Nonlinear Causal Cardiorespiratory Interaction in Response to Color Stimuli

Convergence Cross Mapping (CCM) is a nonlinear method for evaluating causality between time series. The cardiorespiratory interaction between heart rate (HR) and respiration rate (RR) time series in response to different colored lights was studied in this paper. Using ECG and belt-based respiration data for 16 female volunteers (Age: 24.75±1.43) recorded during eyes-closed condition (control), and while exposed to four different colored lights (red, green, blue, and yellow), CCM
HR→RR
and CCM
RR→HR
were calculated. The results suggest that cardiorespiratory interaction (HR→RR and RR→HR) captured by CCM are different in response to four colored visual stimuli. However, statistical analysis of data revealed no statistically significant difference in these parameters (p>0.05) in response to different colored light.