Poster A113, Saturday, March 25, 5:00 – 7:00 pm, Pacific Concourse
Atypical laterality in visual sensory activation and interhemispheric transfer in Autism Spectrum Disorders
Yukari Takarae1, Won Suk Song1, Clifford Saron2; 1Center for Autism and Developmental Disabilities, UT Southwestern, 2Center for Mind and Brain and M.I.N.D. Institute, UC Davis
Cerebral lateralization is a fundamental characteristic of human brain organization, and it is believed that such lateralization ensures the most efficient transcortical integration of information. Autism Spectrum Disorders (ASD) is known for 1) disturbances in normal lateralization and 2) reduced effective connectivity. While the former has been demonstrated as reduced lateralization in language and motor function, the current study adds evidence for abnormal lateral organization in visual processes. We performed 124 channel EEG recordings to examine laterality of sensory function during visuomotor tasks. The participants were 12 to 18 year old children; 18 with ASD and 17 with typical development (TD). Participants performed, in alternating blocks, an antisaccade (ANTI) task that required looking away from a suddenly appearing lateral target, or a prosaccade (PRO) task that required looking toward the target. Occipitoparietal activation was first observed on the contralateral hemisphere, starting approximately at 100 ms after target onset. This was followed by interhemispheric transfer of activation to the ipsilateral side, resembling patterns observed for lateral P1 responses in studies of TD adults. While TD participants showed similar amplitude of activation with both target locations, ASD participants showed greater initial contralateral activation to the left than to the right lateral target. Furthermore, amplitude of the subsequent ipsilateral activation was much reduced in ASD participants, but this was specific to the left target condition. These findings suggest deviations from the typical functional organization in visual processes in ASD, including possible left hemisphere dysfunction and additional connectivity disturbances via the corpus callosum.
Topic Area: PERCEPTION & ACTION: Vision