Figure 4.

Phenotype of spine alterations is validated in hippocampal tissue. (A,B) Sample images of Golgi-impregnation of apical dendrite branches in the CA1 stratum radiatum from WT and KIBRA KO brains (classification of spine types as shown in Figure 1B). (C–F) Quantification of different spine types reveals similar increase of filopodial-like long protrusions as in the neocortical tissue (Figures 1D–G). (G) Frequency distribution of neck lengths across all types of spines (bin width = 0.5 µm), inset shows median and interquartile range. (H–K) Also similar to the somatosensory cortex, the distribution of marker proteins synapsin, VGLUT1, VGAT and synaptopodin is revealed by immunolabeled sections from WT and KO. Series of 10–20 sections from at least 3 animals/genotype were independently assessed by two researchers with no differences in pattern or intensity observed. Data in (C–F) are displayed as means ± SEM; n = 12 dendritic branches from 12 neurons/3 animals. Statistical analysis was done with a Mann-Whitney test (for exact median and U-values see Section Analysis of Hippocampal CA1 Confirms Increase of Filopodial-Like Long Spines but Fails to Reveal LTP Impairments in Young-Adult KIBR KO Mice of main text), and level of significance indicated as **P < 0.01; *P < 0.05; n.s., not significant. Scale bar in (A) = 5 µm (for A,B); in (H1) = 100 µm (for H1–K2).