Quantitative measurements of neurite remodeling. Neurite length and remodeling and soma movement were measured using a series of images of eGFP-expressing hippocampal pyramidal neurons taken at 1 h intervals. The panels on the left (A, C, E) show the data for individual neurons; the data in the right panels (B, D, F) show the mean data ± SEM for all 8 neurons studied. In A, the lengths of the principal neurites from a single neuron is shown. In B, the averaged data from 23 principal neurites of 8 neurons are shown (mean ± SEM). While individual neurite lengths varied (A) there was no net overall outgrowth (B). In C, the "movement index" of the neurites of a single neuron is shown. The "movement index" gives a mathematical average of the movement of neurites normalized to neurite length (see text). In D, the mean movement index for neurites shows a linear increase with time, indicating that there is a comparatively constant rate of remodeling. Movement of the individual somata of 8 neurons (E) and the averaged amount of soma movement (F) exceed the degree of neurite movement.