The use of ionizing radiation as a motivating stimulus.

A review is given on experiments in which ionizing radiation was used as a motivating stimulus to elicit avoidance behavior in animals. Saccharin-flavored water, in a concentration highly preferred to tap water by rats, was used as the conditioned stimulus. Rats drank either saccharin-flavored water or tap water in conjunction with either a sham exposure, a 30-r, or a 57-r dose of gamma rays. Following a single treatment they were tested for saccharin preference (saccharin fluid vs tap water) in their home cages. Animals that drank saccharin-flavored water during actual exposure exhibited a marked aversion for the fluid during the postirradiation tests, whereas the remaining groups continued to display a high preference for the saccharin solution. The effect was dose dependent and persisted for more than 4 weeks following the 6-hr radiation exposure. A dose of 54 r elicited a decrement in postirradiation saccharin preference when the beam was directed at the abdomen. The decrement was not so pronounced as that observed following whole-body exposure with the same dose. The 54-r dose had no appreciable effect when the beam was directed towards the head, thorax, or pelvis. However, depressions in saccharin consumption were produced when the dose to these regionsmore » was raised to 252 r. Therefore, while the abdomen proved to be the most sensitive area, conditioning can be instigated by irradiation of other regions with higher doses. Radiation conditioning has a marked resistance to interference by surgery or drugs.« less