Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
Center for Brain Science, Harvard University, Cambridge, MA 02138, USA.
Neuron. 2013 Oct 16;80(2):494-506. doi: 10.1016/j.neuron.2013.07.049. Epub 2013 Sep 26.
Executing a motor skill requires the brain to control which muscles to activate at what times. How these aspects of control-motor implementation and timing-are acquired, and whether the learning processes underlying them differ, is not well understood. To address this, we used a reinforcement learning paradigm to independently manipulate both spectral and temporal features of birdsong, a complex learned motor sequence, while recording and perturbing activity in underlying circuits. Our results uncovered a striking dissociation in how neural circuits underlie learning in the two domains. The basal ganglia was required for modifying spectral, but not temporal, structure. This functional dissociation extended to the descending motor pathway, where recordings from a premotor cortex analog nucleus reflected changes to temporal, but not spectral, structure. Our results reveal a strategy in which the nervous system employs different and largely independent circuits to learn distinct aspects of a motor skill.
执行一项运动技能需要大脑控制在何时激活哪些肌肉。控制-运动执行和时间安排的这些方面是如何习得的，以及它们所基于的学习过程是否不同，目前还不是很清楚。为了解决这个问题，我们使用了强化学习范式来独立地操纵鸟鸣的光谱和时间特征，鸟鸣是一种复杂的习得运动序列，同时记录和干扰基础回路中的活动。我们的结果揭示了神经回路在两个领域的学习中是如何惊人地分离的。基底神经节对于修改光谱但不修改时间结构是必需的。这种功能上的分离扩展到了下行运动通路，其中来自一个类似于运动前皮质的核的记录反映了时间结构的变化，但光谱结构没有变化。我们的结果揭示了一种策略，即神经系统采用不同的、在很大程度上独立的回路来学习运动技能的不同方面。
