Intersensory vestibular control of standing balance

• Main Author: Shepherd, Myles
• Language: English
• Published: University of British Columbia 2014
• Online Access: http://hdl.handle.net/2429/51613

During standing balance, error signals delivered to the vestibular system through an electrical vestibular stimulus elicit compensatory muscle responses in the appendicular muscles involved in the control of standing. This response is only present in muscles that are active in balancing the whole-body but not present when muscle activity is unrelated to balancing the body. Previous work has shown that visual, vestibular, and proprioceptive cues that are congruent with efferent muscle signals through a robotic simulation of standing balance elicit this vestibular reflex response. The physiological connections between the visual, vestibular and neck somatosensory systems imply that congruency between any of the three sources of information and the efferent muscle signals could elicit a vestibular reflex response, but this has not been tested due to difficulties in isolating sensory feedback during standing balance. A newly constructed robotic balance simulator enabled an experimenter to control the congruency between afferent feedback and motor actions associated with standing balance. Here, we tested whether the vestibular reflexes rely on vestibular cues of self-motion being relevant to the control of standing balance. Eight healthy subjects maintained balance on the robotic balance simulator while vestibular cues of balance were minimized. To achieve this, the robotic balance simulator maintained the whole-body stable in space while providing visual and/or lower-limb somatosensory information that was congruent with the motor control of standing. It was shown that even without vestibular cues of self-motion, a vestibular reflex response can be elicited. These results will lead to a better understanding of the vestibular control of standing balance, and may be applicable to populations with balance deficits. === Education, Faculty of === Kinesiology, School of === Graduate