Extended Data Fig. 4: In vivo whole-cell recordings from DNs upon looming stimulation.
From: Synaptic gradients transform object location to action
a, Left: Schematic of looming array stimuli at different azimuths (32.5°, 45°, 57.5° and 70°). Each loom consists of three dark disks in the white background. Pseudo-colored for clarity. Middle: looming array disk size over time from the beginning of stimulus. Each disk expands from 0° to 30° at 500°/s. Right: Stimulus arrangement projected onto fly’s eye (0° front of fly). To align looming array stimuli more closely with the synaptic gradients, the whole plane of the stimuli was pitched down 20°. b, Top: whole-cell electrophysiological recordings of the GF and DNp04 to looming stimuli at 32.5° in azimuth. Shown are representative traces from a single fly and stimulus. Middle: change of disk size over time. Bottom: baseline region and response region defined in the traces for analysis of DN activity. c, Representative DN responses showing identified spikes (top rasters). d, Representative responses from a single fly for 32.5° (top) and 70° (bottom) azimuth looming stimuli. Representative traces for GF and DNp04 are from a single fly with 6 trials to each stimulus. e, Spike raster plots of DNp04 in 150 ms time window after the onset of looming stimuli. f, Pooled mean of DNp04 spike numbers across individual flies (from “e”). Error bars, SEM; RM one-way ANOVA, Dunnett’s test. g, Averaged response of the representative traces in d shows subthreshold depolarizing responses to looming stimuli. Shaded area under the line shows estimated depolarization from the baseline. h, Pooled mean of integrated potentials for DNp04 and GF across individual flies. Error bars, SD; RM one-way ANOVA, Dunnett’s test. i–j, Mean spike numbers (i) and mean of integrated potentials (j) across trials in individual flies in response to looming stimuli. Colored lines denote the representative traces of each DN in Fig. 3a and Extended Data Fig. 4b. Detailed description of statistical tests and p-values for panels “f, h” is available in Supplementary Table 1.
