[Characterization of the functional relations between cerebral structures: the linear and non-linear].
Two kinds of methods are available in order to assess the functional relationships between different cerebral structures from the analysis of EEG signals: linear and non-linear methods. In this paper, we describe didactically the methodological bases of signal processing. After recalling the significance of the fundamental parameters of a sine wave: frequency, amplitude and phase, we show, from a first example about an epileptic seizure propagation, how a linear variation between phase and frequency can be interpreted as a small time difference between two EEG channels. This linear method hypothesises that these two signals are respectively the input and the output of a linear system. Then, we point out the limits of this method and we introduce non-linear methods. Among the latter, a recent approach introduces a realistic model of EEG which try to relate signal measured quantities to relations between underlying structures which produce them.
Bourriez
J L
JL
Service de Neurophysiologie Clinique, Hôpital Roger Salengro, CHRU de Lille, 59037 Lille, France. jlbourriez@chru-lille.fr
Jacquesson
J M
JM
Derambure
P
P
Guieu
J D
JD
D000465:Algorithms; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography / Q000706:statistics & numerical data*; D004827:Epilepsy / Q000503:physiopathology; D006801:Humans; D016014:Linear Models; D017711:Nonlinear Dynamics; D012815:Signal Processing, Computer-Assisted