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1.
Neuroimage ; 213: 116736, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32171924

RESUMO

It is well known that expectations influence how we perceive the world. Yet the neural mechanisms underlying this process remain unclear. Studies about the effects of prior expectations have focused so far on artificial contingencies between simple neutral cues and events. Real-world expectations are however often generated from complex associations between contexts and objects learned over a lifetime. Additionally, these expectations may contain some affective value and recent proposals present conflicting hypotheses about the mechanisms underlying affect in predictions. In this study, we used fMRI to investigate how object processing is influenced by realistic context-based expectations, and how affect impacts these expectations. First, we show that the precuneus, the inferotemporal cortex and the frontal cortex are more active during object recognition when expectations have been elicited a priori, irrespectively of their validity or their affective intensity. This result supports previous hypotheses according to which these brain areas integrate contextual expectations with object sensory information. Notably, these brain areas are different from those responsible for simultaneous context-object interactions, dissociating the two processes. Then, we show that early visual areas, on the contrary, are more active during object recognition when no prior expectation has been elicited by a context. Lastly, BOLD activity was shown to be enhanced in early visual areas when objects are less expected, but only when contexts are neutral; the reverse effect is observed when contexts are affective. This result supports the proposal that affect modulates the weighting of sensory information during predictions. Together, our results help elucidate the neural mechanisms of real-world expectations.


Assuntos
Encéfalo/fisiologia , Emoções/fisiologia , Motivação/fisiologia , Reconhecimento Psicológico/fisiologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Estimulação Luminosa , Percepção Visual/fisiologia , Adulto Jovem
2.
J Cogn Neurosci ; 30(7): 1023-1032, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29668395

RESUMO

How do we understand the emotional content of written words? Here, we investigate the hypothesis that written words that carry emotions are processed through phylogenetically ancient neural circuits that are involved in the processing of the very same emotions in nonlanguage contexts. This hypothesis was tested with respect to disgust. In an fMRI experiment, it was found that the same region of the left anterior insula responded whether people observed facial expressions of disgust or whether they read words with disgusting content. In a follow-up experiment, it was found that repetitive TMS over the left insula in comparison with a control site interfered with the processing of disgust words to a greater extent than with the processing of neutral words. Together, the results support the hypothesis that the affective processes we experience when reading rely on the reuse of phylogenetically ancient brain structures that process basic emotions in other domains and species.


Assuntos
Encéfalo/fisiologia , Compreensão/fisiologia , Emoções/fisiologia , Leitura , Vocabulário , Adulto , Análise de Variância , Encéfalo/diagnóstico por imagem , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Oxigênio/sangue , Reconhecimento Visual de Modelos/fisiologia , Estimulação Luminosa , Estimulação Magnética Transcraniana , Adulto Jovem
3.
J Exp Psychol Gen ; 146(7): 917-923, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28368191

RESUMO

The nervous system gives preferential treatment to objects near the hands that are candidates for action. It is not yet understood how this process is achieved. Here we show evidence for the mechanism that underlies this process having used an experimental technique that maps the use of spatial frequencies (SFs) during object recognition across time. We used this technique to replicate and characterize with greater precision the coarse-to-fine SF sampling observed in previous studies. Then we show that the visual processing of real-world objects near an observer's hands is biased toward the use of low-SF information, around 288 ms. Conversely, high-SF information presented around 113 ms impaired object recognition when objects were presented near the hands. Notably, both of these effects happened relatively late during object recognition and suggest that the modulation of SF use by hand position is at least partly attentional in nature. (PsycINFO Database Record


Assuntos
Orientação Espacial/fisiologia , Reconhecimento Psicológico/fisiologia , Percepção Visual/fisiologia , Atenção/fisiologia , Feminino , Mãos , Humanos , Masculino , Tempo de Reação/fisiologia , Adulto Jovem
4.
Sci Rep ; 6: 35494, 2016 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-27752088

RESUMO

In neurotypical observers, it is widely believed that the visual system samples the world in a coarse-to-fine fashion. Past studies on Autism Spectrum Disorder (ASD) have identified atypical responses to fine visual information but did not investigate the time course of the sampling of information at different levels of granularity (i.e. Spatial Frequencies, SF). Here, we examined this question during an object recognition task in ASD and neurotypical observers using a novel experimental paradigm. Our results confirm and characterize with unprecedented precision a coarse-to-fine sampling of SF information in neurotypical observers. In ASD observers, we discovered a different pattern of SF sampling across time: in the first 80 ms, high SFs lead ASD observers to a higher accuracy than neurotypical observers, and these SFs are sampled differently across time in the two subject groups. Our results might be related to the absence of a mandatory precedence of global information, and to top-down processing abnormalities in ASD.


