[Contribution towards the study of the average visual-evoked response; non-gaussian character of spontaneous electroencephalographic activity; non-independence of noise and signal; possible non-stationary character of evoked response (author's transl)].

The succession of amplitudes constituting spontaneous electroencephalographic activity cannot be regarded as a strictly normal distribution. Spontaneous activity and the evoked response are not independent. The signal (evoked response)is, in some cases, non-stationary. The average visual-evoked response comprises several successive temporal fragments of which the stationary character varies. This variability of the average visual-evoked response argues in favour of the complexity of its genesis.