Figure 4.

Stability of Internode Number with Age

(A and A′) Individual OLs were imaged in the motor cortex of Opalin–iCreER^T2: Tau–mGFP animals, and the primary cell processes/myelin internodes were marked and counted (white lines in A′). Scale bar, 20 μm.

(B) There was a small but significant decrease in the number of internodes over the course of the study (1-way ANOVA, p < 0.0001). Each data point in (B) is the average from all OLs analyzed in a given mouse. Asterisks indicate values significantly different from P60+10 (^∗∗p < 0.01), and number signs indicate values significantly different from P60+180 (^#p < 0.05 and ^##p < 0.01).

(B′) The number of processes/internodes plotted separately for each individual OL (47 OLs at P60+10, 56 OLs at P60+180, and 66 OLs both at P60+365 and P60+545; n ≥ 4 mice at each age). Error bars represent mean ± SEM.