Showing papers on "Temporal cortex published in 2007"
TL;DR: A quantitative meta-analysis of 70 functional neuroimaging studies demonstrates that the right inferior parietal cortex is also engaged in lower-level (bottom-up) computational processes associated with the sense of agency and reorienting attention to salient stimuli.
Abstract: Accumulating evidence from cognitive neuroscience indicates that the right inferior parietal cortex, at the junction with the posterior temporal cortex, plays a critical role in various aspects of social cognition such as theory of mind and empathy. With a quantitative meta-analysis of 70 functional neuroimaging studies, the authors demonstrate that this area is also engaged in lower-level (bottom-up) computational processes associated with the sense of agency and reorienting attention to salient stimuli. It is argued that this domain-general computational mechanism is crucial for higher level social cognitive processing.
930 citations
TL;DR: Responses elicited by the face images were distinct in aIT but not in the FFA, suggesting that individual-level face information is likely to be present in both regions, but the data suggest that it is more pronounced in a IT.
Abstract: Visual face identification requires distinguishing between thousands of faces we know. This computational feat involves a network of brain regions including the fusiform face area (FFA) and anterior inferotemporal cortex (aIT), whose roles in the process are not well understood. Here, we provide the first demonstration that it is possible to discriminate cortical response patterns elicited by individual face images with high-resolution functional magnetic resonance imaging (fMRI). Response patterns elicited by the face images were distinct in aIT but not in the FFA. Individual-level face information is likely to be present in both regions, but our data suggest that it is more pronounced in aIT. One interpretation is that the FFA detects faces and engages aIT for identification.
516 citations
TL;DR: The cluster analysis showed that IT population responses reconstruct a large part of the intuitive category structure, including the global division into animate and inanimate objects, and further hierarchical subdivisions of animate objects.
Abstract: Our mental representation of object categories is hierarchically organized, and our rapid and seemingly effortless categorization ability is crucial for our daily behavior. Here, we examine responses of a large number (>600) of neurons in monkey inferior temporal (IT) cortex with a large number (>1,000) of natural and artificial object images. During the recordings, the monkeys performed a passive fixation task. We found that the categorical structure of objects is represented by the pattern of activity distributed over the cell population. Animate and inanimate objects created distinguishable clusters in the population code. The global category of animate objects was divided into bodies, hands, and faces. Faces were divided into primate and nonprimate faces, and the primate-face group was divided into human and monkey faces. Bodies of human, birds, and four-limb animals clustered together, whereas lower animals such as fish, reptile, and insects made another cluster. Thus the cluster analysis showed that IT population responses reconstruct a large part of our intuitive category structure, including the global division into animate and inanimate objects, and further hierarchical subdivisions of animate objects. The representation of categories was distributed in several respects, e.g., the similarity of response patterns to stimuli within a category was maintained by both the cells that maximally responded to the category and the cells that responded weakly to the category. These results advance our understanding of the nature of the IT neural code, suggesting an inherently categorical representation that comprises a range of categories including the amply investigated face category.
476 citations
TL;DR: The results demonstrate that the superior anterior temporal cortex plays a key role in social cognition by providing abstract conceptual knowledge of social behaviors and further speculate that these abstract conceptual representations can be associated with different contexts of social actions and emotions through integration with frontolimbic circuits to enable flexible evaluations of social behavior.
Abstract: Social concepts such as "tactless" or "honorable" enable us to describe our own as well as others' social behaviors. The prevailing view is that this abstract social semantic knowledge is mainly subserved by the same medial prefrontal regions that are considered essential for mental state attribution and self-reflection. Nevertheless, neurodegeneration of the anterior temporal cortex typically leads to impairments of social behavior as well as general conceptual knowledge. By using functional MRI, we demonstrate that the anterior temporal lobe represents abstract social semantic knowledge in agreement with this patient evidence. The bilateral superior anterior temporal lobes (Brodmann's area 38) are selectively activated when participants judge the meaning relatedness of social concepts (e.g., honor-brave) as compared with concepts describing general animal functions (e.g., nutritious-useful). Remarkably, only activity in the superior anterior temporal cortex, but not the medial prefrontal cortex, correlates with the richness of detail with which social concepts describe social behavior. Furthermore, this anterior temporal lobe activation is independent of emotional valence, whereas medial prefrontal regions show enhanced activation for positive social concepts. Our results demonstrate that the superior anterior temporal cortex plays a key role in social cognition by providing abstract conceptual knowledge of social behaviors. We further speculate that these abstract conceptual representations can be associated with different contexts of social actions and emotions through integration with frontolimbic circuits to enable flexible evaluations of social behavior.
