Showing papers on "Monocular vision published in 1975"

Progressive changes in kitten striate cortex during monocular vision

Abstract: Following initial rearing in either total darkness or normal illumination, kittens at different ages were subjected to right-eye closure and various periods of vision through the left eye. After the period of monocular vision, single units in striate cortex were tested for visual responsiveness through each eye. A severe reduction in the proportion of units responsive to the deprived eye occurred over the first few days of monocular vision. Functional abnormalities were variably present after 1 day, marked after 2.5 and 3.5 days, and complete after 10 days. Monocular vision produced very much the same effect on ocular dominance of striate units, provided age and duration of suture were identical, regardless of whether kittens had received prior dark- or light-rearing.

Modification of single neurons in the kitten's visual cortex after brief periods of monocular visual experience.

Abstract: Kittens were deprived of form vision by suturing the lids of both eyes, except for a brief period (1, 6 or 20 hours) on the 29th day when the right eye was opened. 6 space and 20 hours of monocular vision produced a distinct shift in the ocular dominance of visual cortical neurons towards the experienced eye, and an increase in the proportion of cells with obvious orientation selectivity. These modifications in the visual cortex were enhanced by a period of “consolidation”: they were somewhat less obvious if recordings were taken immediately after the exposure but were complete 2 days later. Although remarkably little visual experience was needed for these changes, the results contrast with the effects of rearing in an environment of vertical stripes, where only 1 hour of exposure produces much more striking effects. A normal visual environment may have a less powerful organizing influence on cortical neurons than such an environment containing only one orientation.

Optic organ and cervical proprioceptors in maintenance of body equilibrium.

Abstract: Two experiments were made on the functional correlation between the optic organ and the cervical proprioceptors in maintenance of body equilibrium. Experiment I: The effects of weak and strong electric stimulation of the deep nuchal muscles on changes in optokinetic nystagmus and optokinetic after-nystagmus were examined in adult non-albino rabbits with binocular vision. Experiment II: Experiment I was repeated on rabbits with monocular vision giving optokinetic stimulation moving from the side of the blindfolded eye to that of the open eye and applying only weak electric stimulation to the neck muscles. The results obtained were as follows: (1) Experiment I: Weak electric stimulation of the deep nuchal muscles of rabbits with binocular vision tended to promote optokinetic nystagmus with either no significant change or decrease in optokinetic after-nystagmus. Strong electric stimulation had the opposite effects, i.e., it tended to inhibit optokinetic nystagmus and activate optokinetic after-nystagmus. It ...

Binocular summation and peripheral visual response time.

Abstract: Six males were administered a peripheral visual response time test to the onset of brief, small stimuli imaged in 10 degrees arc separation intervals across the dark adapted horizontal retinal meridian under binocular and both monocular viewing conditions. This was done in an attempt to verify the existence of peripheral binocular summation using a response time measure. The results indicated that from 50 degrees arc right to 50 degrees arc left of the line of sight binocular summation is a reasonable explanation for the significantly faster binocular data. The stimulus position by viewing eye interaction was also significant. A discussion of these and other analyses is presented along with a review of related literature.

Vision in Birds

Abstract: In a number of their species, birds possess a very highly developed visual sense combined with the ability to recognise colour. They even make use of this as a means of sex recognition, although in the avian world it is the male that enjoys the thrills associated with personal adornment. Not only do birds recognise the sex of their associates by the colour of their plumes but they also recognise their enemies and rivals. Fortunately, in birds fashions do not change, and in this respect when distinguishing between the sexes they have the advantage over mere man.

The effect of stimulus duration and monocular viewing on the "oblique effect" in peripheral vision.

Abstract: Luminance thresholds were obtained for narrow bars of light in vertical, horizontal and oblique orientations. From 5 degrees to 60 degrees into the periphery, a small but significant elevation in threshold was found for stimuli in oblique orientations. The monocularly obtained data replicate an earlier report using binocular presentations and a stimulus duration of 100 msec. When exposure time was 10 msec or 500 msec, this effect of orientation broke down. Theoretical implications are discussed.