a. Schematic of the viral vector strategy, optical fiber placement and EEG/EMG device implantation used for combined fiber photometry imaging of ILPVT neurons and polysomnographic recordings. b. Representative image depicts GCaMP6s expression and optical fiber placement in IL. c. Sample EEG/EMG recordings of NREM-Wake (left) and Wake-NREM (right) transitions. Dashed lines depict state transitions. d. Heatmap showing individual GCaMP6s responses from ILPVT neurons to NREM-Wake transitions for all subjects. e. Heatmap showing individual GCaMP6s responses from ILPVT neurons to Wake-NREM transitions for all subjects. f. Average GCaMP6s response from ILPVT neurons during Wake-NREM (blue plot) and NREM-Wake (red plot) transitions (dashed line depicts state transition), n = 4 mice. g. Quantification of GCaMP6s responses from ILPVT neurons for all Wake-NREM (left plot) and NREM-Wake (right plot) transitions. AUC, Wake-NREM: Before, −0.14 ± 0.10; After, 188.68 ± 26.92, n = 4 mice, **P=0.006, two-sided Paired sample t-test. NREM-Wake: Before, −0.09 ± 0.21; After, −296.7 ± 49.32, n = 4 mice, **P=0.009, two-sided Paired sample t-test. Box chart legend: box is defined by 25th, 75th percentiles, whiskers are determined by 5th and 95th percentiles, and mean is depicted by the square symbol. Data shown as mean ± s.e.m.