Fig. 1

Development of defensive behaviors to visual threat. a Schemata of the behavioral test. An entrance to the shelter is represented by a dotted line. b Trajectories of mice after expanding disk stimuli were applied. Traces obtained from a single naïve mouse of the indicated age are shown in each panel. c Plots for the development of average velocity during the 10 s before the onset of visual stimuli. d Plots for the development of maximum velocity for escape. The maximum velocity during the 5 s after the onset of visual stimuli was collected. e–h Developmental change in probabilities of escape (e), freezing (f), startle (g) and rearing (h) response to expanding disk stimuli. Smaller symbols connected with dotted lines represent the average probability calculated from the first three trials during the 15-min test period. * or ** represents P < 0.05 or P < 0.01 with Steel–Dwass test following Kruskal–Wallis (KW) test. Error bars, ± SEM