Author ORCID Identifier
Date Available
11-20-2027
Year of Publication
2025
Document Type
Doctoral Dissertation
Degree Name
Doctor of Philosophy (PhD)
College
Arts and Sciences
Department/School/Program
Biology
Faculty
Dr. Bruce F. O'Hara
Faculty
Dr. Lauren N. Whitehurst
Faculty
Dr. Jakub Famulski
Abstract
Sleep is essential for health and survival, yet 30-45% of adults in the US regularly fail to obtain recommended sleep. Although the restorative functions of sleep are increasingly well characterized, the biological mechanisms through which sleep exerts these effects remain incompletely understood. The autonomic nervous system, comprising sympathetic and parasympathetic branches, shows marked stage-dependent fluctuations across the sleep cycle. Parasympathetic activity dominates during non-rapid eye movement sleep, whereas rapid eye movement sleep is accompanied by phasic sympathetic bursts. These changes have long been viewed as passive byproducts of central sleep processes, but the causal impact of ascending autonomic signals on human sleep regulation remains unclear. The dissertation tested whether transcutaneous vagus nerve stimulation, a noninvasive method that activates auricular vagal afferents and engages sleep–wake regulatory brainstem nuclei, can alter sleep architecture. Across two randomized, sham-controlled, within-subject studies (N = 92), participants received 90 minutes of stimulation during either early sleep (following stable N2; Study 1) or late sleep (at 3:30 AM; Study 2). Early-night stimulation increased N2 sleep and reduced REM percentage in men, and also increased spindle density. Together, these results suggest that afferent autonomic input can influence sleep regulation.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2025.529
Recommended Citation
Subramoniam, Anjana, "THE CAUSAL IMPACT OF AUTONOMIC NERVOUS SYSTEM (ANS) MODULATION ON SLEEP ARCHITECTURE AND CARDIOVASCULAR DYNAMICS" (2025). Theses and Dissertations--Biology. 115.
https://uknowledge.uky.edu/biology_etds/115
