The study of human eye movements provides an extremely useful approach to the examination of a variety of cognitive functions. It is obvious that the latency and goal of saccadic eye movements are related to attention. What is not so obvious is that other aspects of cognition such as short-term memory, preparatory set, and inhibition of context inappropriate responses can also be assessed using eye movement techniques. Short-term memory, preparatory set, and inhibition of context inappropriate responses constitute core functions of the prefrontal cortex, the brain region most involved in the control of higher order cognitive processes. We have used a number of different tasks to elicit saccades, including Go/No Go tasks and delayed response tasks. These tasks allow us to independently assess core functions of the prefrontal cortex by measuring the accuracy and latency of memory guided saccades, as well as the frequency of context inappropriate saccades that should be inhibited. Using these tasks we have demonstrated that schizophrenics are impaired in all three core aspects of prefrontal cortex function while children with Attention Deficit Hyperactivity Disorder (ADHD) are impaired in only their ability to inhibit context inappropriate saccades. During the past year we have demonstrated that, similar to children with ADHD, alcoholics are impaired in their ability to inhibit context inappropriate saccades. The smooth pursuit eye movements of alcoholics are completely normal. We have also expanded the number of alcoholics studied and examined eye movements in children who have an increased risk for alcoholism, such as children with a past history of abuse. These children show a pattern of eye movement dysfunction similar to what we have observed in ADHD.
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