Date of Award

Fall 2009

Project Type

Dissertation

Program or Major

Psychology

Degree Name

Doctor of Philosophy

First Advisor

Jill McGaughy

Abstract

Converging evidence supports the hypothesis that the prefrontal cortex is critical for executive control. One prefrontal subregion, the anterior cingulate cortex has previously been shown to be active in situations involving high conflict, presentation of salient, distracting stimuli, and error processing, i.e. situations that occur when learning new response contingencies, when previously learned response strategies fail, or when a shift in attention or responding is required. These situations all involve goal-oriented monitoring of performance in order to effectively adjust cognitive processes. Several neuropsychological disorders, for instance schizophrenia, attention deficit hyperactivity disorder, and obsessive compulsive disorder, are correlated with morphological changes in the anterior cingulate cortex. Individuals with these disorders show impairments on tasks that require goal-oriented monitoring. The current studies used multiple behavioral paradigms to assess the effects of anterior cingulate cortex excitotoxic lesions in rats on executive control. Animals with anterior cingulate cortex lesions showed greater decline in cognitive capacity as tasks progressed, longer response latencies to conflicting stimuli, impaired reversal learning, impaired error processing, and impaired performance in the presence of previously relevant distractors. These results are consistent with the hypothesis that the anterior cingulate cortex is involved in executive control, specifically monitoring impairments in performance that signal the need to adjust cognitive control.

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