Drs. Sangjun Lee & Alexander Opitz (September 2, 2026)

Presenters: Sangjun Lee and Alexander Opitz Department of Biomedical Engineering University of Minnesota https://opitzlab.umn.edu/ Title: Externally controlled traveling-wave dynamics causally shape neural activity and cognition Abstract: Cortical traveling waves (TWs) are spatiotemporal patterns of neural activity that propagate across brain regions during cognition. TWs exhibit diverse propagation dynamics, including direction and speed, which have been associated with distinct modes of neural processing. However, whether TW propagation dynamics causally influence neural activity and cognition remains unknown. Here, we developed a novel non-invasive brain stimulation approach, traveling-wave transcranial alternating current stimulation (twtACS), guided by computational modeling, to externally impose TW dynamics in the human brain. Using intracranial recordings in humans, we first validated that twtACS reliably generated TW-like electric fields, with experimentally measured phase gradients closely matching computational predictions across stimulation conditions. We then showed, using intracranial recordings in nonhuman primates, that twtACS systematically shifted neural spiking timing according to the externally imposed electric fields. Finally, in human cognitive experiments, twtACS produced both direction-dependent and speed-dependent changes in cognitive tasks. Together, these findings provide the first direct causal evidence that externally imposed TW dynamics can shape neural activity and cognition, establishing twtACS as a framework for controlling spatiotemporal brain dynamics and probing the functional role of traveling waves in cognition.