Mell T, Heekeren H R, Marschner A, Wartenburger I, Villringer A, Reischies F M
Department of Neurology, Berlin NeuroImaging Center, Charité, Campus Mitte, Schumannstr. 20/21, 10117 Berlin, Germany.
Neuropsychologia. 2005;43(4):554-63. doi: 10.1016/j.neuropsychologia.2004.07.010. Epub 2004 Sep 28.
The flexible learning of stimulus-reward associations when required by situational context is essential for everyday behavior. Older adults experience a progressive decline in several cognitive functions and show deficiencies in neuropsychological tasks requiring flexible adaptation to external feedback, which could be related to impairments in reward association learning. To study the effect of aging on stimulus-reward association learning 20 young and 20 older adults performed a probabilistic object reversal task (pORT) along with a battery of tests assessing executive functions and general intellectual abilities. The pORT requires learning and reversing associations between actions and their outcomes. Older participants collected fewer points, needed more trials to reach the learning criterion, and completed less blocks successfully compared to young adults. This difference remained statistically significant after correcting for the age effect of other tests assessing executive functions. This suggests that there is an age-related difference in reward association learning as measured using the pORT, which is not closely related to other executive functions with respect to the age effect. In human aging, structural alterations of reward detecting structures and functional changes of the dopaminergic as well as the serotonergic system might contribute to the deficit in reward association learning observed in this study.
根据情境上下文的要求灵活学习刺激-奖励关联对于日常行为至关重要。老年人在多种认知功能方面会逐渐衰退，并且在需要灵活适应外部反馈的神经心理学任务中表现出缺陷，这可能与奖励关联学习受损有关。为了研究衰老对刺激-奖励关联学习的影响，20名年轻人和20名老年人进行了概率性物体反转任务（pORT）以及一系列评估执行功能和一般智力能力的测试。pORT要求学习并反转动作与其结果之间的关联。与年轻人相比，老年参与者获得的分数更少，达到学习标准需要更多的试验次数，并且成功完成的区块更少。在纠正了评估执行功能的其他测试的年龄效应后，这种差异在统计学上仍然显著。这表明，使用pORT测量时，奖励关联学习存在与年龄相关的差异，就年龄效应而言，这种差异与其他执行功能没有密切关系。在人类衰老过程中，奖励检测结构的结构改变以及多巴胺能和血清素能系统的功能变化可能导致了本研究中观察到的奖励关联学习缺陷。
