Independent and integrated skin sensory contributions to postural control

点击翻译按钮获取中文摘要

To maintain balance, humans must utilize vision, vestibular and somatosensory information. The long term objective of my research program is to understand the physiological mechanisms which enable information from the skin, muscles and vestibular system to modulate ongoing tasks and generate appropriate postural responses during standing and walking. My immediate goal is to investigate the mechanisms by which skin contributes to proprioception around the ankle, and identify contributions from the individual receptor types. Decrements in skin input on the foot sole result in deficiencies in balance, demonstrating a role for foot sole skin in balance regulation. Recent work has also shown that skin around the finger, elbow and knee joints contributes to joint position sense and proprioception. This is particularly relevant as we know that humans walk with minimal foot clearance, leaving us susceptible to tripping and therefore dependent on accurate ankle position. Our work aims to further what we know about skin input from the lower limb, with a focus on ankle skin and the top of the foot, since skin in this area is well placed to provide information regarding ankle angle. The first objective of this work is to identify the mechanism by which skin interacts with spindle input to help monitor ankle angle. By using the technique of microneurography, where recordings are made from single afferent nerve fibres in the human, we can isolate individual types of skin and muscle afferents. This will enable us to assess how these sensory sources interact. We also know there are four different types of skin receptor (Fast and slowly adapting, Type I and II) each providing unique input, leading to speculation that each type of receptor may have a unique and important role in balance and locomotion. The second objective is therefore to isolate how the different types of receptor contribute to joint position sense, velocity sense and modulation of sensory input (spindle and other skin receptors). Ultimately the proposed work will study how skin acts both independently and as a facilitator for other sensory sources. This work will bring us one step closer to understanding the impact and extent of skin's influence on static and dynamic postural control.