Effects Of Monocular Deprivation Research Articles

Effect of monocular deprivation on binocular neurones in the owl's visual Wulst.

Despite the two hundred million years during which their evolutionary history was different from mammals, birds possess a central visual apparatus with surprising functional similarities to the striate cortex of cats and monkeys. The visual Wulst of the owl contains neurones which can be binocularly activated and which show precise selectivity for the orientation, direction of movement and binocular disparity of moving straight line contours, all characteristic properties of single neurones recorded from the striate cortex of cats and monkeys. We were interested to determine whether binocular neurones in the owl's Wulst are also sensitive to visual experience in the neonatal period since another important characteristic of binocular neural connections in cat and monkey visuail cortex is their extreme sensitivity to monocular deprivation during the critical period. The preliminary observations we present here, on young, monocularly-deprived owls, suggest that the functional parallel between the mammalian striate cortex and the avian Wulst extends to the phenomenon of plasticity as well.

Reversal of the behavioural effects of monocular deprivation in the kitten.

1. Eighteen kittens were monocularly deprived of vision until the age of 5, 6 or 7 weeks. Their eyes were then reverse-sutured, and they were allowed to survive for 3-63 days, before physiological recording from area 17. 2. At the time the reverse-suture was performed, and immediately before the recording session, each kitten was tested separately in the two eyes to elicit five simple behavioural responses: optokinetic nystagmus, visual startle reaction, visually-guided paw placing, visual following and negotiation of a "visual cliff". 3. Following the opening of their initially deprived eye, all kittens appeared behaviourally blind when forced to use that eye; their performance through the initially open eye was then perfect on all tests. After the period of reversed lid-suture, however, their performance when using the initially deprived eye had improved, while that through the initially open eye deteriorated. This complementary improvement and deterioration was most rapid in kittens reverse-sutured at the age of 5 weeks, and less rapid when reverse-suturing was delayed until the age of 6 or 7 weeks. 4. Most of the kittens showed gross abnormalities of interocular alignment, and exhibited marked exotropia or esotropia. 5. The results of these tests were well correlated with the changes seen in cortical ocular dominance in the same animals.

Reversal of the physiological effects of monocular deprivation in the kitten's visual cortex.

1. Twenty-three kittens were monocularly deprived of vision until the age of 4, 5, 6 or 7 weeks. Their deprived eyes were then opened, and their experienced eyes shut for a further 3-63 days. After this time physiological recordings were made in the visual cortex, area 17. Three control kittens, monocularly deprived for various periods, showed that at the time of reverse-suturing, few neurones could be influenced at all from the deprived eye. 2. Following reverse-suturing, the initially deprived eye regained control of cortical neurones. This switch of cortical ocular dominance was most rapid following reverse-suturing at the age of 4 weeks. Delaying the age of reverse-suturing reduced the rate and then the extent of the cortical ocular dominance changes. 3. The cortex of reverse-sutured kittens is divided into regions of cells dominated by one eye or the other. The relative sizes of these ocular dominance columns changed during reversed deprivation. The columns devoted to the initially deprived eye were very small in animals reverse-sutured for brief periods, but in animals that underwent longer periods of reversed deprivation, the columns driven by that eye were larger, while those devoted to the initially open eye were smaller. 4. Clear progressions of orientation columns across the cortex were apparent in many of the kittens, but, in contrast to the situation in normal or strabismic kittens, these sequences were disrupted at the borders of eye dominance columns: the cortical representations of orientation and ocular dominance were not independent. 5. Binocular units in these kittens were rather rare, but those that could be found often had dissimilar receptive field properties in the two eyes. Commonly, a cell would have a normal orientation selective receptive field in one eye, and an immature, unselective receptive field in the other. Cells that had orientation selective receptive fields in both eyes often had greatly differing orientation preferences in the two eyes, occasionally by nearly 90 degrees. 6. During the reversal of deprivation effects, the proportion of receptive fields exhibiting mature properties declined in the initially experienced eye, while the proportion increased in the initially deprived eye. Similarly, the average band width of orientation tuning of receptive fields in the initially deprived eye decreased, while that of receptive fields in the initially experienced eye increased. 7. One kitten was reverse-sutured twice, to demonstrate that cortical ocular dominance may be reversed a second time, even after one reversal of ocular dominance. 8. It is suggested that the sensitive period for cortical binocular development consists of two phases. In the first phase, all cortical neurones may be modified by experience, but the rate at which they may be modified decreases with age. In the second phase, an increasing number of cortical neurones becomes fixed in their properties, while those that remain modifiable are as modifiable as they were at the end of the first phase. 9...

Reversal of the morphological effects of monocular deprivation in the kittens's lateral geniculate nucleus.

