Space vestibulo-neuroscience in the new century: why proceed in semi-darkness?

With advancing technology, neuroscientists have explored vestibular transducer microstructure and molecular processes, neural pathways of interaction between vestibular visual and proprioceptor systems and neurochemical processes of adaptive change. Progress in space vestibulo-neuroscience will be fostered by focus on interactions among the systems involved in whole-body movement relative to the earth. Description of perceptual and sensorimotor reactions to complex accelerative stimuli during goal-directed and passive movement is crucial to conceptualizing the functional significance of various interactions and viable theory. The vestibulo-ocular reflex is now quantifiable in three dimensions, but description of the dynamics of spatial orientation perception has progressed very little in the 20th century. Much is known about perception of static body tilt, but the dynamics of tilt and movement perception (beyond rotation about an earth-vertical axis) remains relatively unexplored. Innovative procedures and departure from accepted psychophysics are needed. Models developed to predict the dynamics of spatial orientation under complex conditions must be consistent with information at all levels (neural, sensorimotor, and perceptual). To close our eyes to any one aspect of the spatial orientation reaction is to proceed in semi-darkness unnecessarily.