Assuntos
Transtorno do Espectro Autista/psicologia , Reconhecimento Visual de Modelos , Adulto , Transtorno do Espectro Autista/diagnóstico , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Reprodutibilidade dos Testes , Fatores de Tempo
5.
Mol Autism ; 7: 4, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26788281

RESUMO

BACKGROUND: As evidenced in the DSM-V, autism spectrum disorders (ASD) are often characterized by atypical sensory behavior (hyper- or hypo-reactivity), but very few studies have evaluated olfactory abilities in individuals with ASD. METHODS: Fifteen adults with ASD and 15 typically developing participants underwent olfactory tests focused on superficial (suprathreshold detection task), perceptual (intensity and pleasantness judgment tasks), and semantic (identification task) odor processing. RESULTS: In terms of suprathreshold detection performance, decreased discrimination scores and increased bias scores were observed in the ASD group. Furthermore, the participants with ASD exhibited increased intensity judgment scores and impaired scores for pleasantness judgments of unpleasant odorants. Decreased identification performance was also observed in the participants with ASD compared with the typically developing participants. This decrease was partly attributed to a higher number of near misses (a category close to veridical labels) among the participants with ASD than was observed among the typically developing participants. CONCLUSIONS: The changes in discrimination and bias scores were the result of a high number of false alarms among the participants with ASD, which suggests the adoption of a liberal attitude in their responses. Atypical intensity and pleasantness ratings were associated with hyperresponsiveness and flattened emotional reactions, respectively, which are typical of participants with ASD. The high number of near misses as non-veridical labels suggested that categorical processing is functional in individuals with ASD and could be explained by attention-deficit/hyperactivity disorder. These findings are discussed in terms of dysfunction of the olfactory system.


Assuntos
Transtorno do Espectro Autista/fisiopatologia , Odorantes , Condutos Olfatórios/fisiopatologia , Percepção Olfatória , Adulto , Transtorno do Espectro Autista/psicologia , Limiar Diferencial/fisiologia , Emoções/fisiologia , Feminino , Humanos , Hiperestesia/etiologia , Hiperestesia/fisiopatologia , Hiperestesia/psicologia , Hipestesia/etiologia , Hipestesia/fisiopatologia , Hipestesia/psicologia , Masculino , Percepção Olfatória/fisiologia , Prazer , Reconhecimento Psicológico/fisiologia , Limiar Sensorial , Adulto Jovem
6.
Autism Res ; 9(1): 55-66, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25962831

RESUMO

Interpreting emotional expressions appropriately poses a challenge for individuals with autism spectrum disorder (ASD). In particular, difficulties with emotional processing in ASD are more pronounced in contexts where emotional expressions are subtle, automatic, and reflexive-that is, implicit. In contrast, explicit emotional processing, which requires the cognitive evaluation of an emotional experience, appears to be relatively intact in individuals with ASD. In the present study, we examined the brain activation and functional connectivity differences underlying explicit and implicit emotional processing in age- and IQ-matched adults with (n = 17) and without (n = 15) ASD. Results indicated: (1) significantly reduced levels of brain activation in participants with ASD in medial prefrontal cortex (MPFC) and superior temporal gyrus (STG) during implicit emotion processing; (2) significantly weaker functional connectivity in the ASD group in connections of the MPFC with the amygdala, temporal lobe, parietal lobe, and fusiform gyrus; (3) No group difference in performance accuracy or reaction time; and (4) Significant positive relationship between empathizing ability and STG activity in ASD but not in typically developing participants. These findings suggest that the neural mechanisms underlying implicit, but not explicit, emotion processing may be altered at multiple levels in individuals with ASD.


