The central goal of the proposed research is to increase our understanding of how the relation between saccadic eye movements, perception, attention, and motor learning depends on how the saccade is programmed, either reflexively or voluntarily, spontaneously or with effort. The 1st aim is to examine the link between saccades and covert peripheral attention. The main hypothesis is that the linkage between saccades and peripheral shifts of attention depends upon the amount of mental processing necessary to make the saccade. The 2nd aim is to understand how the saccadic system avoids being captured by the constant flux of the visual environment. Our major hypotheses are that depth can play a critical role in filtering out visual distractors, that the ability to filter out distractors depends on the composition of the visual scene, and that it is easier to filter out distractors in an effortful laboratory task than in more natural and spontaneous visual behavior. The 3rd aim is to understand the way in which low-level and high-level processes are used by the saccadic system to """"""""learn"""""""" where to go when a saccade is to be made to a location other than the initial location of a target. Our hypothesis is that the spatial boundary between low and high-level mechanisms depends upon the reflexiveness of the saccade and the ability of the subject to detect the target displacement. The 4th aim is to determine how the relations between saccade generation and spatial perception at the time of the saccade depend upon the type of saccade generated. We hypothesize that this illusion is stronger for express saccades (saccades of very short latencies) than for saccades of longer latency, and that such perceptual differences between saccade types are also present when localizing a visual stimulus briefly flashed around the time of the saccade and when in the awareness of the one's own saccade endpoint. Saccadic eye movement disorders have been implicated in neurological and psychiatric disorders such as attention-deficit hyperactivity disorder (ADHD), Parkinson's Disease, and schizophrenia. They can also result from brain trauma. To the extent that the proposed research is successful in uncovering some of the basic mechanisms underlying the programming of saccades and their relation to attention and perception, we will gain insight into the diagnosis and treatment of eye movement, attentional, and reading disorders.
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