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Jeffrey D. Bower, George J. Andersen; Perceptual learning increases motion discrimination of low contrast Gabors in older observers. Journal of Vision 2010;10(7):1138. doi: 10.1167/10.7.1138.
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© ARVO (1962-2015); The Authors (2016-present)
This study compared the effect of training on the perception of motion in low contrast Gabor patches between older and younger observers. The stimuli were centrally presented Gaussian filtered sine-wave gratings (Gabors). The Gabors were either 5 or .7 degree diameter ( 2σ of the Gaussian filter) and had a contrast of .92, .22, or .028. The task was to judge whether the motion direction of the Gabor patch was to the left or to the right. The experiment took place over 5 days. On each day the observer participated in 6 blocks; one for each contrast/size pair. For each block, a duration thresholds estimating 77.5% correct was derived by averaging the results of randomly interleaved 2/1 and 4/1 staircases. The presentation times ranged from 500 (60 frames) to 16.6 (2 frames) milliseconds. Each block ended after 150 trials. Each participant observed a total of 4500 trials over 5 days. The results indicate a reduction in the amount of observation time needed to discriminate the direction of motion of the .028 contrast Gabors after training. The older observer's thresholds for the 5 degree Gabor improved by 66% ( day-1 = 169ms, day-5 = 67ms) and by 41% for the .7 degree Gabor ( day-1 = 479ms, day-5 = 284ms). The younger observer's thresholds for the 5 degree Gabor improved by 16% ( day-1 = 82ms, day-5 = 67ms) and by 67% for the .7 degree Gabor ( day-1 = 342ms, day-5 = 111ms). The importance of these results to understanding visual cortical plasticity and aging will be discussed.
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