Assuntos
Transtorno do Espectro Autista/fisiopatologia , Mapeamento Encefálico/métodos , Encéfalo/fisiopatologia , Emoções/fisiologia , Adolescente , Adulto , Expressão Facial , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Tempo de Reação , Reprodutibilidade dos Testes , Percepção Social , Adulto Jovem
7.
J Vis ; 15(6): 16, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26024463

RESUMO

The affective prediction hypothesis assumes that visual expectation allows fast and accurate processing of emotional stimuli. The prediction corresponds to what an object is likely to be. It therefore facilitates its identification by setting aside what the object is unlikely to be. It has then been suggested that prediction might be inevitably associated with the inhibition of irrelevant possibilities concerning the object to identify. Several studies highlighted that the facilitation of emotional perception depends on low spatial frequency (LSF) extraction. However, most of them used paradigms in which only the object to identify was present in the scene. As a consequence, there have yet been no studies investigating the efficiency of prediction in the visual perception of stimuli among irrelevant information. In this study, we designed a novel priming emotional Stroop task in which participants had to identify emotional facial expressions (EFEs) presented along with a congruent or incongruent word. To further investigate the role of early extraction of LSF information in top-down prediction during emotion recognition, the target EFE was primed with the same EFE filtered in LSF or high spatial frequency (HSF). Results reveal a reduction of the Stroop interference in the LSF compared to the HSF priming condition, which supports that visual expectation, depending on early LSF information extraction, facilitates the inhibition of irrelevant information during emotion recognition.


Assuntos
Reconhecimento Visual de Modelos/fisiologia , Desempenho Psicomotor/fisiologia , Teste de Stroop , Emoções/fisiologia , Expressão Facial , Feminino , Humanos , Masculino , Tempo de Reação/fisiologia , Percepção Visual , Adulto Jovem
8.
Front Psychol ; 5: 512, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24904514

RESUMO

Visual object recognition is of fundamental importance in our everyday interaction with the environment. Recent models of visual perception emphasize the role of top-down predictions facilitating object recognition via initial guesses that limit the number of object representations that need to be considered. Several results suggest that this rapid and efficient object processing relies on the early extraction and processing of low spatial frequencies (LSF). The present study aimed to investigate the SF content of visual object representations and its modulation by contextual and affective values of the perceived object during a picture-name verification task. Stimuli consisted of pictures of objects equalized in SF content and categorized as having low or high affective and contextual values. To access the SF content of stored visual representations of objects, SFs of each image were then randomly sampled on a trial-by-trial basis. Results reveal that intermediate SFs between 14 and 24 cycles per object (2.3-4 cycles per degree) are correlated with fast and accurate identification for all categories of objects. Moreover, there was a significant interaction between affective and contextual values over the SFs correlating with fast recognition. These results suggest that affective and contextual values of a visual object modulate the SF content of its internal representation, thus highlighting the flexibility of the visual recognition system.

9.
PLoS One ; 8(9): e73879, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24040104

RESUMO

Learning what behaviour is appropriate in a specific context by observing the actions of others and their outcomes is a key constituent of human cognition, because it saves time and energy and reduces exposure to potentially dangerous situations. Observational learning of associative rules relies on the ability to map the actions of others onto our own, process outcomes, and combine these sources of information. Here, we combined newly developed experimental tasks and functional magnetic resonance imaging (fMRI) to investigate the neural mechanisms that govern such observational learning. Results show that the neural systems involved in individual trial-and-error learning and in action observation and execution both participate in observational learning. In addition, we identified brain areas that specifically activate for others' incorrect outcomes during learning in the posterior medial frontal cortex (pMFC), the anterior insula and the posterior superior temporal sulcus (pSTS).


