such difference during sham TMS. We conclude that left LOTC contributes to the discrimination of tool-associated hand actions.
doi:10.3389/fnhum.2014.00591
PMCID: PMC4122187  PMID: 25140142
action knowledge; middle temporal gyrus; tool selectivity; hand selectivity; lateral occipitotemporal cortex
3.  When “ultrarapid” word-related motor activity is not faster than “early” 
doi:10.3389/fnhum.2014.00842
PMCID: PMC4199260  PMID: 25360104
word semantics; motor processes in the brain; electrophysiology; grammatical class; conceptual representation
4.  Tripartite Organization of the Ventral Stream by Animacy and Object Size 
The Journal of Neuroscience  2013;33(25):10235-10242.
Occipito-temporal cortex is known to house visual object representations, but the organization of the neural activation patterns along this cortex is still being discovered. Here we found a systematic, large-scale structure in the neural responses related to the interaction between two major cognitive dimensions of object representation: animacy and real-world size. Neural responses were measured with functional magnetic resonance imaging while human observers viewed images of big and small animals and big and small objects. We found that real-world size drives differential responses only in the object domain, not the animate domain, yielding a tripartite distinction in the space of object representation. Specifically, cortical zones with distinct response preferences for big objects, all animals, and small objects, are arranged in a spoked organization around the occipital pole, along a single ventromedial, to lateral, to dorsomedial axis. The preference zones are duplicated on the ventral and lateral surface of the brain. Such a duplication indicates that a yet unknown higher-order division of labor separates object processing into two substreams of the ventral visual pathway. Broadly, we suggest that these large-scale neural divisions reflect the major joints in the representational structure of objects and thus place informative constraints on the nature of the underlying cognitive architecture.
doi:10.1523/JNEUROSCI.0983-13.2013
PMCID: PMC3755177  PMID: 23785139
5.  Disrupting the brain to validate hypotheses on the neurobiology of language 
Comprehension of words is an important part of the language faculty, involving the joint activity of frontal and temporo-parietal brain regions. Transcranial Magnetic Stimulation (TMS) enables the controlled perturbation of brain activity, and thus offers a unique tool to test specific predictions about the causal relationship between brain regions and language understanding. This potential has been exploited to better define the role of regions that are classically accepted as part of the language-semantic network. For instance, TMS has contributed to establish the semantic relevance of the left anterior temporal lobe, or to solve the ambiguity between the semantic vs. phonological function assigned to the left inferior frontal gyrus (LIFG). We consider, more closely, the results from studies where the same technique, similar paradigms (lexical-semantic tasks) and materials (words) have been used to assess the relevance of regions outside the classically-defined language-semantic network—i.e., precentral motor regions—for the semantic analysis of words. This research shows that different aspects of the left precentral gyrus (primary motor and premotor sites) are sensitive to the action-non action distinction of words' meanings. However, the behavioral changes due to TMS over these sites are incongruent with what is expected after perturbation of a task-relevant brain region. Thus, the relationship between motor activity and language-semantic behavior remains far from clear. A better understanding of this issue could be guaranteed by investigating functional interactions between motor sites and semantically-relevant regions.
doi:10.3389/fnhum.2013.00148
PMCID: PMC3633936  PMID: 23630480
neuromodulation; action understanding; neuroimaging; cognitive neuropsychology; language semantics
6.  Perceptual Grouping and Visual Enumeration 
PLoS ONE  2012;7(11):e50862.
We used lateralized Event-Related Potential (ERP) measures – the N2pc and CDA/SPCN components – to assess the role of grouping by target similarity during enumeration. Participants saw a variable number (0, 1, 2 or 3) of same- or differently-colored targets presented among homogeneous distracters, and performed an enumeration task. Results showed that the N2pc, but not the CDA, was larger for multiple targets of identical color relative to targets of different colors. The findings are interpreted in terms of the effects of grouping on early versus late stages of multiple object processing. Within this framework, they reveal that grouping has an effect on early individuation mechanisms, while later processing mechanisms are less prone to such an influence.
doi:10.1371/journal.pone.0050862
PMCID: PMC3511330  PMID: 23226408
7.  Language-Invariant Verb Processing Regions in Spanish-English Bilinguals 
NeuroImage  2011;57(1):251-261.
