Analysis Of The H-reflex Characteristics In Human Under Conditions Of Simulated Microgravity
- Paper number
IAC-07-A1.I.09
- Author
Dr. Irina Sayenko, Institute for Biomedical Problems, Russia
- Coauthor
Mrs. Tatiana Miller, Institute for Biomedical Problems, Russia
- Year
2007
- Abstract
Objective: The analysis of the dynamic of H-reflex parameters alterations under conditions of simulated microgravity has been provided to understand the mechanisms of the microgravity effects.
Methods: Studies of characteristics of the H- reflexes have been provided in 8 volunteers participant of 7- dry immersion. H-reflex was evoked by electrical stimulation of the tibial nerve in the popliteal fossa starting with the lowest threshold intensity. Electromagnetic response of m. soleus and stimulation intensity were recorded.
Results: Exposures to dry immersion was followed consistently by an intensive hyperreactivity of the H-reflexe, that showed up by significant increase of the thresholds of responses and the increase of the amplitudes. In the first days of exposures the ratio of maximal amplitudes of the motor and reflex responses (Hmax/Mmax) was increased. On day-7 of immersion, Hmax/Mmax averaged 70,42±15,09
Conclusion: Exposure to the simulated microgravity are followed by the signs of hyperreactivacy in the H-reflexes system, that are manifested by lowering the threshold of H-reflexes, as well as by increase of the reflex’s amplitude.
- Abstract document