Assuntos
Mapeamento Encefálico , Aprendizagem/fisiologia , Imageamento por Ressonância Magnética , Adulto , Córtex Cerebral/fisiologia , Cognição/fisiologia , Feminino , Humanos , Masculino , Estimulação Luminosa , Desempenho Psicomotor , Adulto Jovem
10.
Front Hum Neurosci ; 7: 229, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23761743

RESUMO

Psychopathy is a personality disorder frequently associated with immoral behaviors. Previous behavioral studies on the influence of psychopathy on moral decision have yielded contradictory results, possibly because they focused either on judgment (abstract evaluation) or on choice of hypothetical action, two processes that may rely on different mechanisms. In this study, we explored the influence of the level of psychopathic traits on judgment and choice of hypothetical action during moral dilemma evaluation. A population of 102 students completed a questionnaire with ten moral dilemmas and nine non-moral dilemmas. The task included questions targeting both judgment ("Is it acceptable to … in order to …?") and choice of hypothetical action ("Would you … in order to …?"). The level of psychopathic traits of each participant was evaluated with the Levenson Self-Report Psychopathy (LSRP) scale. Logistic regression fitted with the generalized estimating equations method analyses were conducted using responses to the judgment and choice tasks as the dependent variables and psychopathy scores as predictor. Results show that a high level of psychopathic traits, and more specifically those related to affective deficit, predicted a greater proportion of utilitarian responses for the choice but not for the judgment question. There was no first-order interaction between the level of psychopathic traits and other potential predictors. The relation between a high level of psychopathic traits and increased utilitarianism in choice of action but not in moral judgment may explain the contradictory results of previous studies where these two processes were not contrasted. It also gives further support to the hypothesis that choice of action endorsement and abstract judgment during moral dilemma evaluation are partially distinct neural and psychological processes. We propose that this distinction should be better taken into account in the evaluation of psychopathic behaviors.

11.
Proc Natl Acad Sci U S A ; 110(28): 11577-82, 2013 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-23801762

RESUMO

The degree of correspondence between objective performance and subjective beliefs varies widely across individuals. Here we demonstrate that functional brain network connectivity measured before exposure to a perceptual decision task covaries with individual objective (type-I performance) and subjective (type-II performance) accuracy. Increases in connectivity with type-II performance were observed in networks measured while participants directed attention inward (focus on respiration), but not in networks measured during states of neutral (resting state) or exogenous attention. Measures of type-I performance were less sensitive to the subjects' specific attentional states from which the networks were derived. These results suggest the existence of functional brain networks indexing objective performance and accuracy of subjective beliefs distinctively expressed in a set of stable mental states.


Assuntos
Encéfalo/fisiologia , Humanos , Imageamento por Ressonância Magnética , Análise e Desempenho de Tarefas
12.
Front Psychol ; 4: 250, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23720645

RESUMO

Everyone has experienced the potential discrepancy between what one judges as morally acceptable and what one actually does when a choice between alternative behaviors is to be made. The present study explores empirically whether judgment and choice of action differ when people make decisions on dilemmas involving moral issues. Two hundred and forty participants evaluated 24 moral and non-moral dilemmas either by judging ("Is it acceptable to…") or reporting the choice of action they would make ("Would you do…"). We also investigated the influence of varying the number of people benefiting from the decision and the closeness of relationship of the decision maker with the potential victim on these two types of decision. Variations in the number of beneficiaries from the decision did not influence judgment nor choice of action. By contrast, closeness of relationship with the victim had a greater influence on the choice of action than on judgment. This differentiation between evaluative judgments and choices of action argues in favor of each of them being supported by (at least partially) different psychological processes.

13.
Neuropsychologia ; 50(14): 3653-62, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23044278

RESUMO

Anatomical and functional brain studies have converged to the hypothesis that autism spectrum disorders (ASD) are associated with atypical connectivity. Using a modified resting-state paradigm to drive subjects' attention, we provide evidence of a very marked interaction between ASD brain functional connectivity and cognitive state. We show that functional connectivity changes in opposite ways in ASD and typicals as attention shifts from external world towards one's body generated information. Furthermore, ASD subject alter more markedly than typicals their connectivity across cognitive states. Using differences in brain connectivity across conditions, we ranked brain regions according to their classification power. Anterior insula and dorsal-anterior cingulate cortex were the regions that better characterize ASD differences with typical subjects across conditions, and this effect was modulated by ASD severity. These results pave the path for diagnosis of mental pathologies based on functional brain networks obtained from a library of mental states.


