Experimental psychogenic hypertension: Blood pressure changes conditioned to painful stimuli (Schizokinesis)

Summary  

Failure to develop a conditional reflex by stimulation of the cephalad portion of the severed vagosympathetic trunk: Its significance in terms of the central connections of the vagus

Stimulation of the central stump of either vagosympathetic trunk in the dog, the contralateral nerve remaining intact, regularly provoked deep respiratory movements with forceful expiration, followed by a period of apnea, and a fall in blood pressure, systolic and diastolic, of 20–60 mm/Hg. Stimulation of the cephalad portion of the left nerve provoked brief acceleration of heart rate during the period of hyperventilation, followed by bradycardia; when the stimulus was applied to the central stump of the right nerve heart rate remained relatively unchanged. When a 12-second tone as a conditional stimulus (CS) was reinforced during its last six seconds with such stimulation of the vagosympathetic trunk as an unconditional stimulus (US), despite the striking visceromotor responses elicited by the US, no conditional reflex was established even after more than 3,400 trials in 16 dogs (34–781 trials per animal).     

Effect of movement on the cardiac conditional reflex

The cardiac component of the motor conditional reflex to a faradic stimulus to the hind leg in three dogs was measured. The leg was paralyzed by crushing 4 to 5 anterior roots of the lumbar nerves (second to sixth). The cardiac experiments were repeated beginning four days after operation and measurements were taken of the cardiac conditional reflex. A comparison of the increase in cardiac rate to the conditional stimulus before and after operating showed no significant difference in spite of the fact that the dog was unable to lift his leg to the stimulus. From this we conclude that the execution of the movement is not necessary for the increase of heart rate in the cardiac conditional reflex.     

Effects of pentobarbital sodium anesthesia and neurohumoral agents on the cardiac orienting reflex

Studies of the cardiac orienting reflex in 16 dogs, moderately anesthetized and awake are reported. In the anesthetized dogs prominent transient heart rate decrease was commonly noted within one or two beats after the onset of various auditory stimuli, and less often after visual stimuli. This cardiac inhibition was neither as prominent nor as frequent in occurrence in awake dogs. The respiratory cycle at stimulus onset influenced the appearance and degree of heart rate decrease, with the greatest and most frequent decreases occurring during the expiratory phase. Atropine abolished the response. There was little evidence of habituation of this orienting response under anesthesia, although “waxing” and “waning” apparently related to minute-by-minute fluctuations in degree of unconsciousness, occurred. These findings are discussed in relation to neurophysiological and neuroanatomical correlates of orienting responses, hypotheses of orienting and attention and cardiovascular neurohumoral mediators.     

The role of inhibition in neurotic behavior

Neurotic behavior is explained according to the theory of Pavlov as collision between excitation and inhibition. This internal inhibition imposes a burden on the nervous system. The stress can be relieved by what Pavlov called external inhibition, which is actually excitation of another activity. This principle is applied to the human being in explaining the interaction between nervous centers, the advantage of voluntary self-discipline over imposed discipline. Rioting and social unrest is explained in the terms of conflict between excitation and inhibition.