Most sensory information destined for the neocortex is relayed there from the thalamus, where considerable transformation occurs 1,2 . One powerful means of transformation involves interactions between excitatory thalamocortical neurons that carry data to cortex and inhibitory neurons of the thalamic reticular nucleus (TRN) that regulate flow of those data 3-6 . Despite enduring recognition of the TRN's importance 7-9 , understanding of its cell types, their organization, and their functional properties has lagged that of the thalamocortical systems it controls.Here we address this, investigating somatosensory and visual circuits of the TRN. First, in the somatosensory TRN we observed two groups of genetically defined neurons that are topographically segregated, physiologically distinct, and connect reciprocally with independent thalamocortical nuclei via dynamically divergent synapses. Calbindin-expressing cells, located in the central core, connect with the ventral posterior nucleus (VP), the primary somatosensory thalamocortical relay. In contrast, somatostatin-expressing cells, residing along the surrounding edges of TRN, synapse with the posterior medial thalamic nucleus (POM), a higher-order structure that carries both top-down and bottom-up information 10-12 . The two TRN cell groups process their inputs in pathway-specific ways. Synapses from VP to central TRN cells evoke rapid currents that depress deeply during repetitive activity, driving phasic spike output. In contrast, synapses from POM to edge TRN cells evoke slower, sustained currents that drive more persistent spiking. Differences in intrinsic physiology of TRN cell types, including state-dependent bursting, also contribute to these output dynamics. Thus, processing specializations of the two TRN circuits appear to be tuned to the types of signals they carry-the primary central circuit to discrete sensory events, and the higher-order edge circuit to temporally distributed signals integrated from multiple sources. Central and edge circuits of the visual TRN and their associated thalamocortical nuclei closely resemble those of the somatosensory circuits. These results provide fundamental insights about how subnetworks of TRN neurons could differentially process distinct classes of thalamic information.