429 citations
TL;DR: Parietal neurons may selectively increase activity in earlier sensory areas to enable focused spatial attention in monkeys performing a visual matching task.
Abstract: Attention helps us process potentially important objects by selectively increasing the activity of sensory neurons that represent the relevant locations and features of our environment. This selection process requires top-down feedback about what is important in our environment. We investigated how parietal cortical output influences neural activity in early sensory areas. Neural recordings were made simultaneously from the posterior parietal cortex and an earlier area in the visual pathway, the medial temporal area, of macaques performing a visual matching task. When the monkey selectively attended to a location, the timing of activities in the two regions became synchronized, with the parietal cortex leading the medial temporal area. Parietal neurons may thus selectively increase activity in earlier sensory areas to enable focused spatial attention.
405 citations
TL;DR: Evidence is found that increased structural connectivity is associated with the presence of grapheme-color synesthesia, and has a role in the subjective nature of synesthetic color experience.
Abstract: Diffusion tensor imaging allowed us to validate for the first time the hypothesis that hyperconnectivity causes the added sensations in synesthesia. Grapheme-color synesthetes (n = 18), who experience specific colors with particular letters or numbers (for example, 'R is sky blue'), showed greater anisotropic diffusion compared with matched controls. Greater anisotropic diffusion indicates more coherent white matter. Anisotropy furthermore differentiated subtypes of grapheme-color synesthesia. Greater connectivity in the inferior temporal cortex was particularly strong for synesthetes who see synesthetic color in the outside world ('projectors') as compared with synesthetes who see the color in their 'mind's eye' only ('associators'). In contrast, greater connectivity (as compared with non-synesthetes) in the superior parietal or frontal cortex did not differentiate between subtypes of synesthesia. In conclusion, we found evidence that increased structural connectivity is associated with the presence of grapheme-color synesthesia, and has a role in the subjective nature of synesthetic color experience.
391 citations
TL;DR: In this paper, the authors used fMRI to investigate "social brain" activity during perception of fearful faces and found that people with highfunctioning autism or Asperger Syndrome (HFA/AS) showed differential activation of social brain areas during a face-processing task.
386 citations
TL;DR: In this article, the extent of structural brain damage and related cognitive deficits has been little described in alcohol-dependent individuals with preserved social functioning, and the relationship between regional alterations, executive performance, and drinking history was investigated.
384 citations
TL;DR: It is suggested that the "semantic ventral stream" could be constituted by at least two parallel pathways within the left dominant temporal lobe: a direct pathway that connects the posterior temporal areas and the orbitofrontal region, crucial for language semantic processing, since it elicits semantic paraphasia when stimulated and also possibly an indirect pathway subserved by the ILF, not indispensable for language.
