Supraspinal and Sensory Reflex Contributions to Motoneuron Modulation during Steady Contractions in Men and Women

随着年龄的增长，我们的功能性运动能力下降。然而，这种下降在女性中比在男性中更为明显。在接下来的5年中，将进行研究，通过测量年轻（18-25岁）和老年（50 - 75岁）男性和女性的力量稳定性来模拟功能运动，以量化中枢和周围神经系统在这种与年龄相关的功能衰退中的作用，这种功能衰退在性别之间是不同的。这些研究将集中在肱二头肌，这是研究运动神经元活动的微小变化如何影响力量产生的理想场所，特别是在整个生命周期中对日常功能至关重要的前臂控制。实验将使用肌电图（EMG）来测量调节稳定收缩产生的特定肌肉的活动。提出的研究将是第一个在功能运动中确定单个运动单元活动的研究，并通过超声检查在不同年龄的男性和女性的二头肌中测量单个肌肉收缩单元（束）的长度。这项研究将进一步加深我们对脊髓回路的理解，以及它对男性和女性在控制运动方面的不同年龄相关衰退的贡献。该研究项目将培养2名博士生、6名硕士生和5名本科生，使神经生理学和解剖学技术的技术技能发展适用于应用科学和基础科学的科学发现。

As we age, our functional movement declines. However, this decline is more pronounced in women than in men. Over the next 5 years, studies will be conducted where functional movement will be modeled by measures of force steadiness in young (18-25 y) and old (>75 y) men and women to quantify the role of the central and peripheral nervous system in this age-related functional decline that differs between sexes. These studies will focus on the biceps brachii muscle, which is ideal for studying how small changes in motoneuron activity impact force production, especially forearm control that is central to daily function throughout the lifespan. Experiments will use electromyography (EMG), to measure the activity of specific muscles that regulate the production of steady contractions. Studies proposed will be the first to determine single motor unit activity during functional movement and measure the length of individual muscle contractile units (fascicles) through ultrasonography in the biceps in men and women across the age span. This research will collectively further our understanding of spinal circuitry and its contribution to differential age-related decline between men and women in controlled movement. This research program will result in advanced training for 2 PhD students, 6 MSc students, and ~5 undergraduate students, enabling technical skill development in neurophysiology and anatomy techniques applicable to scientific discovery in both applied and basic sciences.