Five choice serial reaction time performance in Mn-exposed animals (A) and in control non-Mn-exposed animals (B). A. Manganese exposure had a significant effect on reaction times, with significantly increased reaction times appearing beginning around the 3rd to 5th months of Mn exposure. Movement times were generally unaffected except at the last timepoint and most of this effect was driven by a single animal. B. In comparison to Mn-exposed animals, control animals performed the task with remarkable stability over the course of the study period. No changes over time were observed in either reaction or movement times in the control animals. Data are presented as means ± SEMs; numbers on x-axis indicate months; *p < 0.05, **p < 0.01, ***p < 0.0001, ^p < 0.001 vs. respective baseline (B) performance).