Abstract: Although advances in diffusion tensor imaging have enabled us to better study the anatomy of the inferior longitudinal fasciculus (ILF), its function remains poorly understood. Recently, it was suggested that the subcortical network subserving the language semantics could be constituted, in parallel with the inferior occipitofrontal fasciculus, by the left ILF, joining the posterior occipitotemporal regions to the temporal pole, then relayed by the uncinate fasciculus connecting the anterior temporal pole to the frontobasal areas. Nevertheless, this hypothesis was solely based on neurofunctional imaging, allowing a cortical mapping but with no anatomofunctional information regarding the white matter. Here, we report a series of 12 patients operated on under local anaesthesia for a cerebral low-grade glioma located within the left temporal lobe. Before and during resection, we used the method of intraoperative direct electrostimulation, enabling us to perform accurate and reliable anatomofunctional correlations both at cortical and subcortical levels. In order to map the ILF. Using postoperative MRI, we correlated these functional findings with the anatomical locations of the sites where language disturbances were elicited by stimulations, both at cortical and subcortical levels. Our goal was to study the potential existence of parallel and distributed language networks crossing the left dominant temporal lobe, subserved by distinct subcortical pathways--namely the inferior occipitofrontal fasciculus and the ILF. Intraoperative stimulation of the anterior and middle temporal cortex elicited anomia in four patients. At the subcortical level, semantic paraphasia were induced in seven patients during stimulation of the inferior occipitofrontal fasciculus, and phonological paraphasia was generated in seven patients by stimulating the arcuate fasciculus. Interestingly, subcortical stimulation never elicited any language disturbances when performed at the level of the ILF. In addition, following a transient postoperative language deficit, all patients recovered, despite the resection of at least one part of the ILF, as confirmed by control MRI. On the basis of these results, we suggest that the "semantic ventral stream" could be constituted by at least two parallel pathways within the left dominant temporal lobe: (i) a direct pathway, the inferior occipitofrontal fasciculus, that connects the posterior temporal areas and the orbitofrontal region, crucial for language semantic processing, since it elicits semantic paraphasia when stimulated; (ii) and also possibly an indirect pathway subserved by the ILF, not indispensable for language, since it can be compensated both during stimulation and after resection.
383 citations
TL;DR: These data provide the first evidence for a direct overlap in the neural bases of color perception and stored information about object-associated color, and they significantly add to accumulating evidence that conceptual knowledge is grounded in the brain's modality-specific systems.
363 citations
TL;DR: FMRI analyses of relationships between severity of state posttraumatic symptoms and neural activation found that state reexperiencing severity was associated positively with right anterior insula activity and negatively with right rostral anterior cingulate cortex (rACC).
Abstract: Research suggests that responses to script-driven trauma imagery in posttraumatic stress disorder (PTSD) include reexperiencing and dissociative symptom subtypes. This functional magnetic resonance imaging (fMRI) study employed a dimensional approach to characterizing script-driven imagery responses, using the Responses to Script-Driven Imagery Scale and correlational analyses of relationships between severity of state posttraumatic symptoms and neural activation. As predicted, state reexperiencing severity was associated positively with right anterior insula activity and negatively with right rostral anterior cingulate cortex (rACC). Avoidance correlated negatively with rACC and subcallosal anterior cingulate activity. In addition, as predicted, dissociation correlated positively with activity in the left medial prefrontal and right superior temporal cortices, and negatively with the left superior temporal cortex. Theoretical and clinical implications are discussed, particularly with respect to an emotion-dysregulation account of PTSD.
TL;DR: PET imaging with 11C-labeled Pittsburgh Compound-B (11C-PIB) helps discriminate Alzheimer disease (AD) from frontotemporal lobar degeneration (FTLD).
Abstract: Background: The PET tracer 11 C-labeled Pittsburgh Compound-B ( 11 C-PIB) specifically binds fibrillar amyloid-beta (Aβ) plaques and can be detected in Alzheimer disease (AD). We hypothesized that PET imaging with 11 C-PIB would discriminate AD from frontotemporal lobar degeneration (FTLD), a non-Aβ dementia. Methods: Patients meeting research criteria for AD (n = 7) or FTLD (n = 12) and cognitively normal controls (n = 8) underwent PET imaging with 11 C-PIB (patients and controls) and 18 F-fluorodeoxyglucose ( 18 F-FDG) (patients only). 11 C-PIB whole brain and region of interest (ROI) distribution volume ratios (DVR) were calculated using Logan graphical analysis with cerebellum as a reference region. DVR images were visually rated by a blinded investigator as positive or negative for cortical 11 C-PIB, and summed 18 F-FDG images were rated as consistent with AD or FTLD. Results: All patients with AD (7/7) had positive 11 C-PIB scans by visual inspection, while 8/12 patients with FTLD and 7/8 controls had negative scans. Of the four PIB-positive patients with FTLD, two had 18 F-FDG scans that suggested AD, and two had 18 F-FDG scans suggestive of FTLD. Mean DVRs were higher in AD than in FTLD in whole brain, lateral frontal, precuneus, and lateral temporal cortex ( p Conclusions: PET imaging with 11 C-labeled Pittsburgh Compound-B ( 11 C-PIB) helps discriminate Alzheimer disease (AD) from frontotemporal lobar degeneration (FTLD). Pathologic correlation is needed to determine whether patients with PIB-positive FTLD represent false positives, comorbid FTLD/AD pathology, or AD pathology mimicking an FTLD clinical syndrome.
