The conditions required for the maintenance of binocularity in the kitten's visual cortex (original) (raw)

Development of binocular vision in the kitten's striate cortex

The Journal of neuroscience : the official journal of the Society for Neuroscience, 1992

Studies of the development and plasticity of the visual pathway are well documented, but a basic question remains open: what is the physiological status of the system prior to extensive visual experience? Somewhat conflicting answers have been put forward, and in a major area, binocular vision, reports have ranged from severe immaturity to well-developed maturity. This is an important question to resolve since binocular cells in the visual cortex are thought to be the neural substrate for stereoscopic depth perception. We have addressed this question by recording from single cells in the striate cortex of kittens at postnatal ages 2, 3, and 4 weeks and from adults for comparison. Gratings with sinusoidal luminance distribution are presented to left, right, or both eyes. For each cell, we determine optimal values for orientation and spatial frequency. Relative phase (retinal disparity) is then varied in a dichoptic sequence so that binocular interaction may be studied. Results are as...

Binocularly deprived cats: binocular tests of cortical cells show regular patterns of interaction

The Journal of neuroscience : the official journal of the Society for Neuroscience, 1988

If an animal is prevented from receiving visual experience during an early developmental phase, pronounced dysfunctions are observed. Physiological tests reveal gross abnormalities in the striate cortex. Cells in visual cortex are either unresponsive of their response characteristics are erratic. Although fewer than normal numbers of binocular cells are found in cats reared with binocular lid suture, a population remains that can be activated by stimulation through either eye. We have studied cortical cells in binocularly deprived cats in order to specify monocular and binocular response characteristics. The primary hypothesis we have examined is that the abnormal response properties of these cells are a result of an irregular structure or substructure of the receptive fields. Kittens were binocularly lid-sutured soon after birth, and were studied physiologically at ages between 7 and 11 months. Standard techniques were used to record from single cells in striate cortex. Drifting gr...

Instructive changes in the kitten's visual cortex and their limitation

Experimental Brain Research, 1982

Kittens were reared wearing masks that contained strong cylindrical lenses, which allowed them to see only contours of one orientation. Selective exposure was alternated between the two eyes on successive days, while each time the other eye was covered by the mask. The total duration of exposure was different in the two eyes, amounting to 50 h for one eye and at least 100 h for the other. This resulted in asymmetric distributions of ocular dominance: neurones preferring precisely the experienced orientation favoured the eye with longer exposure, whereas neurones preferring oblique orientations adjacent to the experienced one surprisingly were dominated by the eye with shorter exposure. Thus neurones originally belonging to this group and dominated by the longer exposed eye must have tuned their orientation preference to the experienced orientation as a result of the longer exposure. Such instructive changes seem to be limited by the original response borders of the cortical neurones, as predicted by Hebb's rules for synaptic plasticity.