TY - JOUR T1 - Selective Discrimination Learning Impairments in Mice Expressing the Human Huntington's Disease Mutation JF - The Journal of Neuroscience JO - J. Neurosci. SP - 10428 LP - 10437 DO - 10.1523/JNEUROSCI.19-23-10428.1999 VL - 19 IS - 23 AU - Lisa A. Lione AU - Rebecca J. Carter AU - Mark J. Hunt AU - Gillian P. Bates AU - A. Jennifer Morton AU - Stephen B. Dunnett Y1 - 1999/12/01 UR - http://www.jneurosci.org/content/19/23/10428.abstract N2 - Cognitive decline is apparent in the early stages of Huntington's disease and progressively worsens throughout the course of the disease. Expression of the human Huntington's disease mutation in mice (R6/2 line) causes a progressive neurological phenotype with motor symptoms resembling those seen in Huntington's disease. Here we describe the cognitive performance of R6/2 mice using four different tests (Morris water maze, visual cliff avoidance, two-choice swim tank, and T-maze). Behavioral testing was performed on R6/2 transgenic mice and their wild-type littermates between 3 and 14.5 weeks of age, using separate groups of mice for each test. R6/2 mice did not show an overt motor phenotype until ∼8 weeks of age. However, between 3.5 and 8 weeks of age, R6/2 mice displayed progressive deterioration in specific aspects of learning in the Morris water maze, visual cliff, two-choice swim tank, and T-maze tasks. The age of onset and progression of the deficits in the individual tasks differed depending on the particular task demands. Thus, as seen in humans with Huntington's disease, R6/2 mice develop progressive learning impairments on cognitive tasks sensitive to frontostriatal and hippocampal function. We suggest that R6/2 mice provide not only a model for studying cognitive and motor changes in trinucleotide repeat disorders, but also a framework within which the functional efficacy of therapeutic strategies aimed at treating such diseases can be tested. ER -