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Biomedical subjects

R Over

Publications and source records attributed to R Over.

At least 37 records · Page 2Linked to original sources
PubMed1977

Orientation masking and the tilt illusion with subjective contours.

Exposure to one edge renders another edge less visible as a function of relative orientation. Experiment 1 showed that orientation-selective masking occurs between phenomenal edges located at sites where the visual display is homogeneous (subjective contours) as well as between edges defined in terms of luminance discontinuity (real edges). In addition, real contours can be masked by subjective contours, and vice-versa. In experiment 2 it was found that the tilt illusion (apparent expansion of the angle formed by intersecting lines) can be induced with subjective as well as with real contours. These results suggest that it is inappropriate to attribute the perception of real and subjective contours to fundamentally different processes.

Form Perception↗
PubMed1976

Consensus opinion and observer accuracy in electrocardiography with reference to coronary arteriographic information.

In this study reader performance in resting electrocardiographic (ECG) reading and case summary interpretation was investigated. Eight cardiologists were asked to read independently 105 paired ECG--Case summary sheets on either two or four occasions. The order of ECG--Case summary inspection for each sheet was randomized over trials. The results show low levels of inter- and intra-reader reliability when physicians report on ECG traces. Reference to coronary arteriographic information confirms that the resting ECG has limited utility in the detection of coronary artery disease.

Angiography↗
PubMed1972

Color adaptation of spatial frequency detectors in the human visual system.

Observers exposed alternately to a vertical grating of one spatial frequency in red light and a vertical grating of different spatial frequency in green light subsequently report frequency-specific color aftereffects when shown gratings in white light. Aftereffects occur, however, only when inspection gratings differ in spatial frequency by one octave or more and the frequency of at least one grating is above 3 cycles per degree. This spatial selectivity of the aftereffect is considered in terms of a neural adaptation model incorporating evidence on the tuning of spatial frequency detectors in the human visual system.

Color Perception↗