PSYCHOSOMATICS 



[741 



vincing insofar as the gastric erosions seen terminally 

 in cases of brain lesions bear no resemblance to those 

 met with in ordinary medical practice. On the basis 

 of the combined evidence Gushing suggested that the 

 hypothalamus provided a mechanism by which psy- 

 chic factors could precipitate the formation of ulcers. 

 The role of the hypothalamus in the pathogenesis of 

 ulcers has recently been reinvestigated by French 

 et al. (18). They carried out repeated stimulation of 

 the hypothalamus in chronically prepared monkeys 

 and found striking gastric alterations in 6 of 10 ani- 

 mals that were tested. In some instances there were 

 focal ulcerations characterized as "large, raised edem- 

 atous lesions with deep purple coloration and gray 

 necrotic center." In an earlier series of investigations, 

 it had been demonstrated that hypothalamic stimula- 

 tion brought about a quick increase in gastric secretion 

 by way of the vagus and a delayed increase through 

 the activation of pituitary-adrenocortical mechanisms. 

 Mahl (44) has reported that chronic fear, as opposed 

 to acute fear, is associated with an increase in gastric 

 acidity in dogs and monkeys. No gastrointestinal 

 lesions were found in his animals. 



Experimental Failure tn Induce Lesions 



possible explanation. It has been shaking to con- 

 cepts of psychosomatic medicine that thus far animal 

 experimentation has failed to show a causal relation- 

 ship between emotional states and the formation of 

 lesions in the gut or elsewhere in the body. But there 

 is the possibility that in such investigation the emotion- 

 inducing conditions have not been sufficiently drastic 

 and continuous. That this is indeed the case is sug- 

 gested by recent studies (58). Some observations 

 made in the author's laboratory bear on this problem. 

 It was found in the process of establishing conditioned 

 cardiac and respiratory responses in cats that if the 

 tests (in which a shock was used as the unconditioned 

 stimulus) were administered more than every 5 min., 

 the cardiac and respiratory rates failed to return to 

 the base-line level. On the contrary, the heart and 

 respiratory rates became and continued so fast 

 throughout a training session that one could distin- 

 guish no differential changes at the time of a test. The 

 same situation appeared in the macaque with the 

 exception that after the first few tests, no amount of 

 elapsed time between tests conducted in the course of 

 a morning was sufficient to allow the signs of sympa- 

 thetic overactivity to abate. This indicates that there 

 was a factor of anticipation that kept alive the animals' 

 response to the test situation. Phylogenetic considera- 



tions, together with what is known about the functions 

 of the prefrontal cortex, are suggestive that differences 

 in the development of this part of the brain in the cat 

 and monkey may partially account for the temporal 

 discrepancies in their behavior in the above situation. 

 In other words, it might be supposed that phylo- 

 genetically with the progressive development of the 

 prefrontal cortex the animal acquires an increased 

 capacity to anticipate the recurrence of an event 

 and, through the neurological substitution of the idea 

 of the event for the event itself, to keep alive the 

 physiological changes that were precipitated by it. 

 From the standpoint of psychosomatic illness and the 

 potentiality of lesion formation, this would perhaps 

 account for a fundamental difference between man 

 and animals. At all events, in the design of animal 

 experiments it would seem of great significance to 

 keep these factors in mind. 



SUGGESTIONS IN REGARD TO FURTHER RESEARCH. Ill 



further research along these lines conditioning tech- 

 niques would appear to offer particular promise as a 

 means of inducing enduring visceral and viscero- 

 somatic changes. It was first observed by Pavlov (52) 

 that in the course of conditioning procedures, some 

 dogs developed signs of what has since been classically 

 referred to as an experimental neurosis. In the United 

 States, Gantt and Liddell have for several years 

 devoted study to experimental neurosis and have 

 identified a number of conditioning procedures that 

 are conducive to its development. 



Problem of specificity. Liddell and co-workers have 

 made some notable observations on sheep and goats 

 that may furnish a lead for investigations on the prob- 

 lem of lesion formation, as well as the problem of 

 specificity. The latter problem pertains to the question 

 of why in a given case the symptoms and signs of an 

 allegedly psychosomatic illness are localized to a par- 

 ticular organ or system of the body. For example, 

 uh\ is it that one patient acquires a peptic ulcer 

 whereas another develops high arterial pressure? Or 

 again, why is it that in the same individual symptoms 

 of peptic ulcer may predominate at one time and 

 those of hypertension at another? Thus far there has 

 been a failure to relate the manifestations of a particu- 

 lar disease to a particular personality structure or to a 

 particular psychological condition or to other factors 

 (12). Liddell and his group found that in some animals 

 the administration of conditioning tests at monoto- 

 nously regular intervals led to unmistakable signs of 

 an experimental neurosis (32). Curiously enough, the 

 animals that were tested at 2-min. intervals seemed 



