Richard A Britten1,2,3, Vania D Duncan1, Arriyam S Fesshaye1, Laurie L Wellman4, Christina M Fallgren5, Larry D Sanford4. 1. Department of Radiation Oncology, Eastern Virginia Medical School, Norfolk, VA, USA. 2. Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA, USA. 3. Leroy T Canoles Jr. Cancer Center, Eastern Virginia Medical School, Norfolk, VA, USA. 4. Department of Pathology & Anatomy, Eastern Virginia Medical School, Norfolk, VA, USA. 5. Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA.
Abstract
PURPOSE: Astronauts on the planned missions to Mars are expected to have to work more autonomously than on previous missions. Thus mission success may be influenced by the astronauts' ability to respond quickly to unexpected problems, processes that require several executive functions. The purpose of this study was to determine the impact that prolonged low dose and low dose rate exposure to neutrons had on two executive functions, and whether the severity and incidence of cognitive impairment was altered by sleep fragmentation. MATERIALS AND METHODS: In this study we assessed the impact that prolonged (six month) low dose rate neutron exposure had on the ability of male Wistar rats to perform in two executive function tasks (i.e. attentional set shifting (ATSET) - a constrained cognitive flexibility task and the UCFlex assay - an unconstrained cognitive flexibility task). In recognition of the fact that astronauts also have to contend with inadequate sleep quantity and quality for much of their time in space, we determined the impact that relatively mild sleep disruption had on the ability to perform in the ATSET test in sham and neutron-irradiated rats. RESULTS: Chronic low dose (18 cGy) and dose-rate (1 mGy/day) exposure of rats to mixed neutron and photon over the course of six months resulted in significant impairment of simple discrimination (SD) performance. Should similar effects occur in astronauts subjected to low dose rate exposure to Space Radiation, the impairment of SD performance would result in a decreased ability to identify and learn the 'rules' required to respond to a new task or situation. Analysis of the behavioral data by kernel density estimation revealed that 40% of rats had severe ATSET impairments. This value may be a best-case scenario because exposure to neutrons also adversely impacted performance in the UCFlex task. Furthermore, when the good performing rats were reevaluated after they had been subjected to sleep fragmentation, additional ATSET performance decrements were observed in the set shifting stages of the ATSET test, with only 7.4% of the neutron exposed rats able to successfully perform ATSET under normal and sleep fragmented conditions, as opposed to ∼55% of shams. CONCLUSION: Protracted low dose and low dose rate neutron exposures impairs executive functions in a high percentage of rats that were normally rested, however further detriments in performance become evident when the rats are subjected to sleep fragmentation.
PURPOSE: Astronauts on the planned missions to Mars are expected to have to work more autonomously than on previous missions. Thus mission success may be influenced by the astronauts' ability to respond quickly to unexpected problems, processes that require several executive functions. The purpose of this study was to determine the impact that prolonged low dose and low dose rate exposure to neutrons had on two executive functions, and whether the severity and incidence of cognitive impairment was altered by sleep fragmentation. MATERIALS AND METHODS: In this study we assessed the impact that prolonged (six month) low dose rate neutron exposure had on the ability of male Wistar rats to perform in two executive function tasks (i.e. attentional set shifting (ATSET) - a constrained cognitive flexibility task and the UCFlex assay - an unconstrained cognitive flexibility task). In recognition of the fact that astronauts also have to contend with inadequate sleep quantity and quality for much of their time in space, we determined the impact that relatively mild sleep disruption had on the ability to perform in the ATSET test in sham and neutron-irradiated rats. RESULTS: Chronic low dose (18 cGy) and dose-rate (1 mGy/day) exposure of rats to mixed neutron and photon over the course of six months resulted in significant impairment of simple discrimination (SD) performance. Should similar effects occur in astronauts subjected to low dose rate exposure to Space Radiation, the impairment of SD performance would result in a decreased ability to identify and learn the 'rules' required to respond to a new task or situation. Analysis of the behavioral data by kernel density estimation revealed that 40% of rats had severe ATSET impairments. This value may be a best-case scenario because exposure to neutrons also adversely impacted performance in the UCFlex task. Furthermore, when the good performing rats were reevaluated after they had been subjected to sleep fragmentation, additional ATSET performance decrements were observed in the set shifting stages of the ATSET test, with only 7.4% of the neutron exposed rats able to successfully perform ATSET under normal and sleep fragmented conditions, as opposed to ∼55% of shams. CONCLUSION: Protracted low dose and low dose rate neutron exposures impairs executive functions in a high percentage of rats that were normally rested, however further detriments in performance become evident when the rats are subjected to sleep fragmentation.
