Targeting the prefrontal-supplementary motor network with online and offline tDCS to modulate disgust: A single-blind and sham-controlled study

Clinical Snapshot

Key Findings

• P Value: Significant decrease in online vs offline group (exact p-value not provided)

• Effect Size: Not reported

• Primary Outcome: Disgust experience during image viewing task

• Nnt Or Sensitivity: Not calculable from available data

• Confidence Interval: Not reported

Clinical Application

Limited by requirement for specialised tDCS equipment and trained personnel; intensive 5-day protocol may be challenging tDCS devices are TGA-regulated; would require specialist neuropsychiatry or research settings; not currently PBS-listed for disgust-related conditions Individuals with high disgust sensitivity, potentially those with contamination-based OCD

Abstract

In certain individuals, disgust experience is abnormally high. This heightened sensitivity serves as a cognitive component that can lead to dysfunction in neural circuits related to emotion processing and psychological disorders such as contamination-based obsessive-compulsive disorder. In this single-blind study, 36 individuals with high disgust sensitivity were randomly assigned to three groups: online, offline, and sham. The online group received intensified and repetitive transcranial direct current stimulation (tDCS) while performing a disgust image watching task, whereas the offline and sham groups performed the task at two time points: immediately before (pre-test) and immediately after (post-test) the stimulation session. The offline group received active tDCS, whereas the sham group received placebo tDCS to control for the interval duration. Anodal and cathodal stimulation was applied to the left dorsolateral prefrontal cortex (l-DLPFC; F3) and pre-supplementary motor area (pre-SMA; FC2), respectively. The intervention consisted of 10 sessions of tDCS (2 sessions per day) over 5 days, with a stimulation intensity of 2 mA for 20 min and a 20-minute interval between sessions. The results showed a significant decrease in disgust experience in the online group compared to the offline group, while there was no significant difference between the online and sham groups. Although these findings suggest potential effects of tDCS combined with a task, further studies are necessary to confirm its efficacy.

References

1. 1.Soltani, P., Morovati, Z., Yousefi Afrashteh, M., Fink-Lamotte, J., & Alizadehgoradel, J. (2026). Targeting the prefrontal-supplementary motor network with online and offline tDCS to modulate disgust: A single-blind and sham-controlled study. Behavioural Brain Research, 116077. https://doi.org/10.1016/j.bbr.2026.116077