Nouns and verbs are fundamental grammatical building blocks of all languages. Studies of brain-damaged patients and healthy individuals have demonstrated that verb processing can be dissociated from noun processing at a neuroanatomical level. In cases where bilingual patients have a noun or verb deficit, the deficit has been observed in both languages. This suggests that the noun-verb distinction may be based on neural components that are common across languages. Here we investigated the cortical organization of grammatical categories in healthy, early Spanish-English bilinguals using functional magnetic resonance imaging (fMRI) in a morphophonological alternation task. Four regions showed greater activity for verbs than for nouns in both languages: left posterior middle temporal gyrus (LMTG), left middle frontal gyrus (LMFG), pre-supplementary motor area (pre-SMA), and right middle occipital gyrus (RMOG); no regions showed greater activation for nouns. Multi-voxel pattern analysis within verb-specific regions showed indistinguishable activity patterns for English and Spanish, indicating language-invariant bilingual processing. In LMTG and LMFG, patterns were more similar within than across grammatical category, both within and across languages, indicating language-invariant grammatical class information. These results suggest that the neural substrates underlying verb-specific processing are largely independent of language in bilinguals, both at the macroscopic neuroanatomical level and at the level of voxel activity patterns.
doi:10.1016/j.neuroimage.2011.04.021
PMCID: PMC3103832  PMID: 21515387
grammatical class; bilingualism; verbs; fMRI; MVPA
8.  What drives the organization of object knowledge in the brain? The distributed domain-specific hypothesis 
Trends in cognitive sciences  2011;15(3):97-103.
Various forms of category-specificity have been described at both the cognitive and neural levels, inviting the inference that different semantic domains are processed by distinct, dedicated mechanisms. Here we argue for an extension of a Domain-Specific interpretation to these phenomena that is based on network-level analyses of functional coupling among brain regions. On this view, domain-specificity in one region of the brain emerges because of innate connectivity with a network of regions that also process information about that domain. Recent findings are reviewed that converge with this framework, and a new direction is outlined for understanding the neural principles that shape the organization of conceptual knowledge.
doi:10.1016/j.tics.2011.01.004
PMCID: PMC3056283  PMID: 21317022
9.  Neural Specificity for Grammatical Operations is Revealed by Content-Independent fMR Adaptation 
The ability to generate novel sentences depends on cognitive operations that specify the syntactic function of nouns, verbs, and other words retrieved from the mental lexicon. Although neuropsychological studies suggest that such operations rely on neural circuits distinct from those encoding word form and meaning, it has not been possible to characterize this distinction definitively with neuroimaging. We used functional magnetic resonance imaging (fMRI) to show that a brain area engaged in a given grammatical operation can be identified uniquely by a monotonic decrease in activation as that operation is repeated. We applied this methodology to identify areas involved selectively in the operation of inflection of nouns or verbs. By contrast, areas involved in processing word meaning do not show this monotonic adaptation across stimuli. These results are the first to demonstrate adaptation in the fMR signal evoked not by specific stimuli, but by well-defined cognitive linguistic operations.
doi:10.3389/fpsyg.2012.00026
PMCID: PMC3274744  PMID: 22347206
nouns; verbs; grammatical class; inflection; fMRI; adaptation
10.  Judging semantic similarity: An event-related fMRI study with auditory word stimuli 
Neuroscience  2010;169(1):279-286.
Much of mental life consists in thinking about object concepts that are not currently within the scope of perception. The general system that enables multiple representations to be maintained and compared is referred to as ‘working memory’ (Repovš and Baddeley, 2006), and involves regions in medial and lateral parietal and frontal cortex (e.g., Smith and Jonides, 1999). It has been assumed that the contents of working memory index information in regions of the brain that are critical for processing and storing object knowledge. To study the processes involved in thinking about common object concepts, we used event related fMRI to study BOLD activity while participants made judgments of conceptual similarity over pairs of sequentially presented auditory words. Through a combination of conventional fMRI analysis approaches and multi-voxel pattern analysis (MVPA), we show that the brain responses associated with the second word in a pair carry information about the conceptual similarity between the two members of the pair. This was the case in frontal and parietal regions involved in the working memory and decision components of the task for both analysis approaches. However, in other regions of the brain, including early visual regions, MVPA permitted classification of semantic distance relationships where conventional averaging approaches failed to show a difference. These findings suggest that diffuse and statistically sub-threshold ‘scattering’ of BOLD activity in some regions may carry substantial information about the contents of mental representations.
