PDF(Pubmed)
Abstract：
Reward seeking requires the coordination of motor programs to achieve goals. Midbrain dopamine neurons are critical for reinforcement, and their activation is sufficient for learning about cues, actions, and outcomes. Here we examine in detail the mechanisms underlying the ability of ventral tegmental area (VTA) and substantia nigra (SNc) dopamine neurons to support instrumental learning. By exploiting numerous behavioral tasks in combination with time-limited optogenetic manipulations in male and female rats, we reveal that VTA and SNc dopamine neurons generate reinforcement through separable psychological processes. VTA dopamine neurons imbue actions and their associated cues with motivational value that allows flexible and persistent pursuit, whereas SNc dopamine neurons support time-limited, precise, action-specific learning that is nonscalable and inflexible. This architecture is reminiscent of actor-critic reinforcement learning models with VTA and SNc instructing the critic and actor, respectively. Our findings indicate that heterogeneous dopamine systems support unique forms of instrumental learning that ultimately result in disparate reward-seeking strategies.SIGNIFICANCE STATEMENT Dopamine neurons in the midbrain are essential for learning, motivation, and movement. Here we describe in detail the ability of VTA and SNc dopamine neurons to generate instrumental reinforcement, a process where an agent learns about actions they can emit to earn reward. While rats will avidly work and learn to respond for activation of VTA and SNc dopamine neurons, we find that only VTA dopamine neurons imbue actions and their associated cues with motivational value that spur continued pursuit of reward. Our data support a hypothesis that VTA and SNc dopamine neurons engage distinct psychological processes that have consequences for our understanding of these neurons in health and disease.
摘要：
寻求奖励需要协调运动计划以实现目标。中脑多巴胺神经元对于强化至关重要，它们的激活足以学习线索，行动,和结果。在这里，我们详细研究了腹侧被盖区（VTA）和黑质（SNc）多巴胺神经元支持工具学习的能力的潜在机制。通过在雄性和雌性大鼠中利用许多行为任务与限时的光遗传学操作相结合，我们揭示了VTA和SNc多巴胺神经元通过可分离的心理过程产生强化。VTA多巴胺神经元赋予行动及其相关线索以激励价值，允许灵活和持久的追求，而SNc多巴胺神经元支持时间限制，精确，特定于行动的学习是不可伸缩和不灵活的。这种架构让人想起演员-评论家强化学习模型，其中VTA和SNc指导评论家和演员，分别。我们的发现表明，异质多巴胺系统支持独特的工具学习形式，最终导致不同的奖励寻求策略。意义声明：中脑的多巴胺神经元对学习至关重要，动机，和运动。在这里，我们详细描述了VTA和SNc多巴胺神经元产生仪器强化的能力，代理学习他们可以发出的动作以获得奖励的过程。虽然大鼠会积极工作并学习对VTA和SNc多巴胺神经元的激活做出反应，我们发现，只有VTA多巴胺神经元赋予行动及其相关线索以激励价值，从而刺激对奖励的持续追求。我们的数据支持一个假设，即VTA和SNc多巴胺神经元参与不同的心理过程，对我们对健康和疾病中这些神经元的理解产生影响。
