Psychology ETDs

Publication Date

Summer 7-13-2025

Abstract

Transcranial electrical stimulation (tES) has shown potential to modulate attention and enhance learning, yet its effects in applied, real-world contexts, remains underexplored. This study investigated the impact of transcranial direct current stimulation (tDCS) and high-frequency transcranial random noise stimulation (hf-tRNS with DC offset) on performance in a synthetic aperture radar (SAR) visual search task requiring both target identification and change detection. Participants (N = 63) were randomly assigned to tDCS, hf-tRNS, or sham conditions, with stimulation applied to the right inferior frontal gyrus (F10) during the training phase. Accuracy served as the primary outcome, with supplementary EEG and eye-tracking data collected to assess attentional correlates.

ANCOVA analyses revealed a significant effect of stimulation on target identification accuracy, with the tDCS group outperforming sham, particularly among low baseline performers. The hf-tRNS condition showed only trend-level effects on performance, with random baseline differences potentially contributing to this outcome. No significant stimulation effects were observed for change detection accuracy. EEG and eye-tracking metrics (e.g. frontal theta, blink rate) exhibited relationships with performance consistent with prior literature, though stimulation-related changes in these indices were minimal. These results suggest that tDCS may selectively enhance attentional performance in complex visual tasks, contingent on task type and individual baseline ability. Findings emphasize the importance of carefully considering cognitive context and individual variability when evaluating the efficacy of noninvasive brain stimulation.

Degree Name

Psychology

Level of Degree

Doctoral

Department Name

Psychology

First Committee Member (Chair)

Vincent P. Clark

Second Committee Member

Jeremy Hogeveen

Third Committee Member

Aaron Winder

Fourth Committee Member

Davin Quinn

Language

English

Keywords

Visual Search, tDCS, tRNS, Neuromodulation, SAR Task

Document Type

Dissertation

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