Figure 4. Food rapidly reduces AGRP neuron activity.

a,b Configuration for deep-brain calcium imaging from AGRP neurons in freely-moving mice. c,d, Image of AGRP^GCaMP6f neurons (c) by deep-brain calcium imaging and their ROI spatial filters (d) for image analysis. Scale bar, 15 μm. e, Change in baseline GCaMP6 fluorescence for neurons in mice under AL-fed and FR conditions (61 neurons, 4 mice). f, From FR mice, GCaMP6f fluorescence traces from subset of individual neurons in (c,d) during chow pellet food consumption. Black line, food delivery. Blue bars, food consumption. g, Normalised Ca²⁺ responses of AGRP neurons (99 neurons, 4 FR mice) during exposure to a chow food pellet (left) and a false food pellet (right). Black lines, chow/false food delivery. Red lines, first contact with chow/false food. h, Mean calcium responses to chow food and false food aligned to delivery time (99 neurons, 4 FR mice). Shading: s.e.m. i, Change in normalised GCaMP6 fluorescence comparing initial baseline activity, first food exposure, and after consuming to satiety (110 neurons, 4 FR mice). j, GCaMP6f fluorescence traces from 2 example neurons (2 mice) during short trials of food (top) and false food (bottom) delivery. k, Mean GCaMP6 fluorescence responses from individual mice to chow food exposure aligned with food delivery (left) and food contact (right). l, Mean GCaMP6 fluorescence responses before (black) and after (red) cued Pavlovian trace conditioning (before: 60 neurons, after: 65 neurons, 3 mice). Black and red bars, range for first lick of liquid food. Shading: s.e.m. ***p<0.001. Values are means ± s.e.m.