Figure 2. Genetically inhibiting PAK1 activity block light effect on memory.

(a,b) Total-PAK1 was undetectable in KO mice in contrast to that in WT mice (n = 4 per group). (c,d) The light treatment before learning had no effects on learning (Light, n = 27, Dark, n = 24; group, F_{(1, 49)} = 0.005, P = 0.946, repeated measured ANOVA), STM (0.5 h, Light, n = 12, Dark, n = 15; t₍₂₅₎ = 0.143, P = 0.888, t test) and LTM (6 h, Light, n = 12, Dark, n = 15; t₍₂₅₎ = 0.558, P = 0.582, t test), and (e) LTM without STM test (6 h, n = 12 per group; t₍₂₂₎ = 0.608, P = 0.550, t test), in relative to those of Dark group in KO mice. (f,g) Active PAK1 was at a very low level and not responsive to the light treatment in DN mice, but it was significantly increased by the light treatment in WT mice (n = 4 per group; F_{(3, 15)} = 10.331, **P = 0.001, one-way ANOVA, the post-hoc test for WT Light group compared to DN Dark, WT Dark and DN Light: ***P = 0.000, **P = 0.002, **P = 0.001), and (h) total-PAK1 was unaffected (F_{(3, 15)} = 0.400, P = 0.756, one-way ANOVA). (i,j) Similar to KO mice, the light treatment produced no effects on learning (Light, n = 24, Dark, n = 26; group, F_{(1, 48)} = 1.664, P = 0.203, repeated measured ANOVA), STM (0.5 h, Light, n = 12, Dark, n = 14; t₍₂₄₎ = 0.783, P = 0.441, t test) and LTM (6 h, Light, n = 12, Dark, n = 14; t₍₂₄₎ = 0.102, P = 0.920, t test), and (k) LTM without STM test (6 h, n = 12 per group; t₍₂₂₎ = 0.053, P = 0.959, t test) compared to those of Dark group in DN mice.