doi:10.1016/j.neuroscience.2010.04.029
PMCID: PMC2908262  PMID: 20412836
11.  Lexical Selection in Multi-Word Production 
In multi-word utterances, target words need to be selected in the context of other target words. In the present study, three hypotheses were tested that differed in their assumptions about whether the lexical selection mechanism considers the activation levels of the other target lexical representations, and whether it takes into account their grammatical class properties. Participants produced adjective + noun and noun + noun utterances in response to colored word and picture + word stimulus displays. In both types of utterances, the frequency of the first and second response was manipulated. The results revealed an effect of the frequency of the second response that did not depend on the utterance type, and additive effects for the frequency of the first and the second response in both utterance types. These results are interpreted in terms of a model of lexical selection that assumes that selection is non-competitive.
doi:10.3389/fpsyg.2011.00081
PMCID: PMC3110419  PMID: 21687451
language production; multi-word naming; noun-phrase production; competitive lexical selection; lexical frequency
12.  Temporal Brain Dynamics of Multiple Object Processing: The Flexibility of Individuation 
PLoS ONE  2011;6(2):e17453.
The ability to process concurrently multiple visual objects is fundamental for a coherent perception of the world. A core component of this ability is the simultaneous individuation of multiple objects. Many studies have addressed the mechanism of object individuation but it remains unknown whether the visual system mandatorily individuates all relevant elements in the visual field, or whether object indexing depends on task demands. We used a neural measure of visual selection, the N2pc component, to evaluate the flexibility of multiple object individuation. In three ERP experiments, participants saw a variable number of target elements among homogenous distracters and performed either an enumeration task (Experiment 1) or a detection task, reporting whether at least one (Experiment 2) or a specified number of target elements (Experiment 3) was present. While in the enumeration task the N2pc response increased as a function of the number of targets, no such modulation was found in Experiment 2, indicating that individuation of multiple targets is not mandatory. However, a modulation of the N2pc similar to the enumeration task was visible in Experiment 3, further highlighting that object individuation is a flexible mechanism that binds indexes to object properties and locations as needed for further object processing.
doi:10.1371/journal.pone.0017453
PMCID: PMC3046149  PMID: 21387002
13.  Gender agreement and multiple referents 
Rivista di linguistica  2008;20(2):285-307.
We report a new pattern of usage in current, spoken Italian that has implications for both psycholinguistic models of language production and linguistic theories of language change. In Italian, gender agreement is mandatory for both singular and plural nouns. However, when two or more nouns of different grammatical gender appear in a conjoined noun phrase (NP), masculine plural agreement is required. In this study, we combined on-line and off-line methodologies in order to assess the mechanisms involved in gender marking in the context of multiple referents. The results of two pronoun production tasks showed that plural feminine agreement was significantly more difficult than plural masculine agreement. In a separate study using offline judgements of acceptability, we found that agreement violations in Italian are tolerated more readily in the case of feminine conjoined noun phrases (e.g., la mela e la banana ‘the:fem apple:fem and the: fem banana: fem’) than masculine conjoined noun phrases (e.g., il fiore e il libro ‘the:mas flower: mas and the:mas book:mas’). Implications of these results are discussed both at the level of functional architecture within the language production system and at the level of changes in language use.*
PMCID: PMC2964885  PMID: 21037930
14.  Grammatical and Phonological Influences on Word Order 
Psychological science  2009;20(10):1262-1268.
