Schedule of Events | Symposia

Non-invasive electrical stimulation modulates resting-state thalamocortical functional connectivity

Poster Session E - Monday, March 31, 2025, 2:30 – 4:30 pm EDT, Back Bay Ballroom/Republic Ballroom

Byoung-Kyong Min¹ (min_bk@korea.ac.kr), Jeehye Seo¹; ¹Korea University

The thalamus plays a crucial role in regulating cortical networks, including the central executive network (CEN) and the default mode network (DMN), which are essential for cognitive processing and resting-state activity. Examining thalamocortical functional connectivity provides insights into how information is transmitted between subcortical and cortical regions. This study aimed to investigate how phase-dependent transcranial alternating current stimulation (tACS) targeting the CEN and DMN affects resting-state thalamocortical connectivity. Twenty-seven participants underwent resting-state fMRI under three conditions: resting-state without tACS, 45°-phase-lag tACS, and 180°-phase-lag tACS. Stimulation was applied to representative nodes of the CEN (bilateral dorsolateral prefrontal cortex [dlPFC] and posterior parietal cortex [PPC]) and the DMN (medial prefrontal cortex [mPFC] and posterior cingulate cortex [PCC]). Functional connectivity and modularity analyses were conducted to examine tACS-mediated changes in resting-state thalamocortical connectivity. In the 45°-phase-lag tACS condition, resting-state functional connectivity between higher-order thalamic nuclei (e.g., the mediodorsal thalamus) and the CEN/DMN was significantly reduced compared to the 180°-phase-lag tACS condition, indicating a tACS-phase-sensitive decrease in thalamic-CEN and thalamic-DMN synchronization. In contrast, resting-state thalamocortical connectivity in attention-related networks was enhanced during the 45°-phase-lag tACS condition, suggesting differential engagement with attention processes. Modularity analysis revealed phase-dependent reorganization, with changes in hub roles and network centrality across phase-lag conditions. Overall, these findings provide evidence for the critical role of phase-dependent tACS in modulating resting-state connectivity between the thalamus and cortex, underscoring its importance for effective tACS-based neuromodulation.

Topic Area: OTHER