Plasticity in the subcortical motor basal ganglia-thalamo-cerebellar network plays a key role in the acquisition and control of long-term memory for new procedural skills, from the formation of population trajectories controlling trained motor skills in the striatum to the adaptation of sensorimotor maps in the cerebellum. However, recent findings demonstrate the involvement of a wider cortical and subcortical brain network in the consolidation and control of well-trained actions, including an area traditionally associated with declarative memory - the hippocampus. Here, we probe which role these subcortical areas play in skilled motor sequence control, from sequence feature selection during planning to their integration during sequence execution. An fMRI dataset collected after participants learnt to produce four finger sequences entirely from memory with high accuracy over several days was examined for both changes in BOLD activity and their informational content in subcortical regions of interest. Although there was a widespread activity increase in effector-related striatal, thalamic and cerebellar regions, the associated activity did not contain information on the motor sequence identity. In contrast, hippocampal activity increased during planning and predicted the order of the upcoming sequence of movements. Our findings show that the hippocampus pre-orders movements for skilled action sequences, thus contributing to the higher-order control of skilled movements. These findings challenge the traditional taxonomy of episodic and procedural memory and carry implications for the rehabilitation of individuals with neurodegenerative disorders.

中文翻译：

---

海马体为熟练的动作序列预先安排动作

皮层下运动基底神经节-丘脑-小脑网络的可塑性在新程序技能的长期记忆的获取和控制中发挥着关键作用，从控制纹状体中训练有素的运动技能的群体轨迹的形成到感觉运动图的适应在小脑中。然而，最近的研究结果表明，更广泛的皮层和皮层下大脑网络参与了训练有素的行动的巩固和控制，其中包括传统上与陈述性记忆相关的区域——海马体。在这里，我们探讨这些皮层下区域在熟练的运动序列控制中发挥的作用，从规划期间的序列特征选择到序列执行期间的集成。参与者在几天内学会完全从记忆中高精度地生成四个手指序列后收集的功能磁共振成像数据集被检查，以检查 BOLD 活动的变化及其在皮层下感兴趣区域的信息内容。尽管效应器相关的纹状体、丘脑和小脑区域的活动广泛增加，但相关活动不包含运动序列同一性的信息。相比之下，海马体活动在计划期间增加并预测即将到来的运动序列的顺序。我们的研究结果表明，海马体为熟练动作序列预先安排动作，从而有助于对熟练动作进行高阶控制。这些发现挑战了情景记忆和程序记忆的传统分类法，并对神经退行性疾病患者的康复具有重要意义。