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Biomedical subjects

T Radil

Publications and source records attributed to T Radil.

At least 73 records · Page 4Linked to original sources
PubMed1989

On the visual orientation of random dot Moiré patterns.

We studied the orientation perception of dot patterns with Moiré effect. The Moiré effect was achieved by rotating the original patterns over small angles. When the angle was increased the effect disappeared while the characteristics of orientation estimation remained unchanged. For relatively small angles the subjects performance can be described by a model based on the concept of least squared distance axis. For large angles of rotation this model has began to be insufficient and a more refined model is proposed here.

Adult↗
PubMed1989

Evolutionary aspects of genito-urinal reflexes.

The favourable effect of vaginal electrical stimulation in patients with urinary incontinence may be caused by activation of ancient reflex mechanisms assuring mutually exclusive function of the female genital and urinary system linked to anatomica structures which were partially common during phylogenesis. Reciprocal inhibition of genital and urinary reflexes and of the corresponding behavior, assuring safe transport of the sperm to the egg, would represent an advantage greatly supported by selective pressure.

Female↗
PubMed1989

Errors in estimating the orientation of dot patterns.

The error in estimating the orientation of a dot pattern was measured as the difference between the orientation of the least-squared-distances line (LS-line) of the pattern and the orientation of a line adjusted by the subject to match the perceived orientation of the pattern. Analysis of the mean errors (averaged over ten subjects) obtained for one hundred patterns confirmed that the orientation of the LS-line represents the orientation of elongated dot-patterns. It is shown that estimated orientation was systematically biased towards the nearest 45 degrees oblique meridian. This bias points to the importance of the +/-45 degrees directions as natural norms for left- and right-side tilt in the frontoparallel plane.

Adult↗
PubMed1989

Is the 45 degrees-oblique a third dominant direction?

Vertical and horizontal are widely accepted as dominant directions or norms of visual orientation in the frontoparallel plane. They are supposed to cause a normalization effect consisting in the apparent rotation of a tilted straight line towards the nearest dominant direction. The evidence for tilt normalization towards the vertical or horizontal visual meridia is indirect. On the other hand, human observers are very sensitive to departures from the vertical and horizontal, which means that most orientations in the frontoparallel plane are termed tilted rather than vertical or horizontal. By measuring directly the orientation of dot patterns we found that estimated orientation was systematically biased towards the nearest 45 degrees-oblique visual meridian. This finding is interpreted as evidence for the existence of an oblique norm in visual tilt.

Form Perception↗