The thalamic reticular nucleus provides spatially and temporally tuned inhibition to the lateral geniculate nucleus across species

Abstract

By proposing a role in spatial attention, Francis Crick piqued interest in the thalamic reticular nucleus (TRN), a GABAergic structure that receives input from relay cells projecting to cortex and feeds back inhibition in return. Importantly, predictions of Crick's hypothesis extend beyond attention to suggest that TRN provides selective, localized inhibition to relay cells and, thus, influences sensory processing per se. To ask if this latter role for TRN holds across species, we compared previous recordings from cat with a novel dataset from mouse, focusing on vision. We estimated receptive field size and structure of reticular cells in the visual sector of TRN and of relay cells in the dorsal lateral geniculate nucleus (dLGN). Cells in both nuclei encoded specific visual features and had receptive fields of comparable size within binocular visual space. Moreover, paired recordings from both structures suggested that TRN is able to promote burst firing in dLGN in addition to modulating spike rate. Thus, TRN is not only important for attentional regulation, but is also able to make fine-tuned contributions to early sensory processing.