Figure 4.

Structural plasticity is completely absent in Cttn-deficient hippocampal neurons. (A) Analysis of dendritic spine density of hippocampal WT and Cttn-KO neurons. n = number of dendrites analyzed. (B) Analysis of the average dendritic spine head diameter under basal conditions as well as 60 min after induction of chemically induced NMDAR-mediated long-term potentiation (cLTP). Note that structural plasticity (i.e., growth of dendritic spine head diameter) is completely missing in Cttn-deficient hippocampal neurons. Representative image depicts maximum intensity projection image of a healthy individual dendritic segment and an example of a dendritic spine head diameter analysis. n = number of dendrites analyzed. Scale bar = 1 µm. (C,D) Recovery curves (EGFP-ß-actin) of individual dendritic spines from (C) WT and (D) Cttn-KO hippocampal neurons under baseline conditions as well as in the first 15 min after chemical induction of LTP. (E) Quantification of the turnover time and the fraction of dynamic actin (the amount of actin the fluorescence of which recovered in the time period of 180 s after the photobleach) under baseline conditions as well as in the first 15 min after chemical induction of LTP. n = number of dendritic spines analyzed. Data information: Statistic tests used: For normal distribution of data: Kolmogorov-Smirnov Test, Parametric Tests: Two-Way ANOVA and Sidak’s Multiple Comparisons, Non-Parametric Tests: Kruskal-Wallis Test and Dunn’s test; data depicted as means ± SEM, detailed information on p values as well as statistical tests is depicted in Table S1; significances are indicated by * p value < 0.05, ** p value < 0.01 and *** p value < 0.001.