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Abstract:
Abstract: Functional neuroimaging studies have consistently
shown activation in occipito-temporal cortex, in particular the
fusiform gyrus, during face viewing. Given the severe social
deficits in autism, an important question is whether
neurofunctional processing in response to faces is abnormal as
well. Six male autistic (age 21-43) and eight gender, age, and
handedness matched normal controls participated in an fMRI
experiment examining hemodynamic responses during a face perception
(i.e., button press to female faces) in comparison to a sensory
control task (i.e., button press to computer morphed circular shape
constructed from, and matched in grayscale and mean luminance to,
face images) in a block design. Regions of interest (ROIs;
fusiform, inferior temporal, and middle temporal gyri) were traced
in native space on high-resolution structural MRIs in each subject.
After motion correction, images were analyzed using a correlation
approach (Bandettini, 1993). Regional activation was computed as
the percentage of significantly activated voxels within an ROI
(p<.05; corrected for number of voxels across all ROIs). As
expected, all normal control subjects showed significant activation
in the fusiform gyrus. Regional activations in the fusiform and
inferior temporal gyri for the autism group were significantly
reduced. These data provide support for the notion that the
behavioral deficits in face processing, and likely social
processing, in autism are accompanied by abnormalities in
neurofunctional organization.
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