426 



PHYSIOLOGY OF STRESS 



but efficiency in terms of work done per unit 

 of energy consumed is greatly reduced (6, 8, 

 31, 40) — the effort is out of proportion to the 

 performance. (See Section V, 6.) And as 

 the stress of increasing effort rises, the spread 

 of tension may increase until the activities 

 involved are no longer even appropriate and 

 may even interfere with one another (8, 18, 

 40). Accessory autonomic, glandular, and 

 other noraially supporting activities may be 

 mobihzed out of all proportion and even at 

 times inappropriately to the specific task. 

 Homeostatic readjustments of the organic 

 factors in equilibrium may be initiated and 

 may persist after the immediate occasion for 

 stress has subsided (2, 78, 101). Even ap- 

 propriate supporting organic changes, as for 

 example the secretion of adrenalin, may have 

 undesirable "side effects" or give rise to un- 

 desirable compensations. Thus, as the or- 

 ganic changes attending performance of duty 

 become excessive or inappropriate they may 

 by this fact acquire the quahfication of an 

 "emotional" response. And as they become 

 effects secondarily and more remotely in- 

 duced they may, as we shall try to show, pro- 

 vide symptoms of "functional" disorders (34, 

 55, 82). 



C. Stress of Perceived Danger-Emotion 



That the perception of external conditions 

 constituting a threat to the safety or security 

 of the individual may give rise to psycho- 

 physiological stress is a natural inference 

 from the nature of the profound physiological 

 changes which may be produced. But of the 

 nature of the mechanisms by which percep- 

 tual patterns projected on the "mental 

 screen" are identified and interpreted as 

 carriers of friendly, neutral, or enemy cargo 

 and, for the latter, translated into a firing 

 signal setting off an appropriately directed 

 reaction, our knowledge is hmited. It is 

 true that psychophysiological "conflict" in 

 such conditions can often be recognized and 

 demonstrated (Luria 79). In an early paper 

 one of the writers postulated central "con- 

 flict" among impulses as a condition in- 



volving a degree of "functional decortication" 

 which might release subcortical mechanism 

 from central control (20). While decorti- 

 cation is consistent with the automatic, in- 

 voluntary and irrational, over-reactive, in- 

 coordinated, asynergic, dysmetric character 

 of the typical emotional reaction, sometimes 

 involving loss of acquired skills and some- 

 times subsequent amnesia for the event, the 

 process is obviously not a simple one. Ken- 

 nard (69) recognized the interrelation of emo- 

 tional states, incoordination, and basal gangli- 

 onic dysfunction. Present evidence suggests 

 that there is not only a central excitation 

 process which may discharge peripheralward 

 to produce autonomic changes, but that 

 there are also effects on basal gangha as well 

 as hypothalamus, which may in turn react 

 back upon the cortex (27). These latter will 

 be considered in Section II, C. 



That sensory stimulation effectively gives 

 rise to cortical effects; that previous expe- 

 rience may "condition" or "sensitize" the 

 organism toward specific types of stimuli 

 (2, 56, 66, 83); and that by man's facility i 

 with symbols he may by suggestion and ra- | 

 tionalization become sensitized to react to a 

 wide range of mentally perceived hazards 

 with which he never has had prior experience, 

 are not matters for controversy. We never- 

 theless are profoundly ignorant of the neuro- i 

 physiological mechanisms by which these \ 

 effects take place. 



The attempt to study emotion in the labo- 

 ratory encounters difficulty in the inadequacy 

 of the laboratory situation. There is always 

 an element of artificiality, of unreality, of the 

 absence of fife and death consequences. Ex- 

 perimenters have tried to provide reafity for 

 their experiments by the use of painful 

 stimuli such as heat or electroshocks (41, 

 86, 89); they have tried removal of postural 

 support; they have employed "frustration"; 

 and they have sought to suggest reafity by 

 resort to hypnosis. But when set beside the 

 harrowing experience of depth bombing, for 

 example, these may not seem too convincing. 

 Even the most satisfactory laboratory ex- 



