Cortical and sensory control of standing balance

站立平衡需要在中枢和外周神经系统内快速处理和整合感觉运动信号，其中包括来自前庭、视觉和躯体感觉线索的信息。直立平衡控制通常是事后才想到的，它的复杂性和重要性只有在神经肌肉系统遭受侮辱或慢性恶化时才会意识到。随着成人年龄的增长，神经肌肉系统会经历退行性变化，其特征是肌肉萎缩，结构和功能下降。尽管有很多关于老年人站立平衡的研究，但许多研究并没有提供对站立所必需的大脑皮层和感觉运动控制的机械性见解。老化的神经肌肉系统提供了一个极好的模型，通过研究皮质和感觉运动信号的整合和转换来加深我们对感觉运动适应的理解，皮质和感觉运动信号在长期改变和妥协的状态下调节平衡。评估神经肌肉系统完整性的一个有效方法是通过肌肉疲劳等干预措施对其施加尖锐的压力。然而，人们对疲劳如何影响站立的感觉运动控制知之甚少。因此，我的研究计划的长期目标是更好地了解与站立平衡和运动的感觉运动控制相关的基本过程。在接下来的五年里，我的实验室将解决两个短期研究目标，这两个目标将有助于实现我的长期目标。第一个短期目标将确定急性(即疲劳)和慢性(即成人衰老)适应如何改变前庭对站立平衡的控制。我们最近报道了一种与年龄相关的前庭运动和前庭感知通路的中枢增益增强。然而，这种中枢敏感度代偿性增加的具体机制及其与平衡感觉运动控制的相关性尚不清楚，我的研究小组的结果将为与年龄相关的前庭平衡控制变化相关的潜在因素提供洞察力。第二个短期目标将通过利用成人的自然衰老和疲劳来确定与皮质对站立的贡献相关的机制。对于年轻人来说，皮质在维持站立平衡方面的参与是有限的。然而，皮质对平衡的贡献可能随着成人的自然衰老而增强，但这一概念尚未得到彻底解决。我的研究小组将确定与使用神经肌肉疲劳和长期适应状态的大脑皮质控制站立平衡有关的机制。拟议的实验将为皮质和感觉(即前庭)相关机制如何通过利用急性和长期改变的状态来调节站立平衡控制提供有价值的见解。

Standing balance entails rapid processing and integration of sensorimotor signals within the central and peripheral nervous system, which include information from vestibular, visual, and somatosensory cues. Upright balance control is typically an afterthought and its complexity and importance is only realized once the neuromuscular system undergoes an insult or chronic deterioration. With adult aging, the neuromuscular system endures degenerative changes, characterized by muscle atrophy and declines in structure and function. Despite much research on standing balance in older adults, many studies do not provide mechanistic insight into the cortical and sensorimotor control necessary for standing. The aged neuromuscular system offers an excellent model to further our understanding of sensorimotor adaptations through investigation into the integration and transformation of cortical and sensorimotor signals that modulate balance in a chronically-altered and compromised state. An effective means to evaluate the integrity of the neuromuscular system is to stress it acutely through an intervention such as muscle fatigue. Yet, little is known about how fatigue affects the sensorimotor control of standing. Thus, the LONG-TERM OBJECTIVE of my research program is to better understand the fundamental processes related to the sensorimotor control of standing balance and movement. Over the next five-years, my lab will address two short-term research objectives that will contribute to the achievement of my long-term objective. The first SHORT-TERM OBJECTIVE will identify how acute (i.e., fatigue) and chronic (i.e., adult aging) adaptations alter the vestibular control of standing balance. We have recently reported an age-related central gain enhancement for vestibulomotor and vestibular perception pathways. However, the specific mechanisms underlying this compensatory increase in central sensitivity and its relevance to the sensorimotor control of balance is unclear, and results from my research group will provide insight into the underlying factors related to the age-related alterations of the vestibular control of balance. The second SHORT-TERM OBJECTIVE will identify mechanisms related to the cortical contributions to standing through exploiting natural adult aging and fatigue. For young, cortical involvement in maintaining standing balance is limited. However, the cortical contributions to balance is likely enhanced with natural adult aging, but this concept has not been addressed thoroughly. My research group will identify mechanisms related to the cortical control of standing balance using neuromuscular fatigue and a chronically-adapted state. The proposed experiments will offer valuable insight into how cortical- and sensory- (i.e., vestibular) related mechanisms modulate standing balance control by exploiting acutely- and chronically-altered states.