Changes in Behaviour Associated with a Nervous System Poison (DDT.)

Abstract

The main purpose of the investigation was to shorn that behaviour measures can he used to investigate the effects of those toxic drugs which produce "biochemical lesions" in the nervous system although the nature of the lesions still remains undetermined. The advantages of this approach are twofold. First, a psychological study may help to uncover the initial effects of the drug, and thus provide evidence which may lead to the ultimate understanding of the action of the drug. Second, and of value from the practical point of view, such a method may be used to detect toxicity. I n this study D.D.T. was used. Two experiments were performed on one control and four experimental groups of albino rats. Problem solving behaviour, speed and pattern of locomotion, and reaction to stress involving visual stimuli were observed.Problem solving behaviour was found to be unaffected by the drug; no changes were found in speed of locomotion, but pattern of locomotion revealed that "ataxia" was one of the initial effects of D.D.T. poisioning. The experimental animals were founcl to be generally less reactive to "stress" : "hyper-irritability'' reported in previous studies being explicable in terms of exaggerated motor responses.The results obtained on "ataxia" showed that the procedure adopted here could be used to detect chronic D.D.T. toxicity in rats. INTRODUCTIONThe study of changes in behaviour following "biochemical lesions" (Peters, 1948) produced in the Central Nervous System (C.N.S.) is a technique developed comparatively recently. It has been used to study the relation existing between physiological and psychological factors (eg. Russell, 1954; Watson, 1955 ; Knopfelmacher et al., I956), and has two advantages. I t is independent of the structural arrangement of the various areas in the brain, thus it overcomes the difficulties introduced by anatomical individual differences. The biochemical changes can in general be maintained for a sufficient length of time to allow experiments on behaviour to be carried out, and in this way it avoids the difficulties introduced by "post-operative'' recovery.Biochemical lesions involve interference with metabolic events. Administration of toxic drugs is an effective and easy method for producing these desired changes. However, if the function in behaviour of a certain structure in the C.N.S. is under investigation, then this technique can only be used fruitfully when the specific nature of the biochemical lesions produced is known to the experimenter. That is to say unless the action of the drug is known it cannot be adequately used as an agent for producing biochemical lesions. In this way a restriction is imposed on the technique. I t is possible to show relationships between certain neuro-physiological processes and behaviour by interfering with the metabolism of nervous tissues. We should, therefore, be able to suggest the possible mode of action of a nervous system poison from a study of associated behaviour changes. This method of approach provides a way of dealing with toxic dr...

Report on pilot study of effects of DDT on maternal behavior

“…The irritability and increased reactivity to stimuli are also characteristic of emotional states. However, Khairy (1959), studying problem-solving behavior, speed and pattern of locomotion, and reaction to stress, found that animals exposed to DDT tended to show less emotional reaction to stress, although this tendency was statistically significant only for urination. There were no significant differences in the measures of ambulation, rearing, preening, defecation, squeaking, and feeding.…”