Spectral analysis of heart rate variability and RVLM neuronal discharge in rats
Spectral analysis was used to study the coherence between the blood pressure (BP) and neuronal discharge (ND), and between the heart rate variability (HRV) and neuronal discharge variability (NDV) in the rostral ventrolateral medulla (RVLM) in rats. The discharges of 28 neurons in the RVLM were recorded. The results revealed that: (1) there is an obvious coherence (k/sup 2/=0.82/spl plusmn/0.18) between ND and BP on spectrum. These neurons were classified as cardiac-related (n=18) if the coherence value was k/sup 2//spl ges/0.80; (2) there is also an evident coherence (k/sup 2/=0.78/spl plusmn/0.13) between NDV and high frequency (HF) component of HRV. These neurons might be HRV-related (n=14) if the coherence value was k/sup 2//spl ges/0.80. It indicates the integration of cardiac cycle and respiratory rhythm in the RVLM that might be important in cardiorespiratory homeostasis.