CONTROL OF COMPLEX MOTOR GESTURES - OROFACIAL MUSCLE RESPONSES TO LOAD PERTURBATIONS OF LIP DURING SPEECH
CONTROL OF COMPLEX MOTOR GESTURES - OROFACIAL MUSCLE RESPONSES TO LOAD PERTURBATIONS OF LIP DURING SPEECH
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DOI：
10.1152/jn.1984.51.4.705
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发表时间：
1984-01-01
影响因子：
2.5
通讯作者：
GRACCO, VL
中科院分区：
文献类型：
--
作者：
ABBS, JH;GRACCO, VL
通过在生成组合的上唇-下唇语音手势期间向下唇施加意外负载来评估上行传入神经对[人类]言语运动控制的贡献。为了消除由于预期或适应造成的潜在污染，仅在 10-15% 的试验中随机施加负载。扰动的物理特征处于自然言语嘴唇动作所涉及的力和运动的正常范围内。第一次引入负载时，观察到多个面部肌肉和嘴唇运动的补偿反应，并且多运动语音目标的实现从未因这些扰动而中断。下唇肌肉出现肌肉反应，暗示纠正、反馈过程。在上唇独立控制的肌肉中也观察到对这些下唇负载的补偿反应，反映了开环感觉运动机制的并行操作。观察到上唇和下唇肌肉在小扰动（1 毫米）和大扰动（15 毫米）下的代偿反应。这些补偿反应的延迟无法通过传统的整体平均来辨别。此外，通过检查个体记录，较低脑干介导的反射潜伏期（即 10-18 毫秒）的反应并不明显。通过使用计算机算法确定各个负载试验的响应延迟，该算法考虑了对照试验中肌电图 (EMG) 的变异性。这些潜伏期测量证实不存在脑干介导的反应，并产生 22-75 毫秒的反应潜伏期。反应潜伏期似乎受到负荷开始和肌肉激活开始之间的时间关系的影响。对各个负载试验的肌肉活动变化的检查揭示了有助于运动补偿的多个肌肉之间的反应幅度的互补变化。如果认为多运动语音手势类似于需要围绕多个关节协调运动的肢体动作，那么这些观察结果可能对肢体运动控制产生影响。在这种情况下，这些语音运动控制数据可能被解释为表明对于复杂的运动，纠正反馈和开环预测过程都在运行，后者参与多个运动子组件之间的协调控制。
The contribution of ascending afferents to the control of [human] speech movement was evaluated by applying unanticipated loads to the lower lip during the generation of combined upper lip-lower lip speech gestures. To eliminate potential contamination due to anticipation or adaptation, loads were applied randomly on only 10-15% of the trials. Physical characteristics of the perturbations were within the normal range of forces and movements involved in natural lip actions for speech. Compensatory responses in multiple facial muscles and lip movements were observed the 1st time a load was introduced, and achievement of the multimovement speech goals was never disrupted by these perturbations. Muscle responses were seen in the lower lip muscles, implicating corrective, feedback processes. Compensatory responses to these lower lip loads were also observed in the independently controlled muscles of the upper lip, reflecting the parallel operation of open-loop, sensorimotor mechanisms. Compensatory responses from both the upper and lower lip muscles were observed with small (1 mm) as well as large (15 mm) perturbations. The latencies of these compensatory responses were not discernible by conventional ensemble averaging. Moreover, responses at latencies of lower brain stem-mediated reflexes (i.e., 10-18 ms) were not apparent with inspection of individual records. Response latencies were determined on individual loaded trials through the use of a computer algorithm that took into account the variability of electromyograms (EMG) among the control trials. These latency measures confirmed the absence of brain stem-mediated responses and yielded response latencies that ranged from 22-75 ms. Response latencies appeared to be influenced by the time relation between load onset and the initiation of muscle activation. Examination of muscle activity changes for individual loaded trials revealed complementary variations in the magnitude of responses among multiple muscles contributing to a movement compensation. These observations may have implications for limb movement control if multimovement speech gestures are considered analogous to a limb action requiring coordinated movements around multiple joints. In this context, these speech motor control data might be interpreted to suggest that for complex movements, both corrective feedback and open-loop predictive processes are operating, with the latter involved in the control of coordination among multiple movement subcomponents.