Reinforcement learning models treat the basal ganglia (BG) as an actor–critic network. The ventral pallidum (VP) is a major component of the BG limbic system. However, its precise functional roles within the BG circuitry, particularly in comparison to the adjacent external segment of the globus pallidus (GPe), remain unexplored. We recorded the spiking activity of VP neurons, GPe cells (actor) and striatal cholinergic interneurons (critic) while monkeys performed a classical conditioning task. Here, we report that VP neurons can be classified into two distinct populations. The persistent population displayed sustained activation following visual cue presentation, was correlated with monkeys’ behavior and showed uncorrelated spiking activity. The transient population displayed phasic synchronized responses that were correlated with the rate of learning and the reinforcement learning model’s prediction error. Our results suggest that the VP is physiologically different from the GPe and identify the transient VP neurons as a BG critic.

强化学习模型将基底神经节（BG）视为行为者-批评者网络。腹侧苍白球（VP）是BG边缘系统的主要组成部分。然而，其在BG电路中的精确功能角色，尤其是与苍白球（GPe）的相邻外部片段相比，仍未被探索。我们记录了当猴子执行经典的调节任务时，VP神经元，GPe细胞（演员）和纹状体胆碱能中间神经元（评论者）的突触活性。在这里，我们报告VP神经元可以分为两个不同的人群。持续的种群在视觉提示后表现出持续的激活，与猴子的行为相关，并表现出不相关的尖峰活动。瞬时群体显示出与学习率和强化学习模型的预测误差相关的阶段性同步响应。我们的结果表明，VP与GPe在生理上有所不同，并将短暂VP神经元确定为BG批评家。