Abstract
It is well-known that the autonomic nervous system responds in different manners by inducing various emotions. Therefore, we have studied on the responses in human blood circulation evoked by emotional stimuli. In our previous studies, we found different correlations between some parameters of blood circulation with different emotions. These features could be detected more clearly by considering the lag time between the parameters that conducted from the blood circulation control system. Generally speaking, heart rate will increase in an exciting emotion. But this accepted concept was not always true in our previous studies and in some other literatures. Therefore, we developed and discussed the analysis technique for the index of the excitation by focusing on respiratory sinus arrhythmia (RSA) which suggested as the index of rest levels of the cardiopulmonary system. In an exciting state, RSA is expected to decrease because of increasing the demand of oxygen. To find the feature of changes in blood circulation, we measured temporal changes in consecutive blood pressure, ECG and respiratory wave during the emotion of fear, excitation, disgust and sadness, respectively. Each minimum coefficient of cross-correlation between heart rate variability in RSA frequency range and the respiratory wave was sought with considering “the time shift” as a lag time. Consequently, the time series of minimum cross-correlation coefficients varied significantly in an exciting emotion from rest. But, whether the time shift that obtained from the minimum value of cross-correlation coefficients between the parameters could be considered as a lag time of the parameters is open to dispute, we discussed it and obtained reasonable results.
