Fig. 1: The dmPFC is suppressed in rats with CMP.

a An experimental schematic for the CMP model and behavioral tests. b The MRI images of the rat GS muscle; the arrows point to the tissue inflammation. c A schematic of von Frey’s mechanical pain test. d The mechanical thresholds of ipsilateral hind paws post MP or sham injury (n = 10; two-way ANOVA with Bonferroni’s post hoc test; *MP versus sham). e A schematic of exploratory behavior in the OFT. f A representative OFT trace. g–i The total distance traveled (g) percent central distance (h) and percent time spent in the central area (i) quantified over five time points (n = 8, two-tailed paired or unpaired Student’s t-test). j The IF images showing the colabeling of neurons and cFos in dmPFC. Scale bar, 500 mm and 50 mm (enlarged insets). k The quantification of cFos⁺ neurons number (n = 4 rats, two-tailed unpaired Student’s t-test). l A schematic of pAAV-hSyn-GCaMP6s injection. m The fiber photometry recordings with confocal image showing viral expression (green) and optical fiber tracks. Nuclei are stained blue (DAPI). Scale bar, 500 µm. n–r A heat map of dmPFC neuronal responses to contralateral hind paw stimuli, and panels n–r correspond to the MP group at 0, 3, 7, 14, and 28 days, respectively. s A representative photometric traces. t The quantification of GCaMP6s signals (n = 6; 8 trials per animal; one-way ANOVA with Bonferroni’s post hoc test). Statistical significance is exhibited as *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001; ns, not significant.