Cortical activity in Parkinson’s disease during executive processing depends on striatal involvement

Abstract

doi:10.1093/brain/awl326 Brain (2007), 130, 233–244 Cortical activity in Parkinson’s disease during executive processing depends on striatal involvement Oury Monchi,1,2 Michael Petrides,3 Beatriz Mejia-Constain1,2 and Antonio P. Strafella3,4 1Functional Neuroimaging Unit, Research Centre, Institut Universitaire de Ge´riatrie de Montre´al, 2Department of Radiology, Universite´ de Montre´al, 3Montreal Neurological Institute, McGill University, Montreal, Quebec and 4UNH-Toronto Western Hospital and CAMH-PET Imaging Center, University of Toronto, Toronto, Ontario, Canada Correspondence to: Oury Monchi, PhD, Centre de recherche, Institut Universitaire de Ge´riatrie de Montre´al, 4565 Queen Mary Road, Montreal, H3W 1W5, QC, Canada E-mail: oury.monchi@umontreal.ca Patients with idiopathic Parkinson’s disease exhibit impairments in executive processes, including planning and set-shifting, even at the early stages of the disease. We have recently developed a new card-sorting task to study the specific role of the caudate nucleus in such executive processes and have shown, using functional magnetic resonance imaging (fMRI) in young healthy adults, that the caudate nucleus is specifically required when a set- shift must be planned. Here the same fMRI protocol was used to compare the patterns of activation in a group of early-stage Parkinson’s disease patients (seven right-handed patients at Hoehn and Yahr stages 1 and 2; mean age 62 years, range 56–70) and matched control subjects. Increased cortical activation was observed in the patients compared with the control group in the condition not specifically requiring the caudate nucleus. On the other hand, decreased cortical activation was observed in the patient group in the condition significantly involving the caudate nucleus. This event-related fMRI study showed a pattern of cortical activation in Parkinson’s disease characterized by either reduced or increased activation depending on whether the caudate nucleus was involved

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