The role of the striatum and hippocampus in planning: a PET activation study in Parkinson's disease.
Previous work has identified the prefrontal cortex (PFC) and striatum as participating in the planning and selection of movements. We compared the brain activation patterns during planning in Parkinson's disease patients and age-matched controls using H(2)(15)O-PET and the Tower of London (TOL) task. In this study, our mildly affected Parkinson's disease group performed as well as the control group but showed a different pattern of neuronal activation. In the two groups, overlapping areas of the PFC were activated but, whereas the right caudate nucleus was activated in the control group, this was not evident in the Parkinson's disease patients. This suggests that normal normal frontal lobe activation can occur in Parkinson's disease despite abnormal processing within the basal ganglia. Moreover, right hippocampus activity was suppressed in the controls and enhanced in the Parkinson's disease patients. This could represent a shift to the declarative memory system in Parkinson's disease during performance of the TOL task, possibly resulting from insufficient working memory capacity within the frontostriatal system.
Dagher
A
A
MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital, London, UK. alain@bic.mni.mcgill.ca
Owen
A M
AM
Boecker
H
H
Brooks
D J
DJ
D000368:Aged; D002421:Caudate Nucleus / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D003071:Cognition; D003342:Corpus Striatum / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006179:Gyrus Cinguli / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D006624:Hippocampus / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D010296:Parietal Lobe / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D010300:Parkinson Disease / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017397:Prefrontal Cortex; D013647:Task Performance and Analysis; D014055:Tomography, Emission-Computed