Grant: Discovery Grants Program - Individual

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.