Central and peripheral mechanisms controlling human postural control

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Human postural control is a complex sensorimotor task that requires the integration of broad neuro-muscular networks to account for constantly changing task and environmental constraints. As a result, postural control has proven difficult to accurately model and its underlying mechanisms remain elusive. The long-term objective of my fundamental research program is to discover the central and peripheral neural mechanisms that contribute to human postural control. One critical element not captured in current models of postural control is the impact of cognitive-emotional factors such as fear and anxiety. This is commonly experienced as sensations of instability and loss of balance when most individuals try to stand or walk on very high surfaces. Such anxiety-balance interactions may contribute to balance problems and falls in those with a fear of falling, and may also impact performance and safety of those who work under threatening or stressful conditions. Therefore, the short-term objectives of my five-year research program are to understand how anxiety influences the sensorimotor control of human stance, through changes in peripheral reflex mechanisms and central neural networks responsible for postural control. We also aim to examine whether anxiety-related changes in posture may be unique to the control of upright stance, or reflect more generalized changes in motor control. The program utilizes the threat of standing on real, or virtual, elevated surface heights to experimentally manipulate anxiety in healthy young adults. Our research will apply advanced electrophysiological techniques to probe how anxiety changes skin and muscle stretch reflex responses during upright stance. We will also employ novel neural imaging techniques to examine how anxiety modifies cortical and sub-cortical networks during real and simulated balance tasks. Finally, we will use an innovative approach to compare how anxiety influences neuro-muscular control of the upper-limb engaged in postural control tasks that are limited to the local joints (e.g balancing an object on a tray) versus contributing to whole-body stability (e.g holding a handrail while standing on an unstable surface). Throughout the research program we will examine important interactions with biological sex and gender, which may influence the anxiety-response, and the corresponding changes in postural control. The results of this research program will provide crucial evidence needed to a) advance our fundamental knowledge, and develop more accurate models, of human postural control b) design new approaches to assess, and mitigate, the potential psychological origins of balance deficits and falls and c) identify novel training and technological solutions to increase performance and safety of those who must live, work or perform in high stress and anxiety environments.