Transcranial ultrasound stimulation of the pulvinar and globus pallidus internus facilitates visual search.

Ultrasound offers a powerful means of modulating human cognition by noninvasively targeting subcortical structures previously accessible only via invasive procedures. While decades of research have mapped cortical circuits of attention, deep hubs such as the basal ganglia and thalamus are increasingly recognized as key nodes in attention networks. We tested whether low-intensity transcranial ultrasound stimulation (TUS) of the globus pallidus internus (GPi) and pulvinar modulates visual search, an attention-dependent task, predicting site-specific effects that reflect distinct basal ganglia-thalamic circuit functions. Focal TUS reduced reaction times, suggesting a facilitation of attention-related task performance. A dissociation emerged across sites: stimulation of both GPi and pulvinar reduced reaction times, but pulvinar yielded more robust benefits for target-present trials at peripheral eccentricities, and improved search efficiency in the same trials. These results support distinct contributions of basal ganglia and thalamic nodes to attention-related behavior and show that TUS can be used to probe circuit-level mechanisms of cognition in humans.