Psychology ETDs

Publication Date

Fall 10-12-2020

Abstract

Modulating sleep architecture to augment memory performance can provide valuable insight into how sleep contributes to memory. Slow wave activity has been identified as an important contributor to sleeps impact on memory. While the beneficial role of SWS in offline consolidation is well established research investigating SWS’s role in post-sleep memory formation is limited. Here we investigated the relationship between SWS and post-sleep learning by modulating slow wave oscillations (SWO) with closed loop transcranial alternating current stimulation (tACS) with an aim toward enhancing learning capacity for object location associations. Thirty-six subjects were randomly assigned to either sham (21) or verum (15) tACS delivered to match the phase and frequency of the dominant slow-wave oscillation during sleep. Participants completed a novel object location memory task the following morning immediately after encoding as well as a delayed test the following evening. Results revealed a significant effect of stimulation condition where sham outperformed verum (ƞ2= 0.135). Planned simple contrasts revealed that verum stimulation significantly reduced object location accuracy by 12.9% in the morning test with the delayed test trending in the same direction with a reduction of 17.8%. These data suggest a decrease in post sleep encoding capacity following a full night of SWS modulation. This result, along with reported benefits of stimulation during a 90-minute nap, suggest that limited augmentation of SWS may accelerate sleep’s beneficial effect on synaptic downscaling, but extended stimulation may drive these processes beyond the sleep systems homeostatic balance, resulting in a negative net effect on post-sleep learning.

Degree Name

Psychology

Level of Degree

Masters

Department Name

Psychology

First Committee Member (Chair)

VINCENT P. CLARK, PH.D.

Second Committee Member

JAMES F. CAVENAGH, PH.D.

Third Committee Member

JEREMY HOGEVEEN, PH.D.

Language

English

Keywords

Closed-Loop stimulation, post-sleep, learning and memory, tACS, SWS, encoding

Document Type

Thesis

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