Orienting to novelty plays a critical role in directing attention and guiding behavior in normal individuals and is disrupted in many disease states. Yet, little is known about the neural substrate of novelty seeking. The proposed research will investigate the neuroanatomical and electrophysiological underpinning of responses to novel stimuli. Non-brain damaged subjects will be studied to determine the link between early stages of C.N.S. responses to novel stimuli using electrophysiological recordings (as measured by the """"""""novelty"""""""" P300) and subsequent stages of information processing and behavioral responses (as measured by subject-controlled stimulus exposure durations). Patients with strokes will be studied to investigate the impact of focal lesions on electrophysiological and behavioral components of novelty seeking and to determine if the frontal cortex plays an essential role in this activity. All subjects will be studied in 1) an Event-Related potential (ERP) Laboratory using specifically designed visual stimuli to evoke different electrophysiological responses and behavioral reactions and 2) an Eye movement Laboratory using visual stimuli to elicit exploratory eye movements. Stroke patients will undergo magnetic resonance imaging (MRI) with 3 dimensional surface reconstruction of the lesion site to precisely delineate the location of structural brain damage.
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