Department of Neuropsychology and Clinical Psychology, Psychological Institute, Johannes-Gutenberg University of Mainz, Germany.
Department of Theoretical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany.
J Affect Disord. 2020 Mar 1;264:400-406. doi: 10.1016/j.jad.2019.11.063. Epub 2019 Nov 12.
Motivational dysregulation represents a core vulnerability factor for bipolar disorder. Whether this also comprises aberrant learning of stimulus-reinforcer contingencies is less clear.
To answer this question, we compared healthy first-degree relatives of individuals with bipolar disorder (n = 42) known to convey an increased risk of developing a bipolar spectrum disorder and healthy individuals (n = 97). Further, we investigated the effects of the behavioral activation system (BAS) on reinforcement learning across the entire sample. All participants were assessed with a probabilistic learning task that distinguishes learning from positive and negative feedback. Main outcome measures included choice frequencies and learning rate parameters generated by computational reinforcement learning algorithms.
First-degree relatives choose more rewarding stimuli more consistently and showed marginally reduced learning rates from unexpected negative feedback. Further, first-degree relatives had lower BAS scores than controls, which were negatively associated with learning rates from unexpected negative feedback.
However as probands also reported other mental disorders such as Attention-Deficit/Hyperactivity Disorder and substance abuse among their first-degree relatives, we cannot know, whether these findings are specific to the risk for bipolar disorder.
The behavior of first-degree relatives of individuals with bipolar disorder, who also display increased BAS sensitivity, is less influenced by unexpected negative feedback. This reduced learning from unexpected negative feedback biases subsequent choices towards stimuli with higher probabilities for a reward. In sum, our results confirm the role of aberrant reinforcement learning in the pathophysiology of bipolar disorder.
动机失调是双相情感障碍的一个核心脆弱性因素。然而，这是否包括刺激-强化关联的异常学习尚不清楚。
为了回答这个问题，我们比较了患有双相情感障碍（BD）的个体的一级亲属（n=42）和健康个体（n=97）。这些一级亲属已知有更高的双相谱系障碍发病风险。此外，我们还研究了行为激活系统（BAS）对整个样本强化学习的影响。所有参与者都接受了一项概率学习任务的评估，该任务可以区分来自正反馈和负反馈的学习。主要的衡量标准包括计算强化学习算法生成的选择频率和学习率参数。
一级亲属更一致地选择更有价值的刺激，且对意外负反馈的学习率略有降低。此外，一级亲属的 BAS 评分低于对照组，且与意外负反馈的学习率呈负相关。
然而，由于先证者的一级亲属也报告了其他精神障碍，如注意缺陷多动障碍和物质滥用，因此我们无法确定这些发现是否特定于双相情感障碍的风险。
双相情感障碍患者的一级亲属的行为，他们也表现出更高的 BAS 敏感性，受意外负反馈的影响较小。这减少了对意外负反馈的学习，从而使后续的选择偏向于奖励概率更高的刺激。总的来说，我们的结果证实了异常强化学习在双相情感障碍病理生理学中的作用。
