科研之友
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摘要
Objectives: To investigate, using functional magnetic resonance imaging, the influence of a long-term dopaminergic therapy on brain activation during a simple motor task in early, previously untreated patients with Parkinson disease. %26lt;br%26gt;Methods: Thirteen patients with Parkinson disease in Hoehn-Yahr stage 1 or 2, with a right predominance of the disease, underwent functional magnetic resonance imaging during self-paced continuous right-hand tapping before and after 6 months of therapy with ropinirole 15 mg/d. The task was monitored online with a dedicated device, which measures the strength and frequency of the tapping. %26lt;br%26gt;Results: All patients with Parkinson disease on ropinirole treatment showed a clinically significant improvement, and their functional magnetic resonance imaging pattern after treatment showed a reduced activation in the right postcentral (primary sensory-motor area), supramarginal and inferior parietal gyri compared with the activation pattern before treatment. No area of increased activation was observed after therapy. %26lt;br%26gt;Conclusions: In line with the classical functional deafferentation hypothesis, dopaminergic stimulation should increase motor cortex activity as a result of restoration of the striatocortical loops. On the contrary, our results challenge this hypothesis as we found decreased cerebral activity after a short-term chronic dopaminergic treatment. We suggest that the recruitment of cortical motor circuits aimed to overcome the functional deficit of the striatocortical loops lessens after dopaminergic treatment.
- 出版日期2014-12
