The purpose of this research continues to be to link variability in the phenotypic expression of specific patterns of a abnormally brain function in individuals with Williams Syndrome (WMS) to variability in brain structure and neurocognitive and genetic profiles as determined in the other projects of this program project. Previously we identified electrophysiological markers of abnormal brain function linked to the processing of faces and abnormal auditory language and sensory processing typical of individuals with WMS. We have begin to develop templates for each of these markers to characterize the variability in the patterns of brain activity across normal controls and individuals with WMS. In the proposed studies we will employ these templates along with modified diagnostic versions of the previous paradigms to assess the extent to which an individual with WMS fits the typical WMS pattern or may fall closer to the normal range. Variability in the expression of the phenotypic markers of brain function linked to specific cognitive functions will in turn be compared with concomitant variability in the genetic structural and neurocognitive profiles. Additionally, we have developed new paradigms to study brain function linked to differential activation of the dorsal and ventral visual streams perception and recognition of facial expressions, and language about spatial relations. We will record event-related potentials during these tasks using a high density array of 64 channels to increase the spatial distribution of our results. Behavioral and ERP data from these experiments will be compared with behavioral measures from standardized tests of language and cognitive capabilities. Variability in will also be compared with that individual's measurement of brain structure for the specific areas of the brain known to mediate that function, e.g. variability in the latency amplitude in the latency amplitude and distribution of ERPs linked to differential activation of the dorsal versus ventral visual streams will be compared with measurements of brain regions known to mediate dorsal versus ventral visual processing (in conjunction with subproject 0003), ERP indices of perception and recognition of facial expression will be compared with measures of the amygdala, which have been found to be abnormal in individuals with WMS. Moreover variability in the ERP patterns which have been found to be abnormal in individuals with WMS. Moreover variability in the ERP patterns elicited in the new studies and diagnostic paradigms described above will be compared with the presence or absence of specific genetic abnormalities typically observed in these individuals (in conjunction with subproject 0005).