Assuntos
Mapeamento Encefálico , Encéfalo/patologia , Transtornos Globais do Desenvolvimento Infantil/patologia , Vias Neurais/patologia , Descanso/fisiologia , Adolescente , Transtorno do Deficit de Atenção com Hiperatividade/etiologia , Transtorno do Deficit de Atenção com Hiperatividade/patologia , Encéfalo/irrigação sanguínea , Criança , Transtornos Globais do Desenvolvimento Infantil/complicações , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Vias Neurais/irrigação sanguínea , Oxigênio/sangue , Adulto Jovem
14.
Soc Cogn Affect Neurosci ; 7(3): 282-8, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21515641

RESUMO

Humans daily face social situations involving conflicts between competing moral decision. Despite a substantial amount of studies published over the past 10 years, the respective role of emotions and reason, their possible interaction, and their behavioural expression during moral evaluation remains an unresolved issue. A dualistic approach to moral evaluation proposes that the right dorsolateral prefrontal cortex (rDLPFc) controls emotional impulses. However, recent findings raise the possibility that the right DLPFc processes emotional information during moral decision making. We used repetitive transcranial magnetic stimulation (rTMS) to transiently disrupt rDLPFc activity before measuring decision making in the context of moral dilemmas. Results reveal an increase of the probability of utilitarian responses during objective evaluation of moral dilemmas in the rTMS group (compared to a SHAM one). This suggests that the right DLPFc function not only participates to a rational cognitive control process, but also integrates emotions generated by contextual information appraisal, which are decisive for response selection in moral judgements.


Assuntos
Conflito Psicológico , Lateralidade Funcional/fisiologia , Julgamento , Moral , Córtex Pré-Frontal/fisiologia , Viés , Mapeamento Encefálico , Comportamento de Escolha , Emoções , Humanos , Masculino , Estimulação Luminosa , Probabilidade , Tempo de Reação , Estimulação Magnética Transcraniana
15.
Int J Psychophysiol ; 83(2): 240-7, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21968196

RESUMO

Autism is a pervasive neurodevelopmental disorder characterized by impairment of communication and social interaction, as well as by high levels of repetitive and ritualistic behaviours. This last dimension results in major difficulties in daily life: clinical reports of individuals with Autism Spectrum Disorder (ASD) show that they present tantrums as a response to change, or restricted interests and repetitive behaviours in order to prevent or minimize change. Such a crucial need to maintain sameness suggests substantial differences in how the ASD brain predicts the environment, and this might have a fundamental role in the deficit revealed in the highly unpredictable social world. Several lines of evidence indicating difficulties in generating or using predictions in ASD due to atypical information processing will be presented in this review. For instance, several studies have revealed that people with ASD demonstrate a unique profile of cognitive abilities, with strategies that depend to an abnormally large extent on sensory systems, at the expense of more integrative processing requiring an awareness of contextual subtleties necessary for prediction. At a more elementary level, patients with autism manifest unusual processing of unpredictable events, which might be rooted in a basic difference in how the brain orients to changing, novel sensory stimuli. This review presents results from ERPs and fMRI studies illustrating the psychophysiological mechanisms and neural bases underlying such phenomena in ASD. We propose that such dysfunction in the ability to build flexible prediction in ASD may originate from impaired top-down influence over a variety of sensory and higher level information processing, a physiopathological hypothesis which dovetails with the cortical under connectivity current theory.


Assuntos
Adaptação Psicológica/fisiologia , Transtornos Globais do Desenvolvimento Infantil/fisiopatologia , Rede Nervosa/fisiopatologia , Criança , Transtornos Globais do Desenvolvimento Infantil/psicologia , Potenciais Evocados/fisiologia , Previsões , Humanos , Imageamento por Ressonância Magnética/métodos
16.
Presse Med ; 40(4 Pt 1): e181-8, 2011 Apr.
Artigo em Francês | MEDLINE | ID: mdl-21269797

