ABNORMALITIES OF NEURAL FUNCTION IN THE PRESENCE OF INADEQUATE NUTRITION 



I g 93 



SEMISTARVATION 



Semistarvation, the prolonged caloric restriction 

 characteristic of famines, has been for ages past the 

 most important type of nutritional deficiency. Much 

 of the literature on this subject was summarized in 

 connection with the presentation of experimental 

 observations made in the course of World War II 



(i33. P 68 9)- 



Important neurophysiological data were obtained 



after World War I when food supplies in Pctrograd 

 became grossly inadequate. The effects on the func- 

 tioning of the central nervous system of dogs urn- 

 studied using Pavlov's technique of conditioned 

 reflexes (80, 224). As in other dietary stresses (cf. 82), 

 one of the early neurophysiological symptoms of 

 semistarvation was the loss of differential inhibition. 

 In the next stage, well-established conditioned re- 

 sponses, elicited under standard conditions, decreased 

 in intensity. The reactivity of the central nervous 

 system was lowered and it became impossible to 

 elaborate new conditioned responses. In time re- 

 sponses to previously conditioned artificial stimuli, 

 such as the sound of a bell, decreased and finally could 

 not be elicited, while the responses to natural condi- 

 tioned stimuli, such as the sight or odor of food, were 

 still retained in considerable force. In the terminal 

 phase of semistarvation even these responses weir 

 greatly reduced. The unconditioned salivary reflex 

 continued to function throughout, although the in- 

 tensity of the response was depressed. 



American authors (6, 225) who have produced 

 bodily stunting by a quantitatively inadequate diet, 

 even when started before weaning (19), found no 

 significant impairment of maze learning ability. 



There are many reports on behavior under condi- 

 tions of 'natural' starvation (47; 104, p. 235; 155, p. 

 783). Plaut (212) differentiates three stages: chronic 

 fatigue, occasional apparent and temporary improve- 

 ment (adaptation), and 'psychic cachexia." Leyton 

 (145), writing on the basis of his experience in German 

 camps for prisoners of war, pointed out that the rear 

 tions to the reduction of diet from that of the frontline 

 soldier to the meager camp fare could be divided into 

 many stages. At first there is a loss of the natural feel- 

 ing of well-being. With time, hunger increases in 

 intensity until all thought becomes concentrated on 

 food. Next comes a progressive physical and mental 

 lethargy. Endurance was markedly decreased. Poly- 

 uria became severe. Muscular action became pro- 

 gressively slower, with signs of exceedingly slow 

 cerebration in advanced inanition. Sexual desire was 



reduced while desire for tobacco greatly increased. 

 Standards of cleanliness were lowered and pride in 

 personal appearance lost. Moral standards deterio- 

 rated. Physical examination revealed sluggish tendon 

 reflexes. The sight remained good, except for rare 

 cases of mild night blindness. Hearing was normal or 

 acute. Sensations of touch and temperature were not 

 impaired. 



In advanced semistarvation (104, p. 174) the mus- 

 culature becomes extremely atrophied. Adynamia, 

 myalgia and gastrocnemic cramps are prominent 

 symptoms. The terminal phase is characterized by 

 reduction and retardation of all mental processes, 

 with oligokinesia and bradykinesia, oligomimics and 

 bradylalia (104, p. 252). Quantitative observations on 

 changes in the basic aspects of nervous function in 

 man are vrrv limited. Marked increases in vestibular 

 chronaxia were reported (41)1 in emaciated men. 



According to Russian observations on semistar- 

 vation made in World War II (216), the motor 

 adynamy results from lack of energy-yielding sub- 

 stances, decreased muscle mass, alterations in the 



activity of motor nervous centers and possiblv other 

 factors. Physical exertion lead- i.ipidlv to exhaustion 

 which m. iv pass into coma. In advanced stages the 

 sensor) thresholds are increased and pain sensitivity 

 is diminished. The reaction of the pupils to lighl is 

 weak, the arterial pressure low, the pulse slow, the 

 bowels constipated and the adrenals atrophied. In 

 regard to psychic alterations 1 1 }, asthenia was con- 

 sidered the principal syndrome in advanced semi- 

 starvation, characterized bv sluggish intellectual 

 processes, decreased ability to concentrate and in- 

 capacity for sustained mental effort. There is a lower- 

 ing of all higher interests and feelings, and a tendency 

 to dav dreaming. Both irritability and restlessness, 

 and apathy, bordering on abulia, are present Some 

 patients exhibit character disorders such as sullen- 

 neSS, obstinacy or lack of tact. Psychoses were rare 

 even at the height of the Leningrad famine (cf. 32). 

 1 lallucinations and other psychotic symptoms wen- 

 present mostly in those cases in which caloric defi- 

 ciency was complicated by pellagra, infection or 

 trauma. 



The symptoms of 'natural' semistarvation were 

 produced under controlled conditions (133) in a study 

 in which initially normal young men lost one fourth 

 of their initial body weight in the course of 24 wk. 

 Sensory functions (133, p. 675) were remarkably 

 resistant to this nutritional stress. Visual threshold 

 remained unaltered. The acuity of hearing actually 

 increased — a small change that was reversed in the 



