Lever-pressing behavior of albino rats during prolonged exposures to x-radiation.

Our laboratory is vitally concerned with radiobiological problems of space flight. The discovery of the Van Allen belt suggests that these and similar radiation areas may limit space travel and space exploration unless the degree, nature, and seriousness of the space-radiation problem is further elucidated. Our problem then is concerned with changes in performance rate of learned responses during successive periods of exposure to various intensities and doses of radiation. It is not principally concerned, as earlier studies have been, with perception of radiation or with learning mediated by the radiation stimulus. Although the experimental design permits actual study of behavior during radiation, this behavior would be expected to be dependent on the previous radiation history of the animal. The results of the study must therefore be interpreted in the light of animals exposed to a stimulus of a certain intensity as well as an accumulated dose. Only a few studies have been concerned with the behavior of organisms during exposure to ionizing radiation. All report generalized responses mediated by alterations in the physiologic state of the organism. One exception noted apparent perception and a learned response. For example, Reid et al. (1) observed that monkeys exposed to superlethal doses of 1000 r/min evidenced differences in vomiting and retching when compared to sham-irradiated controls. In addition, these authors observed a significant increase in scratching behavior for the irradiated monkeys of this study over the nonirradiated controls. This reaction was concentrated between 112 and 4 minutes after the