19 research outputs found
Pupil dilation reflects the dynamic integration of audiovisual emotional speech
Emotional speech perception is a multisensory process. When speaking with an individual we concurrently integrate the information from their voice and face to decode e.g., their feelings, moods, and emotions. However, the physiological reactionsâsuch as the reflexive dilation of the pupilâassociated to these processes remain mostly unknown. That is the aim of the current article, to investigate whether pupillary reactions can index the processes underlying the audiovisual integration of emotional signals. To investigate this question, we used an algorithm able to increase or decrease the smiles seen in a personâs face or heard in their voice, while preserving the temporal synchrony between visual and auditory channels. Using this algorithm, we created congruent and incongruent audiovisual smiles, and investigated participantsâ gaze and pupillary reactions to manipulated stimuli. We found that pupil reactions can reflect emotional information mismatch in audiovisual speech. In our data, when participants were explicitly asked to extract emotional information from stimuli, the first fixation within emotionally mismatching areas (i.e., the mouth) triggered pupil dilation. These results reveal that pupil dilation can reflect the dynamic integration of audiovisual emotional speech and provide insights on how these reactions are triggered during stimulus perception
Autisme, sillon temporal supérieur (STS) et perception sociale : études en imagerie cérébrale et en TMS
Autism is a pervasive developmental disorder associated with alterations of neural circuits. Neuroimaging studies in autism have revealed anatomo-fonctional abnormalities, particularly located within the superior temporal sulcus (STS). In normal subjects, STS is largely implicated in social perception and social cognition. Deficits in social cognition and particularly in social perception are the core symptoms of autism. Indeed, abnormalities of social perception have been described in adults and children with autism. These abnormalities are characterized by a lack of preference for the eyes. In this thesis, we have shown that it is possible to modulate neural activity within the right STS using a transcranial magnetic stimulation (TMS) protocol, with significant effects on social perception parameters, measured by eye-tracking during passive visualization of social scenes. Furthermore, social perception parameters were correlated with rest cerebral blood flow (CBF), measured with arterial spin labelling (ASL) MRI. We have shown that the healthy young volunteers who looked more to the eyes during passive visualization of social scenes were those who had higher rest CBF values within right temporal regions. In addition, this correlation was also observed in children with autism: children who looked more to the eyes during passive visualization of social scenes were those who had higher rest CBF values within right temporal regions. Finally, preliminary results concerning application of the TMS protocol in adults with autism open up new perspectives on innovate therapeutically strategies.Les troubles du spectre autistique sont vraisemblablement liĂ©s Ă des altĂ©rations des circuits neuronaux au cours du dĂ©veloppement. Des Ă©tudes en imagerie cĂ©rĂ©brale ont mis en Ă©vidence des anomalies anatomo-fonctionnelles localisĂ©es notamment au niveau du sillon temporal supĂ©rieur (STS) dans lâautisme. Chez le sujet sain, le STS est impliquĂ© dans la perception et la cognition sociale, dont les dysfonctionnements sont au coeur des symptĂŽmes autistiques. En effet, des anomalies de la perception sociale, notamment un manque de prĂ©fĂ©rence par les yeux, ont Ă©tĂ© mises en Ă©vidence dans lâautisme. Dans cette thĂšse nous avons montrĂ© quâil est possible de moduler lâactivitĂ© neuronale du STS droit Ă lâaide de la stimulation magnĂ©tique transcranienne (TMS) avec un impact significatif sur la perception sociale, mesurĂ©e par lâeye-tracking. En effet, suite Ă une inhibition du STS, des jeunes volontaires sains regardent moins les yeux des personnages dans les scĂšnes sociales. Par ailleurs, cette perception sociale a Ă©tĂ© corrĂ©lĂ©e au dĂ©bit sanguin cĂ©rĂ©bral (DSC) au repos, mesurĂ© en IRM avec la sĂ©quence arterial spin labelling. Ainsi, les volontaires sains qui regardaient le plus les yeux des personnages Ă©taient ceux chez qui le DSC au repos Ă©tait plus Ă©levĂ© au niveau des rĂ©gions temporales droites. De plus, cette corrĂ©lation a Ă©tĂ© Ă©galement observĂ©e chez des enfants avec autisme: les enfants qui regardaient le plus les yeux des personnages Ă©taient ceux chez qui le DSC au repos Ă©tait plus important au niveau des rĂ©gions temporales droites. Enfin, les rĂ©sultats prĂ©liminaires concernant lâapplication de la TMS chez des adultes avec autisme ouvrent des nouvelles perspectives thĂ©rapeutiques
Autism, superior temporal sulcus (STS) and social perception : brain imaging and TMS studies
