Cerebellar morphology and behavioural correlations of the vestibular function alterations in weightlessness.

In humans and other vertebrates, the range of disturbances and behavioural changes induced by spaceflight conditions are well known. Sensory organs and the central nervous system (CNS) are forced to adapt to new environmental conditions of weightlessness. In comparison with peripheral vestibular organs and behavioural disturbances in weightlessness conditions, the CNS vestibular centres of vertebrates, including the cerebellum, have been poorly examined in orbital experiments, as well as in experimental micro- and hypergravity. However, the cerebellum serves as a critical control centre for learning and sensory system integration during space-flight. Thus, it is referred to as a principal brain structure for adaptation to gravity and the entire sensorimotor adaptation and learning during weightlessness. This paper is focused on the prolonged spaceflight effects on the vestibular cerebellum evidenced from animal models used in the Bion-M1 project. The changes in the peripheral vestibular apparatus and brainstem primary vestibular centres with appropriate behavioural disorders after altered gravity exposure are briefly reviewed. The cerebellum studies in space missions and altered gravity are discussed.

Mice in Bion-M 1 space mission: training and selection.

After a 16-year hiatus, Russia has resumed its program of biomedical research in space, with the successful 30-day flight of the Bion-M 1 biosatellite (April 19-May 19, 2013). The principal species for biomedical research in this project was the mouse. This paper presents an overview of the scientific goals, the experimental design and the mouse training/selection program. The aim of mice experiments in the Bion-M 1 project was to elucidate cellular and molecular mechanisms, underlying the adaptation of key physiological systems to long-term exposure in microgravity. The studies with mice combined in vivo measurements, both in flight and post-flight (including continuous blood pressure measurement), with extensive in vitro studies carried out shortly after return of the mice and in the end of recovery study. Male C57/BL6 mice group housed in space habitats were flown aboard the Bion-M 1 biosatellite, or remained on ground in the control experiment that replicated environmental and housing conditions in the spacecraft. Vivarium control groups were used to account for housing effects and possible seasonal differences. Mice training included the co-adaptation in housing groups and mice adaptation to paste food diet. The measures taken to co-adapt aggressive male mice in housing groups and the peculiarities of "space" paste food are described. The training program for mice designated for in vivo studies was broader and included behavioral/functional test battery and continuous behavioral measurements in the home-cage. The results of the preliminary tests were used for the selection of homogenous groups. After the flight, mice were in good condition for biomedical studies and displayed signs of pronounced disadaptation to Earth's gravity. The outcomes of the training program for the mice welfare are discussed. We conclude that our training program was effective and that male mice can be successfully employed in space biomedical research.