CrebB::GFP was removed from neurons and antibody stainings were conducted along with appetitive olfactory conditioning experiments. (A, B) Brains were stained with anti-GFP antibodies (green), anti-Repo antibodies (red) and DAPI (blue). (A, A’, A’) In CrebBcKO, tubGal80ts brains, CrebB::GFP was detected in most of the cells. (B, B’, B’’) After pan-neuronal induction of CrebB::GFP knockout, GFP was only expressed in Repo-positive glia cells. Scale bars: 50 μm. (C–E) Short-term, middle-term and long-term memory performance was assessed. (C,D) Pan-neuronal CrebB knockout did not affect STM (N ≥ 10) and MTM (N = 8). (E) LTM, tested 24 h after conditioning, was severely impaired in flies with induced CrebB knockout in all neurons. Memory performance of male CrebBcKO/Y; tubGal80ts/UAS-FLP; nSyb-Gal4/+ flies was significantly lower than in female flies (CrebBcKO/+; tubGal80ts/UAS-FLP; nSyb-Gal4/+), and in male flies of the parental control flies. N ≥ 9. Bar graphs represent the mean and error bars represent the standard error of the mean (SEM). Asterisks denote significant differences between groups; *p<0.05, **p<0.01 (Welch two sample t-test).