Temporal modulation sensitivity and pulse-detection thresholds for chromatic and luminance perturbations.
We studied temporal processing of chromatic and luminance perturbations of a 600-nm field, measuring both modulation sensitivity (sinusoidal frequencies from 0.25 to 40 Hz) and pulse-detection thresholds (pulse durations from 5 to 2560 msec) for mean luminances of 0.9 to 900 Td and field sizes of 0.5 degrees to 8 degrees. Chromatic stimuli were produced by antiphase modulation of lights matched by heterochromatic flicker photometry. Both mean luminance and field size affected sensitivity, and the magnitude of field-size effects increased with mean luminance. We derived both luminance and chromatic impulse response functions for each set of experimental conditions, using the modulation-sensitivity data. At high mean luminances and large field sizes the chromatic impulse response functions are complex, suggesting contributions from both chromatic and luminance mechanisms. Pulse-detection data were fitted by a peak detector model based on these impulse response functions.
Eye Research Laboratories, University of Chicago, Illinois 60637.
W H
WH
Swanson
T
T
Ueno
V C
VC
Smith
J
J
Pokorny
D003116:Color; D003118:Color Perception / Q000502:physiology; D005074:Evoked Potentials, Visual; D006801:Humans; D008027:Light; D010775:Photic Stimulation / Q000295:instrumentation / Q000379:methods; D012684:Sensory Thresholds; D013702:Temporal Lobe / Q000502:physiology*; D014794:Visual Fields; D014796:Visual Perception / Q000502:physiology*