کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6802840 | 1433515 | 2018 | 52 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Independent effects of age and levodopa on reversal learning in healthy volunteers
ترجمه فارسی عنوان
اثرات مستقل سن و لوودوپا در یادگیری معکوس در داوطلبان سالم
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
سالمندی
چکیده انگلیسی
The dopamine overdose hypothesis has provided an important theoretical framework for understanding cognition in Parkinson's disease. It posits that effects of dopaminergic therapy on cognition in Parkinson's disease depend on baseline dopamine levels in brain regions that support different functions. Although functions performed by more severely dopamine-depleted brain regions improve with medication, those associated with less dopamine deficient areas are actually worsened. It is presumed that medication-related worsening of cognition owes to dopamine overdose. We investigated whether age-related changes in baseline dopamine levels would modulate effects of dopaminergic therapy on reward learning in healthy volunteers. In a double-blind, crossover design, healthy younger and older adults completed a probabilistic reversal learning task after treatment with 100/25Â mg of levodopa/carbidopa versus placebo. Older adults learned more poorly than younger adults at baseline, being more likely to shift responses after misleading punishment. Levodopa worsened stimulus-reward learning relative to placebo to the same extent in both groups, irrespective of differences in baseline performance and expected dopamine levels. When order effects were eliminated, levodopa induced response shifts after reward more often than placebo. Our results reveal independent deleterious effects of age group and exogenous dopamine on reward learning, suggesting a more complex scenario than predicted by the dopamine overdose hypothesis.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Neurobiology of Aging - Volume 69, September 2018, Pages 129-139
Journal: Neurobiology of Aging - Volume 69, September 2018, Pages 129-139
نویسندگان
Andrew Vo, Ken N. Seergobin, Penny A. MacDonald,