Processing 3D form and 3D motion: respective contributions of attention-based and stimulus-driven activity.

This study aims at segregating the neural substrate for the 3D-form and 3D-motion attributes in structure-from-motion perception, and at disentangling the stimulus-driven and endogenous-attention-driven processing of these attributes. Attention and stimulus were manipulated independently: participants had to detect the transitions of one attribute--form, 3D motion or colour--while the visual stimulus underwent successive transitions of all attributes. We compared the BOLD activity related to form and 3D motion in three conditions: stimulus-driven processing (unattended transitions), endogenous attentional selection (task) or both stimulus-driven processing and attentional selection (attended transitions).

The visual perception of plane tilt from motion in small field and large field: psychophysics and theory.

Subjects indicated the tilt of dotted planes rotating in depth, in monocular viewing, under perspective projection. The responses depended on the FOV (field of view) and on the angle W between the tilt and frontal translation (orthogonal to the rotation axis). Response accuracy increased with the FOV, and decreased with W.

Measurement of the visual contribution to postural steadiness from the COP movement: methodology and reliability.

We studied the reliability of different measures of the visual contribution to postural steadiness by recording the postural sway during standing with eyes open (EO) or eyes closed (EC). The COP trajectory was recorded in 21 subjects aged 42-61 standing on a firm or foam support. The improvement of postural steadiness due to vision was measured with a higher reliability (i.

Postural stability in primary open angle glaucoma.

Background: This study evaluated the visual contribution to postural steadiness in primary open angle glaucoma (POAG), in correlation with the mean deviation (MD) measured through conventional perimetry, and with the Advanced Glaucoma Intervention Study (AGIS) score, which quantifies the extent of losses in the visual field.

Methods: In 35 POAG patients and 21 age-matched normal subjects, the sway of the centre of pressure of the feet, on a firm or foam support, was recorded. The subjects stood on a force-plate with eyes closed, or with one or two eyes open.

Motion perception in glaucoma patients: a review.

Most of the histopathological and psychophysical studies in glaucoma reveal a preferential damage to the magnocellular (M) pathway although a few of them support a damage to the parvocellular (P) pathway as well. In glaucoma, the visual fields are usually evaluated by conventional perimetry. However, it has been demonstrated that 20-40% of ganglion cells are lost before field defects are detected using conventional perimetry.