The broad goal of this project is to examine the brain circuitry underling emotion in autistic and comparison subjects. In response to previous reviews, we now restrict data collect to the Wisconsin site. All studies will involve functional magnetic resonance imaging (fMRI) during tasks designed to probe different aspects of affective function. In addition, all studies will also use eye tracking in the scanner to ascertain precisely where subjects are fixating during stimulus presentation since some of the extant neuroimaging data in autistic subjects are assumed to be a function of the fact that autistic subjects are exhibiting gaze aversion and not foveating the stimuli to the same degree as controls. Since the last submission, we have collected pilot data on 8 participants with autism and 10 controls illustrating our capability for measuring gaze patterns in the scanner, recording electrodermal activity in the scanner and successfully collecting fMRI data. In each of the proposed studies, analyses will be conducted on all trials, as well as restricted to only those trials during which subjects are fixating on the stimuli. Aim 1 is to test the hypothesis that when fixating on social stimuli (e.g., faces) autistic subjects will show increased activation in the amygdala and increased electrodermal activity. Aim 2 will test the hypothesis that autistic subjects will show more fixation to non-social positive stimuli while controls will show more fixation to social positive stimuli. In circuitry associated with positive affective responding such as the ventral striatum, we predict that autistic subjects will show the greatest activation in response to ideographic non-social stimuli while controls will show the greatest activation to ideographic social stimuli. We predict that autistic subjects will show greater activation in the amygdala and other regions associated with negative affect in response to social vs non-social stimuli while controls will not show amygdala activation in this contrast. Aim 3 will use a task that involves the presentation of congruent and incongruent faces and voices. We predict that autistic subjects will show less activation in the anterior cingulate cortex in response to the incongruent conditions compared with the congruent conditions relative to controls. We will also test a sample of children with social phobia to use a second comparison group to ascertain the extent to which the deficits observed for autistic subjects are specific to this population.