The ability of transcranial alternating current stimulation (tACS) to augment underlying rhythmic fluctuations of neuronal activity
provides meaningful implications in the treatment of neuropsychiatric disorders characterized by aberrations in neural oscillations. However,
in evaluating its clinical utility, evidence is lacking for the efficacy of tACS to induce long-term (> 24 hours) plastic changes that
translate to lasting behavioral outcomes. Here, we repeatedly administered alpha-frequency tACS across 4 consecutive days in 38 healthy
adults to evaluate lasting changes in local alpha power and directed connectivity as well as clinically-relevant indices of anxious arousal
and affective sensory processing. Replicating previous findings, participants who received active stimulation (vs. a sham control group)
demonstrated transient increases in resting occipito-parietal alpha power that lasted 30 minutes post-stimulation, reflecting acute
entrainment to the exogenous electrical stimulation. However, these effects were short-term, returning to baseline levels 24 hours after
stimulation. Conversely, long-term increases in intrinsic posteriorī frontal alpha-frequency connectivity emerged and persisted across all 4
days, reflecting plastic-changes in directed cortico-cortical networks. These lasting connectivity changes were paralleled by sustained
decreases in anxious arousal and increases in perceived pleasantness of auditory stimuli. These findings suggest that while local oscillatory
activity may be constrained by a self-sustaining thalamo-cortical loop that restores cortical oscillations to baseline, long-range
oscillatory connectivity may strengthen over time through plastic synaptic changes in intrinsic cortico-cortical networks. The lasting
augmentation of this inter-areal oscillatory network via tACS provides meaningful implications in an array of affective and cognitive
processes that are orchestrated through the integrity of these global networks. This provides novel extensions of tACS applications, shifting
neuromodulatory targets from local oscillations to global oscillatory networks to progress the clinical utility of this
technology. / A Thesis submitted to the Department of Psychology in partial fulfillment of the requirements for the degree
of Master of Science. / Fall Semester 2017. / September 27, 2017. / Includes bibliographical references. / Wen Li, Professor Directing Thesis; Natalie Sachs-Ericsson, Committee Member; Lisa Eckel, Committee
Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_604958 |
| Contributors | Clancy, Kevin J. (author), Li, Wen (professor directing thesis), Sachs-Ericsson, Natalie J. (committee member), Eckel, Lisa A. (committee member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Psychology (degree granting departmentdgg) |
| Publisher | Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text, master thesis |
| Format | 1 online resource (62 pages), computer, application/pdf |
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