Reversible Behavioral Deficits in Rats during a Cycle of Demyelination-Remyelination of the Fimbria
Panel A, Total distance traveled during active place avoidance. Rats injected with LPC or saline traveled a similar distance at both 4 and 14 days (F(3,19) = 1.71). Panel B, Representative tracks of rats 4 or 14 days after saline or LPC injection on the final (6th) trial of active place avoidance. Red lines indicate the shock zone boundaries and the red circles indicate the locations where shocks were delivered. Panel C, Summary of the number of shock zone entrances in each trial of active place avoidance. At 4 days, saline- and LPC-injected animals showed a significant effect of treatment (F(1,10) = 16.31, p<0.005) and trial (F(5,50) = 4.20, p<0.005) with no interaction of treatment and trial (F(5,50) = 0.47). At 14 days, saline and LPC-injected animals had an no significant effect of treatment (F(1,10) = 0.23), but there was a significant effect of trial (F(5,55) = 5.81, p<0.001). Saline-treated animals analyzed at 4 and 14 days showed no significant effect of days (F(1,12) = 1.78), but there was a significant effect of trial (F(5,60) = 3.35, p<0.0005). LPC-injected rats at 4 and 14 days, trended toward an effect of days (F(1,9) = 4.0, p = 0.08) but had a significant effect of trial (F(5,45) = 10.4 p<0.0001) and a significant interaction of treatment and trial (F(5,45) = 2.62, p<0.05). These data suggest that saline-injected animals acquired the active place avoidance task at both 4 and 14 days, whereas LPC-injected animals acquired the task only at 14 days. Saline- and LPC-injected animals differed in their acquisition the task at 4, but not 14 days.