Atypical visio-temporal processing in Schizophrenia and Autism Spectrum Disorders revealed by the continuous Wagon Wheel Illusion
43.424, Monday, May 13, 8:30 am - 12:30 pm, Orchid Ballroom
Jasin Wong1, Ya-Ping Chen1, Susan Shur-Fen Gau2, Yi-Ling Chien2, Rufin VanRullen3,4, Chien-Te Wu1,2; 1School of Occupational Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan, 2Department of Psychiatry, National Taiwan University Hospital & College of Medicine, Taipei, Taiwan, 3Université de Toulouse, Centre de Recherche Cerveau et Cognition, Université Paul Sabatier, Toulouse, France, 4CNRS, UMR 5549, Faculté de Médecine de Purpan, Toulouse, France
Mental disorders such as schizophrenia and autism spectrum disorders (ASD) are mainly characterized by psychosocial dysfunction, but atypical perception is one of their additional common features that can provide important insight into the underlying psychopathological mechanisms. The observed abnormality of temporal processing in these patient populations has been proposed to reflect altered patterns of neuronal oscillatory synchrony. Here, we use the continuous version of the Wagon Wheel Illusion (c-WWI, in which observers report illusory reversals of a continuous, periodically moving stimulus, possibly caused by an oscillatory motion sampling mechanism), as a non-invasive behavioral approach to explore psychopathological changes in perception-related oscillatory synchrony patterns. Thus far, we have collected data from 4 groups: schizophrenia (n = 11), schizophrenia controls (n = 11), ASDs (n = 6), and ASD-controls (n = 6). Each participant watched computer-generated wheels (12 cycles of a sinusoidally modulated luminance pattern, 100% contrast) continuously rotating clockwise (or counter-clockwise) for 60 sec at the center of a CRT monitor (144 Hz refresh rate to minimize temporal framing artifacts); they continuously reported the perceived rotation direction. The c-WWI magnitude was measured as the relative duration of illusory motion perception. Temporal rotation frequencies were pseudorandomly selected from 2, 7, 10, 13, 16, 19, 21 Hz (4 trials each), and the actual rotation direction was randomized across trials. A 2-way ANOVA with factors "frequencies" and "group" (patients vs. controls) revealed a marginal interaction effect for the schizophrenia group (F7,140 = 1.82, p = .17; c-WWI peaked at higher temporal frequencies in patients) and a significant interaction effect for the autism group (F7,70 = 3.7, p <.05; c-WWI peaked at lower temporal frequencies in patients). Our preliminary results suggest that the c-WWI could be a powerful tool to non-invasively probe the relationship between temporal processing and neuronal oscillations in mental disorders.