Biomedical subjects

Revital Shani

Publications and source records attributed to Revital Shani.

3 recordsLinked to original sources

PubMed2006

Psychometric curves of lateral facilitation.

Visibility of an oriented stimulus may be enhanced by nearby stimuli that are co-aligned with the target. However, the underlying mechanism governing this facilitation is controversial. Here we measured the dependence of percent correct detection on the target's contrast (psychometric curve) with and without flankers, where flankers were either collinear with or orthogonal to the target. We find that the effect of collinear flankers can be described as a translation of the psychometric function along the linear contrast axis. This behavior is consistent, within experimental error, with two types of models: (1) non-linear transduction of target contrast with collinear flankers having additive effects on contrast, and (2) uncertainty reduction (Pelli, 1985) by collinear flankers. We discuss properties of collinear facilitation that can help deciding between these two models.

Contrast Sensitivity↗

PubMed2005

Eccentricity effects on lateral interactions.

We attempted to resolve an apparent conflict between the lack of psychophysical evidence of collinear facilitation at the near-periphery and physiological evidence from the monkey showing collinear effects extra-fovealy. We compared collinear and orthogonal configurations to discount facilitation due to reduced positional uncertainty. Detection thresholds were measured for Gabor targets at eccentricities of 0 degrees - 4 degrees, flanked by collinear or orthogonal flankers. Like in previous reports in the literature, results varied among subjects when the stimulus position was off-fixation. We found reduced facilitation at eccentricities as small as 1 degrees - 2 degrees. Moreover, facilitation did not increase when the stimuli were M-scaled or when observers received more practice. However, a larger proportion of subjects showed collinear facilitation when attention was directed to the tested configurations. The results suggest that differences in allocation of attention along the visual field may affect the underlying lateral interactions, consequently resulting in eccentricity effects as well as inter-observer variability.

Adolescent↗

PubMed2004

Effectiveness of home rehabilitation after stroke in Israel.

On discharge from an acute general hospital after a stroke, 191 patients were in need of, and were appropriate for, multidisciplinary rehabilitation. One-hundred-and-one patients (52.4%) received it in a rehabilitation institution as inpatients (the institutional rehabilitation group (IR) group) and 91 patients received it at home (the home rehabilitation (HR) group). Patients in the HR group had their mobility, activities of daily living (ADL), range of movements, tonus, coordination and sensation determined on admission to home rehabilitation and on discharge from it, 6 weeks to 2 months later. This group contained more women and more patients able to walk with devices and who were partially independent in ADL. The IR group consisted of more men and more patients with diabetes and marked difficulties in ADL and ambulation. In both groups the Barthel index and the Frenchay activities index were determined 1 year after the stroke by way of a telephone interview and no meaningful differences were found between the two groups. IR was considerably more expensive than HR. In Israel there exists a subpopulation of acute stroke survivors in need of, and appropriate for, multidisciplinary rehabilitation that can be provided at home; such rehabilitation was found to be effective in the short and long term, as well as cost effective.

Activities of Daily Living↗