New observations on the violet mechanism in man as revealed by the VECP.

The violet mechanism of the human visual system was studied in 14 trichromats by recording visually evoked cortical potential (VECP). Stimulus was a 10 degrees test light of 451 or 489 nm and of 700 ms duration, superimposed on a 15 degrees steady adaptation field of 574 nm (20,000 td). The violet mechanism was identified by measuring the relative radiation intensity necessary for a constant response to 489 and 451 nm.

[Spectral sensitivity of off-response in human VECP during selective chromatic adaptation (author's transl)].

The spectral sensitivity of the visual system of man during selective chromatic adaptation was determined. The criterion was an off-response of constant amplitude in the evoked cortical potential. Criterion of height of response differed among the subjects investigated.