Healthy aging impairs face discrimination ability.

Face images enable individual identities to be discriminated from one another. We aimed to quantify age-related changes in different aspects of face identity discrimination. Face discrimination sensitivity was measured with a memory-free "odd-one-out" task.

The Effect of Age-Related Macular Degeneration on Components of Face Perception.

Purpose: Patients with age-related macular degeneration (AMD) experience difficulty with discriminating between faces. We aimed to use a new clinical test to quantify the impact of AMD on face perception and to determine the specific aspects that are affected.

Methods: The Caledonian face test uses an adaptive procedure to measure face discrimination thresholds: the minimum difference required between faces for reliable discrimination.

From individual features to full faces: Combining aspects of face information.

We investigated how information from face features is combined by comparing sensitivity to individual features with that for external (head shape, hairline) and internal (nose, mouth, eyes, eyebrows) feature compounds. Discrimination thresholds were measured for synthetic faces under the following conditions: (a) full-faces; (b) individual features (e.g.

Contributions of individual face features to face discrimination.

Faces are highly complex stimuli that contain a host of information. Such complexity poses the following questions: (a) do observers exhibit preferences for specific information? (b) how does sensitivity to individual face parts compare? These questions were addressed by quantifying sensitivity to different face features. Discrimination thresholds were determined for synthetic faces under the following conditions: (i) 'full face': all face features visible; (ii) 'isolated feature': single feature presented in isolation; (iii) 'embedded feature': all features visible, but only one feature modified.

The Caledonian face test: A new test of face discrimination.

This study aimed to develop a clinical test of face perception which is applicable to a wide range of patients and can capture normal variability. The Caledonian face test utilises synthetic faces which combine simplicity with sufficient realism to permit individual identification. Face discrimination thresholds (i.

Distinct lower visual field preference for object shape.

Humans manipulate objects chiefly within their lower visual field, a consequence of upright posture and the anatomical position of hands and arms.This study tested the hypothesis of enhanced sensitivity to a range of stimuli within the lower visual field. Following current models of hierarchical processing within the ventral steam, discrimination sensitivity was measured for orientation, curvature, shape (radial frequency patterns), and faces at various para-central locations (horizontal, vertical, and main diagonal meridians) and eccentricities (5° and 10°).

Detecting shapes in noise: tuning characteristics of global shape mechanisms.

The proportion of signal elements embedded in noise needed to detect a signal is a standard tool for investigating motion perception. This paradigm was applied to the shape domain to determine how local information is pooled into a global percept. Stimulus arrays consisted of oriented Gabor elements that sampled the circumference of concentric radial frequency (RF) patterns.

Global shape processing deficits are amplified by temporal masking in migraine.

Purpose: Individuals with migraine show subtle defects in a range of visual tasks compared to nonmigraineurs. Increased neuronal noise can account for some of these deficits. To examine the generality of increased noise in migraine, masking effects were compared in migraineurs and headache-free controls using a shape discrimination task, thought to involve processing in extrastriate cortical areas.

Long-range inhibitory mechanisms in the visual system are impaired in migraine sufferers.

Background: After viewing dynamic noise surrounding a homogeneous grey patch (artificial scotoma), observers perceive a prolonged twinkling-noise after-image within the unstimulated area. It has been suggested that noise-stimulated neurons induce a long-range inhibition in neurons within the artificial scotoma, which generates a rebound signal perceived as twinkling noise following noise termination. We used this paradigm to test whether migraineurs have enhanced excitability or weakened inhibition.

Visual noise selectively degrades vision in migraine.

Purpose. Migraine is a disabling condition with underlying neuronal mechanisms that remain elusive. Migraineurs experience hyperresponsivity to visual stimuli and frequently experience visual disturbances.

The useful field of view test, normative data in children of school age.

Purpose: The incidence of early brain injury in children is rising, mainly because of changing reproductive demographics and better perinatal care. Early brain injury may be associated with altered visual perception and visuospatial attention. The useful field of view test (UFOV) has been developed to assess visual attention and processing speed in the elderly.

Judging the shape of moving objects: discriminating dynamic angles.

Studies of shape perception have typically focused on static shapes. Studies of motion perception have mainly investigated speed and direction. None have addressed performance for judging the shape of moving objects.

Configural masking of faces: evidence for high-level interactions in face perception.

The perception of a stimulus can be impaired when presented in the context of a masking pattern. To determine the timing and the nature of face processing, the effect of various masks on the discriminability of faces was investigated. Results reveal a strong configural effect: the magnitude of masking depends on the similarity between mask and target.