title: Investigation of the effects of head irradiation with gamma rays and protons on startle and pre-pulse inhibition behavior in mice.
abstract: With the increased international emphasis on manned space exploration, there is a growing need to understand the impact of the spaceflight environment on health and behavior. One particularly important aspect of this environment is low-dose radiation. In the present studies, we first characterized the γ- and proton-irradiation dose effect on acoustic startle and pre-pulse inhibition behaviors in mice exposed to 0-5 Gy brain-localized irradiation, and assessed these effects 2 days later. Subsequently, we used 2 Gy to assess the time course of γ- and proton-radiation effects on startle reactivity 0-8 days after exposure. Exposures targeted the brain to minimize the impact of peripheral inflammation-induced sickness behavior. The effects of radiation on startle were subtle and acute. Radiation reduced the startle response at 2 and 5 Gy. Following a 2-Gy exposure, the response reached a minimum at the 2-day point. Proton and γ-ray exposures did not differ in their impact on startle. We found there were no effects of radiation on pre-pulse inhibition of the startle response.
authors.affiliation: Department of Psychology, Radiation Research Laboratories, Loma Linda University and Medical Center, Loma Linda, California 92350, USA. phaerich@llu.edu
authors.forename: Paul
authors.initials: P
authors.lastname: Haerich
authors.forename: Cara
authors.initials: C
authors.lastname: Eggers
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Pecaut
mesh_terms: D018685:Anesthetics, Inhalation / Q000494:pharmacology; D000818:Animals; D016371:Cranial Irradiation / Q000009:adverse effects*; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays / Q000009:adverse effects*; D006185:Habituation, Psychophysiologic / Q000528:radiation effects; D007530:Isoflurane / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011522:Protons / Q000009:adverse effects*; D011897:Random Allocation; D013216:Reflex, Startle / Q000528:radiation effects*; D012149:Restraint, Physical; D055139:Sensory Gating / Q000528:radiation effects*; D013026:Space Flight
chemical_list: D018685:Anesthetics, Inhalation; D011522:Protons; D007530:Isoflurane