1. It is known that adaptation to a grating pattern causes a rise in the contrast threshold for test gratings of similar spatial frequency and orientation.2. We find this after-effect also to be disparity-specific. Adaptation to a grating at zero horizontal disparity (at the same distance as the fixation point) causes a greater elevation of threshold for patterns at the same disparity than for those at nearby disparities, closer or more distant than the fixation point.3. Adaptation to a grating at some disparity other than zero causes a disparity-specific elevation of threshold centred on the adapting disparity.4. This finding also applies if the observer adapts to a grating but single bright bars are used as the test stimuli.5. The disparity-specific ;tuning curves' revealed by these techniques are quite broad, having a half-width at half-amplitude of several min of disparity.6. Adaptation to a grating at one disparity causes an apparent change in the distance of test gratings at nearby disparities.7. We compare these psychophysical experiments with the properties of disparity-selective binocular neurones in the visual cortex of cats and monkeys.

Adaptation, Ocular↗

PubMed1972

A second neural mechanism of binocular depth discrimination.

1. Rotation of an object about its horizontal axis, towards or away from the viewer's eyes, usually causes the images of its contours to have slightly different orientations on the two retinae.2. We recorded action potentials from binocular neurones in the cat's visual cortex and measured their orientation-selectivity carefully in both eyes.3. The optimal orientation for a single cell is not necessarily identical on both retinae. For a large sample of cells there is a range of more than + 15 degrees (S.D. about 6-9 degrees ) in the difference of preferred orientation in the two eyes. These interocular differences in receptive field properties cannot be attributed to rotation of the eyes or to the errors of measurement.4. During simultaneous binocular stimulation the images must not only lie in the correct place on both retinae but also have exactly the right orientation for both receptive fields in order to elicit the maximum response from a neurone.5. Therefore certain binocular cells respond specifically to objects tilted in three-dimensional space towards the cat, or away from it.

Action Potentials↗

PubMed1972

Brain functions.

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Animals↗

PubMed1971

Perceptual fading of a stabilized cortical image.

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Adaptation, Ocular↗

PubMed1971

Modification of the visual cortex by experience.

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Animals↗