The thalamic reticular nucleus (TRN), an entirely GABAergic shell-shaped structure, is reciprocally connected with the thalamus, where it circulates - via the thalamocortical and corticothalamic axons - temporal and multimodal information. At the single-cell level, the reciprocal TRN-thalamus connections are organized to generate TRN-mediated recurrent and lateral inhibitions in the thalamus. The TRN cells have powerful intrinsic oscillatory properties and communicate with each other via electrical and synaptic synapses, thereby generating nearby immediate functional couplings (synchronized activities) and intra-TRN remote lateral inhibitions. The organization of its anatomo-functional subdivisions and connectome makes the TRN a modular set of filters, which functions as a whole. Thereby, the TRN resembles a “combinatorial matrix” tightly and loosely involved in the thalamocortical integration, attention-related filtering, and transfer of specific (sensory and motor) and contextual (cognitive and emotional) information during both bottom-up and top-down processing.