Abstract
In this study, we carried out a psychophysical experiment to measure the eye and location specificity of contrast detection learning. Five subjects underwent thirty daily training sessions to detect a near-threshold circular checkerboard (eccentricity: 4째; location: lower-left or lower-right visual quadrant; diameter:5째; spatial frequency:1 cycles/째; mean luminance:16 cd/m2). Subjects was trained with only one eye. A daily session consisted of 30 QUEST staircases of 40 trials. In a trial, the checkerboard was presented in one of two 200 ms intervals. Subjects were asked to make a 2-AFC judgment of the interval in which the checkerboard appeared. Before and after training, we measured subjects contrast detection thresholds in four conditions (with reference to the trained stimulus): the same spatial location in the same eye, the same location in the opposite eye, the opposite spatial location (i.e. the opposite visual field) in the same eye, and the opposite location in the opposite eye. After training, subjects performance improvements in the four conditions were 6.76%, 2.33%, 12.42%, and 24.57%, respectively.On one hand, the moderate transfer between spatial locations in different visual fields suggests that some high-level mechanisms play a role in the contrast detection learning. On the other hand, the little transfer between two eyes implies a significant monocular component in the learning. Future brain imaging and neurophysiological studies should investigate if contrast detection learning could modify the functional properties of monocular neurons in V1 and LGN.
Meeting abstract presented at VSS 2014