Mechanisms of increasing stress tolerance during transcranial magnetic stimulation in people with intellectual work

Abstract

Introduction. In modern conditions humans are exposed to the high level of stress that causes the gain in psychosomatic disorders. The problem of tolerance to increasing stress is becoming more and more urgent. The study of the possibilities of the dorsolateral prefrontal cortex stimulation, which affects the mechanisms of autonomic regulation, is of clinical interest.
 The aim of the study is to research the mechanisms of the resistance to increasing stress after transcranial magnetic stimulation of the dorsolateral prefrontal cortex of the right hemisphere in young males engaged in mental work. 
 Materials and methods. Thirty four healthy male 20 to 22 years students were observed. Transcranial magnetic stimulation of the dorsolateral prefrontal cortex projection at the F4 point in the electrode system marked “10–20” was carried out with an individually determined stimulus intensity in the amount of 300 stimuli with a frequency of 1 Hz. Autonomic effects were evaluated using spectral analysis of heart rate variability before and after stimulation. Seven-test was used as a stress test.
 Results. The predominance of oscillations in the low frequency of heart rate variability, indicating sympathetic activation, was determined in the examined young men, engaged in mental labour. After stimulation of the prefrontal cortex, there was an increase in heart rate variability, to a greater extent very low frequency oscillations associated with the central mechanisms of parasympathetic activity. During the stress test, the increase in adaptive capabilities was manifested by a less pronounced decrease in heart rate variability in comparison to the reaction before stimulation. A model of the effect of stimulation of the dorsolateral prefrontal cortex on heart rate variability was proposed.
 Limitations. The study is limited to the evaluation of spectral parameters of heart rate variability in 34 young healthy students before and after transcranial magnetic stimulation of the dorsolateral prefrontal cortex.
 Conclusion. Stimulation of the prefrontal cortex increased the adaptive capabilities of the body and can be used to increase stress resistance in people with intellectual work.