TL;DR: This work shows that repetitive transcranial magnetic stimulation delivered to the superior temporal cortex causes macroscopic cortical changes in gray matter in the auditory cortex as early as within 5 days of continuous intervention, and suggests that cortical plasticity on a structural level in adult humans is already detectable after 1 week.
Abstract: Activation-dependent brain plasticity in humans on a structural level has been demonstrated in adults after 3 months of training a visiomotor skill. The exact timescale of usage-dependent structural changes, whether days, months, or years, is, however, still debated. A better understanding of the temporal parameters may help elucidate to what extent this type of cortical plasticity contributes to fast adapting cortical processes that may be relevant to learning and effects of treatments. Using voxel-based morphometry, we are able to show that repetitive transcranial magnetic stimulation delivered to the superior temporal cortex causes macroscopic cortical changes in gray matter (GM) in the auditory cortex as early as within 5 days of continuous intervention. These structural alterations are mirrored by changes in cortical evoked potentials attributed to the GM changes and demonstrate the rapid dynamics of these processes, which occur within a time range characteristic for the onset of behavioral effects induced by a variety of treatment methods for neuropsychiatric diseases. Our finding suggests that cortical plasticity on a structural level in adult humans is already detectable after 1 week, which provides support for fast adjusting neuronal systems, such as spine and synapse turnover, and contradicts slow evolving mechanisms, such as neuronal or glial cell genesis.
TL;DR: It is argued that the putamen engages in cortical initiation while the cerebellum amplifies and refines this signal to facilitate correct decision making to have distinct roles in language processing.
TL;DR: The ARMS was associated with reductions in gray matter volume in areas that are also reduced in schizophrenia, suggesting that these are a correlate of an increased vulnerability to psychosis.
TL;DR: A baseline for comparison with pathologic changes in human brain volume between ages 58 and 95 years is established and relative regional differences in cortical GM volume with age occurred in the frontal, parietal and temporal lobes, but not in medial temporal lobe or in posterior cingulate.
TL;DR: Dense H3 binding was detected in medial temporal cortex samples from severe cases of Alzheimer's disease, suggesting for the first time that H3 receptors are preserved in late-stage disease.
