Author ORCID Identifier

https://orcid.org/0000-0002-9307-7706

Date Available

6-15-2026

Year of Publication

2025

Document Type

Doctoral Dissertation

Degree Name

Doctor of Philosophy (PhD)

College

Arts and Sciences

Department/School/Program

Psychology

Faculty

Thomas G. Adams

Faculty

Christal Badour

Abstract

Background: The right inferior frontal gyrus (rIFG) is implicated in stop signal reaction time (SSRT) performance – a common measure of inhibitory control – and emotional expression and control. Individuals with posttraumatic stress disorder (PTSD) exhibit poorer stop SSRT performance, which is associated with rIFG hypoactivity. Neuromodulation of the rIFG with transcranial direct current stimulation (tDCS) can significantly improve inhibitory control and reduce fearful responding to threatening stimuli. Research has yet to test the effects of multifocal tDCS targeting the rIFG on inhibitory control or emotional reactivity in individuals with PTSD.

Methods: The current study aims to examine the impact of multifocal tDCS targeting the rIFG on SSRT and emotional reactivity to trauma-related cues in a sample of women with elevated PTSD symptoms related to interpersonal violence (IPV; n=38). Participants completed three blocks of the SSRT task (block 1 [baseline], block 2 [online tDCS] and block 3 [offline tDCS]) followed by an emotion provocation task. They were randomized to receive 15-mins of multifocal tDCS targeting the rIFG or sham tDCS; delivered offline for 11.5-mins after block 1 of the SST and online for 3.5-mins during block 2 of the SST.

Results: A significant block by condition interaction on SSRT performance was observed (p < .05). Post-hoc probes revealed that individuals in the active tDCS condition exhibited faster SSRT performance compared to individuals in the sham condition during the follow-up blocks. However, block-specific analyses revealed that the impact of condition on SSRT was only significant during the online tDCS block (block 2, p < .001). No effect of tDCS on emotional reactivity was observed (p’s > .05).

Discussion: These findings suggest that multifocal tDCS of the rIFG is associated with transient improvements in inhibitory control among individuals with elevated PTSD symptoms. While rIFG tDCS may hold promise for enhancing cognitive functions like inhibitory control, its transient effects highlight the need for further investigation into the optimal timing and dosing of stimulation to achieve lasting benefits.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2025.256

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Available for download on Monday, June 15, 2026

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