(A) The distribution of average speeds for the entire population of tracked control and Dab1-/- mDA neurons. Overall distribution of average soma speeds of mDA neurons is not significantly altered in Dab1-/- slices compared to controls. Note that entire distribution of control (solid black line) and Dab1-/- mDA neurons (dashed black line) were compared (p=0.0657, Mann-Whitney’s test, n = 806 control, 844 Dab1-/- mDA neurons). (B) The same analysis as shown in (A) was carried out for the distributions of maximum (max) speed. At the population level (distributions were compared), max-speeds of Dab1-/- mDA neurons were shifted significantly towards slower speeds compared to controls (p<0.0001, Mann-Whitney’s test, n = 806 control, 844 Dab1-/- mDA neurons). Non-migratory (max-speed 0–10 μm/hr), slow (30–10 μm/hr), moderate (60–30 μm/hr) and fast cells (>60 μm/hr) are indicated by dark red, light red, yellow and light green background colors, respectively. (C,D) Total displacement (3D) of mDA neurons is significantly higher in moderate compared to slow mDA neurons, and higher in fast mDA neurons compared to moderate neurons in both control (C) and Dab1-/- (D) brains (****p<0.0001, **p<0.01, Kruskal-Wallis test; n = 680 control; n = 639 Dab1-/- cells, three slices/genotype). (E,F) Directionality (defined as ratio of total displacement to path length) in control and Dab1-/- slices is the least in slow mDA neurons, higher in moderate mDA neurons and the highest in fast mDA neurons (*p<0.05, **p<0.01, ****p<0.0001, Kruskal-Wallis test; n = 680 control; n = 639 Dab1-/- cells, three slices/genotype).