Spontaneous morphological changes of hippocampal dendritic spines under basal conditions. (A) Representative images of a cultured hippocampal neuron transfected to express cytosolic EGFP. Zoomed images of the same dendrite at two time points, as shown by the schematic diagram below. Examples of growing spines and shrinking spines are depicted by triangles and circles, respectively. Scale bar in all panels: 5 μm. (B) A cumulative probability plot of spine volume (arbitrary units) for 1421 spines from 20 neurons at t = 0 (black) and t = 10 (green). (C) A cumulative probability plot of normalised spine volume to show spine dynamics over a 10 min period. To obtain this, the volume at t = 10 was divided by the volume at t = 0 for each of the 1421 spines. The dotted lines depict no change (black) or a change of ± 25% (grey). Inset: Data were subdivided into growing, shrinking or “stable” spines, based on the changes (±25%) over this 10 min period, for illustrative purposes.