Long Lasting Protein Synthesis- and Activity-Dependent Spine Shrinkage and Elimination after Synaptic Depression
Figure 4
Spine shrinkage and elimination mediated by mGluR-LTD is long lasting.
A) Representative two-photon images (maximum-intensity z-stack projections) of secondary dendrites from CA1 neurons transfected with Dendra-2C before and after LTD induction (DHPG). Z-stacks projections were collected once every 30 min for 12 h. Empty arrowheads indicate spines that shrink or eliminate and filled arrowheads indicate spines that do not change or grow 12 h and 24 h after LTD induction. B) Spine shrinkage was observed for over 24 hours following LTD induction. Normalization was performed as a percent of the average baseline volume of each spine (pooled data from 4 cells). C) Long lasting spine shrinkage and elimination are independent of initial spine size. Two-dimensional plot of initial versus final spine head diameter (µm) (15 min before and 12 h or 24 h after LTD). Spines which fall along the horizontal line do not show a change in volume. D) Quantification of spines that shrink, grow, or do not change after 12 h of mGluR-LTD induction from pooled data of 53 spines/4 cells. The shaded area within the shrinkage bar corresponds to the percentage of spines which are eliminated. *p<0.001. Error bars indicate means ± SEM.