Publication Date

2019-02-20

Availability

Embargoed

Embargo Period

2020-02-20

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Neuroscience (Medicine)

Date of Defense

2017-06-15

First Committee Member

Miguel A. Perez-Pinzon

Second Committee Member

Jae K. Lee

Third Committee Member

R. Grace Zhai

Fourth Committee Member

Thomas J. Sick

Fifth Committee Member

M. Danielle McDonald

Abstract

Cardiac arrest effects over half a million people in the United States annually. A lack of brain perfusion results in a global brain ischemia resulting in cell death in several regions including the hippocampus, an area important for learning and memory. Nearly half the survivors of cardiac arrest suffer from cognitive deficits. While there remains no well accepted therapy for these patients, it has been shown that exercise after focal brain ischemia (i.e. stroke) enhances both motor and cognitive function. But this has never been explored in the setting of cardiac arrest. In this study, we determined that a brief period of exercise of sufficient intensity enhances contextual but not spatial memory after cardiac arrest. This improvement was not due to acute effects of exercise as contextual memory was tested over a week after the last exercise session. Additionally, the enhancement in contextual memory was not correlated to enhanced hippocampal BDNF signaling despite increased BDNF protein levels in exercised animals. Likewise, there was no increase in neuronal proliferation in the dentate gyrus in exercised animals. Neuroprotection was not increased with exercise after cardiac arrest and exercise may enhance cell death after cardiac arrest. Further studies are needed to ascertain the mechanism of exercise-mediated enhancement of contextual memory after cardiac arrest.

Keywords

brain ischemia; cognition; exercise; fear; cardiac arrest; memory

Available for download on Thursday, February 20, 2020

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