Adaptation mechanisms in spatial vision--I. Bleaches and backgrounds.
To examine how the mechanisms of bleaching and background adaptation affect spatial pattern vision, contrast detection thresholds were measured in the fovea for sinusoidal (increment-Gabor) targets, during long-term dark adaptation following full bleaches, and against steady adapting backgrounds of various intensities. The dark-adaptation curves were found to be invariant in shape over the range of spatial frequencies tested (1-15 c/deg); in other words, the amplitude sensitivity functions were invariant during dark adaptation. These results support the hypothesis that bleaching adaptation is local and multiplicative. On the other hand, the background-adaptation curves measured for different spatial frequencies were found to converge as background intensity increased; the amplitude sensitivity functions became flatter. These results reject the equivalent-background hypothesis.
Hahn
L W
LW
Center for Vision and Image Sciences, University of Texas at Austin 78712, USA.
Geisler
W S
WS
D000221:Adaptation, Ocular / Q000502:physiology*; D000328:Adult; D003623:Dark Adaptation / Q000502:physiology; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D012168:Retinal Pigments / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology
D012168:Retinal Pigments