Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK.
Department of Psychology, Durham University, Durham, UK.
Neurobiol Aging. 2022 Oct;118:34-43. doi: 10.1016/j.neurobiolaging.2022.06.003. Epub 2022 Jun 20.
Vigor reflects how motivated people are to respond to stimuli. We previously showed that, on average, humans are more vigorous when a higher rate of reward is available, and that this relationship is modulated by the dopamine precursor levodopa. Dopamine signaling and probabilistic reward learning deteriorate across the adult life span, and thus, the relationship between vigor and reward may also change in aging. We tested this assertion and assessed whether it correlates with D1 dopamine receptor availability, measured using Positron Emission Tomography. We registered response times of 30 older and 30 younger participants during an oddball discrimination task where rewards varied systematically between trials. The average reward rate had a similar impact on vigor in both age groups. There was a weak positive association between ventral striatal dopamine receptor availability and the effect of average reward rate on response time. Overall, the effect of reward on response vigor was similar in younger and older adults, and weakly correlated with dopamine D1 receptor availability.
活力反映了人们对刺激做出反应的动力。我们之前的研究表明，在平均水平上，当有更高的奖励率时，人类的活力更高，而这种关系受到多巴胺前体左旋多巴的调节。多巴胺信号和概率奖励学习在成年期会逐渐恶化，因此，活力与奖励之间的关系在衰老过程中也可能发生变化。我们检验了这一说法，并评估了它是否与使用正电子发射断层扫描术测量的 D1 多巴胺受体可用性相关。我们记录了 30 名老年参与者和 30 名年轻参与者在一个偶发辨别任务中的反应时间，在这个任务中，奖励在试验之间系统地变化。在两个年龄组中，平均奖励率对活力都有类似的影响。腹侧纹状体多巴胺受体可用性与平均奖励率对反应时间的影响之间存在微弱的正相关。总的来说，奖励对反应活力的影响在年轻和年长的成年人中是相似的，并且与多巴胺 D1 受体可用性弱相关。
