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United States Department of Agriculture

Agricultural Research Service

Research Project: NEUROCOGNITION/NEUROSCIENCE

Location: Human Nutrition Research Center on Aging

Title: Comparison of the effects of partial-or-whole-body exposures to 16O particles on cognitive performance in rats

Authors
item Rabin, Bernard -
item Shukitt-Hale, Barbara
item Carrihill-Knoll, Kirsty -

Submitted to: Radiation Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 13, 2013
Publication Date: March 10, 2014
Citation: Rabin, B.M., Shukitt Hale, B., Carrihill-Knoll, K.L. 2014. Comparison of the effects of partial-or-whole-body exposures to 16O particles on cognitive performance in rats. Radiation Research. 181:251-257.

Interpretive Summary: A ground-based system (NASA Space Radiation Laboratory) was used to study the effects of exposure of high energy particles and charge (HZE particles) on cognitive performance. In this study, exposure to these particles was applied to the whole-body or restricted to the head or body only of the subjects to determine the differences in cognition between different exposures. Irradiating the whole body might have greater effects on cognitive performance, possibly by exascerbating the effects produced from irradiating the head. To test these possibilities, three groups of rats were exposed to 16O particles (1000 MeV/n): (1) head-only; (2) body-only; (3) whole-body. Cognitive performance was measured using the elevated plus-maze, novel object recognition, spatial location memory, and responding on an ascending schedule. The results indicated that performance on the spatial location memory task was disrupted by exposure restricted to the body-only. For the operant responding task, irradiating the whole-body produced a more dramatic decrease in performance than exposures restricted to the head. The findings are discussed in terms of non-targeted effects resulting from exposure to HZE particles and suggest that the results of different studies that utilize varied patterns of exposure may not be directly comparable. Also, these results suggest that astronauts may be at a greater risk for HZE particle-induced cognitive deficits than previously thought.

Technical Abstract: Studies using a ground-based system (NASA Space Radiation Laboratory) to study the effects of exposure to particles of high energy and charge (HZE particles) on cognitive performance have interchangeably used whole-body exposures or exposures restricted to the head of the subject. It is possible that radiating the body might modulate the effects of irradiation on cognitive performance by exerting an independent effect on cognitive performance, or by interacting with the effects on cognitive performance produced by irradiating the head. To test these possibilities, three groups of rats were exposed to 16O particles (1000 MeV/n): (1) head-only; (2) body-only; (3) whole-body. Cognitive performance was measured using the elevated plus-maze, novel object recognition, spatial location memory, and operant responding on an ascending fixed-ratio schedule. The results indicated that performance on the spatial location memory task was disrupted by exposure restricted to the body-only. For the operant responding task, irradiating the whole-body produced a more severe performance decrement than exposures restricted to the head. The results are discussed in terms of non-targeted effects resulting from exposure to HZE particles and suggest that the results of different studies that utilize different patterns of exposure may not be directly comparable. Also, these results suggest that astronauts may be at a greater risk for HZE particle-induced cognitive deficits than previously thought.

Last Modified: 8/21/2014
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