Entities:
Keywords:
Space radiation; attentional set shifting; creative problem solving; executive function; neutrons; sleep fragmentation
Authors: Christopher W Jones; Mathias Basner; Daniel J Mollicone; Christopher M Mott; David F Dinges Journal: Sleep Date: 2022-03-14 Impact factor: 5.849
Authors: Jeffrey S Willey; Richard A Britten; Elizabeth Blaber; Candice G T Tahimic; Jeffrey Chancellor; Marie Mortreux; Larry D Sanford; Angela J Kubik; Michael D Delp; Xiao Wen Mao Journal: J Environ Sci Health C Toxicol Carcinog Date: 2021
Authors: M Abend; S A Amundson; C Badie; K Brzoska; R Hargitai; R Kriehuber; G O'Brien; S Schüle; E Kis; S A Ghandhi; K Lumniczky; S R Morton; D Oskamp; P Ostheim; C Siebenwirth; I Shuryak; T Szatmári; M Unverricht-Yeboah; E Ainsbury; C Bassinet; U Kulka; U Oestreicher; Y Ristic; F Trompier; A Wojcik; L Waldner; M Port Journal: Sci Rep Date: 2021-05-07 Impact factor: 4.379
Authors: Ebrahim Afshinnekoo; Ryan T Scott; Matthew J MacKay; Eloise Pariset; Egle Cekanaviciute; Richard Barker; Simon Gilroy; Duane Hassane; Scott M Smith; Sara R Zwart; Mayra Nelman-Gonzalez; Brian E Crucian; Sergey A Ponomarev; Oleg I Orlov; Dai Shiba; Masafumi Muratani; Masayuki Yamamoto; Stephanie E Richards; Parag A Vaishampayan; Cem Meydan; Jonathan Foox; Jacqueline Myrrhe; Eric Istasse; Nitin Singh; Kasthuri Venkateswaran; Jessica A Keune; Hami E Ray; Mathias Basner; Jack Miller; Martha Hotz Vitaterna; Deanne M Taylor; Douglas Wallace; Kathleen Rubins; Susan M Bailey; Peter Grabham; Sylvain V Costes; Christopher E Mason; Afshin Beheshti Journal: Cell Date: 2020-11-25 Impact factor: 66.850
Authors: Balaji Krishnan; Chandramouli Natarajan; Krystyn Z Bourne; Leila Alikhani; Juan Wang; Allison Sowa; Katherine Groen; Bayley Perry; Dara L Dickstein; Janet E Baulch; Charles L Limoli; Richard A Britten Journal: Int J Mol Sci Date: 2021-04-01 Impact factor: 5.923
Authors: Ivan Soler; Sanghee Yun; Ryan P Reynolds; Cody W Whoolery; Fionya H Tran; Priya L Kumar; Yuying Rong; Matthew J DeSalle; Adam D Gibson; Ann M Stowe; Frederico C Kiffer; Amelia J Eisch Journal: Front Behav Neurosci Date: 2021-10-11 Impact factor: 3.558
Authors: Evagelia C Laiakis; Maisa Pinheiro; Tin Nguyen; Hung Nguyen; Afshin Beheshti; Sucharita M Dutta; William K Russell; Mark R Emmett; Richard A Britten Journal: Front Physiol Date: 2022-08-26 Impact factor: 4.755