Strain-dependent differences in LTP and hippocampus-dependent memory in inbred mice - PubMed (original) (raw)

Figure 2

Performance of BL/6, DBA/2, CBA and 129/SvEms mice in the Morris water maze task. (A) Mice were trained with one trial a day for 13 consecutive days in the hidden-platform version of the water maze. The average time to reach the platform (latency) is plotted versus trial day. BL/6, 129/SvEms, and DBA/2 mice improved significantly with training (P < 0.001), whereas CBA mice did not (_P_ > 0.05). (B) The graph shows the results of a probe trial given on day 14, 1 day after the completion of training. BL/6 and 129/SvEms mice spent significantly more time in the training quadrant (TQ) than in the adjacent quadrants to the left of TQ (TQ vs. AL, _F_1,22 = 3.62, P < 0.001 for BL/6; _F_1,16 = 4.39, _P_ < 0.001 for 129/SvEms mice), to the right of TQ (TQ vs. AR, _F_1,22 = 3.18, _P_ < 0.005 for BL/6; _F_1,16 = 2.43, _P_ < 0.05 for 129/SvEms mice), or opposite TQ (TQ vs. OQ, _F_1,22 = 8.26, _P_ < 0.0001 for BL/6; _F_1,16 = 7.18, _P_ < 0.0001 for 129/SvEms mice). DBA/2 mice spent an equal amount of time in the TQ and the AR quadrants (_F_1,32 = 0.17, _P_ > 0.05) but spent significantly more time in the TQ than in the AL quadrant (_F_1,32 = 3.63, P < 0.001) or in the OQ quadrant (_F_1,32 = 5.57, P < 0.0001). CBA mice searched at chance levels in all four quadrants (TQ vs. AL, _F_1,14 = 0.09, P = 0.34; TQ vs. AR, _F_1,14 = 0.07, P = 0.93; TQ vs. OQ, _F_1,14 = 2.06, P = 0.05). (C) BL/6 and 129/SvEms mice also crossed the exact site where the platform was located during training significantly more often than in the AR quadrant (TQ vs. AR, _F_1,22 = 3.18, P < 0.005 for BL/6; _F_1,16 = 3.10, P < 0.005 for 129/SvEms mice), the AL quadrant (TQ vs. AL, _F_1,22 = 3.10, P < 0.005 for BL/6; _F_1,16 = 4.28, P < 0.0001 for 129/SvEms mice), or the OQ quadrant (TQ vs. OQ, _F_1,22 = 5.20, P < 0.0001 for BL/6; _F_1,16 = 5.43, P < 0.0001 for 129/SvEms mice). DBA/2 mice crossed the TQ and the AR quadrants a similar number of times (_F_1,32 = 1.54, P = 0.13). However, DBA/2 mice crossed the equivalent sites in the AL (_F_1,32 = 3.71, P < 0.001) and OQ (_F_1,32 = 4.35, P < 0.0001) quadrants fewer times. CBA mice crossed similarly in all four quadrants (TQ vs. AL, _F_1,14 = 2.04, P = 0.32; TQ vs. AR, _F_1,14 = 0.85, P = 0.41; TQ vs. OQ, _F_1,14 = 0.78, P = 0.44).