Abstract: 6-[(3-Cyclobutyl-2,3,4,5-tetrahydro-1H-3-benzazepin-7-yl)oxy]-N-methyl-3-pyridinecarboxamide hydrochloride (GSK189254) is a novel histamine H(3) receptor antagonist with high affinity for human (pK(i) = 9.59 -9.90) and rat (pK(i) = 8.51-9.17) H(3) receptors. GSK189254 is >10,000-fold selective for human H(3) receptors versus other targets tested, and it exhibited potent functional antagonism (pA(2) = 9.06 versus agonist-induced changes in cAMP) and inverse agonism [pIC(50) = 8.20 versus basal guanosine 5'-O-(3-[(35)S]thio)triphosphate binding] at the human recombinant H(3) receptor. In vitro autoradiography demonstrated specific [(3)H]GSK189254 binding in rat and human brain areas, including cortex and hippocampus. In addition, dense H(3) binding was detected in medial temporal cortex samples from severe cases of Alzheimer's disease, suggesting for the first time that H(3) receptors are preserved in late-stage disease. After oral administration, GSK189254 inhibited cortical ex vivo R-(-)-alpha-methyl[imidazole-2,5(n)-(3)H]histamine dihydrochloride ([(3)H]R-alpha-methylhistamine) binding (ED(50) = 0.17 mg/kg) and increased c-Fos immunoreactivity in prefrontal and somatosensory cortex (3 mg/kg). Microdialysis studies demonstrated that GSK189254 (0.3-3 mg/kg p.o.) increased the release of acetylcholine, noradrenaline, and dopamine in the anterior cingulate cortex and acetylcholine in the dorsal hippocampus. Functional antagonism of central H(3) receptors was demonstrated by blockade of R-alpha-methylhistamine-induced dipsogenia in rats (ID(50) = 0.03 mg/kg p.o.). GSK189254 significantly improved performance of rats in diverse cognition paradigms, including passive avoidance (1 and 3 mg/kg p.o.), water maze (1 and 3 mg/kg p.o.), object recognition (0.3 and 1 mg/kg p.o.), and attentional set shift (1 mg/kg p.o.). These data suggest that GSK189254 may have therapeutic potential for the symptomatic treatment of dementia in Alzheimer's disease and other cognitive disorders.
TL;DR: Results demonstrate that even passive viewing of facial expressions activates a wide network of brain regions that were also involved in the execution of similar expressions, including the IFG/insula and the posterior parietal cortex.
Abstract: Facial expressions contain both motor and emotional components. The inferior frontal gyrus (IFG) and posterior parietal cortex have been considered to compose a mirror neuron system (MNS) for the motor components of facial expressions, while the amygdala and insula may represent an “additional” MNS for emotional states. Together, these systems may contribute to our understanding of facial expressions. Here we further examine this possibility. In three separate event-related fMRI experiment, subjects had to (1) observe (2) discriminate and (3) imitate facial expressions. Stimuli were dynamic neutral, happy, fearful and disgusted facial expressions, and in Experiments 1 and 2, an additional pattern motion condition. Importantly, during each experiment, subjects were unaware of the nature of the next experiments. Results demonstrate that even passive viewing of facial expressions activates a wide network of brain regions that were also involved in the execution of similar expressions, including the ...
TL;DR: The neural basis for color perception is addressed, using targeted single-unit recording in alert macaque monkeys, guided by functional magnetic resonance imaging (fMRI) of the same subjects, to suggest thatcolor perception is mediated by specialized neurons that are clustered within the extrastriate brain.
TL;DR: Evidence is provided that the level of impairment in the naming process reflects the distribution of tissue dysfunction in particular regions of the left anterior, inferior and posterior middle/superior temporal cortex, posterior inferior frontal and inferior parietal cortex.
Abstract: We hypothesized that distinct cognitive processes underlying oral and written picture naming depend on intact function of different, but overlapping, regions of the left hemisphere cortex, such that the distribution of tissue dysfunction in various areas can predict the component of the naming process that is disrupted.To test this hypothesis, we evaluated 116 individuals within 24 h of acute ischaemic stroke using a battery of oral and written naming and other lexical tests, and with magnetic resonance diffusion and perfusion imaging to identify the areas of tissue dysfunction. Discriminant function analysis, using the degree of hypoperfusion in various Brodmann’s areascBA 22 (including Wernicke’s area), BA 44 (part of Broca’s area), BA 45 (part of Broca’s area), BA 21 (inferior temporal cortex), BA 37 (posterior, inferior temporal/fusiform gyrus), BA 38 (anterior temporal cortex) and BA 39 (angular gyrus)cas discriminant variables, classified patients on the basis of the primary component of the naming process that was impaired (defined as visual, semantics, modality-independent lexical access, phonological word form, orthographic word form and motor speech by the pattern of performance and types of errors across lexical tasks). Additionally, linear regression analysis demonstrated that the areas contributing the most information to the identification ofpatientswith particularlevels of impairmentin the naming processwerelargelyconsistent with evidence for the roles of these regions from functionalimaging.This study provides evidence that the levelof impairment in the naming process reflects the distribution of tissue dysfunction in particular regions of the left anterior, inferior and posterior middle/superior temporal cortex, posterior inferior frontal and inferior parietal cortex. While occipital cortex is also critical for picture naming, it is likely that bilateral occipital damage is necessary to disrupt visual recognition.These findings provide new evidence that a network of brain regions supports naming, but separate components of this network are differentially required for distinct cognitive processes or representations underlying the complex task of naming pictures.
