Fig. 6 Random walk analysis of MTs end behavior. (A) plus and minus ends of free MTs; (B) ends of long MTs. Mean square displacement in µm2 versus time. The results for plus ends for both free and long MTs are closely approximated by linear regression (dashed lines, 95% confidence intervals) and are statistically indistinguishable from each other. Minus ends on average show negligible displacement activity.