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PREFRONTAL AND PARIETAL CONTRIBUTIONS TO SPATIAL WORKING MEMORY

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title
PREFRONTAL AND PARIETAL CONTRIBUTIONS TO SPATIAL WORKING MEMORY
author
Li, Sihai
abstract
Working memory is one of the most critical cognitive functions, the seat of which is generally recognized as the dorsolateral prefrontal cortex (dlPFC). Persistent stimulus-selective activity in the prefrontal cortex, even without the presence of a visual stimulus, has been shown to determine the variation of an animal’s behavioral responses. However, recent studies have called into question the precise role of the prefrontal cortex (PFC) in cognitive functions. Activation of posterior parietal cortex (PPC) has also been reported during working memory tasks. Recent studies raised a series of unanswered questions about the specific roles of these two cortical areas in working memory. Here, we acquired behavioral responses and neurophysiological recordings from non-human primates performing spatial working memory tasks to address two primary questions: First, do fluctuations of neural activity from both cortical areas cause deviations in behavioral responses in the Oculomotor Delayed Response (ODR) task? Second, does activity in both cortical areas influence a subject’s categorical judgements based on working memory recall in a novel, Match-Stay-Nonmatch-Go task? No significant differences of tuning bias and correlation of firing rate and behavior deviations were found in the ODR task. In the second experiment, similar influences of neuronal responses on working memory behavior were found in both prefrontal and posterior parietal cortex. Neuronal responses from both areas demonstrated similar drifts between correct and error trials as predicted in the bump attractor model. Choice probability between correct and error trials was significantly different from chance at the end of delay period based on the neurophysiological data from both cortical areas. These results suggest that working memory is influenced by a distributed network of cortical areas, including the dorsolateral prefrontal and posterior parietal cortex, instead of a single cortical area.
contributor
Constantinidis, Christos (committee chair)
Hampson, Robert (committee member)
Stanford, Terrence (committee member)
Salinas, Emilio (committee member)
Rowland, Benjamin (committee member)
date
2020-05-29T08:36:09Z (accessioned)
2022-05-28T08:30:13Z (available)
2020 (issued)
degree
Neurobiology & Anatomy (discipline)
embargo
2022-05-28 (terms)
identifier
http://hdl.handle.net/10339/96849 (uri)
language
en (iso)
publisher
Wake Forest University
type
Dissertation

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