Functional roles of cerebrocerebellar communication system in prism adaptation of reaching

在我们的大脑中，从视觉空间到运动空间的坐标转换是实现手臂达到目标的关键。鉴于腹侧运动前皮质(PMV)和小脑在感觉运动整合和棱镜适应中的重要作用，本研究探讨了小脑通讯系统在运动执行和学习中的作用。首先，将少量神经解剖学示踪剂(生物素化葡聚糖胺，BDA)注入猴PMV，发现标记神经元密集分布在运动丘脑X区。其次，在每个试验…的准备阶段，在执行伸腕和屈腕任务的猴子中，从电生理学角度确定了投射到包括PMV在内的皮质运动区的丘脑神经元，在该任务中，运动方向由听觉线索指示。更多，然后是三种类型的感觉信号(视觉、听觉或触觉)中的一种来启动运动。在大脑皮层运动区，神经元记录到两种主要的任务相关活动：(1)运动相关活动，在运动开始前立即出现阶段性变化；(2)集合相关活动，即在指令信号呈现后的整个准备阶段活动的持续变化。研究发现，大多数活动都偏爱手腕运动方向。相比之下，没有记录到信号相关的神经元活动和通道特定的运动相关活动，尽管这种活动经常在皮质运动区被观察到。结果表明，从小脑到皮质运动区的投射系统在运动参数的确定和运动的启动中起着重要作用，但对坐标变换所需的感觉运动转换的作用较小。较少

Transformation of coordinates from visual to motor space in our brain is essential to achieve target-reaching by arm. Since it was found that the ventral premotor cortex(PMv) as well as cerebellum plays an important role in the sensorimotor integration and prism adaptation, it was investigated in this study how the cerebrocerebellar communication system contribute to the motor execution and learning. First, when a small amount of neuroanatomical tracer(Biotinylated Dextran Amine,BDA) was injected in to the PMv of monkeys where neurons with movement-related activity reflecting visual space were most frequently recorded, it was found that labeled neurons were densely located in area X of the motor thalamus. Second, thalamic neurons projecting to the cortical motor areas including the PMv were identified electrophysiologically in monkeys performing a wrist extension and flexion task in which the movement direction was instructed by auditory cues during the preparation period in each trial … More , followed by one of the three type of sensory signals(visual, auditory, or tactile) to initiate the movement. Two major task-related activities were recorded from the neurons, as found in the cortical motor areas : (1)movement-related activity with phasic changes immediately before movement onset and (2)set-related activity, a sustained change of activity throughout the preparation period after the instruction signal was presented. A majority of the activities were found to have preference for wrist movement directions. By contrast, no signal-related neuronal activity and modality specific movement-related activity were recorded, although such activities were frequently observed in the cortical motor areas. The results suggest that the projection system from the cerebellum to the cortical motor areas plays important roles in determination of movement-parameters and movement initiation, but contribute much less to sensorimotor conversion which is necessary for transformation of coordinates. Less