Attention does not modulate neural responses to social stimuli in autism spectrum disorders

We investigated whether individuals with autism spectrum disorders (ASD) would show attentional modulation for social (face) and non-social (house) stimuli. Sixteen individuals with ASD and 16 matched control participants completed a task in which pairs of face and house stimuli were present on every trial, with one of the pairs randomly assigned to attended locations and the other to unattended locations. Both mass-univariate (SPM) and region of interest analyses suggested that responses to houses were modulated by attention in both groups, but that only the control participants demonstrated attentional modulation of face-selective regions. Thus, the participants with ASD demonstrated a lack of attentional modulation which was particularly evident for the social stimulus. Analyses of effective connectivity indicated that these results were due to a failure of attention to modulate connectivity between extrastriate areas and V1. We discuss bow these results may suggest a mechanism to explain the reduced salience of social stimuli in ASD. (c) 2006 Elsevier Inc. All rights reserved.