Figure 4
Properties of spine shrinkage in vivo. (A) The ratio of head volume shrinkage (−ΔVH) >30% among stimulated spines and shrinkage longevity. The left stacked bar chart depicts the ratio of shrunken spines to remaining spines for all dendrites (17). The right chart depicts the distribution of shrinkage durations. Numbers in the bars indicate the number of spines. (B) The bar graph depicts spine shrinkage (i.e., changes in head volume [ΔVH]) in the absence (−19% ± 4%; median = −18%, IQR = −37%:−1.5%; 43 spines) and in the presence (1.1% ± 3.3%; median = 2.0%, IQR = −5.8%:6.4%; 12 spines) of the NMDA receptor antagonist APV. Error bars represent the standard error of the mean (SEM). **p < 0.00014, based on Wilcoxon signed-rank test (versus zero). (C) The average amplitude of shrinkage among stimulated spines and their neighboring spines <3 µm away (−8.5% ± 3.6%; median = −9.6%, IQR = −22.0%:5.5%; 56 spines) or 3–10 µm (2.5% ± 3.1%; median = 2.5%, IQR = −10.4%:14.2%; 59 spines) from stimulated spines. *p < 0.05 and **p < 0.01, based on Wilcoxon signed-rank test (versus zero). The error bars represent SEM. (D) Spine shrinkage among neighboring spines (ΔVNeighbors) at <3 µm is plotted against spine shrinkage of stimulated spines (ΔVStimulated). The average values are calculated within the ranges of ΔVStimulated, as indicated above the plot and in Supplementary Fig. S5B. Samples within each range are indicated by color codes. Error bars represent standard deviation. Spine shrinkage spread is analyzed via a one-way ANOVA (p < 0.05). *p < 0.05, based on Tukey’s post hoc multiple comparison tests; **p < 0.01, based on Wilcoxon signed-rank test (compared to zero).
