Ts65Dn mice are a genetic model for Down syndrome. Both individuals with Do
wn syndrome and Ts65Dn mice have reduced cerebellar volumes and the cerebel
lum is involved in motor learning. Conflicting results have been reported o
n the motor learning abilities of Ts65Dn mice, which may be related to proc
edural differences between the motor learning tasks used in different labor
atories and/or variability in phenotype because of the segregating backgrou
nd on which the mice are maintained. In this study, we examined learning in
three types of motor tasks (peg running, accelerating rotorod, and rotatin
g rod) which were initially easy for mice and gradually increased in diffic
ulty Ts65Dn mice learned the peg running task as well as controls, and lear
ned the accelerating rotorod and rotating rod tasks as well as, and even be
tter than, controls. These data indicate that Ts65Dn mice are not impaired
in motor learning. (C) 2001 John Wiley & Sons, Inc.