New Concerns for Neurocognitive Function during Deep Space Exposures to Chronic, Low Dose-Rate, Neutron Radiation

eNeuro. 2019 Aug 22;6(4):ENEURO.0094-19.2019. doi: 10.1523/ENEURO.0094-19.2019. Print Jul/Aug 2019.

Abstract

As NASA prepares for a mission to Mars, concerns regarding the health risks associated with deep space radiation exposure have emerged. Until now, the impacts of such exposures have only been studied in animals after acute exposures, using dose rates ∼1.5×105 higher than those actually encountered in space. Using a new, low dose-rate neutron irradiation facility, we have uncovered that realistic, low dose-rate exposures produce serious neurocognitive complications associated with impaired neurotransmission. Chronic (6 month) low-dose (18 cGy) and dose rate (1 mGy/d) exposures of mice to a mixed field of neutrons and photons result in diminished hippocampal neuronal excitability and disrupted hippocampal and cortical long-term potentiation. Furthermore, mice displayed severe impairments in learning and memory, and the emergence of distress behaviors. Behavioral analyses showed an alarming increase in risk associated with these realistic simulations, revealing for the first time, some unexpected potential problems associated with deep space travel on all levels of neurological function.

Keywords: cognitive dysfunction; electrophysiology; long-term potentiation; low dose-rate; neutrons; space radiation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Anxiety / etiology
  • Cognition / radiation effects*
  • Cosmic Radiation / adverse effects*
  • Depression / etiology
  • Extinction, Psychological / radiation effects
  • Hippocampus / radiation effects*
  • Male
  • Memory / radiation effects
  • Mice, Inbred C57BL
  • Neurons / radiation effects
  • Neutrons / adverse effects*
  • Photons / adverse effects*
  • Social Behavior
  • Synaptic Transmission / radiation effects*