Huntington's Disease (HD) is an autosomal-dominant inherited progressive neurodegenerative disease from the group of CAG repeat/polyglutamine diseases and is characterized by a triad of psychiatric alterations, dementia and motor dysfunction. On a sub-cellular level, a mutation with extended CAG tri-nucleotide repeats has been identified as the cause of HD. The therapeutic effects of certain substances can be tested on neurotoxically-induced or transgenic animal models with expanded CAG-repeats. In the present invention, transgenic rats were generated and characterized for human HD. Said rat model for human HD and other diseases of the CNS carries 51 CAG repeats under the control of a rat promoter and has a slow progressive neurological phenotype, closely reflecting human HD syndrome. The comparability of the rat model in relation to human HD is characterized by neuropathological, neuroradiological and neurochemical modifications accompanied by typical behavioral symptoms.