Fig. 8

The ZIr-PAG projection mediates the modulatory effects on defense behaviors. a Experimental paradigm. LED was applied to PAG, and muscimol was injected into ZIr as to prevent antidromic stimulation. b Normalized average speed responding to noise without (gray) and with (blue) LED stimulation plotted for an example animal. c Summary of noise-induced peak speed without and with activation of ZIr-PAG projections. ***p = 0.003, two-sided paired t-test, n = 8 animals. d Summary of noise-induced travel distance without and with activation of ZIr-PAG projections. *p = 0.021, two-sided paired t-test, n = 8 animals. e Percentage of time freezing during presentations of CS alone without and with activation of ZIr-PAG projections in conditioned mice. ***p < 0.001, two-sided paired t-test, n = 10 animals. Solid symbol represents mean ± s.d. for all panel