Electrophysiological potentials in the hippocampus during recognition memory

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Bridget Byrd (Creator)
Institution
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/
Advisor
Julian Keith

Abstract: Neural circuits within the medial temporal lobe, including the hippocampus, support recognition memory. Patients and animals with circumscribed hippocampus damage experience significant episodic memory deficits but their general intellectual abilities remain intact. The present thesis sought to determine whether electrical field potentials generated in the hippocampus during a recognition memory task are influenced by stimulus repetition. Electroencephalography (EEG) is a non-invasive technique used to measure the voltage changes on the scalp in regards to a specific cognitive event. Event related potentials (ERP) is a post-hoc analysis of recorded EEG and allows the voltage changes to be time-locked to the occurrence of an event. EEG/ERP analysis was used to measure the voltage change in normal, healthy college students in a recognition memory task. When visual stimuli are presented repeatedly certain ERP components that are associated with recognition memory are attenuated, although some discrepancies exist in the literature. Beamforming spatial filtering analysis is a source estimation technique that allows inferences to be made about the locations of generators of the evoked potentials that are recorded at the scalp. In the current study, a repetition effect was observed for pictures and words at select electrode sites. Pictures and words previously seen (“Old’) had significantly decreased peak amplitude compared to pictures and words that had not been seen before. Although stimulus repetition clearly attenuated electrophysiological signals recorded on certain regions of the scalp, beamforming analysis of the hippocampus showed that these changes were not accompanied by similar changes in the field potentials generated within the hippocampus. Interestingly, however, pictures and words produced markedly different hippocampal field potentials.

Additional Information

Publication
Thesis
A Thesis Submitted to the University of North Carolina Wilmington in Partial Fulfillment of the Requirements for the Degree of Master of Arts
Language: English
Date: 2009
Keywords
Evoked potentials (Electrophysiology)--Experiments, Memory--Physiological aspects, Psychobiology, Recognition (Psychology)--Physiological aspects, Recognition (Psychology)--Testing
Subjects
Psychobiology
Recognition (Psychology) -- Testing
Evoked potentials (Electrophysiology) -- Experiments
Memory -- Physiological aspects
Recognition (Psychology) -- Physiological aspects