Evidence for dissociable motor skills in Huntington’s disease patients

Abstract

It has been proposed that the striatum is critical for acquiring new motor skills. Previous experiments have shown that patients with striatal dysfunction are impaired in acquiring new motor skills, but the tasks have always used stimuli that move in a repeating, predictable pattern. Four experiments showed that Huntington’s disease (HD) patients are impaired in learning such skills, but can learn at a normal rate skills that require the learning of a new perceptual-motor mapping. HD patients were impaired in learning a repeating motor sequence in a keypressing task. When the repeating sequence was removed and the stimulus-response mapping was made spatially incompatible, HD patients showed normal learning. HD patients learned a maze task when responding with a computer mouse but were impaired on a variation that required keypress responses. Control subjects showed no sensitivity to the repetitive sequence of movements in the mouse version, but part of their knowledge was sequence based in the keypress version. The neural basis of motor skill components is discussed. © 1993, Psychonomic Society, Inc.. All rights reserved.