Cone spectral sensitivity and chromatic adaptation as revealed by human flicker-electroretinography

Abstract

The human ERG response to a 40 Hz stimulus was measured using a synchronous detection technique (lock-in amplifier). Thus it was possible to record spectral sensitivity quickly and easily. Check experiments showed that only the cones contributed to the total response. Adaptation to a red background of3.7 × 10 4 trolands, and a blue background of2.2 × 10 4 trolands caused selective depression of spectral sensitivity. Neither green nor white adaptation altered the spectral sensitivity. The results of parallel experiments on a protanope indicated that no change in spectral sensitivity took place during his exposure to intense coloured backgrounds. Measurements of the influence of chromatic adaptation were also performed using a psychophysical threshold criterion for sensitivity. The results are in close agreement with the ERG data. The recovery of the response after exposure to coloured backgrounds of various intensities indicated that the selective depression of the luminous spectral sensitivity can be due to both neural adaptation and to bleaching of the photopigments.