Les troubles du spectre autistique sont vraisemblablement liĂ©s Ă des altĂ©rations des circuits neuronaux au cours du dĂ©veloppement. Des Ă©tudes en imagerie cĂ©rĂ©brale ont mis en Ă©vidence des anomalies anatomo-fonctionnelles localisĂ©es notamment au niveau du sillon temporal supĂ©rieur (STS) dans lâautisme. Chez le sujet sain, le STS est impliquĂ© dans la perception et la cognition sociale, dont les dysfonctionnements sont au coeur des symptĂŽmes autistiques. En effet, des anomalies de la perception sociale, notamment un manque de prĂ©fĂ©rence par les yeux, ont Ă©tĂ© mises en Ă©vidence dans lâautisme. Dans cette thĂšse nous avons montrĂ© quâil est possible de moduler lâactivitĂ© neuronale du STS droit Ă lâaide de la stimulation magnĂ©tique transcranienne (TMS) avec un impact significatif sur la perception sociale, mesurĂ©e par lâeye-tracking. En effet, suite Ă une inhibition du STS, des jeunes volontaires sains regardent moins les yeux des personnages dans les scĂšnes sociales. Par ailleurs, cette perception sociale a Ă©tĂ© corrĂ©lĂ©e au dĂ©bit sanguin cĂ©rĂ©bral (DSC) au repos, mesurĂ© en IRM avec la sĂ©quence arterial spin labelling. Ainsi, les volontaires sains qui regardaient le plus les yeux des personnages Ă©taient ceux chez qui le DSC au repos Ă©tait plus Ă©levĂ© au niveau des rĂ©gions temporales droites. De plus, cette corrĂ©lation a Ă©tĂ© Ă©galement observĂ©e chez des enfants avec autisme: les enfants qui regardaient le plus les yeux des personnages Ă©taient ceux chez qui le DSC au repos Ă©tait plus important au niveau des rĂ©gions temporales droites. Enfin, les rĂ©sultats prĂ©liminaires concernant lâapplication de la TMS chez des adultes avec autisme ouvrent des nouvelles perspectives thĂ©rapeutiques.Autism is a pervasive developmental disorder associated with alterations of neural circuits. Neuroimaging studies in autism have revealed anatomo-fonctional abnormalities, particularly located within the superior temporal sulcus (STS). In normal subjects, STS is largely implicated in social perception and social cognition. Deficits in social cognition and particularly in social perception are the core symptoms of autism. Indeed, abnormalities of social perception have been described in adults and children with autism. These abnormalities are characterized by a lack of preference for the eyes. In this thesis, we have shown that it is possible to modulate neural activity within the right STS using a transcranial magnetic stimulation (TMS) protocol, with significant effects on social perception parameters, measured by eye-tracking during passive visualization of social scenes. Furthermore, social perception parameters were correlated with rest cerebral blood flow (CBF), measured with arterial spin labelling (ASL) MRI. We have shown that the healthy young volunteers who looked more to the eyes during passive visualization of social scenes were those who had higher rest CBF values within right temporal regions. In addition, this correlation was also observed in children with autism: children who looked more to the eyes during passive visualization of social scenes were those who had higher rest CBF values within right temporal regions. Finally, preliminary results concerning application of the TMS protocol in adults with autism open up new perspectives on innovate therapeutically strategies
Central Nervous System Complications in Cystinosis: The Role of Neuroimaging
Despite improvement in the specific treatment, clinical and anatomo-functional central nervous system (CNS) abnormalities of various severities are still observed in cystinosis patients. Patients who develop CNS complications today have a worse compliance to cysteamine treatment. Radiological studies have shown that cortical or central (ventriculomegaly) atrophy is observed in more than two thirds of cystinosis patients’ magnetic resonance imaging (MRI) and correlates with the intelligence quotient score. Half of cystinosis patients have marked aspecific white matter hyperintensities. The development of advanced neuroimaging techniques provides new tools to further investigate CNS complications. A recent neuroimaging study using a voxel-based morphometry approach showed that cystinosis patients present a decreased grey matter volume in the left middle frontal gyrus. Diffusion tensor imaging studies have shown white matter microstructure abnormalities in children and adults with cystinosis, respectively in areas of the dorsal visual pathway and within the corpus callosum’s body. Finally, leucocyte cystine levels are associated with decreased resting cerebral blood flow, measured by arterial spin labelling, in the frontal cortex, which could be associated with the neurocognitive deficits described in these patients. These results reinforce the relevance of neuroimaging studies to further understand the mechanisms that underline CNS impairments
Neural basis of interindividual variability in social perception in typically developing children and adolescents using diffusion tensor imaging
International audienceHumans show great interindividual variability in the degree they engage in social relationship. The neural basis of this variability is still poorly understood, particularly in children. In this study, we aimed to investigate the neural basis of interindividual variability in the first step of social behavior, that is social perception, in typically developing children. For that purpose, we first used eye-tracking to objectively measure eye-gaze processing during passive visualization of social movie clips in 24 children and adolescents (10.5â±â2.9ây). Secondly, we correlated eye-tracking data with measures of fractional anisotropy, an index of white matter microstructure, obtained using diffusion tensor imaging MRI. The results showed a large interindividual variability in the number of fixations to the eyes of characters during visualization of social scenes. In addition, whole-brain analysis showed a significant positive correlation between FA and number of fixations to the eyes,mainly in the temporal part of the superior longitudinal fasciculi bilaterally, adjacent to the posterior superior temporal cortex. Our results indicate the existence of a neural signature associated with the interindividual variability in social perception in children, contributing for better understanding the neural basis of typical and atypical development of a broader social expertise
