Contribution of central and peripheral vision to the regulation of stance

Postural adaptation was analyzed in four conditions of vision (complete vision, peripheral vision, central vision and no-vision) and two conditions of ankle somatosensory information (normal and altered support surface with a 5-cm-thick foam support). Subjects were more stable with than without vision. This was observed whether subjects had complete or partial vision (central or peripheral). They were also more stable on the normal than on the altered support surface. Beyond these well-established results, the present experiment demonstrates the complementary role of central and peripheral vision to the regulation of posture. Within a trial, subjects reduced the range and speed of their postural oscillations. The rapidity and quality of this adaptation were a function of the sensory information available. When somatosensory information was not altered, the contribution of central and peripheral vision to the regulation of posture could not be differentiated. When somatosensory information was altered, central vision was more efficient than peripheral vision for regulating medio-lateral oscillations, whereas peripheral vision was more efficient than central vision for regulating antero-posterior oscillations. The involvement of the different sensory systems for stabilizing posture and their interaction has to be interpreted with regard to the experimental context and the operating characteristics of each sensory system.