1. Eleven kittens were deprived of vision in one eye until the age of between 5 and 14 weeks. Their eyes were then reverse-sutured, they were allowed to survive for a further 3-63 days, and their brains were then examined histologically. 2. Measurement of the cross-sectional area of cells in the lateral geniculate nucleus (LGN) showed that when the reversal of lid suture was performed at the age of 8 or 14 weeks, the mean cell size was smaller in laminae connected to the initially closed right eye than it was in other laminae. 3. When the reversal of lid suture took place at 5 or 6 weeks of age there was a reversal of interlaminar size differences: the initially deprived eye was then connected to laminae containing larger cells. Even within 3 days after the reversal of lid suture, most of the morphological effects of the initial suture had been abolished, and they were fully reversed within 12 days. 4. These results are compared with physiological changes in the visual cortex of these and similarly reared animals.

Early and permanent effects of monocular deprivation on pattern discrimination and visuomotor behavior in cats

Visuomotor behavior and pattern discrimination were studied in a group of cats raised with one eye closed by eyelid suturing 7–10 days after birth. At the age of 8–10 months the animals were forced to use their deprived eye by reversal of eye closure (closing the normal eye and opening the deprived one). Visuomotor behavior and pattern discrimination were tested before as well as after reverse closure, to compare performances of the deprived eye with those of the non-deprived eye. In order to get optimal visuomotor experience, the animals were kept in large playrooms for at least 4 h each day. Except for normal tactile placing responses, visually triggered extension responses and uncertain jumping, 2 years after reverse closure all other tests (visually guided reaching, visual cliff behavior, obstacle avoidance, tracking, jumping, and visual blink responses) still showed impairments; the optokinetic nystagmus was asymmetric. In contrast with this partial behavioral recovery, pattern discrimination in a simple nose-push training ☐ requiring no complicated visuomotor coordination was found to be positive. Discriminations of gratings of different orientations, starting 4 weeks after reverse closure, appeared to be normal, in comparison with performance using the non-deprived eye of the same cats tested before reverse closure. Form discrimination was also found to be positive; some monocularly deprived cats required more trials than normal cats in upright vs. reversed solid triangles discrimination, but succeeding form problems were mastered within the same range as found in normal cats. Apparently behavioral defects after monocular deprivation are due to deficiencies in visuomotor control rather than in pattern identification.

Postcritical-period reversal of effects of monocular deprivation on striate cortex cells in the cat.

1. The possibility that effects of monocular deprivation on cat striate cortex could be reversed after the developmental critical period by removal of the normal eye was investigated. In addition, the time course of any postcriticalperiod reversal was studied. Single-unit recording was conducted in the striate cortex of kittens anesthetized with nitrous oxide.2. Six control kittens were raised with monocular lid suture until they were 4-8 mo old (group MD). In agreement with previous investigators, from 0-10% of the striate cortex cells could be driven by visual stimulation of the deprived eye in these kittens.3. Eleven kittens were raised with monocular lid suture until they were 4-5 mo old, at which time the normal eye was enucleated. In five of these (group MD-DE-immediate), recording was conducted in striate cortex on the day of the enucleation. In these animals, 29-39% of the striate cortex cells could be driven by the deprived eye. In four kittens (group MD-DE-3 mo), the deprived eye remained closed for an additional 3 mo before recording was conducted. In these animals, 17-45% of the striate cortex cells could be driven by the deprived eye. In two kittens (group MD-DE greater than 12 mo), the deprived eye remained closed for 14-15 mo after the normal eye was enucleated. In these kittens, 26-40% of the striate cortex cells could be driven by the deprived eye. Thus, removal of the normal eye after the critical period in monocularly drprived kittens results in a rapid increase in the percent of striate cortex cells that can be driven by visual stimulation of the deprived eye, and there is no further increase in responsiveness over a period of more than a year.4. The receptive-field properties of the cells which responded to the deprived eye following enucleation of the normal eye were usually abnormal; 61% of them had nonspecific receptive fields, 39% of the responsive cells were direction selective, and only 12% were both direction and orientation selective.5. The increase in responsive cells was observed in the striate cortex of both hemispheres. However, the increase was greater in the hemisphere contralateral to the deprived eye. The responsive cells tended to occur in clusters of two to four adjacent cells separated by regions containing nonresponsive cells. These clusters were not related to the horizontal cortical layers; however, they may be related to the ocular dominance columns in striate cortex.6. Several mechanisms were considered for the present findings, including neuronal sprouting, denervation supersensitivity, and release from inhibition. It was suggested that the increased responsiveness to the deprived eye was probably not the result of rapid sprouting in the 4- to 5-mo-old kittens. If this is so, then the results indicate that functional connections from the deprived layers of the DLG to the striate cortex remain following rearing with monocular deprivation...

