title: Flicker and suprathreshold spatial summation: evidence for a two-channel model of achromatic brightness.
mesh_terms: D000328:Adult; D005260:Female; D005425:Flicker Fusion; D006801:Humans; D008027:Light; D008297:Male; D012684:Sensory Thresholds; D012858:Size Perception; D014796:Visual Perception