DEPENDENCE OF VISUAL STABILIZATION OF POSTURAL SWAY ON THE CORTICAL MAGNIFICATION FACTOR OF RESTRICTED VISUAL-FIELDS

Monocular visual stabilization of fore-aft and lateral body sway was t ested posturographically in normal subjects (wearing visual field blin ds) as a function of visual field size and location of the visual fiel d on the central or peripheral retina. Body sway applied to a force- m easuring platform is less with central (foveal) vision when central an d peripheral visual fields have the same area. If, however, the periph eral field size is corrected by the cortical magnification factor of t he retina in the primary cortex, body sway is stabilized by the periph eral retina to the same extent. Thus, there is no functional specializ ation of central and peripheral retina with respect to balance control . Visual stabilization of upright stance is a function of field size a nd cortical representation of the retina. The central and the peripher al retina have different thresholds to detect motion; this was surpris ingly not reflected in measurements of normal fore-aft and lateral bod y sway.