title: Patterns of Longitudinal Neural Activity Linked to Different Cognitive Profiles in Parkinson's Disease.
abstract: Mild cognitive impairment in Parkinson's disease (PD) has been linked with functional brain changes. Previously, using functional magnetic resonance imaging (fMRI), we reported reduced cortico-striatal activity in patients with PD who also had mild cognitive impairment (MCI) vs. those who did not (non-MCI). We followed up these patients to investigate the longitudinal effect on the neural activity. Twenty-four non-demented patients with Parkinson's disease (non-MCI: 12, MCI: 12) were included in the study. Each participant underwent two fMRIs while performing the Wisconsin Card Sorting Task 20 months apart. The non-MCI patients recruited the usual cognitive corticostriatal loop at the first and second sessions (Time 1 and Time 2, respectively). However, decreased activity was observed in the cerebellum and occipital area and increased activity was observed in the medial prefrontal cortex and parietal lobe during planning set-shift at Time 2. Increased activity in the precuneus was also demonstrated while executing set-shifts at Time 2. The MCI patients revealed more activity in the frontal, parietal and occipital lobes during planning set-shifts, and in the parietal and occipital lobes, precuneus, and cerebellum, during executing set-shift at Time 2. Analysis regrouping of both groups of PD patients revealed that hippocampal and thalamic activity at Time 1 was associated with less cognitive decline over time. Our results reveal that functional alteration along the time-points differed between the non-MCI and MCI patients. They also underline the importance of preserving thalamic and hippocampal function with respect to cognitive decline over time.
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal Montréal, QC, Canada.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Nagano-Saito
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal Montréal, QC, Canada.
authors.forename: Mohamed S
authors.initials: MS
authors.lastname: Al-Azzawi
authors.affiliation: Departments of Clinical Neurosciences and Radiology, University of CalgaryCalgary, AB, Canada; Hotchkiss Brain InstituteCalgary, AB, Canada.
authors.forename: Alexandru
authors.initials: A
authors.lastname: Hanganu
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal Montréal, QC, Canada.
authors.forename: Clotilde
authors.initials: C
authors.lastname: Degroot
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal Montréal, QC, Canada.
authors.forename: Béatriz
authors.initials: B
authors.lastname: Mejia-Constain
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal Montréal, QC, Canada.
authors.forename: Christophe
authors.initials: C
authors.lastname: Bedetti
authors.affiliation: Department of Neurology and Neurosurgery, McGill University Montreal, QC, Canada.
authors.forename: Anne-Louise
authors.initials: AL
authors.lastname: Lafontaine
authors.affiliation: Centre Hospitalier de l'Université de Montréal Montréal, QC, Canada.
authors.forename: Valérie
authors.initials: V
authors.lastname: Soland
authors.affiliation: Centre Hospitalier de l'Université de Montréal Montréal, QC, Canada.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Chouinard
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Gériatrie de MontréalMontréal, QC, Canada; Departments of Clinical Neurosciences and Radiology, University of CalgaryCalgary, AB, Canada; Hotchkiss Brain InstituteCalgary, AB, Canada; Department of Neurology and Neurosurgery, McGill UniversityMontreal, QC, Canada.
authors.forename: Oury
authors.initials: O
authors.lastname: Monchi
keywords: Parkinson's disease; Wisconsin Card Sorting Task; functional magnetic resonance image; longitudinal study; mild cognitive impairment