Therapeutic drug monitoring of tacrolimus in pancreas transplantation at SĂŁo Lucas Hospital Monitoramento terapĂȘutico de tacrolimus em transplante de pĂąncreas no Hospital SĂŁo Lucas
Tacrolimus (FK 506), a potent immunosuppressive drug used in prevention and treatment of rejection of transplanted organs, exhibits efficacy related to its blood levels and has a narrow therapeutic index. These factors require frequent monitoring of patients blood levels, in attempt to adjust the dose to reach the best drug concentration with minimum side effects. In this historic study, the authors evaluated tacrolimus blood profile in patients submitted to pancreas transplantation between June 2002 and March 2004. The results show that blood levels were, mostly, within subtherapeutic (39.1%) and toxic (43.4%) ranges. Considering post-transplantation period, subtherapeutic levels were more frequent until three months after the graft receiving (51.1%) and between three and six months (41.9%), whereas toxic levels were more common six months after the transplantation (63%). Patients who received pancreas/kidney transplantation showed a tendency to present toxic levels. The same did not happen with the patients who received isolated pancreas and pancreas after kidney; these patients presented subtherapeutic blood levels in all post-transplantation periods. The results found in this study reassure the importance of therapeutic monitoring to achieve the adequate blood levels of tacrolimus following pancreas transplantation.<br>O tacrolimus (FK506), um potente imunossupressor utilizado na profilaxia e no tratamento de rejeiçÔes pĂłs-transplante, exibe eficĂĄcia relacionada com sua concentração sangĂŒĂnea e possui estreita janela terapĂȘutica. Esses fatores requerem o freqĂŒente monitoramento dos nĂveis sangĂŒĂneos em pacientes que fazem uso do fĂĄrmaco, tendo como objetivo o ajuste de dose para uma concentração terapĂȘutica Ăłtima com efeitos colaterais mĂnimos. Este estudo retrospectivo foi realizado atravĂ©s do acesso Ă base de dados do LaboratĂłrio de Patologia ClĂnica do Hospital SĂŁo Lucas, da PontifĂcia Universidade CatĂłlica do Rio Grande do Sul (PUCRS), e teve por objetivo analisar o perfil das concentraçÔes sanguĂneas de tacrolimus em pacientes transplantados de pĂąncreas, no perĂodo de junho de 2002 a março de 2004. Os resultados mostram que as concentraçÔes se encontravam, em sua maioria, em nĂveis subterapĂȘuticos (39,1%) e tĂłxicos (43,4%). Considerando-se o perĂodo pĂłs-transplante, nĂveis subterapĂȘuticos foram mais freqĂŒentes nos perĂodos de zero a trĂȘs meses (51,1%) e de trĂȘs a seis meses (41,9%) apĂłs o transplante, enquanto nĂveis tĂłxicos (63%) foram mais freqĂŒentes apĂłs seis meses. Pacientes que receberam pĂąncreas/rim simultĂąneo apresentaram, de maneira geral, mais concentraçÔes em nĂveis tĂłxicos; o mesmo nĂŁo aconteceu em pacientes que receberam pĂąncreas isolado e pĂąncreas pĂłs-rim. Os pacientes que receberam pĂąncreas isolado e pĂąncreas pĂłs-rim tenderam a apresentar nĂveis subterapĂȘuticos em todos os perĂodos pĂłs-transplante considerados. Os resultados obtidos neste trabalho demonstram a importĂąncia do monitoramento terapĂȘutico, uma vez que seus resultados orientam o ajuste das doses
2.20 RESTING-STATE CEREBRAL BLOOD FLOW IN THE SUPERIOR TEMPORAL SULCUS CORRELATES WITH SOCIAL PERCEPTION IMPAIRMENTS IN CHILDREN WITH AUTISM SPECTRUM DISORDER
Tuning Eye-Gaze Perception by Transitory STS Inhibition
International audienceProcessing eye-gaze information is a key step to human social interaction. Neuroimaging studies have shown that superior temporal sulcus (STS) is highly implicated in eye-gaze perception. In autism, a lack of preference for the eyes, as well as anatomo-functional abnormalities within the STS, has been described. To date, there are no experimental data in humans showing whether it is possible to interfere with eye-gaze processing by modulating STS neural activity. Here, we measured eye-gaze perception before and after inhibitory transcranial magnetic stimulation (TMS) applied over the posterior STS (pSTS) in young healthy volunteers. Eye-gaze processing, namely overt orienting toward the eyes, was measured using eye tracking during passive visualization of social movies. Inhibition of the right pSTS led participants to look less to the eyes of characters during visualization of social movies. Such effect was specific for the eyes and was not observed after inhibition of the left pSTS nor after placebo TMS. These results indicate for the first time that interfering with the right pSTS neural activity transitorily disrupts the behavior of orienting toward the eyes and thus indirectly gaze perception, a fundamental process for human social cognition. These results could open up new perspectives in therapeutic interventions in autism