Sensory conflict theory of space motion sickness: an anatomical location for the neuroconflict.

Most investigators understand sensory conflict to mean a discontinuity between either visual, proprioceptive, and somatosensory input, or semicircular canal and otolith input. Few hypotheses have attempted to define specific physiological mechanisms linking the conflict with the sickness. Suggestions that the theory be renamed the neural mismatch theory allow for the possibility that central integrative mechanisms are involved in interpreting the significance of the sensory environment and that the conflict between visual or vestibular input systems or between separate components of the vestibular system is of secondary importance to mismatch occurring between ongoing sensory experience and long-term memory. This paper describes the role of the limbic system in integration of sensory information and long-term memory, in the expression of the symptoms of motion sickness, and the impact of anti-motion sickness drugs and stress hormones on limbic system function. The limbic system may be the neural mismatch center of the brain.