Perturbations in the fundamental brain processes that underlie eye movement may be linked to the psychological and neural abnormalities seen in individuals with autism spectrum disorders. To test this hypothesis, researchers must be able to characterize eye movements of participants during behavioral tasks and in functional magnetic resonance imaging (fMRI) studies.
Marlene Behrmann and her colleagues at Carnegie Mellon University in Pittsburgh have acquired a high-end MRI-compatible eye tracker for this purpose. They have begun conducting imaging experiments to characterize how the brain takes in visual information from the environment. Their preliminary findings indicate that these processes differ in individuals with autism compared with their neurotypical counterparts.
The researchers tracked the eye movements of individuals with autism during a variety of tasks. Ensuring that gaze remains fixed on one point during an fMRI session (thereby dissociating eye movements from shifts of attention) has allowed Behrmann’s team to conclude that the visual system of individuals with autism responds inconsistently or in a highly changeable manner to visual input. This inconsistency is not simply due to the fact that individuals with autism move their eyes in an unusual fashion. Rather, this is a direct result of unreliable signal production in the visual cortex of the brain.