Pulvinar subregions influence select cortical pathways in humans

The pulvinar is a large, multisensory thalamic hub with distinct subregions and widespread cortical connectivity. This widespread connectivity is thought to regulate the flow of information across the cortex, and recent studies have leveraged the pulvinar for neuromodulation. The evolutionary expansion, particularly for the medial pulvinar in humans, highlights the importance to study selective pulvinar influence across the human cortex. We therefore used single-pulse electrical stimulation to causally map the influence of pulvinar on cortex in thirty patients (14 female) implanted with stereotactic EEG for drug-resistant epilepsy monitoring. In individual subjects, we found that stimulation of the lateral pulvinar influenced striate and extrastriate regions, while ventral medial pulvinar stimulation preferentially influenced lateral temporal cortices. Across all subjects, the dorsomedial pulvinar stimulation influenced parietal cortex. Furthermore, these effects were captured by a compact set of large-scale cortical gradients, including outputs along a dorsal-ventral, anterior-posterior, and medial-lateral pulvinar axis. These findings demonstrate that pulvinar subregions influence select cortical networks in humans. These maps of influence may guide further development of pulvinar subregions as distinct neuromodulation targets. Significance statement Mapping the effective connectivity of pulvinar subregions is essential to delineate how the pulvinar can influence cortical information flow during perception. In addition, understanding how distinct regions of the pulvinar influence the cortex is critical for tailoring neuromodulation devices to engage specific cortical networks. Using intracranial stimulation, we provide a causal map of pulvinar subregion influence and summarize it with gradients that capture its large-scale organization.