Volkow N D, Gur R C, Wang G J, Fowler J S, Moberg P J, Ding Y S, Hitzemann R, Smith G, Logan J
Medical Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
Am J Psychiatry. 1998 Mar;155(3):344-9. doi: 10.1176/ajp.155.3.344.
Although it is documented that brain dopamine activity declines with age, the functional significance of this is not known. This study assessed the relation between measures of brain dopamine activity and indexes of motor and cognitive function in healthy individuals.
Thirty healthy volunteers aged 24-86 years were studied with positron emission tomography and [11C]raclopride to assess dopamine D2 receptors. All subjects underwent a neuropsychological test battery that included tasks found to be sensitive to dopamine alterations in patients with neurodegenerative disease and control tasks.
Transfer of [11C]raclopride from plasma to brain in the striatum and cerebellum was not affected by age. In contrast, D2 receptor availability in the caudate and putamen declined with age. Correlations between D2 receptors and neuropsychological test performance were strongest for the motor task (Finger Tapping Test) and were also significant for most tasks involving frontal brain regions, including measures of abstraction and mental flexibility (Wisconsin Card Sorting Test) and attention and response inhibition (Stroop Color-Word Test, interference score). These relationships remained significant after control for age effects.
Age-related decreases in brain dopamine activity are associated with a decline in motor function and may also contribute to impaired performance on tasks that involve frontal brain regions. Interventions that enhance dopamine activity may improve performance and quality of life for the elderly. The fact that correlations remained significant after age effects were partialed out suggests that dopamine activity may influence motor and cognitive performance irrespective of age.
尽管有文献记载脑多巴胺活性会随年龄下降，但其功能意义尚不清楚。本研究评估了健康个体脑多巴胺活性指标与运动及认知功能指标之间的关系。
对30名年龄在24 - 86岁的健康志愿者进行正电子发射断层扫描及使用[11C]雷氯必利来评估多巴胺D2受体。所有受试者均接受了一套神经心理测试，其中包括对神经退行性疾病患者多巴胺改变敏感的任务以及对照任务。
[11C]雷氯必利从血浆向纹状体和小脑的脑内转运不受年龄影响。相比之下，尾状核和壳核中的D2受体可用性随年龄下降。D2受体与神经心理测试表现之间的相关性在运动任务（手指敲击测试）中最强，在大多数涉及额叶脑区的任务中也很显著，包括抽象和心理灵活性测量（威斯康星卡片分类测试）以及注意力和反应抑制（斯特鲁普颜色 - 文字测试，干扰分数）。在控制年龄效应后，这些关系仍然显著。
与年龄相关的脑多巴胺活性下降与运动功能下降有关，也可能导致涉及额叶脑区任务的表现受损。增强多巴胺活性的干预措施可能改善老年人的表现和生活质量。在排除年龄效应后相关性仍然显著这一事实表明，多巴胺活性可能独立于年龄影响运动和认知表现。
