Motor unit function: central descending and sensory reflex modulation

运动单位功能：中枢下降和感觉反射调节

• 批准号: 312038-2006
• 负责人: Jakobi, Jennifer
• 金额: $ 1.46万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=396632
• 关键词: Motor; unit; function; central; descending

It is understood that muscle strength is lower, force steadiness decreases and functional ability declines with advancing age.  The mechanisms of these changes have not been clearly elucidated and until recently gender differences were not recognized.  Because purposeful movement is merely a combination of lengthening and shortening contractions, it is imperative to understand MU activity of the agonist and antagonist during these simple activities. The overall objectives of these experiments are to identify and determine the contributions of central descending and sensory reflex pathways to the modulation of motor neuron activity and subsequent effect on force control in the quadriceps of young and old women. Our working hypothesis is that sensory feedback and central descending pathways work collectively to code MU output (recruitment, discharge rate, synchronization and coherence of MUs), however this 'collective coding' differs between contraction types (isometric, lengthening, shortening) and is altered with age. Moreover, because there are differential age-related declines between men and women in functional ability and strength and both of these elements are closely linked to MU activity it is plausible that a gender difference in MU activity might exist.  To my knowledge, to date, MU activity has not been purposely studied in healthy young and old women.  These studies will not only characterize agonist and antagonist MU activity during anisometric quadriceps contractions in women, but contribute to our understanding of the contribution of sensory reflex and supraspinal descending input on MU activity and age-related alterations in force control.

据了解，随着年龄的增长，肌肉力量下降，力量稳定性下降，功能能力下降。  这些变化的机制尚未明确阐明，直到最近性别差异才得到认识。  因为有目的的运动仅仅是延长和缩短收缩的组合，所以有必要了解这些简单活动期间主动肌和拮抗肌的 MU 活动。这些实验的总体目标是识别和确定中枢下降和感觉反射通路对运动神经元活动调节的贡献以及随后对年轻和老年女性股四头肌力量控制的影响。我们的工作假设是，感觉反馈和中枢下行通路共同编码 MU 输出（MU 的复张、放电速率、同步性和连贯性），但是这种“集体编码”在收缩类型（等长、延长、缩短）之间有所不同，并且会随着年龄的增长而改变。此外，由于男性和女性在功能能力和力量方面存在与年龄相关的下降差异，并且这两个因素都与 MU 活动密切相关，因此 MU 活动可能存在性别差异。  据我所知，迄今为止，尚未在健康的年轻和老年女性中专门研究 MU 活动。  这些研究不仅将表征女性股四头肌不等长收缩期间的激动剂和拮抗剂 MU 活动，而且有助于我们了解感觉反射和脊髓上下行输入对 MU 活动的贡献以及与年龄相关的力控制变化。