Fig. 1

Optogenetic activation of IPN neurons elicits place avoidance. a Upper: Schematic of recording set-up; lower: light-evoked current (1 s, 100 pA scale) and action potentials in IPN neurons (50 ms, 10 mV scale). b Fluorescent image of IPN ChR2 expression (green) and proximal VTA (magenta TH staining) (250 μm scale). c Timeline and schematic of experimental set-up. d Preferences for photo-stimulation side vs. no stimulation side in RTPT with 20 Hz stimulation; unpaired t-test (two-tailed), t₁₂ = 2.922, P = 0.0128, n = 7 mice per group. e Representative heat maps of animal positions during 20 Hz and 1 Hz stimulation. f Time spent (5 min bins) on photo-stimulation side (blue box) and no-stimulation side (grey box) at 20 Hz and g at 1 Hz. Data presented as mean ± SEM, * P < 0.05