a, Schematic of virus injection and recording configuration in acute slices. b, Representative image of GFP labeling neurons by S1HL infusion of retro-AAV-CaMKIIα-GFP. Scale bar, 100 µm. c, Representative images of POGlu neurons (yellow) labeled by retro-GFP (green) injected in the S1HL and AAV-CaMKIIα-mCherry injected in PO (red). Left scale bar, 100 µm; right scale bar, 20 µm. d, e, Sample traces and data of firing rates (d) and rheobase values (e) recorded from the S1HLGlu projecting POGlu neurons of the mice treated with saline and CFA 3D (n = 30 cells per group from 3 mice; d: F1,58 = 14.38, P < 0.001; e: t58 = 4.89, P < 0.0001). f, g, Sample traces and data of firing rates (f) and rheobase values (g) recorded from the S1HLGlu projecting POGlu neurons of the mice treated with sham and SNI 7D (n = 30 cells per group from 3 mice; f: F1,58 = 24.51, P < 0.0001; g: t58 = 4.867, P < 0.0001). h, Schematic illustration of an electrophysiological recording in the PO of freely moving C57 mice with PO infusion of AAV-DIO-ChR2-mCherry and S1HL infusion of retro-AAV-CaMKIIα-Cre. i, Typical image of AAV-DIO-ChR2-mCherry viral expression within the PO. Scale bar, 200 µm. j, Example recording of spontaneous and light-evoked spikes from a POGlu neuron. k, Overlay of light-evoked (blue) and averaged spontaneous (orange) spike waveforms from the example unit. l, All recorded light sensitive neurons (n = 24) were classified as WS putative pyramidal cells (red, n = 22) and non-pyramidal cells (blue, n = 2) using unbiased κ-means cluster algorithm based on three electrophysiological properties: firing rate, trough to peak duration and half width. Inset, average waveform of an example pyramidal neuron illustrating the methodology used to measure trough to peak duration and half width. m, Example recording of spontaneous spikes (left) and data (right) showing the S1HLGlu projecting POGlu firing rate in the mice treated with saline and CFA 3D (n = 5 cells from 3 mice for Saline; n = 7 cells from 3 mice for CFA; t10 = 3.304, P = 0.008). n, Example recording of spontaneous spikes (left) and data (right) showing the S1HLGlu projecting POGlu firing rate in the mice treated with sham and SNI 7D (n = 5 cells from 3 mice for per group; t8 = 2.999, P = 0.017). Significance was assessed by two-way repeated measures ANOVA with post hoc comparison between groups in d and f, and two-tailed unpaired Student’s t-test in e, g, m, and n. All data are presented as the mean ± s.e.m. * P < 0.05, ** P < 0.01, *** P < 0.001. For detailed statistics information, see Supplementary Table 1.