Abstract
Higher-order thalamic nuclei, such as the visual pulvinar, play essential roles in shaping cortical dynamics and connecting functionally-related cortical and subcortical brain regions. A coherent framework describing pulvinar function remains elusive due to its anatomical complexity, involvement in diverse cognitive processes, and the limited experimental tools available in many species. We combined large-scale anatomical circuit mapping with high-density electrophysiological recordings to dissect a homolog of pulvinar in mice, the lateral posterior nucleus (LP). We define three LP subregions based on correspondence between connectivity and functional properties. These subregions form parallel corticothalamic loops and contain separate representations of visual space. Silencing visual cortex or the superior colliculus revealed that these input sources drive activity and shape visual tuning in separate LP subregions. By specifying the information carried by distinct circuits through LP and identifying their downstream targets, our data provide a roadmap for understanding pulvinar function in visual processing and behavior.