Many fMRI studies have documented motion-sensitivity in the human occipital cortex and several have examined sensitivity to binocular disparity. However, selectivity to the stereo-defined depth of a moving luminance-defined stimulus has not been examined with fMRI. We used an fMRI adaptation paradigm to examine such selectivity. On each trial of an event-related design, two brief rotating dot p...

Gårding et al. (Vis Res 1995;35:703-722) proposed a two-stage theory of stereopsis. The first uses horizontal disparities for relief computations after they have been subjected to a process called disparity correction that utilises vertical disparities. The second stage, termed disparity normalisation, is concerned with computing metric representations from the output of stage one. It uses vert...

In depth cue-conflict conditions, various depth cues could represent different extents of depth. Previous studies have investigated the perceived size of negative afterimage in depth cue-correlated conditions in which different cues introduce almost the same amounts of depth to the visual system. This study examined the perceived size of the afterimage in the human observers in a condition that...

Past work has suggested that the medial superior temporal area (MST) is involved in the initiation of three kinds of eye movements at short latency by large-field visual stimuli. These eye movements consist of (1) version elicited by linear motion (the ocular following response), (2) vergence elicited by binocular parallax (the disparity vergence response), and (3) vergence elicited by global m...

AIM To provide evidence that a near clinical gradient AC/A ratio could instead reflect the CA/C relationship (the accommodation driven by response to disparity). DESIGN Case control study. METHODOLOGY 27 emmetropic participants with heterophoria <4 PD, 19 with intermittent distance exotropia, and 17 with near exophoria >6 PD were tested. A remote haploscopic photorefractor, which can measur...

We used the sequential stereopsis paradigm and apparatus described by Enright (Vision Research, 36, (1996) 307-312). The observer's task was to set targets to equidistance in Experiments 1-3, and to make them co-planar in Experiment 4. However, it is argued that in all experiments observers exploited a co-planarity setting strategy. Sequential stereopsis produced good performance throughout in ...

PURPOSE This study was designed to evaluate the minimum interocular correlation (IOC) needed by the visual system to correctly perceive a static stereoscopic stimulus as a function of normal aging. It was also our goal to evaluate the feasibility of clinical charts testing this aspect of visual perception. METHODS Stereoscopic IOC threshold was determined in 100 normal observers (average age ...

We tested the ability of normal subjects to alter the conjugacy of their saccades in a position-specific manner. Five subjects dichoptically viewed a stereogram produced by two random-dot patterns. They immediately perceived a three-dimensional wedge with its apex closer to them. They were asked to saccade for 15 min back and forth between the apex and two lateral dots of the wedge. For fixatio...

We tested between two coding mechanisms that the brain may use to retain distance information about a target for a reaching movement across vergence eye movements. If the brain was to encode a retinal disparity representation (retinal model), i.e., target depth relative to the plane of fixation, each vergence eye movement would require an active update of this representation to preserve depth c...

In the course of running an eye-tracking experiment, one computer system or subsystem typically presents the stimuli to the participant and records manual responses, and another collects the eye movement data, with little interaction between the two during the course of the experiment. This article demonstrates how the two systems can interact with each other to facilitate a richer set of exper...