Evidence suggests that dopamine activity provides a US-related prediction error for Pavlovian conditioning and the reinforcement signal supporting the acquisition of habits. However, its role in goal-directed action is less clear. There are currently few studies that have assessed dopamine release as animals acquire and perform self-paced instrumental actions. Here we briefly review the literature documenting the psychological, behavioral and neural bases of goal-directed actions in rats and mice, before turning to describe recent studies investigating the role of dopamine in instrumental learning and performance. Plasticity in dorsomedial striatum, a central node in the network supporting goal-directed action, clearly requires dopamine release, the timing of which, relative to cortical and thalamic inputs, determines the degree and form of that plasticity. Beyond this, bilateral release appears to reflect reward prediction errors as animals experience the consequences of an action. Such signals feedforward to update the value of the specific action associated with that outcome during subsequent performance, with dopamine release at the time of action reflecting the updated predicted action value. More recently, evidence has also emerged for a hemispherically lateralised signal associated with the action; dopamine release is greater in the hemisphere contralateral to the spatial target of the action. This effect emerges over the course of acquisition and appears to reflect the strength of the action-outcome association. Thus, during goal-directed action, dopamine release signals the action, the outcome and their association to shape the learning and performance processes necessary to support this form of behavioral control.

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纹状体多巴胺在目标导向行动中发挥什么作用？

有证据表明，多巴胺活动为巴甫洛夫条件反射提供了与美国相关的预测误差，并提供了支持习惯习得的强化信号。然而，它在目标导向行动中的作用尚不清楚。目前很少有研究评估动物获得并执行自定进度的工具动作时多巴胺的释放。在这里，我们简要回顾了记录大鼠和小鼠目标导向行为的心理、行为和神经基础的文献，然后转向描述最近研究多巴胺在乐器学习和表现中的作用。背内侧纹状体是支持目标导向行动的网络中心节点，其可塑性显然需要多巴胺的释放，其相对于皮质和丘脑输入的时间决定了可塑性的程度和形式。除此之外，当动物经历某种行为的后果时，双边释放似乎反映了奖励预测错误。此类信号前馈以更新与后续表演期间的结果相关的特定动作的值，动作时的多巴胺释放反映了更新的预测动作值。最近，还出现了与该动作相关的半球偏侧信号的证据。动作空间目标的对侧半球多巴胺释放较多。这种效应在习得过程中出现，似乎反映了行动与结果关联的强度。因此，在目标导向的行动过程中，多巴胺的释放会发出行动、结果及其关联的信号，以塑造支持这种形式的行为控制所需的学习和表现过程。