title: Brightness induction and suprathreshold vision: effects of age and visual field.
abstract: A variety of visual capacities show significant age-related alterations. We assessed suprathreshold contrast and brightness perception across the lifespan in a large sample of healthy participants (N=155; 142) ranging in age from 16 to 80 years. Experiment 1 used a quadrature-phase motion cancelation technique (Blakeslee & McCourt, 2008) to measure canceling contrast (in central vision) for induced gratings at two temporal frequencies (1 Hz and 4 Hz) at two test field heights (0.5° or 2°×38.7°; 0.052 c/d). There was a significant age-related reduction in canceling contrast at 4 Hz, but not at 1 Hz. We find no age-related change in induction magnitude in the 1 Hz condition. We interpret the age-related decline in grating induction magnitude at 4 Hz to reflect a diminished capacity for inhibitory processing at higher temporal frequencies. In Experiment 2 participants adjusted the contrast of a matching grating (0.5° or 2°×38.7°; 0.052 c/d) to equal that of both real (30% contrast, 0.052 c/d) and induced (McCourt, 1982) standard gratings (100% inducing grating contrast; 0.052 c/d). Matching gratings appeared in the upper visual field (UVF) and test gratings appeared in the lower visual field (LVF), and vice versa, at eccentricities of ±7.5°. Average induction magnitude was invariant with age for both test field heights. There was a significant age-related reduction in perceived contrast of stimuli in the LVF versus UVF for both real and induced gratings.
authors.affiliation: Center for Visual and Cognitive Neuroscience, Department of Psychology, North Dakota State University, Fargo, ND 58108, USA. Electronic address: mark.mccourt@ndsu.edu.
authors.forename: Mark E
authors.initials: ME
authors.lastname: McCourt
authors.affiliation: Center for Visual and Cognitive Neuroscience, Department of Psychology, North Dakota State University, Fargo, ND 58108, USA.
authors.forename: Lynnette M
authors.initials: LM
authors.lastname: Leone
authors.affiliation: Center for Visual and Cognitive Neuroscience, Department of Psychology, North Dakota State University, Fargo, ND 58108, USA.
authors.forename: Barbara
authors.initials: B
authors.lastname: Blakeslee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D006801:Humans; D008029:Lighting; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation / Q000379:methods; D012044:Regression Analysis; D012684:Sensory Thresholds / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology*; D055815:Young Adult
keywords: Aging; Contrast; Induction; Suprathreshold; Visual field