Figure 3.

Reduced number of active CA3-CA1 synapses in CaMK-Scrib^−/− mice. (A and B) Representative low magnification electron micrographs of hippocampal CA1 stratum radiatum region of Control (A_a) and CaMK-Scrib^−/− (B_a) mice and a higher magnification of a spinous synapse, marked by an asterisks in the respective low magnification panels (A_b and B_b). Scale bar = 588 nm (A_a, B_a) and 88 nm (A_b, B_b). (C and D) Shifted distribution of PSD thickness (C) and PSD length (D) towards smaller PSDs (shorter than 200 nm) in the stratum radiatum of CaMK-Scrib^−/− (red) compared to Control (black) (n = 1892/4 mice). Data were compared using Mann–Whitney, P = 0.001 (C) and P < 0.01 (D). (E) Input-output relationship was reduced in CaMK-Scrib^−/− slices (red) with respect to Control (black) (n = 12/6, P < 0.0001). Scale bars = 10 ms; 0.2 mV. Data were compared using two-way ANOVA, genotype effect, P < 0.001. (F) Similar PPRs at 25, 50, 100, or 200 ms in Control and CaMK-Scrib^−/− slices (n = 6). Scale bars = 50 ms; 50 (Control) and 20 (CaMK-Scrib^−/−) µV. Data were compared using Mann–Whitney. (G) Representative mEPSCs traces from Control (G_a) and CaMK-Scrib^−/− (G_b) CA1 neurons. Scale bars = 75 ms; 5 pA. (H) Similar average amplitudes of mEPSCs at Control and CaMK-Scrib^−/− CA3-CA1 synapses (n = 5). Data were compared using Mann–Whitney. (I) Average frequency of mEPSCs was decreased in CaMK-Scrib^−/− compared to Control CA3-CA1 synapses (n = 5). Data were compared using Mann–Whitney, P < 0.05. Data are represented as mean ± SEM.