Neural Correlates for Anticipating and Observing Goal-Directed Actions in Autism

We investigated possible atypicalities in activation of cortical motor-related circuits in young adults with Autism Spectrum Conditions (ASC) and typical-development (TD) when observing others' actions. Activation of these circuits is reflected by suppression of power in EEG-Mu oscillations (8-13 Hz). Despite strong indications for functional distinctions between the upper (10.5-13 Hz) and lower (8-10.5 Hz) Mu-subbands, their separation remained unchartered territory in ASC research. Recordings were made from central, sensorimotor and occipital areas, while goal-directed actions that varied in the extent of both social interaction and biological motion were presented in video-clips. Anticipatory Mu suppression in response to upcoming actions was found exclusively at the sensorimotor site, in both groups. That is, during the presentation of a color signal embedded in the videos, which indicated whether or not an action would ensue, significantly more Mu-suppression occurred when the signal indicated an upcoming action. No such anticipatory activity occurred at central and occipital sites. During action observation, both groups showed significantly larger Mu suppressions in (i) the lower compared to the upper Mu band, and at (ii) sensorimotor compared to occipital and central sites. Extent of social interaction and biological motion of the actions did not significantly affect responses in either group. The groups did not differ significantly from each other in either band, condition or hemisphere. At the sensorimotor site, there was an overall tendency-though no significant evidence-for less desynchronisation to observed actions, and for more synchronization to no-action events (still image), in ASC compared to TD.