Department of Psychology, Ludwig Maximilian University Munich, Munich 80802, Germany.
Department of Psychology, University of Basel, Basel 4055, Switzerland.
Soc Cogn Affect Neurosci. 2022 Apr 1;17(4):398-407. doi: 10.1093/scan/nsab101.
Motivation is a hallmark of healthy aging, but the motivation to engage in effortful behavior diminishes with increasing age. Most neurobiological accounts of altered motivation in older adults assume that these deficits are caused by a gradual decline in brain tissue, while some psychological theories posit a switch from gain orientation to loss avoidance in motivational goals. Here, we contribute to reconcile the psychological and neural perspectives by providing evidence that the frontopolar cortex (FPC), a brain region involved in cost-benefit weighting, increasingly underpins effort avoidance rather than engagement with age. Using anodal transcranial direct current stimulation together with effort-reward trade-offs, we find that the FPC's function in effort-based decisions remains focused on cost-benefit calculations but appears to switch from reward-seeking to cost avoidance with increasing age. This is further evidenced by the exploratory, independent analysis of structural brain changes, showing that the relationship between the density of the frontopolar neural tissue and the willingness to exert effort differs in young vs older adults. Our results inform aging-related models of decision-making by providing preliminary evidence that, in addition to cortical thinning, changes in goal orientation need to be considered in order to understand alterations in decision-making over the life span.
动机是健康老龄化的标志，但随着年龄的增长，人们参与费力行为的动机会减弱。大多数关于老年人动机改变的神经生物学解释假设，这些缺陷是由脑组织逐渐减少引起的，而一些心理学理论则假设在动机目标上从收益导向转变为损失回避。在这里，我们通过提供证据来调和心理学和神经学的观点，该证据表明，额极皮层（frontopolar cortex，FPC）是一个参与成本效益权衡的大脑区域，随着年龄的增长，它越来越多地支持避免努力，而不是参与努力。我们使用经颅直流电刺激阳极刺激和努力-奖励权衡，发现 FPC 在基于努力的决策中的功能仍然集中在成本效益计算上，但随着年龄的增长，它似乎从寻求奖励转变为避免成本。这进一步通过对结构脑变化的探索性、独立分析得到证实，表明额极神经组织密度与努力意愿之间的关系在年轻人和老年人中存在差异。我们的研究结果为与衰老相关的决策模型提供了信息，初步证据表明，为了理解整个生命周期中决策的改变，除了皮质变薄外，还需要考虑目标导向的变化。
