Reconfiguration of the Cognitive Control Network Induced by Cerebral and Cerebro-Cerebellar Transcranial Direct Current Stimulation.

Cognitive control can be modulated by noninvasive brain stimulation, but it remains unclear how different stimulation protocols are associated with task-related network organization. To characterize behavioral and brain-network profiles, we recorded brain activity and behavioral performance while participants completed a cognitive control task during functional magnetic resonance imaging. Profiles were compared across a pre-stimulation session and two sessions following high-definition transcranial direct current stimulation (HD-tDCS): single-site stimulation of the presupplementary motor area/dorsal anterior cingulate cortex (preSMA/dACC) and dual-site stimulation of the preSMA/dACC plus the left posterolateral cerebellum. Drift-diffusion modeling showed reliable switching costs across sessions, with smaller latent costs in the dual-site than in the single-site session. Effective-connectivity analyses indicated threshold-sensitive reductions in retained cerebro-cerebellar and right prefrontal edges in the dual-site session. Model-based graph analyses indicated protocol-dependent differences in estimated network topology, including higher small-worldness in the single-site session and session-specific associations between graph metrics and latent behavioral costs. Together, these findings suggest that single-site medial-frontal and dual-site cerebro-cerebellar HD-tDCS were associated with distinct cognitive-control profiles at both behavioral and modeled network levels. Rather than reflecting a uniform enhancement of connectivity, the dual-site protocol appeared to engage a different network configuration supporting cognitive control.