Plot of Sholl analyses of dendrite bifurcations and spine density of F-ERF and S-ERF neurons.

A sample of 10 pyramidal cells (5 F-ERF neurons and 5 S-ERF neurons) were analyzed. In A and C, the dark curve represents the mean result from the F-ERF neurons, and the dashed curve, the mean result for the S-ERF neurons. Error bars represent ± SEM. (A) Dendrite Sholl analysis of the two types of neurons. Inset illustrates the method of Sholl analysis, Bar = 20 µm. Number of Sholl intersections along the dendritic trees at all distances from the soma revealed statistically significant differences between the F-ERF and S-ERF neurons (t-test, P<0.05). (B) Comparison of total number of Sholl intersections between the F-ERF and S-ERF cells. Number of intersections was counted in 200 µm radius from the soma along the dendritic tree. The mean intersections for F-ERF cell group (n = 5) is 198.011.9 and that for the S-ERF cell group (n = 5) is 126.214.2. The difference is significant (P<0.05, t-test). (C) Plots of spine densities as a function of distance from the soma. Number of spines was calculated per 20 µm dendrite. The dendrites of F-ERF neurons have a higher spine density than S-ERF neurons, especially at the proximal segments of dendrites (20, 40, 60 µm levels from cell body, t-test, P<0.01). (D) Comparison of mean spine density between the F-ERF and S-ERF cells. Spine density (number of spines/10 µm dendrite) was averaged for the sample of cells in 200 µm radius from the soma. The mean spine density for the F-ERF neuron group is 4.030.67 and that for the S-ERF neuron group is 3.330.37. The difference is not significant (P>0.05, t-test). All values were obtained after correction for shrinkage.