Effect of mild cognitive impairment on the patterns of neural activity in early Parkinson's disease.
We have previously observed decreased activation of corticostriatal loops involved in planning (cognitive loop) and execution (motor loop) of a set shift in patients with early Parkinson's disease (PD) compared with control subjects. Here, we aimed to assess whether cognitive impairment in PD could drive these differences. Nondemented patients underwent a comprehensive neuropsychological evaluation and participated in our Wisconsin Card Sorting task functional magnetic resonance imaging protocol. Patients were separated into 2 groups according to the presence of mild cognitive impairment (MCI). Patients with MCI displayed reduced activity in the cognitive corticostriatal loop, which includes the caudate nucleus and prefrontal cortex while planning a set shift, whereas non-MCI patients exhibited activation patterns similar to those of healthy participants from our previous studies. Furthermore, reduced activation was observed in the premotor cortex of the MCI patients. Finally, hippocampal activity, correlated with individual memory scores, suggesting a compensatory mechanism in patients with preserved memory. These results suggest that the presence of MCI in PD affects activity in the prefrontal cortex and caudate nucleus as well as motor-related regions.
Centre de recherche, Institut universitaire de Gériatrie de Montréal, Montréal, Québec, Canada.
Atsuko
A
Nagano-Saito
Claudine
C
Habak
Beatriz
B
Mejía-Constaín
Clotilde
C
Degroot
Laura
L
Monetta
Thomas
T
Jubault
Christophe
C
Bedetti
Anne-Louise
AL
Lafontaine
Sylvain
S
Chouinard
Valérie
V
Soland
Alain
A
Ptito
Antonio P
AP
Strafella
Oury
O
Monchi
D000368:Aged; D003071:Cognition; D060825:Cognitive Dysfunction / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D003342:Corpus Striatum / Q000503:physiopathology*; D056344:Executive Function; D005260:Female; D006624:Hippocampus / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D017397:Prefrontal Cortex / Q000503:physiopathology*
Compensation; Hippocampus; MCI; Parkinson's disease; Prefrontal cortex; Striatum; fMRI