TL;DR: Electrophysiological recordings were performed in epileptic patients with pharmacologically resistant partial epilepsy and selective attention was found to affect steady-state responses in the primary auditory cortex, and transient and sustained evoked responses in secondary auditory areas.
Abstract: In noisy environments, we use auditory selective attention to actively ignore distracting sounds and select relevant information, as during a cocktail party to follow one particular conversation. The present electrophysiological study aims at deciphering the spatiotemporal organization of the effect of selective attention on the representation of concurrent sounds in the human auditory cortex. Sound onset asynchrony was manipulated to induce the segregation of two concurrent auditory streams. Each stream consisted of amplitude modulated tones at different carrier and modulation frequencies. Electrophysiological recordings were performed in epileptic patients with pharmacologically resistant partial epilepsy, implanted with depth electrodes in the temporal cortex. Patients were presented with the stimuli while they either performed an auditory distracting task or actively selected one of the two concurrent streams. Selective attention was found to affect steady-state responses in the primary auditory cortex, and transient and sustained evoked responses in secondary auditory areas. The results provide new insights on the neural mechanisms of auditory selective attention: stream selection during sound rivalry would be facilitated not only by enhancing the neural representation of relevant sounds, but also by reducing the representation of irrelevant information in the auditory cortex. Finally, they suggest a specialization of the left hemisphere in the attentional selection of fine-grained acoustic information.
TL;DR: Evidence is provided of an altered emotional modulation of cognitive processing in euthymic bipolar patients, indicated by an overactivation in ventral-limbic, temporal, and dorsal brain structures during emotional go/nogo conditions in patients relative to comparison subjects.
Abstract: Objective: Although euthymic bipolar patients show minimal manic and depressive symptoms, they continue to show impaired emotional regulation and cognitive functioning. Few studies have directly examined the interference of emotional information with cognitive processes and its underlying cerebral mechanisms in euthymic bipolar patients. The authors examined the emotional modulation of cognitive processes and its underlying neural mechanisms in euthymic bipolar patients. Method: Seventeen euthymic bipolar patients and 17 healthy comparison subjects underwent functional magnetic resonance imaging (MRI) while performing an emotional and nonemotional go/nogo task. Neural responses associated with the overall task performance, as well as with the impact of emotional information on the task performance, were assessed. Results: Bipolar disorder patients exhibited increased activity in the temporal cortex, specifically to emotional go/nogo conditions, as well as in the orbitofrontal cortex, the insula, the cauda...
TL;DR: This investigation represents the first extensive proteomic investigation of corticalLBs, and it is expected that characterization of the proteins in the cortical LBs may reveal novel mechanisms by which LB forms and pathways leading to neurodegeneration in DLB and/or advanced PD.
Abstract: Lewy body (LB) inclusions are one of the pathological hallmarks of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). One way to better understand the process leading to LB formation and associated pathogenesis responsible for neuro-degeneration in PD and DLB is to examine the content of LB inclusions. Here, we performed a proteomic investigation of cortical LBs, obtained by laser capture microdissection from neurons in the temporal cortex of dementia patients with cortical LB disease. Analysis of over 2500 cortical LBs discovered 296 proteins; of those, 17 had been associated previously with brainstem and/or cortical LBs. We validated several proteins with immunohistochemical staining followed by confocal microscopy. The results demonstrated that heat shock cognate 71 kDa protein (also known as HSC70, HSP73, or HSPA10) was indeed not only colocalized with the majority of LBs in the temporal cortex but also colocalized to LBs in the frontal cortex of patients with diffuse LB disease. Our investigation represents the first extensive proteomic investigation of cortical LBs, and it is expected that characterization of the proteins in the cortical LBs may reveal novel mechanisms by which LB forms and pathways leading to neurode-generation in DLB and/or advanced PD. Further investigation of these novel candidates is also necessary to ensure that the potential proteins in cortical LBs are not identified incorrectly because of incomplete current human protein database.