During the grammatical encoding of spoken multiword utterances, various kinds of information must be used to determine the order of words. For example, whereas in adjective-noun utterances like “red car”, word order can be determined on the basis of the word's grammatical class information, in noun-noun utterances like “…by car, bus, or…”, word order cannot be determined on the basis of a word's grammatical class information. We investigated whether a word's phonological properties play a role in grammatical encoding. In four experiments participants produced multiword utterances in which the words' onset phonology was manipulated. Phonological-onset relatedness yielded inhibitory effects in noun-noun utterances, no effects in noun-adjective utterances, and facilitatory effects in adjective-noun, noun-verb, and adjective-adjective-noun utterances. These results cannot be explained by differences in the stimulus displays used to elicit the utterances and suggest that grammatical encoding is sensitive to the phonological properties of words.
doi:10.1111/j.1467-9280.2009.02429.x
PMCID: PMC2761505  PMID: 19694981
15.  Category-specific organization in the human brain does not require visual experience 
Neuron  2009;63(3):397-405.
Summary
The ventral stream refers to a neural pathway that projects from early visual areas through to anterior temporal cortex, and comprises regions in ventral and lateral occipital-temporal cortex. The ventral stream is critical for recognizing visually presented objects. Functional imaging studies of the human brain have shown that different regions within the ventral stream show differential activation to nonliving (tools, houses) and living stimuli (animals, faces). The causes of these category preferences are widely debated. Using functional magnetic resonance imaging, we find that the same regions of the ventral stream that show category preferences for nonliving stimuli and animals in sighted adults, show the same category preferences in adults who are blind since birth. Both blind and sighted participants had larger blood oxygen-level dependent (BOLD) responses in the medial fusiform gyrus for nonliving stimuli compared to animal stimuli, and differential BOLD responses in lateral occipital cortex for animal stimuli compared to nonliving stimuli. These findings demonstrate that the medial-to-lateral bias by conceptual domain in the ventral stream does not require visual experience in order to develop, and suggest the operation of innately determined domain-specific constraints on the organization of object knowledge.
doi:10.1016/j.neuron.2009.07.012
PMCID: PMC2743253  PMID: 19679078
16.  The word class effect in the picture–word interference paradigm 
The word class effect in the picture–word interference paradigm is a highly influential finding that has provided some of the most compelling support for word class constraints on lexical selection. However, methodological concerns called for a replication of the most convincing of those effects. Experiment 1 was a direct replication of Pechmann and Zerbst (2002; Experiment 4). Participants named pictures of objects in the context of noun and adverb distractors. Naming took place in bare noun and sentence frame contexts. A word class effect emerged in both bare noun and sentence frame naming conditions, suggesting a semantic origin of the effect. In Experiment 2, participants named objects in the context of noun and verb distractors whose word class relationship to the target and imageability were orthogonally manipulated. As before, naming took place in bare noun and sentence frame naming contexts. In both naming contexts, distractor imageability but not word class affected picture naming latencies. These findings confirm the sensitivity of the picture–word interference paradigm to distractor imageability and suggest the paradigm is not sensitive to distractor word class. The results undermine the use of the word class effect in the picture–word interference paradigm as supportive of word class constraints during lexical selection.
doi:10.1080/17470210903377380
PMCID: PMC2908256  PMID: 19998070
Lexical access; Lexical selection; Grammatical class; Imageability; Picture–word interference
17.  Concepts and Categories: A Cognitive Neuropsychological Perspective 
One of the most provocative and exciting issues in cognitive science is how neural specificity for semantic categories of common objects arises in the functional architecture of the brain. More than two decades of research on the neuropsychological phenomenon of category-specific semantic deficits has generated detailed claims about the organization and representation of conceptual knowledge. More recently, researchers have sought to test hypotheses developed on the basis of neuropsychological evidence with functional imaging. From those two fields, the empirical generalization emerges that object domain and sensory modality jointly constrain the organization of knowledge in the brain. At the same time, research within the embodied cognition framework has highlighted the need to articulate how information is communicated between the sensory and motor systems, and processes that represent and generalize abstract information. Those developments point toward a new approach for understanding category specificity in terms of the coordinated influences of diverse regions and cognitive systems.
