Extended Data Fig. 2: iChloC activation strongly reduces neuronal firing and disrupts defensive behaviour without affecting basal locomotion.

a, Example voltage traces showing a VGluT2⁺ dmSC neuron expressing iChloC responding to current steps in control conditions (light off, left) and during continuous illumination with 473-nm light (light on, right). b, Summary of the relationship between current injection and action potential firing showing a strong reduction in firing upon illumination (left, average 87.9 ± 3% reduction across all steps, P = 1.7 × 10⁻⁹ for a main effect of light, two-way repeated measures ANOVA; P < 0.05 for simple effects of light on current steps larger than 100 pA), as well as a strong reduction in input resistance (right, 73.2 ± 3% reduction, P = 1.23 × 10⁻⁸, t-test)^. Summary data are pooled from 6 dPAG and 3 dmSC cells. c, For the 18% of trials in which VGluT2⁺ mice expressing iChloC in the dmSC escape from threat stimuli during continuous illumination (light on), the vigour of escape is significantly lower (77 ± 7% of light off) when compared to escapes elicited without iChloC activation (light off; n = 7 trials, n = 6 out of 9 mice, P = 0.0253, paired t-test). d, Movement during exploration is not affected by iChloC activation in dPAG- or dmSC-targeted mice in the absence of threat, quantified as the maximum speed in the 5-s stimulation period (light on) or control period (light off) as a percentage of the 5-s pre-stimulation period (P = 0.8767 for dPAG, P = 0.3443 for dmSC, U-test). e, Optic fibre placements for all experiments in dPAG (n = 6 mice, blue circles) and dmSC (n = 9 mice, magenta circles), coordinates are in mm and from bregma. Mouse brain images adapted from ref. ⁴⁶ and reproduced with permission from Elsevier.