title: [Pattern of vestibular reactions and sensory interactions in weightlessness (data of the experiment "Optokinesis")].
abstract: This paper presents results of studying spontaneous and evoked optokinetic, opto-oculomotor and vestibulo-oculomotor reactions in microgravity. The examinations were performed during the 7-day Soviet-Indian and 237-day Salyut-7 missions. During an early stage of adaptation to microgravity the following changes occurred: enhanced spontaneous activity of the eyes, including spontaneous nystagmus in one of the crewmembers, decline of the efficiency of saccadic pursuit (disappearance of saccades in the course of pursuit of a moving stimulus, decrease of the saccadic amplitude, emergence of correction microsaccades in response to fixation events), and decrease of the threshold of the optokinetic nystagmus. The compensatory counter-rotation of the eyeballs during head side-to-side movements with open eyes in dark glasses did not disappear but slightly decreased, being slightly accompanied by low-amplitude nystagmus. When rocking the head with open eyes, one of the cosmonauts showed a complete eye destabilization and other cosmonauts displayed high-amplitude nystagmus. In response to head rotation with open eyes they developed clonic nystagmus. Vestibular stimulation in the form of active head movements helped to normalize the pattern of opto-ocular responses.
authors: L N
authors: LN
authors: Kornilova
authors: G
authors: G
authors: Bodo
authors: I K
authors: IK
authors: Tarasov
authors: V N
authors: VN
authors: Alekseev
mesh_terms: D000222:Adaptation, Physiological; D004585:Electrooculography; D005133:Eye Movements; D006801:Humans; D011187:Posture; D012438:Saccades; D013026:Space Flight; D014722:Vestibule, Labyrinth / Q000502:physiology*; D014893:Weightlessness
vernacular_title: Kharakter vestibuliarnykh reaktsiĭ i mezhanalizatornykh vzaimodeĭstviĭ v usloviiakh nevesomosti (po dannym éksperimenta "Optokinez").