Department of Translational Research in Psychiatry, Max Planck Institute of Psychiatry and International Max Planck Research School for Translational Psychiatry (IMPRS-TP), Munich, Germany.
Department of Psychiatry and Psychotherapy, University of Tübingen, Calwerstr. 14, 72076 Tübingen, Germany.
Eur Neuropsychopharmacol. 2020 Jun;35:17-29. doi: 10.1016/j.euroneuro.2020.03.023. Epub 2020 May 11.
When facing decisions to approach rewards or to avoid punishments, we often figuratively go with our gut, and the impact of metabolic states such as hunger on motivation are well documented. However, whether and how vagal feedback signals from the gut influence instrumental actions is unknown. Here, we investigated the effect of non-invasive transcutaneous auricular vagus nerve stimulation (taVNS) vs. sham (randomized cross-over design) on approach and avoidance behavior using an established go/no-go reinforcement learning paradigm in 39 healthy human participants (23 female) after an overnight fast. First, mixed-effects logistic regression analysis of choice accuracy showed that taVNS acutely impaired decision-making, p = .041. Computational reinforcement learning models identified the cause of this as a reduction in the learning rate through taVNS (∆α = -0.092, p = .002), particularly after punishment (∆α = -0.081, p = .012 vs. ∆α =-0.031, p = .22). However, taVNS had no effect on go biases, Pavlovian response biases or response time. Hence, taVNS appeared to influence learning rather than action execution. These results highlight a novel role of vagal afferent input in modulating reinforcement learning by tuning the learning rate according to homeostatic needs.
当面临接近奖励或避免惩罚的决策时，我们通常凭直觉做出选择，而代谢状态（如饥饿）对动机的影响也有充分的记录。然而，肠道的迷走神经反馈信号是否以及如何影响工具性动作尚不清楚。在这里，我们使用经过验证的 Go/No-Go 强化学习范式，在 39 名健康人类参与者（23 名女性）禁食一夜后，调查了非侵入性经皮耳迷走神经刺激（taVNS）与假刺激（随机交叉设计）对接近和回避行为的影响。首先，对选择准确性的混合效应逻辑回归分析表明，taVNS 急性损害了决策制定，p = 0.041。计算强化学习模型确定了这种影响的原因是通过 taVNS 降低了学习率（∆α = -0.092，p = 0.002），特别是在受到惩罚后（∆α = -0.081，p = 0.012 与 ∆α = -0.031，p = 0.22）。然而，taVNS 对 Go 偏差、巴甫洛夫反应偏差或反应时间没有影响。因此，taVNS 似乎影响学习而不是动作执行。这些结果强调了迷走神经传入输入在根据体内平衡需求调整学习率来调节强化学习方面的新作用。