doi:10.1146/annurev.psych.60.110707.163532
PMCID: PMC2908258  PMID: 18767921
category-specific semantic deficits; apraxia; semantic organization; domain specific; sensory motor
18.  Semantic Interference in a Delayed Naming Task: Evidence for the Response Exclusion Hypothesis 
In 2 experiments participants named pictures of common objects with superimposed distractor words. In one naming condition, the pictures and words were presented simultaneously on every trial, and participants produced the target response immediately. In the other naming condition, the presentation of the picture preceded the presentation of the distractor by 1,000 ms, and participants delayed production of their naming response until distractor word presentation. Within each naming condition, the distractor words were either semantic category coordinates of the target pictures or unrelated. Orthogonal to this manipulation of semantic relatedness, the frequency of the pictures’ names was manipulated. The authors observed semantic interference effects in both the immediate and delayed naming conditions but a frequency effect only in the immediate naming condition. These data indicate that semantic interference can be observed when target picture naming latencies do not reflect the bottleneck at the level of lexical selection. In the context of other findings from the picture–word interference paradigm, the authors interpret these data as supporting the view that the semantic interference effect arises at a postlexical level of processing.
doi:10.1037/0278-7393.34.1.249
PMCID: PMC2908266  PMID: 18194068
semantic interference effect; lexical selection by competition; picture-word interference; delayed naming; response exclusion hypothesis
19.  The role of the dorsal visual processing stream in tool identification 
Psychological science  2010;21(6):772-778.
The dorsal visual processing stream subserves object directed action, while the ventral visual processing stream subserves visual object recognition. Little is known about how information computed by dorsal stream structures influences object recognition. We used Continuous Flash Suppression to functionally isolate the information computed by the dorsal stream from that computed by the ventral stream. We show that the information originating from the dorsal stream influences not only decisions requiring superordinate category knowledge, but also decisions that entail the selection of a basic-level object. We further show that the information computed by the dorsal stream does not carry specific functional information about objects. Our results indicate that the dorsal stream, in isolation from the ventral stream, is agnostic as to the identity of the objects that it processes. Instead, we suggest that structures within the dorsal stream compute motor-relevant information (e.g., graspability) that influences the identification of manipulable objects.
doi:10.1177/0956797610371343
PMCID: PMC2908271  PMID: 20483820
20.  The Representation of Tools in Left Parietal Cortex Is Independent of Visual Experience 
Psychological science  2010;21(6):764-771.
Tool use depends on processes represented in distinct regions of left parietal cortex. We studied the role of visual experience in shaping neural specificity for tools in parietal cortex by using functional magnetic resonance imaging with sighted, late-blind, and congenitally blind participants. Using a region-of-interest approach in which tool-specific areas of parietal cortex were identified in sighted participants viewing pictures, we found that specificity in blood-oxygen-level-dependent responses for tools in the left inferior parietal lobule and the left anterior intraparietal sulcus is independent of visual experience. These findings indicate that motor- and somatosensory-based processes are sufficient to drive specificity for representations of tools in regions of parietal cortex. More generally, some aspects of the organization of the dorsal object-processing stream develop independently of the visual information that forms the major sensory input to that pathway in sighted individuals.
doi:10.1177/0956797610370754
PMCID: PMC2908275  PMID: 20483823
tools; blind humans; conceptual knowledge; dorsal visual pathway; fMRI
21.  The cumulative semantic cost does not reflect lexical selection by competition☆ 
Acta psychologica  2010;134(3):279-289.
The cumulative semantic cost describes a phenomenon in which picture naming latencies increase monotonically with each additional within-category item that is named in a sequence of pictures. Here we test whether the cumulative semantic cost requires the assumption of lexical selection by competition. In Experiment 1 participants named a sequence of pictures, while in Experiment 2 participants named words instead of pictures, preceded by a gender marked determiner. We replicate the basic cumulative semantic cost with pictures (Exp. 1) and show that there is no cumulative semantic cost for word targets (Exp. 2). This pattern was replicated in Experiment 3 in which pictures and words were named along with their gender marked definite determiner, and were intermingled within the same experimental design. In addition, Experiment 3 showed that while picture naming induces a cumulative semantic cost for subsequently named words, word naming does not induce a cumulative semantic cost for subsequently named pictures. These findings suggest that the cumulative semantic cost arises prior to lexical selection and that the effect arises due to incremental changes to the connection weights between semantic and lexical representations.