TL;DR: During viewing of food-related stimuli, leptin replacement reduced brain activation in regions linked to hunger while enhancing activation in areas linked to inhibition and satiety, suggesting therapeutic targets for human obesity.
Abstract: A missense mutation in the ob gene causes leptin deficiency and morbid obesity. Leptin replacement to three adults with this mutation normalized body weight and eating behavior. Because the neural circuits mediating these changes were unknown, we paired functional magnetic resonance imaging (fMRI) with presentation of food cues to these subjects. During viewing of food-related stimuli, leptin replacement reduced brain activation in regions linked to hunger (insula, parietal and temporal cortex) while enhancing activation in regions linked to inhibition and satiety (prefrontal cortex). Leptin appears to modulate feeding behavior through these circuits, suggesting therapeutic targets for human obesity.
TL;DR: It is demonstrated that differential activation of the human pSTC during action perception versus action performance predicts self-reported altruism.
Abstract: Although the neural mechanisms underlying altruism remain unknown, empathy and its component abilities, such as the perception of the actions and intentions of others, have been proposed as key contributors. Tasks requiring the perception of agency activate the posterior superior temporal cortex (pSTC), particularly in the right hemisphere. Here, we demonstrate that differential activation of the human pSTC during action perception versus action performance predicts self-reported altruism.
TL;DR: A core decompositional network linking left inferior frontal cortex with superior and middle temporal cortex, connected via the arcuate fasciculus is argued for, handling the processing of regularly inflected words (such as joined or treats).
Abstract: This paper outlines a neurocognitive approach to human language, focusing on inflectional morphology and grammatical function in English. Taking as a starting point the selective deficits for regular inflectional morphology of a group of non-fluent patients with left hemisphere damage, we argue for a core decompositional network linking left inferior frontal cortex with superior and middle temporal cortex, connected via the arcuate fasciculus. This network handles the processing of regularly inflected words (such as joined or treats), which are argued not to be stored as whole forms and which require morpho-phonological parsing in order to segment complex forms into stems and inflectional affixes. This parsing process operates early and automatically upon all potential inflected forms and is triggered by their surface phonological properties. The predictions of this model were confirmed in a further neuroimaging study, using event-related functional magnetic resonance imaging (fMRI), on unimpaired young adults. The salience of grammatical morphemes for the language system is highlighted by new research showing that similarly early and blind segmentation also operates for derivationally complex forms (such as darkness or rider). These findings are interpreted as evidence for a hidden decompositional substrate to human language processing and related to a functional architecture derived from non-human primate models.
TL;DR: The results show that hypertension significantly affects resting brain function in older individuals and suggest that duration of hypertension contributes significantly to the patterns of change over time.
Abstract: Background and Purpose— Changes in patterns of regional cerebral blood flow (rCBF) were assessed over a period of 6 years in 14 treated hypertensive participants (HTNs) and 14 age-matched healthy older participants (healthy controls [HCs]) in the Baltimore Longitudinal Study of Aging. Methods— Resting-state PET scans collected at years 1, 3, 5, and 7 were used to determine differences in longitudinal patterns of rCBF change in HTNs relative to HCs. Pulse pressure, arterial pressure, systolic/diastolic blood pressure, and hypertension duration were also correlated with patterns of rCBF change in the HTN group. Results— Relative to HCs, the HTN group shows greater rCBF decreases in prefrontal, anterior cingulate, and occipital areas over time, suggesting that these regions are more susceptible to hypertension-related dysfunction with advancing age. The HTN group also fails to show preservation of function over time in motor regions and in the temporal cortex and hippocampus as observed in HC. Although pulse...
