The role of eye movement in upright postural control

Abstract

Vision contributes to upright postural control by providing afferent feedback to the cerebellum. Vision is generally classified into central and peripheral vision. In measurements of postural sway, in which participants are required to maintain a stable upright posture while fixating on a visual target, non-retinal eye positional information due to the fixation is used as well as the retinal information from both visual fields. However, little is known about the role of non-visual eye positional information in postural control. This study examined the role of non-visual eye position information in upright postural control by comparing participants' centre of pressure (COP) sway between two experimental conditions: (1) a space-fixed visual target condition (control), in which eye movement was not controlled, and (2) a head-fixed visual target condition (treatment), in which eye movement was inhibited. Using 12 university students, COP sway and electrooculograms (EOG) were measured under both conditions. In the space-fixed condition, participants maintain an upright posture while fixating on a visual target fixed on a screen 1 m in front of them. In the headfixed condition, participants maintained an upright posture while gazing at a target moving in sync with their head sway on the screen. The COP was evaluated by path length, area, root mean square, velocity and position. Eye movements were evaluated by the mean eye movement angle. The mean eye movement angle was significantly larger in the vertical direction then in the horizontal direction in both experimental conditions and was also found to be larger in the space-fixed condition than in the head-fixed condition. No significant different was found in any COP parameter between both conditions. It was suggested that non-visual eye position information from the external eye muscles to the sensory perception system contributes little to postural stabilisation under the measurement conditions used in this study.

Task-specific and variability-driven activation of cognitive control processes during motor performance

“…The observation that balance control during the PAD condition was not related to executive function measures is intriguing given that standing on an unstable base of support decreases the reliability of sensory information from plantar mechanoreceptors 37 , 38 and creates unexpected mechanical perturbations when compressive loads are applied and released 39 . There is evidence that the visual system is the primary sensory system used to maintain upright postural control 40 – 42 , and that standing on a foam surface with eyes open leads to an increase in the reliance on visual and/or vestibular inputs to control posture 43 , 44 , corrective muscle and torque activity 45 , and co-contraction of leg and trunk muscles 46 . Thus, the short-latency postural responses that occur when standing on an instable surface with eyes open is likely to more heavily involve subcortical brainstem and spinal cord structures (e.g., stretch reflex and non-reciprocal inhibition) 47 , 48 .…”

Static and dynamic single leg postural control performance during dual-task paradigms

“…The visual system is the primary sensory system used in maintaining postural control. [66][67][68] Visual stimulation of the peripheral visual field decreases postural sway in the direction of the observed visual stimulus to the anterior-posterior direction rather than the medial-lateral direction. 69 Individuals use peripheral vision for visual stabilization of spontaneous or visually induced body sway to control posture.…”

Postural balance in young adults: The role of visual, vestibular and somatosensory systems

“…They also found that reliance on vision was dominant among the younger population. Although it is a known fact that vision is the primary sensory system used in balance (Merla & Spaulding, 1997; Poole, 1991; Uchiyama & Demura, 2009), it must be noted that one can stand in the dark and remain upright.…”