Weekly values of the withdrawal reflex latency test. At week-1 all animals failed in responding to the noxious thermal stimulus within the 12 sec cut-off time. No differences between the percentages of motor deficit obtained by the Extensor Postural Thrust (EPT) test. * Significantly different from week-0 all groups pooled together (p < 0.05). Results are presented as mean and standard error of the mean (SEM).