Gaze behavior during navigation with reduced acuity.

Navigating unfamiliar indoor spaces while visually searching for objects of interest is a challenge faced by people with visual impairment. We asked how restricting visual acuity of normally sighted subjects would affect visual search and navigation in a real world environment, and how their performance would compare to subjects with naturally occurring low vision. Two experiments were conducted.

Orientation-selective contrast adaptation measured with SSVEP.

Exposure to oriented luminance contrast patterns causes a reduction in visual sensitivity specifically for the adapter orientation. This orientation selectivity is probably the most studied aspect of contrast adaptation, but it has rarely been measured with steady-state visually evoked potentials (SSVEPs), despite their becoming one of the more popular methods of human neuroscience. Here, we measured orientation selective adaptation by presenting a plaid stimulus of which the horizontal and vertical grating reversed contrast at different temporal frequencies, while recording EEG signals from occipital visual areas.

Indoor Spatial Updating With Impaired Vision.

Purpose: Spatial updating is the ability to keep track of position and orientation while moving through an environment. We asked how normally sighted and visually impaired subjects compare in spatial updating and in estimating room dimensions.

Methods: Groups of 32 normally sighted, 16 low-vision, and 16 blind subjects estimated the dimensions of six rectangular rooms.

Indoor Spatial Updating with Reduced Visual Information.

Purpose: Spatial updating refers to the ability to keep track of position and orientation while moving through an environment. People with impaired vision may be less accurate in spatial updating with adverse consequences for indoor navigation. In this study, we asked how artificial restrictions on visual acuity and field size affect spatial updating, and also judgments of the size of rooms.

Equalization and decorrelation in primary visual cortex.

There are many theories on the purpose of neural adaptation, but evidence remains elusive. Here, we discuss the recent work by Benucci et al. (Nat Neurosci 16: 724-729, 2013), who measured for the first time the immediate effects of adaptation on the overall activity of a neuronal population.

Extracting the mean size across the visual field in patients with mild, chronic unilateral neglect.

Previous studies suggest that normal vision pools information from groups of objects in a display to extract statistical summaries (e.g., mean size).

Characteristics of the filled-in surface at the blind spot.

Our visual system can restore information missing within the portion of the retinal image corresponding to the blind spot where the optic nerve exits the eye. Previous studies of the properties of filled-in surfaces at the blind spot have found similarities and dissimilarities between filled-in and real surfaces and have therefore not provided a consistent view of the characteristics of the filled-in surface. First, we investigated whether filling-in utilizes a contour integration mechanism.