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Inhibition of Superior Temporal Sulcus Activity by Repetitive Transcranial Magnetic Stimulation: The Effects On Social Perception and Implications for Autism

Thursday, 2 May 2013: 09:00-13:00
Banquet Hall (Kursaal Centre)
A. Saitovitch1, T. Popa2, D. Grévent3, R. Calmon4, S. Meunier2, N. Chabane5, F. Brunelle1, Y. Samson6, N. Boddaert1 and M. Zilbovicius1, (1)INSERM Unity 1000, Necker Hospital, Paris, France, (2)University Pierre et Marie Curie, ICM - Pitié-Salpêtrière Hospital, Paris, France, (3)Inserm Research Unit 1000; Necker Hospital, Paris, France, (4)Inserm Research Unit 1000 “Neuroimaging and Psychiatry”, Paris, France, (5)INSERM Unity 1000, Robert Debre Hospital, Paris, France, (6)Pitié-Salpêtrière Hospital, Paris, France
Background:  The superior temporal sulcus (STS) is known to be implicated in social perception and social cognition processes. Previous brain imaging studies have suggested that abnormalities within the STS would be related to social impairments in autism. Anatomo-functional abnormalities of the STS occurring very early in brain development could be one of the first steps in the cascade of neuronal dysfunction in autism.

Objectives: We aimed to study the effects of controlled and non-invasive STS inhibition with rTMS (repetitive Transcranial Magnetic Stimulation) on social perception parameters in healthy young subjects.

Methods: Fifteen healthy subjects (mean age = 22,0 ± 2,5) were recruited for the study. All subjects underwent a structural MRI for a precise localization of the stimulation target for each individual. Subjects underwent both sham stimulation and inhibitory rTMS delivered over the right posterior STS (mean Talairach coordinates: 50  -53  15). Gaze parameters were measured with a Tobii-120 eye-tracker during passive visualization of social movies before and after each stimulation session. The eyes of the characters in each movie were selected as areas of interest to be analyzed. Eye-tracking data was processed with Tobii Studio® software. Data was submitted to a repeated ANOVA with corrections for multiple comparisons, with fixations to the eye-areas before and at several time-points after each stimulation as the repeated factor, and stimulation type as the between group factor.  

Results: Repeated ANOVA showed a significant stimulation effect of the stimulation type on social perception parameter (F (1, 14) = 9,48; p = 0,008). Post-hoc analysis showed a significant reduction of fixations to eyes-areas after rTMS, but not after Sham.

Conclusions: The results of our study show that STS activity can be modulated by a non-invasive painless procedure, such as rTMS, with significant behavioral effects on social perception. These results open up new perspectives on therapeutic strategies in autism.

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