Abstract

Astronauts on interplanetary missions - such as to Mars - will be exposed to space radiation, a spectrum of highly-charged, fast-moving particles that includes 56Fe and 28Si. Earth-based preclinical studies show space radiation decreases rodent performance in low- and some high-level cognitive tasks. Given astronaut use of touchscreen platforms during training and space flight and given the ability of rodent touchscreen tasks to assess functional integrity of brain circuits and multiple cognitive domains in a non-aversive way, here we exposed 6-month-old C57BL/6J male mice to whole-body space radiation and subsequently assessed them on a touchscreen battery. Relative to Sham treatment, 56Fe irradiation did not overtly change performance on tasks of visual discrimination, reversal learning, rule-based, or object-spatial paired associates learning, suggesting preserved functional integrity of supporting brain circuits. Surprisingly, 56Fe irradiation improved performance on a dentate gyrus-reliant pattern separation task; irradiated mice learned faster and were more accurate than controls. Improved pattern separation performance did not appear to be touchscreen-, radiation particle-, or neurogenesis-dependent, as 56Fe and 28Si irradiation led to faster context discrimination in a non-touchscreen task and 56Fe decreased new dentate gyrus neurons relative to Sham. These data urge revisitation of the broadly-held view that space radiation is detrimental to cognition.

Document Type

Article

Publication Date

2-17-2020

Notes/Citation Information

Published in Scientific Reports, v. 10, issue 1, article no. 2737.

© The Author(s) 2020

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Digital Object Identifier (DOI)

https://doi.org/10.1038/s41598-020-59419-z

Funding Information

Research supported by NASA grants NNX07AP84G (to BPC and AJE), NNX12AB55G (to AJE and BPC), and NNX15AE09G (to AJE) and NIH grants to AJE DA007290, DA023555, and DA016765. CWW was supported by an NIH Institutional Training grant (DA007290, PI: AJE, David W. Self), and SY was supported by an NIH Institutional Training Grant (MH076690, PI: CA Tamminga), a PENN McCabe award, an 2019 IBRO travel grant and NARSAD Young Investigator Grant from the Brain and Behavior Research Foundation.

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