[Intensity of spontaneous activity and mean visual evoked response during calculation of variable mean. New technique for measuring retinocortical time (author's transl)].

Various statistical discrimination indices reveal deflections regarded as significant before the 20th ms after stimulation (probably equivalent to Bickford responses or subcortical activity) and between the 20th and 23rd ms (early fractions of MVER). The independence of signal and noise is discussed. Considerations concerning the calculation of retinocortical time are developed.