Effects of adaptation on the temporal envelope of amplitude-modulated flickering light

This study sought to investigate the way in which the temporal envelope of amplitude-modulated (AM) flickering light is processed in the visual system. To this end, we measured the effects of adaptation on a low-frequency (2 Hz) envelope of AM flickering light with a high carrier frequency (16 Hz). The results showed that sensitivity to the envelope of the AM flickering light was reduced by adaptation to the low temporal frequency, although the AM flickering light had a frequency component at the carrier frequency but not at the frequency corresponding to the envelope. These results suggest that the low-frequency temporal envelope, composed exclusively of high-frequency (first order) Fourier energy, is encoded by a low-frequency selective channel.

► Threshold for low/high frequency increased after adaptation to low/high frequency.
► Threshold for low frequency envelope increased after adaptation to the low frequency.
► Low temporal envelope is mediated by the lower temporal channel.