Overman Margot Juliëtte, Browning Michael, O'Shea Jacinta
Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX3 9DU England.
Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, OX3 7JX England.
Cognit Ther Res. 2021;45(5):869-884. doi: 10.1007/s10608-020-10146-9. Epub 2020 Oct 5.
Cognitive models of mood disorders emphasize a causal role of negative affective biases in depression. Computational work suggests that these biases may stem from a belief that negative events have a higher information content than positive events, resulting in preferential processing of and learning from negative outcomes. Learning biases therefore represent a promising target for therapeutic interventions. In this proof-of-concept study in healthy volunteers, we assessed the malleability of biased reinforcement learning using a novel cognitive training paradigm and concurrent transcranial direct current stimulation (tDCS).
In two studies, young healthy adults completed two sessions of negative (n = 20) or positive (n = 20) training designed to selectively increase learning from loss or win outcomes, respectively. During training active or sham tDCS was applied bilaterally to dorsolateral prefrontal cortex. Analyses tested for changes both in learning rates and win- and loss-driven behaviour. Potential positive/negative emotional transfer of win/loss learning was assessed by a facial emotion recognition task and mood questionnaires.
Negative and positive training increased learning rates for losses and wins, respectively. With negative training, there was also a trend for win (but not loss) learning rates to decrease over successive task blocks. After negative training, there was evidence for near transfer in the form of an increase in loss-driven choices when participants performed a similar (untrained) task. There was no change in far transfer measures of emotional face processing or mood. tDCS had no effect on any aspect of behaviour.
Negative training induced a mild negative bias in healthy adults as reflected in loss-driven choice behaviour. Prefrontal tDCS had no effect. Further research is needed to assess if this training procedure can be adapted to enhance learning from positive outcomes and whether effects translate to affective disorders.
情绪障碍的认知模型强调消极情感偏见在抑郁症中的因果作用。计算研究表明，这些偏见可能源于一种信念，即消极事件比积极事件具有更高的信息含量，从而导致对消极结果的优先处理和学习。因此，学习偏见是治疗干预的一个有前景的目标。在这项针对健康志愿者的概念验证研究中，我们使用一种新颖的认知训练范式和同步经颅直流电刺激（tDCS）评估了有偏见的强化学习的可塑性。
在两项研究中，年轻健康成年人完成了两节消极（n = 20）或积极（n = 20）训练，分别旨在选择性地增加从损失或胜利结果中的学习。在训练期间，对双侧背外侧前额叶皮层施加主动或伪tDCS。分析测试了学习率以及胜利和损失驱动行为的变化。通过面部情绪识别任务和情绪问卷评估胜利/损失学习潜在的正/负情绪转移。
消极和积极训练分别提高了损失和胜利的学习率。对于消极训练，在连续的任务块中，胜利（而非损失）学习率也有下降趋势。消极训练后，有证据表明存在近迁移，即当参与者执行类似（未训练）任务时，损失驱动选择增加。情绪面孔加工或情绪的远迁移指标没有变化。tDCS对行为的任何方面均无影响。
消极训练在健康成年人中诱发了一种轻微的消极偏见，这体现在损失驱动的选择行为中。前额叶tDCS没有效果。需要进一步研究来评估这种训练程序是否可以调整以增强从积极结果中的学习，以及效果是否能转化到情感障碍中。
