腹侧被盖区多巴胺神经元参与奖励身份预测。
Ventral Tegmental Dopamine Neurons Participate in Reward Identity Predictions.
机构信息
Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, MD 21218, USA.
Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, MD 21218, USA.
出版信息
Curr Biol. 2019 Jan 7;29(1):93-103.e3. doi: 10.1016/j.cub.2018.11.050. Epub 2018 Dec 20.
Dopamine (DA) neurons in the ventral tegmental area (VTA) and substantia nigra (SNc) encode reward prediction errors (RPEs) and are proposed to mediate error-driven learning. However, the learning strategy engaged by DA-RPEs remains controversial. RPEs might imbue predictive cues with pure value, independently of representations of their associated outcome. Alternatively, RPEs might promote learning about the sensory features (the identity) of the rewarding outcome. Here, we show that, although both VTA and SNc DA neuron activation reinforces instrumental responding, only VTA DA neuron activation during consumption of expected sucrose reward restores error-driven learning and promotes formation of a new cue→sucrose association. Critically, expression of VTA DA-dependent Pavlovian associations is abolished following sucrose devaluation, a signature of identity-based learning. These findings reveal that activation of VTA- or SNc-DA neurons engages largely dissociable learning processes with VTA-DA neurons capable of participating in outcome-specific predictive learning, and the role of SNc-DA neurons appears limited to reinforcement of instrumental responses.
腹侧被盖区(VTA)和黑质(SNc)中的多巴胺(DA)神经元编码奖励预测误差(RPE),并被提议介导错误驱动的学习。然而,DA-RPE 所采用的学习策略仍存在争议。RPE 可能会赋予预测线索纯粹的价值,而不考虑与其相关结果的表示。或者,RPE 可能会促进对奖励结果的感官特征(身份)的学习。在这里,我们表明,尽管 VTA 和 SNc DA 神经元的激活都增强了工具性反应,但只有在预期蔗糖奖励消费期间 VTA DA 神经元的激活才能恢复错误驱动的学习,并促进新线索→蔗糖关联的形成。至关重要的是,在蔗糖贬值后,VTA 依赖性条件反射关联的表达被消除,这是基于身份学习的特征。这些发现表明,VTA 或 SNc-DA 神经元的激活涉及到很大程度上可分离的学习过程,VTA-DA 神经元能够参与特定于结果的预测学习,而 SNc-DA 神经元的作用似乎仅限于强化工具性反应。