Modern mathematical and biophysical approaches for investigating the physiological regulations
à 11h en salle C. Brot
Modern mathematical methods, suitable for biomedical signal processing, show an increased importance for research in the field of central control of vital functions. Neuronal structures involved in their production are defined as complex nonlinear systems. Time-frequency energy distribution derived from wavelet transform enabled multiresolution analysis of respiratory patterns during different conditions. The results showed that damping of electroneurographic high frequency oscillations, typical by high O2 demands, seems to be a characteristic sign for defensive aspiration reflex, which is not influenced by anesthesia, contrary to other respiratory patterns. Thus, it probably becomes dominant during hypoxia/hypercapnia conditions. Approximate entropy, a nonlinear measure of irregularity, indicates level of predictability in a time series. Approximate entropy showed reduced electromyographic complexity during airway reflex activity. On the other side, the higher complexity of eupnea is understood as a more random behavior. In conclusion, multiresolution analysis and tools of nonlinear dynamics are extending our understanding of physiological regulations, as well as their quantitative changes during pathological stages.
Fluides & Matériaux Complexes
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