DYNAMIC CONTROL OF THE PERIORAL SYSTEM DURING SPEECH - KINEMATIC ANALYSES OF AUTOGENIC AND NONAUTOGENIC SENSORIMOTOR PROCESSES
DYNAMIC CONTROL OF THE PERIORAL SYSTEM DURING SPEECH - KINEMATIC ANALYSES OF AUTOGENIC AND NONAUTOGENIC SENSORIMOTOR PROCESSES
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DOI：
10.1152/jn.1985.54.2.418
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发表时间：
1985-01-01
影响因子：
2.5
通讯作者：
ABBS, JH
中科院分区：
文献类型：
--
作者：
GRACCO, VL;ABBS, JH
通过在与b音的口腔闭合运动相关的上下唇联合手势中对下唇施加意外负荷来评估对言语运动控制的传入贡献。在.apprx中随机引入负载。15%的试验来减少受试者的预期或适应。共有490项负荷试验（5名新手受试者）分布在一个有限的间隔（100 ms）内，集中于与闭唇运动相关的激动剂肌肉收缩的开始。上下唇对这些扰动的运动学调整进行了详细的研究。在所有受试者中，负载引起的上下唇位移、运动时间和闭合速度的变化具有统计学意义，并且在首次引入扰动时观察到。目标间隔内的负载时间变化导致补偿性调整部位（上唇对下唇）和运动响应幅度的系统性变化。这些运动变化似乎反映了潜在控制过程的动态性，并清楚地对比了自生（下唇）和非自生（上唇）补偿动作的不同响应特征。尽管上唇和下唇的调整都有助于扰动补偿，但当负荷发生在肌肉激活前20-55 ms时，自源性反应占主导地位。对于这些早期负载，自体反应提供了.apprx。赔偿总额的75%。对于较晚的负载，当进化的语音运动动作受到更多时间限制时，非自生（开环）补偿占主导地位，提供.apprx。赔偿总额的65%。上唇和下唇代偿反应强度的变化与面部肌肉激活的时间过程不平行。在激动剂肌肉激活开始前10-15毫秒，下唇运动调节减少，而在激动剂开始后10-20毫秒，上唇运动调节增加。这些反应的动态调节是独立于面部运动神经元兴奋控制的，可能涉及通过核上中心的感觉运动加工。代偿性运动位移与扰动位移的大小高度相关，特别是在激动剂肌肉发作之前引入的负荷，反映了校准良好的再调整。对后期载荷的响应与扰动位移的关系不太一致。虽然补偿性位移以校准的方式表现出来，但移动速度和移动时间的调整变化较大，似乎从属于位移调整。其中1名受试者的运动速度和运动时间与其他受试者有显著差异。即使在言语等运动任务中，在某些时间限制是明显的，神经系统控制过程在分离这些运动变量方面也具有灵活性。来自口周区域的传入信息以多种方式用于控制言语的嘴唇运动。在激动剂肌肉激活之前，基于校准良好的反应，传入信息似乎用于指定和更新控制参数，作为所谓的运动编程的一部分。一旦运动执行正在进行中，传入输入主要通过非自生调整来塑造不断发展的运动输出，以确保实现多运动目标。
Afferent contributions to the motor control of speech were evaluated by applying unanticipated loads to the lower lip during the combined upper lip-lower lip gesture associated with the oral closing movements for a b sound. Loads were introduced randomly in .apprx. 15% of the trials to minimize subject anticipation or adaptation. A total of 490 load trials (in 5 naive subjects) were distributed within a restricted interval (100 ms) centered on the initiation of agonist muscle contraction associated with the lip-closing movements. Kinematic adjustments of the upper and lower lips to these perturbations were examined in detail. In all subjects, load-induced changes in upper and lower lip displacement, movement time, and closing velocity were statistically significant and observed the 1st time a perturbation was introduced. Load timing variations within the target interval resulted in systematic changes in the site of the compensatory adjustments (upper versus lower lip) and in the magnitude of the kinematic responses. These kinematic changes appeared to reflect the dynamic nature of underlying control processes and clearly contrasted the different response characteristics of autogenic (lower lip) and nonautogenic (upper lip) compensatory actions. Although both upper and lower lip adjustments contributed to perturbation compensations, autogenic responses predominated when loads occurred 20-55 ms before muscle activation. For these early loads, autogenic responses provided .apprx. 75% of the total compensation. For later loads, when the evolving speech motor action was more time constrained, nonautogenic (open-loop) compensations predominated, providing .apprx. 65% of the total compensation. The variations in upper and lower lip compensatory response magnitude did not parallel the time course of facial muscle activation. Lower lip kinematic adjustments were reduced 10-15 ms prior to the onset of agonist muscle activation, whereas upper lip adjustments increased in magnitude 10-20 ms after agonist onset. The dynamic modulation of these responses is controlled independently from facial motoneuron excitation, possibly involving sensorimotor processing via supranuclear centers. The compensatory movement dsiplacements were highly related to the magnitude of the perturbation displacement, especially for loads introduced prior to agonist muscle onset, reflecting a well-calibrated readjustment. Responses to later loads were less consistently related to perturbation didplacement. Although compensatory displacements were manifest in a calibrated manner, adjustments in movement velocity and movement time were more variable and appeared to be subordinate to displacement adjustments. In 1 of the subjects movement velocity and movement time was strikingly different from those of the other subjects. Even in a motor task such as speech, where some temporal constraints are manifest, the nervous system control process has flexibility in disassociating these kinematic variables. Afferent information from the perioral region is used in multiple ways in control of lip movements for speech. Prior to agonist muscle activation, based on the well-calibrated responses, afferent information is seemingly used to specify and update control parameters as part of what was termed motor programming. Once motor execution is under way, afferent input is used to shape the evolving motor output, primarily via nonautogenic adjustments, to ensure achievement of multimovement goals.