Thesis
Combining neurophysiology and behavioral measures to identify biomarkers of clinical and preclinical hippocampus-dependent memory dysfunction
Master of Science (M.S.), Drexel University
Jun 2023
DOI:
https://doi.org/10.17918/00001783
Abstract
Memory is a critical piece of the human experience. This is why damage or degradation to neural memory networks and related brain structures is so devastating; memory shapes what we understand to be our lives and 'world.' Episodic memory generates context for the present based on past experience and allows us to make predictions about the future. The hippocampus is a structure with a crucial role in episodic memory. On the other hand, long-term consolidation of episodic memories requires a series of highly connected networks that must work together to encode, store, and retrieve information. The precise orchestration of electrophysiological oscillations, or oscillation coupling, facilitates consolidation of memory traces in the brain, particularly in offline sleep states. Hallmark sleep oscillations, slow oscillations, and thalamocortical spindles, couple with hippocampal sharp wave ripples to establish a cortical-subcortical dialog necessary for long-term memory consolidation. The current study aims to explore the effect on behavior when there are alterations to typical sleep oscillations originating from the hippocampus (SWR). To address these questions, we employed intracranial electroencephalography (iEEG) to directly record hippocampal oscillations and neocortical oscillations from within the brain. Using this method allows us to gain a unique temporal and spatial perspective on electrophysiological biomarkers of memory not easily accessible with other methods. Results from this study uncovered evidence of SWR features specific to patients with left mesial temporal sclerosis and a higher degree of variability among patients with seizure foci not localized to either hippocampus. There were also notable findings related to the relationship between SWR features and performance on the Rey Auditory Verbal Learning Test (RAVLT). Taken together, this study provides a meaningful contribution to work examining the role of SWR in humans and their potential as a biomarker for long-term memory processes.
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Details
- Title
- Combining neurophysiology and behavioral measures to identify biomarkers of clinical and preclinical hippocampus-dependent memory dysfunction
- Creators
- Elizabeth Espinal - Drexel University, Psychological and Brain Sciences (Psychology)
- Contributors
- Evangelia G. Chrysikou (Advisor) - Drexel University, Psychological and Brain Sciences (Psychology)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- vi, 60 pages
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- Psychological and Brain Sciences (Psychology); College of Arts and Sciences; Drexel University
- Other Identifier
- 991021212413804721