RESUMO

AIM: No tools are currently available in France, for the detection of autism without mental retardation (high functioning autism and Asperger syndrome here referred as TED SDI). Use of screening tests by first-line clinicians would allow better detection of children who are likely to display such difficulties and to improve patients' care. In England, 3 questionnaires have been evaluated: Autism Spectrum Quotient (AQ), Empathy Quotient (EQ), and Systemizing Quotient (SQ). This is the translation and evaluation of 3 questionnaires in France for TED SDI and control adolescents. METHODS: The translation of the questionnaires into French required two simultaneous translations, two back-translations and two consensus meetings. This is a cross-sectional study comparing scores obtained with the three AQ, EQ and SQ questionnaires. These questionnaires were completed by the parents of four groups of adolescents 11-18 years: 100 TED SDI adolescents (50 with IQ ≥ 85 and 50 with 70≤IQ<85), 50 adolescents with another psychiatric disorder (TP) and 200 control adolescents (T). RESULTS: 580 questionnaires have been sent to 40 recruiting centres. By the 28th of February, 2010, 277 completed questionnaires were received completed (TED SDI: 70 (70%); TP: 25 (50%) et T: 182 (91%)). In the control group, 92 girls (mean 14.4±1.7 years) and 66 boys (14.5±1.7 years) were recruited. In the TED SDI group, 4 girls (14.3±2.4 years) and 42 boys (14.5±1.7 years) were recruited. One girl (81) and 6 boys (72.2±7.7) have an IQ between 70 and 85, and 3 girls (95.3±4.2) and 36 boys (102.9±12) have an IQ higher than 85. In the TP group, 9 girls (15.9±1.7 years) and 4 boys (15.8±1.9 years) were recruited. CONCLUSION: The aim of this study is to make the AQ, EQ and SQ questionnaires available in French for French speaking clinicians. This study will allow a rigorous evaluation of the usefulness of the AQ questionnaire in the screening of TED SDI in adolescents.


Assuntos
Síndrome de Asperger/diagnóstico , Síndrome de Asperger/epidemiologia , Transtorno Autístico/diagnóstico , Transtorno Autístico/epidemiologia , Comparação Transcultural , Empatia , Inteligência , Programas de Rastreamento/estatística & dados numéricos , Determinação da Personalidade/estatística & dados numéricos , Inquéritos e Questionários , Adolescente , Criança , Estudos Transversais , Feminino , França , Humanos , Masculino , Transtornos Mentais/diagnóstico , Transtornos Mentais/epidemiologia , Transtornos Mentais/psicologia , Valores de Referência , Reprodutibilidade dos Testes , Tradução
17.
Neuropsychologia ; 49(2): 254-63, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21110988

RESUMO

Over the last years, increasing evidence has fuelled the hypothesis that Autism Spectrum Disorder (ASD) is a condition of altered brain functional connectivity. The great majority of these empirical studies relies on functional magnetic resonance imaging (fMRI) which has a relatively poor temporal resolution. Only a handful of studies has examined networks emerging from dynamic coherence at the millisecond resolution and there are no investigations of coherence at the lowest frequencies in the power spectrum-which has recently been shown to reflect long-range cortico-cortical connections. Here we used electroencephalography (EEG) to assess dynamic brain connectivity in ASD focusing in the low-frequency (delta) range. We found that connectivity patterns were distinct in ASD and control populations and reflected a double dissociation: ASD subjects lacked long-range connections, with a most prominent deficit in fronto-occipital connections. Conversely, individuals with ASD showed increased short-range connections in lateral-frontal electrodes. This effect between categories showed a consistent parametric dependency: as ASD severity increased, short-range coherence was more pronounced and long-range coherence decreased. Theoretical arguments have been proposed arguing that distinct patterns of connectivity may result in networks with different efficiency in transmission of information. We show that the networks in ASD subjects have less Clustering coefficient, greater Characteristic Path Length than controls - indicating that the topology of the network departs from small-world behaviour - and greater modularity. Together these results show that delta-band coherence reveal qualitative and quantitative aspects associated with ASD pathology.


