Patterns of Longitudinal Neural Activity Linked to Different Cognitive Profiles in Parkinson's Disease
Atsuko Nagano-Saito1, Mohamed S Al-Azzawi1, Alexandru Hanganu2
1Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal Montréal, QC, Canada.
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.
Insights
Functional brain changes in Parkinson's disease (PD) with mild cognitive impairment (MCI) were tracked over 20 months. Preserving thalamic and hippocampal function is key to mitigating cognitive decline in PD patients.
Area of Science:
- Neuroscience
- Cognitive Neurology
- Medical Imaging
Background:
- Mild cognitive impairment (MCI) is a common non-motor symptom in Parkinson's disease (PD).
- Previous functional magnetic resonance imaging (fMRI) studies showed altered cortico-striatal activity in PD patients with MCI.
- Longitudinal changes in neural activity related to cognitive function in PD are not well understood.
Purpose of the Study:
- To investigate the longitudinal effects of mild cognitive impairment on brain activity in Parkinson's disease patients.
- To compare functional brain changes over time between PD patients with and without MCI.
- To identify neural correlates of cognitive decline in Parkinson's disease.
Main Methods:
- Longitudinal fMRI study involving 24 non-demented Parkinson's disease patients (12 MCI, 12 non-MCI).
- Participants performed the Wisconsin Card Sorting Task during two fMRI sessions, 20 months apart.
- Analysis of functional brain activity changes between Time 1 and Time 2, and correlation with cognitive decline.
Main Results:
- Non-MCI patients maintained typical corticostriatal activity, while MCI patients showed increased frontal, parietal, and occipital lobe activity.
- Both groups exhibited altered cerebellar and occipital activity, with increased medial prefrontal cortex and parietal lobe activity during planning set-shifts at Time 2.
- Higher baseline thalamic and hippocampal activity in PD patients predicted less cognitive decline over the study period.
Conclusions:
- Functional brain alterations during cognitive tasks evolve differently in Parkinson's disease patients with and without mild cognitive impairment.
- Thalamic and hippocampal activity are crucial for preserving cognitive function and mitigating decline in Parkinson's disease.
- fMRI can reveal longitudinal neural changes associated with cognitive status in Parkinson's disease.
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