The submedius thalamic nucleus regulates laryngeal-evoked respiratory reflexes in anesthetized rats via connectivity to the ventrolateral orbital cortex. A, B, The SubM has dense projections to the VLO, as revealed by anterograde (A) and retrograde (B) neuroanatomical tracing. C, Schematic summary of the physiological experiment design to test the effect of bilateral electrolytic lesioning of the VLO (insert photomicrograph demonstrates example lesion site) or sham lesions on SubM-mediated modulation of laryngeal reflexes. D, Laryngeal stimulation-evoked changes in respiratory rate for lesion VLO (N = 5) and sham VLO (N = 3) plus microinjection of vehicle into the SubM. E, Laryngeal stimulation-evoked changes in respiratory rate for lesion VLO (N = 6) and sham VLO (N = 4) plus microinjection of 5-HT into the SubM. F, Blood pressure stimulus–response curves for lesion VLO (N = 5) and sham VLO (N = 3) plus microinjection of vehicle into the SubM. G, Blood pressure response curves for lesion VLO (N = 6) and sham VLO (N = 4) plus microinjection of 5-HT into the SubM. *p < 0.05, **p < 0.01, ****p < 0.0001, two-tailed unpaired t test (D–G). AI, Agranular insula; CI, claustrum; mt, mamillary tract; rf, rhinal fissure; VM, ventromedial thalamus.