Fig. 6: The vLGN-PAG circuit mediates the fear of heights.

a–c c-Fos⁺ cells in PAG subregions (dmPAG, dlPAG, lPAG, vlPAG) after height exposure (n = 5 mice/group). Calcium imaging of glutamatergic neurons in l/vlPAG. Cre-dependent GCaMP6s virus vectors were injected into the l/vlPAG of Vglut2-Cre mice, and optic fibers were implanted (d). Heatmaps (e) and time-based Ca²⁺ fluctuations (f) during control and height exposures are presented. Each short bar to the left of (e) indicates one mouse (n = 6 mice). g Comparison of the Ca²⁺ elevation amplitude based on the area under the curve (AUC) calculated from (f). Pan-neuronal (h–j) and glutamatergic (k, l) inhibition effects in l/vlPAG on height fear, with Go and ST (i–l) indicating OHP descent/stay outcomes at the end of the 30-min test (control n = 12, 11, and 10, and CNO group n = 14, 7, and 11 in i, j, and l, respectively). m, n Effects of glutamatergic neuron modulation in l/vlPAG on the fear of heights, shown with pie charts. o–q Local inhibition of vLGN-PAG axon terminals, with virus injections in vLGN and l/vlPAG. CNO was applied through cannula duplets implanted in the l/vlPAG region (o). Results of OHP tests and contextual fear conditioning tests are shown in (p) and (q) (n = 8 mice/group in p and 5 mice/group in q). Pink dots symbolize individual mice. Data are presented as the mean ± S.E.M. with a one-tailed (^$) or two-tailed (^#) Student’s t-test. The chi-square test (^) is used in (i) and (l). Source data are provided as a Source Data file.