Task-related activity in the ventral thalamus, a major target of basal ganglia output, is often assumed to be permitted or triggered by changes in basal ganglia activity through gating- or rebound-like mechanisms. To test those hypotheses, we sampled single-unit activity from connected basal ganglia output and thalamic nuclei (globus pallidus-internus [GPi] and ventrolateral anterior nucleus [VLa]) in monkeys performing a reaching task. Rate increases were the most common peri-movement change in both nuclei. Moreover, peri-movement changes generally began earlier in VLa than in GPi. Simultaneously recorded GPi-VLa pairs rarely showed short-time-scale spike-to-spike correlations or slow across-trials covariations, and both were equally positive and negative. Finally, spontaneous GPi bursts and pauses were both followed by small, slow reductions in VLa rate. These results appear incompatible with standard gating and rebound models. Still, gating or rebound may be possible in other physiological situations: simulations show how GPi-VLa communication can scale with GPi synchrony and GPi-to-VLa convergence, illuminating how synchrony of basal ganglia output during motor learning or in pathological conditions may render this pathway effective. Thus, in the healthy state, basal ganglia-thalamic communication during learned movement is more subtle than expected, with changes in firing rates possibly being dominated by a common external source.

腹侧丘脑中的任务相关活动是基底神经节输出的主要目标，通常被认为是通过门控或反弹样机制由基底神经节活动的变化允许或触发的。为了检验这些假设，我们从执行伸手任务的猴子中连接的基底神经节输出和丘脑核（苍白球内部 [GPi] 和腹外侧前核 [VLa]）中采样了单个单元的活动。速率增加是两个核中最常见的运动周围变化。此外，VLa 中的运动周围变化通常比 GPi 中开始得更早。同时记录的 GPi-VLa 对很少表现出短时间尺度的峰与峰之间的相关性或缓慢的跨试验协变，并且两者都同样呈正值和负值。最后，自发的 GPi 爆发和暂停都伴随着 VLa 速率小幅缓慢的降低。这些结果似乎与标准门控和回弹模型不兼容。尽管如此，在其他生理情况下，门控或反弹也是可能的：模拟显示 GPi-VLa 通信如何随着 GPi 同步和 GPi-to-VLa 收敛而扩展，阐明运动学习期间或病理条件下基底神经节输出的同步如何导致这种情况途径有效。因此，在健康状态下，习得运动期间基底神经节-丘脑的通讯比预期更加微妙，放电率的变化可能由共同的外部源主导。