Subjective luminous line perception under changing g-load and body-positions in parabolic flight

Five healthy subjects were subjected to parabolic flight with laterally tilted head, trunk, or body position. A vertical luminous line was viewed by the subjects in a head-fixed goggle device. During normal, hyper- and hypogravity phases subjective luminous line orientation was measured. The data imply that stimulation of the neck position receptors markedly influences the perception of the subjective vertical as well as mechanisms of convergence of otolithic signals and visual information within the brain.