(a) Short- or long-term effect of Rac1 [WT (wild-type), CA (constitutively-active), or DN] on spine morphology in mature neurons. Bars, -fold changes of spine size by introduction with Rac1-CA or -DN relative to that with Rac1-WT. (b) Short- or long-term effect of DISC1 knockdown (in green) or overexpression (in red) in mature neurons. (c) Reduced spine size by knockdown of DISC1 for 6 days in primary cortical culture. (d) Decrease in mEPSC by long-term DISC1 knockdown. (e) Spine deterioration (decreased spine size) by long-term knockdown of DISC1 was normalized by overexpression of DISC1-FL, but not by that of DISC1-ΔKal-7. *P < 0.05, #P < 0.001. (f) Spine deterioration (decreased mEPSC frequency) by long-term knockdown of DISC1 was normalized by overexpression of DISC1-FL, but not by that of DISC1-ΔKal-7. Bar, s.e.m. *P < 0.05. Scale bar, 10 μm.