Layer-6-corticothalamic-control-of-thalamic-relay-neurons

Shared raw data of "Somatosensory control of thalamic relay neurons is regulated by two distinct layer 6 feedback systems" The medial posterior (POm) and ventral posterior medial (VPM) thalamic nuclei sort and filter somatosensory information that is sent to primary somatosensory cortex(S1). Corticothalamic feedback from distinct cell populations of S1 layer 6(S1L6) targets both POm and VPM. To differentiate their roles, electrophysiological recordings were conducted in awake mice during optogenetic photoinactivation of S-L6B-Drd1R-expressing neurons (that project to POm), or S1-L6-Ntsr1-expressing neurons (that project to POm and VPM). Photoinactivation of either pathway suppressed POm activity when whiskers were deflected, regardless of the whisking-state, but S1L6-Ntsr1-POm inputs were most affected when whisker deflection occurred during non-whisking. Conversely, S1L6-Ntsr1-VPM inputs responded to whisker deflections during whisking. We identified a novel projection from S1L6-Drd1R-expressing neurons to zona incerta, indicating a role for this GABAergic structure in a corticothalamic circuit that specifically modulates POm. These results indicate corticothalamic control of somatosensory thalamus is regulated, in a context-dependent manner, by two distinct S1L6 feedback systems that support the precision and fine-tuning of somatosensory perception. Highlights: Cre-driver mouse lines were used to optogenetically target cells of somatosensory cortex layer 6 (S1L6) that express dopamine D1 receptors (Drd1R) or neurotensin receptor 1 (Ntsr1) These populations both send inputs to the medial posterior thalamic nucleus (POm), whereas the ventral posterior medial thalamus (VPM) receives S1L6-Ntsr1-inputs only Neuroanatomical tracing identified a novel projection from S1-L6-Drd1R-expressing neurons to zona incerta (that projects back to POm) Electrophysiological recordings conducted from awake mice, during different whisking states and photoinactivation of S1-L6-Ntsr1-expressing or S1-L6-Drd1R-expressing neurons, revealed distinct roles for these S1L6-thalamic inputs during whisker deflection These corticothalamic inputs regulate the somatosensory thalamus in a context-dependent manner.