Discrimination of global-motion signal strength.
The ability of observers to discriminate differences in global-motion-signal strength (that is the proportion of coherently moving dots in a field of randomly moving dots) was determined for both first and second-order stimuli. Observers could accurately discriminate differences in signal intensity for all reference signal levels tested; 20-100%. A similar pattern of performance was obtained for both types of stimuli. The observed first-order signal-discrimination performance is compatible with the results of electrophysiological studies that have investigated the dependence of the firing rate of V5 cells (also called the middle temporal area) upon global-motion signal intensity.
Edwards
M
M
School of Optometry, University of California, Berkeley 94720, USA. mark@hering.berkeley.edu
Badcock
D R
DR
D004056:Differential Threshold / Q000502:physiology; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D011601:Psychophysics