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. 2005 Apr 20;25(16):4169–4180. doi: 10.1523/JNEUROSCI.0590-05.2005

Figure 8.

Figure 8.

Presymptomatic YAC128 mice show cognitive deficit in strategy shifting. Two-month-old YAC128 mice were tested in the swimming T-maze test with reversal. A, During the normal phase of the test, both YAC128 and WT mice learned to swim to the platform, and no differences were observed (trial: F(11,242) = 11.0, p < 0.001; genotype by trial: F(11,242) = 0.3, p = 1.0; genotype: F(1,22) = 0.0, p = 0.9). During the reversal phase, when the location of the platform was switched, YAC128 mice required significantly more time to find the platform than WT mice (WT, 4.9 ± 0.4 s; YAC128, 9.5 ± 1.2 s; p = 0.003). Error bars represent SEM. sec, Seconds. B, After the platform was switched to the opposite arm of the T-maze, none of the WT mice swam down the stem of the T-maze. In contrast, 3 of the 12 YAC128 mice retraced their steps to the starting position before swimming to the platform. This resulted in the YAC128 mice exhibiting more arm entries en route to the platform (χ2 = 6.0; p = 0.05). At this age, the swimming speed of YAC128 mice is equal to that of WT mice, indicating that motor coordination is normal at this time point (WT, 45 ± 6 cm/s; YAC128, 45 ± 6 cm/s; p = 0.99). n = 12 WT, 12 YAC128.