Fig. 3

a A portion of Fig. 1 showing a sympathetic nerve stimulation (SNS) command and the heart rate (HR) response. The data are displayed as 10-Hz resampled signals. bpm beats/min. b A transfer function from SNS to HR. The gain and phase plots and the coherence (Coh.) associated with the transfer function are shown. c A model transfer function (Eq. 3) fitted to the estimated transfer function. d Plots showing the gain and phase of the model transfer function versus those of the estimated transfer function. The model transfer function described the estimated transfer function with reasonable accuracy. The dotted lines indicate the line of identity