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In humans, as well as most animal species, perception of object motion is critical to successful interaction with the surrounding environment. Yet, as the observer also moves, the retinal projections of the various motion components add to each other and extracting accurate object motion becomes computationally challenging. Recent psychophysical studies(More)
Transparent motion stimuli allow us to investigate how visual motion is processed in the presence of multiple sources of information. We used stereo random-dot kinematograms to determine how motion processing is affected by the difference in direction and depth of two overlapping motion components. Observers judged whether a noise dot display contained one(More)
Estimation of time-to-arrival for moving objects is critical to obstacle interception and avoidance, as well as to timing actions such as reaching and grasping moving objects. The source of motion information that conveys arrival time varies with the trajectory of the object raising the question of whether multiple context-dependent mechanisms are involved(More)
Previous studies of heading perception suggest that human observers employ spatiotemporal pooling to accommodate noise in optic flow stimuli. Here, we investigated how spatial and temporal integration mechanisms are used for judgments of heading through a psychophysical experiment involving three different types of noise. Furthermore, we developed two ideal(More)
The task of parceling perceived visual motion into self- and object motion components is critical to safe and accurate visually guided navigation. In this paper, we used functional magnetic resonance imaging to determine the cortical areas functionally active in this task and the pattern connectivity among them to investigate the cortical regions of(More)
The detection of looming, the motion of objects in depth, underlies many behavioral tasks, including the perception of self-motion and time-to-collision. A number of studies have demonstrated that one of the most important cues for looming detection is optic flow, the pattern of motion across the retina. Schrater et al. have suggested that changes in(More)
The characterization of visual field loss provides a valuable diagnostic metric for studying the effects of damage to the retina, optic nerve or visual cortex. We describe a tool, the Quadrant Vision Perimeter (QVp), to rapidly and accurately measure visual fields. In addition to measuring the location of visual deficits, the tool can assess(More)
BACKGROUND We compared the functional brain connectivity produced during resting-state in which subjects were not actively engaged in a task with that produced while they actively performed a visual motion task (task-state). MATERIAL AND METHODS In this paper we employed graph-theoretical measures and network statistics in novel ways to compare, in the(More)
Segmentation of the visual scene into relevant object components is a fundamental process for successfully interacting with our surroundings. Many visual cues, including motion and binocular disparity, support segmentation, yet the mechanisms using these cues are unclear. We used a psychophysical motion discrimination task in which noise dots were displaced(More)
BACKGROUND Understanding the dynamics of our surrounding environments is a task usually attributed to the detection of motion based on changes in luminance across space. Yet a number of other cues, both dynamic and static, have been shown to provide useful information about how we are moving and how objects around us move. One such cue, based on changes in(More)