Fig. 2

Behavioral impairments associated with hα-syn overexpression in rats. a Spontaneous locomotor activity at baseline (Bsl) and at 4, 8, 12 and 16 weeks after surgery. b Stepping test at baseline and at 4,8,12 and 16 weeks after surgery. c Color-coded stick diagram decomposition of hindlimb movement for a representative healthy and AAV-hα-syn rat during crossing of an elevated horizontal ladder with irregularly spaced rungs (spacing 5.2 +/− 0.3 cm). The corresponding endpoint trajectory is shown below. The colour code indicated the instantaneous velocity of the endpoint, while the arrows report the orientation and intensity of the foot push-off at swing onset. Light grey: stance; dark grey: hit; yellow: slip; dark red: miss. d Pie charts summarize total percentage of hits, slips, and misses (total of 182 steps evaluated, n are indicated in the legend boxes). Below percentage of hits, slips and misses are quantified as histogram plots. e The same representation is shown for a representative healthy and Parkinsonian rat during overground locomotion. f Principal component (PC) analysis was applied on 89 gait parameters measured during overground locomotion (10–15 gait cycles/hindlimb/rat, n = 4 healthy and n = 6 AAV-hα-syn rats). Each gait cycle is represented as a dots in the new space created by PC1–3. Histogram plot depicts mean values of PC1 scores for each experimental group. g Histogram plots represent mean values of parameters with high factor loading (|factor loading| > 0.5) on PC1, illustrating the most salient differences in motor control between the two groups. Numbers refer to Additional file 1: Table S1. *p < 0.05; **p < 0.01; ***p < 0.001; $ p < 0.05 vs 4 weeks time point; error bars, SEM; PC, Principal Component; a.u., arbitrary unit