doi:10.1016/j.actpsy.2010.02.009
PMCID: PMC2908277  PMID: 20347062
Cumulative semantic cost; Semantic interference; Lexical access; Picture naming; Semantic access
22.  Concepts are more than percepts: the case of action verbs 
Several regions of the posterior-lateral-temporal cortices (PLTC) are reliably recruited when participants read or listen to action verbs, relative to other word and non-word types. This PLTC activation is generally interpreted as reflecting the retrieval of visual-motion features of actions. This interpretation supports the broader theory, that concepts are comprised of sensory-motor features. We investigated an alternative interpretation of the same activations: PLTC activity for action verbs reflects the retrieval of modality-independent representations of event concepts, or the grammatical types associated with them, i.e., verbs. During an fMRI scan, participants made semantic-relatedness judgments on word pairs varying in amount of visual-motion information. Replicating previous results, several PLTC regions showed higher responses to words that describe actions versus objects. However, we found that these PLTC regions did not overlap with visual-motion regions. Moreover, their response was higher for verbs than nouns, irrespective of visual-motion features. For example, the response of the PLTC is equally high to action verbs (e.g. to run) and mental verbs (e.g. to think), and equally low to animal nouns (e.g. the cat) and inanimate natural kind nouns (e.g. the rock). Thus PLTC activity for action verbs might reflect the retrieval of event concepts, or the grammatical information associated with verbs. We conclude that concepts are abstracted away from sensory-motor experience and organized according to conceptual properties.
doi:10.1523/JNEUROSCI.3039-08.2008
PMCID: PMC2752357  PMID: 18971476
language; sensorymotor; temporal; concept; memory; visual motion
23.  Processing Nouns and Verbs in the Left Frontal Cortex: A Transcranial Magnetic Stimulation Study 
Journal of cognitive neuroscience  2008;20(4):707-720.
Neuropsychological and neurophysiological studies suggest that the production of verbs in speech depends on cortical regions in the left frontal lobe. However, the precise topography of these regions, and their functional roles in verb production, remains matters of debate. In an earlier study with repetitive transcranial magnetic stimulation (rTMS), we showed that stimulation to the left anterior midfrontal gyrus disrupted verb production, but not noun production, in a task that required subjects to perform simple morphological alternations. This result raises a number of questions: for example, is the effect of stimulation focal and specific to that brain region? Is the behavioral effect limited to rule-based, regular transformations, or can it be generalized over the grammatical category? In the present study, we used rTMS to suppress the excitability of distinct parts of the left prefrontal cortex to assess their role in producing regular and irregular verbs compared to nouns. We compared rTMS to sham stimulation and to stimulation of homologous areas in the right hemisphere. Response latencies increased for verbs, but were unaffected for nouns, following stimulation to the left anterior midfrontal gyrus. No significant interference specific for verbs resulted after stimulation to two other areas in the left frontal lobe, the posterior midfrontal gyrus and Broca's area. These results therefore reinforce the idea that the left anterior midfrontal cortex is critical for processing verbs. Moreover, none of the regions stimulated was preferentially engaged in the production of regular or irregular inflection, raising questions about the role of the frontal lobes in processing inflectional morphology.
doi:10.1162/jocn.2008.20045
PMCID: PMC2567816  PMID: 18052789
24.  Action-related properties of objects shape object representations in the ventral stream 
Neuron  2007;55(3):507-520.
Summary
The principles driving the organization of the ventral object-processing stream remain unknown. Here we show that stimulus-specific repetition suppression (RS) in one region of the ventral stream is biased according to motor-relevant properties of objects. Quantitative analysis confirmed that this result was not confounded with similarity in visual shape. A similar pattern of biases in RS according to motor-relevant properties of objects was observed in dorsal stream regions in the left hemisphere. These findings suggest that neural specificity for ‘tools’ in the ventral stream is driven by similarity metrics computed over motor-relevant information represented in dorsal structures. Support for this view is provided by converging results from functional connectivity analyses of the fMRI data and a separate neuropsychological study. More generally, these data suggest that a basic organizing principle giving rise to ‘category-specificity’ in the ventral stream may involve similarity metrics computed over information represented elsewhere in the brain.
doi:10.1016/j.neuron.2007.07.011
PMCID: PMC2000824  PMID: 17678861

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