Fig. 5: The nose → OB→aPir → MD circuit controls 2MBA-triggered retching-like behavior.

a Schematic for in vivo multi-tetrode electrophysiological recording in the MD or NAc. b Representative traces (left) and summarized data (right) of firing rates in MD neurons before and during retching-like behavior (n = 30 cells from 5 mice, P < 0.0001). c Representative traces (left) and summarized data (right) of firing rates in NAc neurons before and during retching-like behavior (n = 30 cells from 5 mice). d Schematic for in vivo fiber photometry recoding of MD^Glu neurons in CaMK2-Cre mice. e, f Representative trace (e) and heatmaps (f) of time-locked Ca²⁺ transient activity of 2MBA-triggered retching-like behavior. Gray bars in (e) indicate bouts of retching-like behavior. The dashed line in (f) indicates the onset of retching-like behavior (n = 5 mice). g Schematic (top) and representative image (bottom) for in vivo microendoscope imaging of aPir-innervated MD neurons in C57 mice. h, i Summarized data showing the events (h) and averaged z-score (i) of GCaMP6m-expressing MD neurons before and during retching-like behavior (n = 30 cells from 4 mice, h, P = 0.0063; i, P < 0.0001). j Schematic for optogenetic inhibition of the nose→OB→aPir→MD circuit. k Representative image showing virus expression in the OB. Scale bar, 100 µm. l Left: Representative image showing virus expression and cannula tract in the aPir. Scale bar, 100 μm. Right: Typical images showing the DsRed-labeled neurons colocalized with EGFP⁺ signals in the aPir. Scale bar, 10 μm. m, n Example raster plots (m) and counts (n) of retching-like behavior with inhibition of the nose→OB→aPir→MD circuit (n = 10 mice per group, P < 0.0001). o Summarized data of electromyography (EMG) recordings of diaphragm muscle with inhibition of the nose→OB→aPir→MD circuit (n = 10 mice per group, P < 0.0001 (left) and P < 0.0001 (right)). p Summarized data of CPA tests with inhibition of the nose→OB→aPir→MD circuit (n = 10 mice per group, P = 0.3984 (left) and P = 0.7533 (right)). Significance was assessed using two-tailed unpaired Student’s t tests in panels (n–p), and two-tailed paired Student’s t tests in panels (b, c, h and i). All data are presented as means ± s.e.m. **P < 0.01, ***P < 0.001, n.s., not significant. For detailed statistical information, see Supplementary Table 1. Source data are provided as a Source Data file.