The effect of dark and equiluminant occlusion on the interocular transfer of visual aftereffects

Abstract

Lehmkuhle and Fox [(1976) Vision Research, 16, 428-430] reported that interocular transfer (IOT) of a translational motion aftereffect (MAE) was greater if the non-adapting eye viewed an equiluminant field than if it viewed a dark field. They recommended equiluminant occlusion of the non-adapted eye when measuring IOT of aftereffects. We tested this proposal in three experiments. First, we assessed IOT with equiluminant and dark occlusion for three different classes of aftereffects. Although transfer was greater with equiluminant occlusion for the translational MAE, there was no significant difference in the amount of transfer for the tilt aftereffect or the contrast threshold elevation effect. Second, we tested the hypothesis that spuriously large IOT could be the result of an aftereffect from tracking eye movements in the non-adapting eye. When potential tracking movements were reduced by using rotating spokes, a rotating spiral or contracting concentric circles, there was a corresponding reduction in the occlusion-dependent transfer. Third, we found that luminance shifts had no influence on the amount of transfer when all contours were eliminated from the non-adapting eye. We conclude that the type of occlusion used for measuring IOT of the translational MAE is important only when visible contours in the non-adapting eye contribute to the adapting process.

Unbiased Measures of Interocular Transfer of Motion Adaptation

“…The logic behind this is that the units that integrate more sophisticated motion exist in extrastriate areas (such as MT and MST) that are largely binocular, whereas linear motion might also be encoded by monocular neurons in V1. However, surprisingly few studies have directly compared relevant conditions (see table 1), and not all those that have found evidence supporting this arrangement (McColl & Mitchell, 1998;Timney et al, 1996). Our experiments find the opposite pattern of results, with translational motion typically producing stronger IOT (mean of 86%) than motion requiring large receptive fields (mean of 51%) (see figures 6c and 6d, and figures 8a and 8b).…”

Detecting Structure in Glass Patterns: An Interocular Transfer Study

“…Participants viewed the stimuli in a dimly lit room at a distance of 57 cm, using a chin-rest for stability. All adaptation and test stimuli were presented monocularly on a dark background; the other eye viewed an equiluminant dark background (luminance 14.5 cd m À2 ) devoid of features (Timney et al 1996). Each individual Glass pattern consisted of 300 individual bright dots, each 0.2 deg60.2 deg square, presented on a dark background.…”