Date of Award

Summer 2002

Document Type

Thesis

Degree Name

Master of Science in Biomedical Engineering - (M.S.)

Department

Biomedical Engineering Committee

First Advisor

Stanley S. Reisman

Second Advisor

Benjamin Martin Bly

Third Advisor

Tara L. Alvarez

Abstract

Autism is a neurodevelopmental disorder that is defined by deficits in social and emotional impairments and this study aims to identify specific brain regions involved during facial processing. The simple task of focusing on the face during social interactions for the normal group is found difficult by the autistic group.

In this study, functional magnetic resonance imaging (fMRI) was used as subjects performed two experimental tasks (EXPLICIT and IMPLICIT) in which a series of photographs of nine males and nine females displaying three affective states (6 fear, 6 happy and 6 neutral) and six scrambled- face control stimuli were presented to the subjects. Subjects were required to attend to and recognize the emotional content of the face (explicit task) or recognize the gender of the face (implicit task).

The autistic as well as the control group showed activation in the temporal lobe (middle and superior temporal gyrus) during explicit processing of facial expressions. Implicit processing of faces found that the autistic group showed significantly more activation in the left middle temporal gyrus, bilateral superior temporal gyrus than the control group.

The differences in face processing between the normal and autistic group probably arise out of the fact that autistic individuals have reduced social interest and do not regard the face as socially important.

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