TL;DR: Exposure to expression levels of MET and members of the MET signaling pathway in postmortem cerebral cortex from ASD cases and healthy control subjects is examined.
Abstract: Objective
Multiple genes contribute to autism spectrum disorder (ASD) susceptibility. One particularly promising candidate is the MET gene, which encodes a receptor tyrosine kinase that mediates hepatocyte growth factor (HGF) signaling in brain circuit formation, immune function, and gastrointestinal repair. The MET promoter variant rs1858830 allele “C” is strongly associated with ASD and results in reduced gene transcription. Here we examined expression levels of MET and members of the MET signaling pathway in postmortem cerebral cortex from ASD cases and healthy control subjects.
Methods
Protein, total RNA, and DNA were extracted from postmortem temporal cortex gray matter samples (BA 41/42, 52, or 22) belonging to eight pairs of ASD cases and matched control subjects. MET protein expression was determined by Western blotting; messenger RNA expression of MET and other related transcripts was assayed by microarray and quantitative reverse transcriptase polymerase chain reaction.
Results
MET protein levels were significantly decreased in ASD cases compared with control subjects. This was accompanied in ASD brains by increased messenger RNA expression for proteins involved in regulating MET signaling activity. Analyses of coexpression of MET and HGF demonstrated a positive correlation in control subjects that was disrupted in ASD cases.
Interpretation
Altered expression of MET and related molecules suggests dysregulation of signaling that may contribute to altered circuit formation and function in ASD. The complement of genes that encode proteins involved in MET activation appears to undergo long-term compensatory changes in expression that may be a hallmark contribution to the pathophysiology of ASD. Ann Neurol 2007
TL;DR: It is shown that the brain responses for processing of verbs with specific motor meanings differ not only from that of other motor verbs, but, crucially, that the comprehension ofverbs with motor meanings differs fundamentally from the processing of verb with abstract meanings.
Abstract: The interaction between language and action systems has become an increasingly interesting topic of discussion in cognitive neuroscience. Several recent studies have shown that processing of action verbs elicits activation in the cerebral motor system in a somatotopic manner. The current study extends these findings to show that the brain responses for processing of verbs with specific motor meanings differ not only from that of other motor verbs, but, crucially, that the comprehension of verbs with motor meanings (i.e., greifen, to grasp) differs fundamentally from the processing of verbs with abstract meanings (i.e., denken, to think). Second, the current study investigated the neural correlates of processing morphologically complex verbs with abstract meanings built on stems with motor versus abstract meanings (i.e., begreifen, to comprehend vs. bedenken, to consider). Although residual effects of motor stem meaning might have been expected, we see no evidence for this in our data. Processing of morphologically complex verbs built on motor stems showed no differences in involvement of the motor system when compared with processing complex verbs with abstract stems. Complex verbs built on motor stems did show increased activation compared with complex verbs built on abstract stems in the right posterior temporal cortex. This result is discussed in light of the involvement of the right temporal cortex in comprehension of metaphoric or figurative language.
TL;DR: Functional magnetic resonance imaging is used to study spatial selectivity in the human middle temporal cortex (area MT or V5), an area that is clearly implicated in motion perception and shows that the response of MT is modulated by gaze direction, generating a spatialSelectivity based on screen rather than retinal coordinates.
Abstract: Many neurons in the monkey visual extrastriate cortex have receptive fields that are affected by gaze direction. In humans, psychophysical studies suggest that motion signals may be encoded in a spatiotopic fashion. Here we use functional magnetic resonance imaging to study spatial selectivity in the human middle temporal cortex (area MT or V5), an area that is clearly implicated in motion perception. The results show that the response of MT is modulated by gaze direction, generating a spatial selectivity based on screen rather than retinal coordinates. This area could be the neurophysiological substrate of the spatiotopic representation of motion signals.