Grants and Contributions:

Grant or Award spanning more than one fiscal year. (2017-2018 to 2022-2023)

We often use our hands to for balance. For example, when we use a cane or grab a safety rail our hands provide additional support to keep us from falling. Other times, the things we hold can cause us to lose our balance, such as when a dog pulls at its leash. Therefore, the sensory cues coming from the hands are an important source of information that our nervous system can use to help control balance. The work in this proposal will develop our knowledge of how sensory information from the hands is used by the nervous system to help control balance. Touching a stable support with a single finger decreases the amount a person sways. Recently, work in my laboratory showed that people reacted as though they were falling if the support they were touching was unexpectedly moved. Work in the present proposal will identify the specific sensory cues from the fingertip that can trigger this powerful reaction of the body. I also showed that this reaction was only seen the first time the touch support was moved. Afterwards, people simply tracked the disturbance with their arms. I propose that the change in response produced by the touch displacement shows that the nervous system can quickly change how it uses sensory cues from the fingers, likely by planning several options ahead of time. If so, this new theory will revolutionize our thinking about how the nervous system controls balance when faced with unexpected disturbances. Studies in this proposal will determine whether changes in motor systems of the brain support this idea. The influence of touch in balance control is much more powerful when the eyes are closed. Plus, visual cues can be very misleading, which is why people lean and sway in virtual reality environments. An important question is how sensory information from different sources is used to control balance when the inputs are unreliable or conflict with each other. To better understand how the nervous system resolves conflict in sensory systems for balance control I will test balance reactions that arise when vision and touch provide unreliable signals. This program of study will provide important, fundamental knowledge about how the nervous system uses fingertip sensory input to help control balance. This will advance our fundamental knowledge of the human nervous system, which will be of importance for Canadian researchers in areas such as robotics, engineering, exercise sciences and health sciences. This in turn will assist in the development of advanced technologies in these areas, including devices to improve the quality of life for Canadians living with disabilities and safer robotics used in the Canadian work place. For example, artificial arms are being developed that include touch sensors to help control the hand and arm. These same sensors could also be used to provide relevant information for balance control. My research will provide important new knowledge to allow this to happen.