Assuntos
Síndrome de Asperger/patologia , Transtorno Autístico/patologia , Mapeamento Encefálico , Córtex Cerebral/fisiopatologia , Ritmo Delta/fisiologia , Vias Neurais/fisiopatologia , Adolescente , Adulto , Síndrome de Asperger/fisiopatologia , Transtorno Autístico/fisiopatologia , Córtex Cerebral/patologia , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Rede Nervosa/patologia , Rede Nervosa/fisiopatologia , Adulto Jovem
18.
Soc Cogn Affect Neurosci ; 3(2): 135-43, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19015104

RESUMO

Several recent studies suggest that autism may result from abnormal communication between brain regions. We directly assessed this hypothesis by testing the presence of abnormalities in a model of the functional cerebral network engaged during explicit emotion processing in adults with high functioning autism or Asperger syndrome. Comparison of structural equation models revealed abnormal patterns of effective connectivity, with the prefrontal cortex as a key site of dysfunction. These findings provide evidence that abnormal long-range connectivity between structures of the 'social brain' could explain the socio-emotional troubles that characterize the autistic pathology.


Assuntos
Transtorno Autístico/fisiopatologia , Emoções/fisiologia , Vias Neurais/fisiologia , Córtex Pré-Frontal/fisiologia , Percepção Social , Adulto , Estudos de Casos e Controles , Expressão Facial , Feminino , Fixação Ocular/fisiologia , Humanos , Relações Interpessoais , Masculino , Modelos Neurológicos , Reconhecimento Psicológico/fisiologia , Valores de Referência , Comportamento Social , Adulto Jovem
19.
Can J Psychiatry ; 53(7): 469-77, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18674405

RESUMO

OBJECTIVE: The Empathy Quotient (EQ) is a self-report that was developed to measure the cognitive and affective aspects of empathy. We further evaluated its validity in 2 studies. METHOD: The psychometric qualities of the French version of the EQ, and its correspondence with 2 other measures of empathy (Interpersonal Reactivity Index and the Empathy Scale of the Impulsiveness-Venturesomeness-Empathy Questionnaire), and with dimensions of the emotional state (depression and anxiety), were evaluated in a sample of 410 students (201 men and 209 women). Second, the clinical validity of the EQ was investigated in participants expected to have dysfunctional empathy. For this purpose, EQ scores of 16 people with autistic spectrum disorder (ASD) were collected. RESULTS: The EQ showed satisfying internal, convergent, test-retest and discriminant validity. The confirmatory factorial analyses suggested a 3-factor structure offered a good fit to the data. The women's superiority in empathy was replicated. As expected, the ASD EQ scores were very low. CONCLUSION: This study provides further evidence that the EQ is reliable in this population and should be recommended to estimate empathy problems, notably in individuals with troubled interpersonal interaction patterns.


Assuntos
Empatia , Idioma , Adulto , Canadá , Comparação Transcultural , Análise Fatorial , Feminino , França , Humanos , Masculino , Reprodutibilidade dos Testes
20.
Neuroimage ; 42(3): 1207-13, 2008 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-18588987

RESUMO

Observational learning allows individuals to acquire knowledge without incurring in the costs and risks of discovering and testing. The neural mechanisms mediating the retrieval of rules learned by observation are currently unknown. To explore this fundamental cognitive ability, we compared the brain responses when retrieving visuomotor associations learned either by observation or by individual learning. To do so, we asked eleven adults to learn two sets of arbitrary visuomotor associations: one set was learned through the observation of an expert actor while the other was learned by trial and error. During fMRI scanning, subjects were requested to retrieve the visuomotor associations previously learned under the two modalities. The conjunction analysis between the two learning conditions revealed a common brain network that included the ventral and dorsal lateral prefrontal cortices, the superior parietal lobe and the pre-SMA. This suggests the existence of a mirror-like system responsible for the storage of rules learned either by trial and error or by observation of others' actions. In addition, the pars triangularis in the right prefrontal cortex (BA45) was found to be selective for rules learned by observation. This suggests a preferential role of this area in the storage of rules learned in a social context.


Assuntos
Mapeamento Encefálico , Encéfalo/fisiologia , Aprendizagem/fisiologia , Adulto , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Estimulação Luminosa , Desempenho Psicomotor/fisiologia
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