Evidence that binocular competition affects the postnatal development of Y-cells in the cat's lateral geniculate nucleus

Cats reared from birth with the lids of one eye sutured develop abnormalities of their geniculo-cortical systems: geniculate neurons in layers that are deprived of visual input grow less than those receiving visual inputs from the normal eye4,1°; the percentage of recordable geniculate cells that are Y-cells is greatly reduced in the deprived layers9; cortical neurons lose most of their input from the deprived eyeS, 11-13 and when the cats are using the deprived eye they show limited visually guided behavior 2,7. However, these abnormalities occur primarily in the binocular segments of the geniculo-striate system, within which the central, binocularly viewed portion of the visual field is mapped. In the monocular segment the neurons are relatively unaffected. Thus, the geniculate neurons are of normal size a, the proportion of Y-cells is normal 9, cortical cells in area 17 can be driven from the deprived eye and some display normal receptive field properties8, ~3. Finally, these cats can respond appro- priately to objects moving in the monocular segment of the visual field of the deprived eye 7. These differences in the effects of monocular deprivation upon the monocular and binocular segments of the visual pathways are most easily explained by a develop- mental mechanism involving binocular competition that occurs during development between neurons innervated by one eye and neurons innervated by the other. Monoc- ular suture upsets this balance; neurons in the deprived geniculate laminae develop abnormally because they are at some disadvantage relative to the non-deprived neurons, and as a result the deprived cells fail to develop a significant number of functional cortical connections. In the monocular segment, by definition, there can be no binocular competition, and thus the deprived neurons in the monocular seg- ment develop without many of the abnormalities found in the binocular segment. Since the monocular segment receives from the peripheral visual field and the binoc- ular segment from the more central parts of the visual field, it has been necessary to show that the differences between the monocular and the binocular segments are not merely differences between the central and the peripheral parts of the visual pathways. This has been done by rearing cats that have one eye closed and a limited, fairly central lesion placed in the retina of the other eye. In these cats the deprived visual

The effect of monocular deprivation on synaptic terminals in the visual cortex of rabbits. A quantitative electron microscopic study

The effect of prolonged (7 month) monocular deprivation (right eye sutured) on the density of synapses (N A) and the number of synaptic vesicles (N ves) in the visual cortex of rabbits is studied. The results can be summarized as follows: (1) No changes (N A and N ves) are observed in the non-deprived hemisphere (visual areas I and II, motor cortex) as compared to control animals. (2) N A has not changed, as compared to control animals, in the binocular field of the deprived visual cortex. (3) A significant rise in N A, as compared to control animals, is observed in the monocular field of area I and in the motor cortex of the deprived cortex. This rise is similar to that found after recovery from prolonged dark rearing. (4) The increase in N A is mainly restricted to the laminae I–III, indicating that, most likely, we are not dealing with an increase in specific visual afferents. (5) The deprived visual cortex shows a significant decrease (16%) in N ves. This decrease is less pronounced than after dark rearing (40%). This probably points to the fact that eye suturing does not fully prevent light penetration. The results are discussed in the light of recent discussions on the plasticity of synapses and the effect of retinal input on the development of the visual system.

Reversal of the physiological effects of monocular deprivation in kittens: further evidence for a sensitive period.

1. It was confirmed that suturing the lids of one eye (monocular deprivation), until only 5 weeks of age, leaves virtually every neurone in the kitten's visual cortex entirely dominated by the other eye. On the other hand, deprivation of both eyes causes no change in the normal ocular dominance of cortical neurones, most cells being clearly binocularly driven.2. Kittens were monocularly deprived until various ages, from 5 to 14 weeks, at which time reverse suturing was performed: the initially deprived right eye was opened and the left eye closed for a further 9 weeks before recording from the visual cortex.3. Reverse suturing at 5 weeks caused a complete switch in ocular dominance: every cell was dominated by the initially deprived right eye. Reverse suturing at 14 weeks, however, had almost no further effect on ocular dominance: most cells were still driven solely by the left eye. Animals reverse sutured at intermediate ages had cortical neurones strongly dominated by one eye or the other, and they were organized into clear columnar groups according to ocular dominance.4. Thus, between 5 weeks and 4 months of age, there is a period of declining sensitivity to both the effects of an initial period of monocular deprivation and the reversal of those effects by reverse suturing.5. The small proportion of binocular cells in reverse sutured kittens (which have never had simultaneous binocular vision) often differed considerably in their receptive field properties in the two eyes. In particular, if the cells were orientation selective in both eyes the two preferred orientations could differ by up to 70 degrees .6. The relative importance of innate and environmental contributions to the properties of cortical cells is discussed.

Projection of X- and Y-cells of the cat's lateral geniculate nucleus to areas 17 and 18 of visual cortex.

