Behavioral effects of ionizing radiations: 1955-61.

Abstract

The pertinent literature is comprehensively reviewed and over 200 references are cited. General conclusions reached on the basis of this survey are summarized. Prenatally irradiated mammals exhibit behavior patterns that may be best described as fearfulness, as well as a variety of other behavioral deviations, confirming that the developing nervous system is highly radiosensitive. It is apparent that doses up to several thousand roentgens do not interfere with learning of relatively difficult problems whenever radiation malaise or motivational changes do not inhibit performance. Actually, the evidence points in the other direction, i.e., that in many types of problems irradiated animals learn more rapidly than do controls. The simplest explanation of the superior learning in irradiated animals takes into account their decreased distractibility and narrow focus of attention. Ionizing radiations do not produce losses in learned habits if performance is tested soon after irradiation or within a few months afterwards. Drive, as a major determinant of performance, is influenced by homeostatic mechanisms, and when ionizing radiations affect these, performance may be altered. It has been shown that low doses of x rays are visible, and visual functions, especially scotopic, are depressed by ionizing radiations. It is assumed that the photochemical processesmore » in the receptors are affected. Radiation-induced changes have also been reported for hearing, taste, and smell, but the findings have been equivocal, including reports of enchanced, lowered, or unaffected sensitivity. So far no good evidence is available for morphological changes in the nervous system in organisms irradiated in adulthood. A variety of behavioral symptoms occurs in the acute phases of radiation illness, but on the human level only qualitative data are available. It has been assumed that radiation induces or mimics aging, yet on the behavioral level there are only limited data bearing on this hypothesis. (BBB)« less