Study of the role of gravity in neurosensorimotor mechanisms of disorders of spatial orientation (disorientation, vertigo, dizziness, imbalance and impaired visual perception) in a real and simulated weightlessness using innovative computerized multimodal stimulation and specially developed hardware-software complexes «SENSOMOTOR», «VIRTUAL», «OCULOSTIM», «OCULOSTIM-CM».
1. Theme of research
The mechanism of interaction of the vestibular system and visual / visual-manual tracking in a real and simulated weightlessness
2. A brief review of the problem, its urgency, the comparison with the level of domestic and foreign researches
For the implementation of visual tracking and precise hand coordination it’s necessary to have both the proper functioning of individual sensory systems (primarily visual, vestibular and motor), and their clear, coordinated interaction in the integrative structures of the central nervous system (CNS). In previous studies it was shown that during the process of human adaptation to weightlessness there are recorded changes in vestibular-ocular reactions (absence or decrease of amplitude of the static torsional otolith-cervical reflex, decrease of the threshold of vestibular nystagmus and increase of the vestibular reactivity) that are associated with the direct effect of weightlessness on the vestibular receptors. However, weightlessness by eliminating the support and minimizing the proprioceptive afferentation may also affect the vestibular function indirectly (as it was shown by the results of immersion experiments) through the central integrative multisensory structures of the CNS, where the convergence of afferent signals of different sensory modalities takes place (primarily – visual, vestibular, support and motor).
Thus, weightlessness leads to the disappearance of the influence of gravity on the otolith receptors and removal of support afferentation which are accompanied by violation of the habitual pattern of the multisensory integration and its subsequent reorganization. Which in turn may affect the accuracy and performance of the visual-manual tracking through existing central multisensory connections (especially between the vestibular and oculomotor nuclei). Currently, however, its not completely clear how accuracy of the visual-manual tracking is depended on the state of vestibular and support inputs, and on the different vestibular subsystems (otoliths and canals).
It is important to clarify the mechanisms of the vestibular-visual interaction with the aim of improving the examination/survey, prognosis, prophylaxis and correction of visual-manual tracking, which is the basis of the professional operators activity of cosmonauts.
3. Brief justification of theoretical novelty
This field of research is new and priority in terms of explaining the role of gravity factor in the mechanisms of interaction between the vestibular system and visual / visual-manual tracking, as well as for the development of effective methods of assessment and prognosis of various vestibular-oculomotor disorders affecting the accuracy of the visual and visual-manual tracking during and after spaceflight. Works to be performed are original, have no analogues in domestic and foreign literature and are necessary to create a methodology for prediction, prevention and correction of the vestibular-oculomotor disturbances in altered gravitational environment.
4. Expected results
Received data and criteria to assess the vestibular-visual interaction and visual-manual tracking will improve diagnosis and prognosis of stability of spatial perception to the vestibular and visual impairment, both during and after spaceflight, and for patients in clinic.
Results of work can be used in medical control to assess the effectiveness of cosmonauts preflight preparation/training, to evaluate the recommended methods of prophylaxis and monitoring of the vestibular-visual system and visual-manual tracking when adverse effects of weightlessness affects the body, as well as in clinical practice for the early diagnosis and effective treatment.