|RABIN, BERNARD - University Of Maryland|
|CARRIHIHLL-KNOLL, KIRSTY - University Of Maryland|
Submitted to: Radiation Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2015
Publication Date: 9/10/2015
Citation: Rabin, B.M., Carrihihll-Knoll, K.L., Shukitt Hale, B. 2015. Comparison of the effectiveness of exposure to low LET helium particles (4He) and gamma rays (137Cs) on the disruption of cognitive performance. Radiation Research. 184:266-272.
Interpretive Summary: Rats were exposed to either of two types of radiation, namely, Helium particles or Cesium gamma rays, and the effects of irradiation on brain function were evaluated. The results indicated that exposure to low doses of helium particles disrupted performance on a variety of mental tasks, one of which indicates baseline anxiety, another of which indicates an ability to recognize a location (spatial memory), and another indicating motivation and responsiveness to changes in the environment. Performance was not disrupted, however, by helium exposure in a test measuring the ability to recognize an object (learning and memory). In contrast, following exposure to cesium gamma rays, only the performance in the task measuring baseline anxiety was affected. Because exposure to both types of radiation produces a molecular stress-reaction in the brain, these results indicate that radiation-produced molecular stress may be necessary, but not sufficient, for radiation-induced disruption of brain performance.
Technical Abstract: Rats were exposed to either Helium (4He) particles (1000 MeV/n; 0.1 – 10 cGy; head-only) or Cesium 137Cs gamma rays (50 – 400 cGy; whole body) and the effects of irradiation on cognitive performance evaluated. The results indicated that exposure to doses of 4He particles as low as 0.1 cGy disrupted performance on a variety of cognitive tasks including, plus-maze performance (baseline anxiety), novel location recognition (spatial performance) and operant responding on an ascending fixed-ration reinforcement schedule (motivation and responsiveness to changes in environmental contingencies) but not on novel object recognition performance (learning and memory). In contrast, following exposure to 137Cs gamma rays only plus-maze performance was affected. There were no significant effects on any other task. Because exposure to both types of radiation produce oxidative stress, these results indicate that radiation produced oxidative stress may be a necessary condition for the radiation-induced disruption of cognitive performance, but it is not a sufficient condition.