Figure 7.

Cognitive deficits are primarily responsible for increased latencies to reach the platform in swimming tests. A, The swimming speed of the mice was assessed by measuring how long the mice took to swim linearly to the platform (P) along the top of the T in the swimming T-maze. YAC128 mice swam slower than WT mice, indicating a deficit in motor coordination at 8.5 months of age (WT, 48.2 ± 2.7 cm/s; YAC128, 39.1 ± 2.0 cm/s; p = 0.01). B, Using swimming speed to calculate the difference in latency to reach the platform predicted by motor deficit alone and comparing this to the actual difference observed reveals that motor dysfunction only accounts for a small percentage of the difference. Most of the difference in the latency to reach the platform results from cognitive deficits. n = 12 WT, 13 YAC128. sec, Seconds.