Effects of head-only or whole-body exposure to very low doses of 4He (1000 MeV/n) particles on neuronal function and cognitive performance

Authors: RABIN, BERNARD - University Of Maryland School Of Medicine; POULOSE, SHIBU - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; BIELINSKI, DONNA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; Shukitt-Hale, Barbara

Submitted to: Life Sciences in Space Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2019
Publication Date: 2/5/2019
Citation: Rabin, B.M., Poulose, S.M., Bielinski, D.F., Shukitt Hale, B. 2019. Effects of head-only or whole-body exposure to very low doses of 4He (1000 MeV/n) particles on neuronal function and cognitive performance. Life Sciences in Space Research. 20:85-92. https://doi.org/10.1016/j.lssr.2019.02.001.
DOI: https://doi.org/10.1016/j.lssr.2019.02.001

Interpretive Summary: Astronauts in outer space are exposed to radioactive particles which vary in their amount of energy. Previous research has shown that as particle energy decreases the dose needed to affect brain performance also decreases. Since a significant portion of the radiation experienced by astronauts comes from low-energy helium (4He) particles, we sought to establish the lowest dose of 4He that can produce changes in brain performance. The results indicated that changes in rat brain cell function and brain performance could be observed following both head-only and whole-body exposures to 4He at doses as low as 0.01 to 0.025 cGy units. Therefore, astronauts in outer space may be at a greater risk for radiation-induced damage than previously anticipated.

Technical Abstract: On exploratory class missions, astronauts will be exposed to a range of heavy particles which vary in linear energy transfer (LET). Previous research has shown a direct relationship between particle LET and cognitive performance such that, as particle LET decreases the dose needed to affect cognitive performance also decreases. Because a significant portion of the total dose experienced by astronauts may be expected to come from exposure to low LET 4He particles, it would be important to establish the threshold dose of 4He particles that can produce changes in cognitive performance. The results indicated that changes in neuronal function and cognitive performance could be observed following both head-only and whole-body exposures to 4He particles at doses as low as 0.01 to 0.025 cGy. These results, therefore, suggest the possibility that astronauts on exploratory class missions may be at a greater risk for HZE-induced deficits than previously anticipated.