Interaction of the processes of autonomous control of the heart rate during the cognitive tasks

The work revealed a change in the interaction between the processes of sympathetic and parasympathetic control of the heart rhythm and infra-slow oscillations of brain potentials with a frequency of less than 0.5 Hz during stress-inducing cognitive tasks. Stress test was performed for 63 healthy men. The stress test included Stroop color word test and mental arithmetic tests. Electroencephalogram and the sequences of RR-intervals were analyzed. The signals were filtered in the low frequency range from 0.05 to 0.15 Hz and the high frequency range from 0.15 to 0.40 Hz. The phase coherence coefficient and directional coupling indices based on the method of phase dynamics modeling were calculated.