Temporal processing Flashcards
What does spatial processing process?
Resolution thresholds and the human sensitivity to contrast
What is temporal frequency?
Rate at which the luminance varies
At what TF is the maximum contrast sensitivity under photopic conditions?
6-8Hz
What is the critical flicker frequency
Highest TF that can be resolved at amximal contrast
Why is there a low TF roll off?
Due to the effects of center-surround inhibition in ganglion cells
Why is there a high TF roll off?
Represents the inherent photochemical/neural limitation of signal generation within retinal cells
What is the temporal integration period?
Ability to sum light quanta over a specified time period
What is the definition of bloch’s law?
Threshold for detection of a flash is reached when the criterion total luminous energy is reached
What does an increase in teporal frequency cause? (4)
Increase flicker rate
Decrease in duration of ON/OFF phases of stimulus
Detection threshold increases
Contrast sensitivity decreases
What is the effect on the tCSF of an increase in background luminance? (2)
Absolute threshold increases
Crtital time decreases
What is the effect on the tCSF of an increase in target size?
Absolute threshold decreases
Critical time decreases
What is the Ferry-Porter law?
The CFF increases approximately lineraly with the logarithm of the retinal illuminance
What is the Granit-Harper law?
CFF increases linerly with log of stimulus size
Broca-sulzer effect
Light for a given luminance flashed for 50-100ms will appear brighter than light of the same luminance presented continuously
Brucke-Bartley effect
Light flashed at 10Hz will appear rbighter than the same flash presented continuously
