a, Images of male PND25 wildtype (βII-SpNexWT) mice and mice lacking βII-spectrin only in cortical and hippocampal projection neurons (βII-SpNexKO) driven by Nex-Cre. b–e, Magnitude of acoustic startle responses (b,d) and percent of prepulse inhibition (c,e) in βII-SpWT mice and mice with partial (βII-SpHet) and complete (βII-SpKO) loss of βII-spectrin in neural progenitors driven by Nestin-Cre. Trials included no stimulus (NoS) trials and acoustic startle stimulus (AS; 120 dB) alone trials. Data in b and c represent mean ± SEM (n = 15 βII-SpWT and n = 5 βII-SpKO male mice). Data in d and e represent mean ± SEM (n = 12 male mice/genotype). Fisher’s PLSD tests following repeated measures ANOVA. b,*P < 0.05, **P < 0.01. c–e, P > 0.05. f, Latency to fall from an accelerating rotarod. Trials 4 and 5 were given 48 h after the first three trials. g,h, Latencies to find the hidden escape platform during acquisition (g) and reversal (h) learning phases of the Morris water maze test for βII-SpWT and βII-SpHet mice. Data represent mean ± SEM of four trials per day. Fisher’s PLSD tests following repeated measures ANOVA. f–h, P > 0.05. i,j, Mice were given a one-minute probe trial without the platform following the acquisition and reversal phases of the Morris water maze test. Target indicates the site where the platform had been located in each phase. Measures were taken of swim path crossings over the target location or corresponding areas in the other quadrants. Within-genotype repeated measures ANOVA, effect of quadrant (the repeated measure), **P = 0.0012, ****P < 0.0001. k,l, Preference for social novelty during a three-chamber choice task. Within-genotype repeated measures ANOVA, *P = 0.0145, **P = 0.0052. Data in f–l represent mean ± SEM (n = 12 male mice/genotype). m, Lack of significant genotype effects on anxiety-like behavior in the elevated plus maze, marble-burying assay, and open field; sensory ability in the buried food test for olfactory function and hot plate test for thermal sensitivity; and vision and swimming ability in the Morris water maze. Data represent mean ± SEM (n = 12 male mice/genotype). Within-genotype repeated measures ANOVA, P > 0.05.