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[Motor association cortex activity in Parkinson's disease--a functional MRI study]
1Department of Neurology, Yamaguchi University School of Medicine, Japan.
Abstract:
The purpose of this study was to examine the activation of motor association cortex using functional magnetic resonance imaging (fMRI) in patients with Parkinson's disease (PD) and control subjects during performed hand movements. There were 26 patients with PD (12 patients with Hoehn and Yahr stage I-II, 14 patients with stage III) and 8 control subjects. Functional imaging was performed using a 1.5 tesla MRI system equipped with a single-shot, echo-planar pulse sequence. The significant signal changes were observed within the primary sensorimotor area, the supplementary motor area (SMA), and the parietal association area in both PD and control subjects. In PD subjects, the SMA was less activated than in control subjects; there were significant differences in the number of pixels activated in SMA between control and Yahr III group (p < 0.01), and between Yahr I-II and Yahr III group (p < 0.01). Our results demonstrated that movement related cerebral activity in the SMA is reduced in PD subjects, consistent with previously published data using other methods. It is well known from anatomical studies that one of the major cortical outputs of the basal ganglia is the SMA. This may explain the hypoactivation of the SMA in PD. Studies using fMRI provide a promising method not only for localizing cortical activation related to voluntary movements but also for investigating pathophysiology of movement disorders.
Insights
Functional magnetic resonance imaging (fMRI) revealed reduced supplementary motor area (SMA) activation during hand movements in Parkinson's disease (PD) patients. This hypoactivation correlates with disease severity, offering insights into PD motor control deficits.
Area of Science:
- Neuroscience
- Neurology
- Medical Imaging
Background:
- Parkinson's disease (PD) is a neurodegenerative disorder affecting motor control.
- The basal ganglia play a crucial role in motor function, with outputs influencing cortical areas like the supplementary motor area (SMA).
Purpose of the Study:
- To investigate motor association cortex activation using functional magnetic resonance imaging (fMRI) in Parkinson's disease (PD) patients and healthy controls during hand movements.
- To assess differences in brain activity between PD patient groups of varying severity and controls.
Main Methods:
- Functional magnetic resonance imaging (fMRI) was employed using a 1.5 tesla MRI scanner.
- 26 patients with Parkinson's disease (Hoehn and Yahr stages I-III) and 8 control subjects performed hand movements during imaging.
Main Results:
- Significant signal changes were observed in the primary sensorimotor area, SMA, and parietal association area in both groups.
- Parkinson's disease patients exhibited reduced activation in the SMA compared to controls.
- A significant decrease in SMA activation was found between controls and the Yahr III PD group (p < 0.01), and between Yahr I-II and Yahr III groups (p < 0.01).
Conclusions:
- Movement-related cerebral activity in the SMA is reduced in Parkinson's disease patients, consistent with prior research.
- The observed SMA hypoactivation in PD may be linked to altered basal ganglia-cortical pathways.
- fMRI is a valuable tool for studying the pathophysiology of movement disorders like Parkinson's disease.