CONTROL PROPERTIES OF AGED HUMAN MOTOR UNITS

描述：(调查人员摘要)这项建议的目标是 以确定老年人使用什么策略来控制运动神经元的放电。 首席调查员的初步工作表明，老年人 可以使用替代方案来控制运动神经元。例如, 电机单元的异常断路行为，增加了 发动机单元的点火和双发点火的异常发生 被观察到了。此外，来自其他实验室的工作已经显示出 马达单元老化，尽管需要保持力量和精度在 每天的活动。建议进行实验以解决以下关键问题 问题：1)老年人使用什么策略来激活运动单位 在随意肌肉收缩过程中？2)协同和拮抗 肌肉对老年人的运动动作采取替代策略吗？ 3)老年人使用什么运动单位控制策略来做出反应 突如其来的动摇平衡？本提案中描述的实验 将在年轻人和老年人使用第一背部进行 自愿运动中的骨间肌群和胫前肌群 最大自愿力量的100%。排放 将使用专门的四条线识别单个电机单元 针电极和计算机辅助分解复合材料的技术 发信号给单独的机动部队发射列车。长期目标是 确定是否使用替代电机控制策略来维护 老年人的最佳运动能力。

DESCRIPTION: (Investigator's Abstract) The objective of this proposal is to determine what strategies aged adults use to control motorneuron firing. Preliminary work by the Principal Investigator suggests that the elderly may use alternative schemes for controlling motorneurons. For example, unusual derecruitment behavior of motor units, increased synchronization in the firing of motor units and unusual occurrence of doublet firing have been observed. In addition, work from other laboratories has shown loss of motor units with age despite the need to maintain force and precision in daily movements. Experiments are proposed to address the following key questions: 1) What strategies do older adults use to activate motor units during voluntary muscle contraction? 2) Do synergistic and antagonistic muscles adopt alternative strategies for motor action in older individuals? 3) What motor unit control strategies do older adults use to respond to sudden distrubances in balance? The experiments described in this proposal will be conducted in young and old adults using the first dorsal interosseous and anterior tibialis muscle groups during voluntary effort ranging up to 100 percent of maximal voluntary strength. Discharges of single motor units will be recognized using a specialized quadrifilar needle electrode and a computer aided technique to decompose the composite signal into individual motor unit firing trains. The long term goal is to determine whether an alternative motor control strategy is used to maintain optimal motor activity in the elderly.