Extended Data Fig. 10: Organizational and operational scheme for somatosensory circuits of the TRN.
From: Two dynamically distinct circuits drive inhibition in the sensory thalamus
a, Schematic illustrating the organization of the somatosensory sector of the TRN. Excitatory inputs from the primary VP thalamic nucleus innervate the CB-dense central zone of TRN (green cells), whereas higher-order POM inputs innervate the SOM-dense edges (red cells). The inhibitory projections of TRN cells to the VP and POM seem to reciprocate the patterns of their inputs (coloured axons in the schematic). The spatial organization of the neurochemically distinct TRN cell types, and the stark segregation of their primary and higher order connections, suggest a core-shell organization for somatosensory circuits of the TRN. b, Distinct responses of central and edge TRN cells to their thalamic inputs. The spiking responses of central and edge cells are determined by the dynamic synaptic properties of their respective thalamic inputs combined with the intrinsic physiological properties of the TRN cells themselves. The spiking of central cells evoked by VP input is phasic, with strong initial bursts that deeply depress with repetitive stimulation; this is consistent with a core circuit that processes transient sensory signals. By contrast, the spiking responses of edge cells to POM input are more sustained, with initially weaker but more persistent activation; this shell-like circuit is suited to processing temporally distributed higher-order signals.
