Vasil'eva O N
Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow.
Neurosci Behav Physiol. 2007 Sep;37(7):659-68. doi: 10.1007/s11055-007-0066-8.
The central mechanism of motor programming was studied using a model of precise horizontal flexion of the arm at the elbow joint. Training was performed in the dark to ensure that formation of the motor program was based predominantly on the use of proprioceptive afferentation. The target was not demonstrated before training: subjects determined the angle of arm flexion during training, the moment at which the target position was reached being identified by a brief LED flash. Subjects had to perform the movement as quickly and accurately as possible. The amplitude, speed, and accuracy of the movement were measured in real time. The ten subjects were divided into two groups for initial training to precise movements, using two different protocols: flexion of the elbow to 70 degrees and to 55 degrees . At the second stage of the experiment, each subject's initial target position was suddenly changed (from 70 degrees to 55 degrees and vice versa). Training was continued until a stable accuracy in the new conditions was achieved (with errors of no more than 5% of the specified amplitude). The nature of the transformation in the kinematics of the precise movement in response to the change in the single task parameter illuminated the fundamental principle of organization of the supraspinal motor command for movements of this type. For both specified flexion amplitudes, the ratio between the acceleration and deceleration phases of the movement were identical during the period of skill fixation. On average, 70% of the total amplitude of flexion was accounted for by the acceleration phase and 30% by the deceleration phase. Adaptation of the precise movement to changes in the specified horizontal elbow flexion angle (i.e., re-achievement of the required movement accuracy in the changed conditions) during rearrangement was completed by inversion of these values. According to the results of previous studies, the most informative measure for analysis of the dynamics of the controlling central command was the acceleration of the movement. In terms of current concepts of the mechanism of motor control, the acceleration plateau can be regarded as mirroring long-term depression--the voltage plateau in Purkinje cells and motoneurons. Data processing involved calculation of the integral acceleration in both phases of the movement in relation to the angle of flexion (phase plots). These data underlie our understanding of the mechanism of transformation of movement kinematics responsible for the formation of a new central command.
使用手臂在肘关节处精确水平屈曲的模型研究运动编程的核心机制。训练在黑暗中进行，以确保运动程序的形成主要基于本体感觉传入信息的使用。训练前不展示目标：受试者在训练期间确定手臂屈曲角度，目标位置到达时刻通过短暂的LED闪光来识别。受试者必须尽可能快速且准确地执行动作。实时测量动作的幅度、速度和准确性。十名受试者被分为两组进行精确动作的初始训练，采用两种不同方案：将肘部屈曲到70度和55度。在实验的第二阶段，每个受试者的初始目标位置突然改变（从70度变为55度，反之亦然）。继续训练，直到在新条件下达到稳定的准确性（误差不超过指定幅度的5%）。精确动作的运动学响应单一任务参数变化时的转变性质，阐明了这种类型运动的脊髓上运动指令组织的基本原理。对于两种指定的屈曲幅度，在技能固定期间，动作的加速和减速阶段之间的比率是相同的。平均而言，屈曲总幅度的70%由加速阶段占据，30%由减速阶段占据。在重新安排期间，精确动作适应指定水平肘部屈曲角度的变化（即在变化条件下重新达到所需的动作准确性）是通过这些值的反转来完成的。根据先前研究的结果，分析控制中枢指令动态的最具信息量的指标是动作的加速度。就当前运动控制机制的概念而言，加速度平台可被视为反映长时程抑制——浦肯野细胞和运动神经元中的电压平台。数据处理涉及计算动作两个阶段相对于屈曲角度的积分加速度（相位图）。这些数据是我们理解负责形成新中枢指令的运动学转变机制的基础。