Projection of X- and Y-cells of the cat's lateral geniculate nucleus to areas 17 and 18 of visual cortex.

Effects of monocular deprivation on the cat's visual cortex.

Effects of monocular deprivation on the cat's visual cortex.

Consequences of monocular deprivation on visual behaviour in kittens.

1. Kittens were raised for a period with one of their eyes closed by suture of the lids. The age at suture and the duration of deprivation were varied systematically. When the cat was a year or more old, the normal and deprived eyes were compared using behavioural procedures which made graded demands on visual function.2. In kittens deprived from birth, the duration of eye closure determined the severity of the defect in vision with the deprived eye. A cat with an eye closed for the first 4-6 weeks showed as a permanent effect only a lowering of the visual acuity. When closure was extended through the first 7 weeks the visual acuity was further lowered but the animal still showed good visual guidance of paw placement. Further extension of deprivation through the first 16 weeks led to a still more severe defect; such animals showed no indication of visual guidance of paw placement or of pattern discrimination. They were influenced visually by stimuli that differed in luminosity.3. The upper age limit of the susceptibility to deprivation was determined by varying the age at eye closure. Waiting until 1 month of age before closing the eye conferred no appreciable protection. Waiting until 2 months of age, however, reduced the damage. Deprivation starting at 4 months of age or later produced no effect we could detect. Thus, susceptibility is greatest during the second month after birth and then falls until by 4 months of age the kitten, like the adult cat, suffers no permanent consequences of monocular light and form deprivation.4. After exclusive use of the deprived eye for a period, brought about by closure of the normal eye, visual control with the deprived eye was better than in similarly deprived cats whose normal eye was never closed. Improvement in the deprived eye was also seen in an animal whose normal eye was closed after both eyes had been open for more than one year.5. Relating the behavioural results to the neurophysiological findings in the visual cortex in the same or similarly deprived cats shows that the grading of visual defects with age and length of deprivation was generally paralleled by a change in proportion of cortical cells driven by stimulation of the deprived eye. The effect of reversal of eye closure in improving behavioural control was not, however, accompanied by an increase in the ability of the deprived eye to drive cortical cells.

Visual evoked response of single cells and of the EEG in primary visual area of the cat.

Visual evoked response of single cells and of the EEG in primary visual area of the cat.

The effect of monocular deprivation on the synaptic contacts of the visual cortex.

AbstractThe effect of visual deprivation on synaptic contacts in the visual cortex was studied with the electron microscope. The deprivation was achieved by unilateral lid suture in 14‐day old white rats before eye opening after which the animals were kept for 8 weeks. The density and the size of synaptic contacts in the upper part of the visual cortex (from the surface of layer II up to V) were estimated. The mean density of synapses of the visual cortex supplied by the deprived eye was 20% less than on the control side, the upper levels of the cortex being more affected. The mean size of synaptic contacts was larger (+7.5%) in the upper levels of the deprived cortex. No right left difference in density and size were found in control animals.

Extent of recovery from the effects of visual deprivation in kittens.

Seven kittens were used, and the various procedures of deprivation and subsequent studies are summarized in Table 1. In six animals the Iids of one eye were closed for the first 3 months of life. In the recovery period two of these kittens had the deprived eye opened. The other four had the deprived eye opened and the other (previously open) eye was closed. The seventh animal had both eyes closed for 3 months; the right eye was then opened. Recovery periods

RECEPTIVE FIELDS AND FUNCTIONAL ARCHITECTURE IN TWO NONSTRIATE VISUAL AREAS (18 AND 19) OF THE CAT.

RECEPTIVE FIELDS AND FUNCTIONAL ARCHITECTURE IN TWO NONSTRIATE VISUAL AREAS (18 AND 19) OF THE CAT.

EFFECTS OF MONOCULAR DEPRIVATION IN KITTENS.

EFFECTS OF MONOCULAR DEPRIVATION IN KITTENS.

EFFECTS OF VISUAL DEPRIVATION ON MORPHOLOGY AND PHYSIOLOGY OF CELLS IN THE CATS LATERAL GENICULATE BODY.

EFFECTS OF VISUAL DEPRIVATION ON MORPHOLOGY AND PHYSIOLOGY OF CELLS IN THE CATS LATERAL GENICULATE BODY.

RECEPTIVE FIELDS OF CELLS IN STRIATE CORTEX OF VERY YOUNG, VISUALLY INEXPERIENCED KITTENS.

RECEPTIVE FIELDS OF CELLS IN STRIATE CORTEX OF VERY YOUNG, VISUALLY INEXPERIENCED KITTENS.

Discharge patterns and functional organization of mammalian retina.

Discharge patterns and functional organization of mammalian retina.