U Yinon's research while affiliated with Tel Aviv University and other places
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Publications (90)
In a group of chickens studied after lid suture in the first month post hatching an unusually high myopia was found (n = 8 eyes; average: -21.87 Diopters). The non-operated eyes of these chicks had the same optical properties (n = 4; +0.93 Diopters) as the eyes of the normal control chicks (n = 12; +0.81 Diopters). Although enlargement of the whole...
It is well known that in the mammalian visual cortex the neurons, sharing similar response properties, are grouped together into functional units, known as cortical columns. The orientation and ocular dominance columnar organization is a fundamental element for both the anatomical and physiological features of the visual cortex. Nonetheless, little...
The objective of the present study was to reveal the amount of preservation of the most prominent features of the visual cortex: orientation and ocular dominance columns. It has been assumed that because of its inherent organization, the fragment of cells that would survive following lesioning would preserve the orientation and ocular dominance pro...
In addition to visually driven cells we found within the lateral suprasylvian visual cortex of cats a considerable number of auditory and/or bimodal cells. Most of the visually driven cells were direction and orientation selective with responses that were neither highly stimulus time locked nor very stable. Most of the auditory responses were also...
Given that cells in visual cortical area 18 in cats encode information of complex shapes, in addition to conventional stimuli like bars and gratings, we studied the capability of single cells in this area to 'identify' animated contours. The recorded cells were not selective to specific animated contours, whereas they were highly sensitive to the c...
Early blindness in humans and experimental visual deprivation in animal models are known to induce compensatory somatosensory and/or auditory activation of the visual cortex. An abnormal hydrocephalic cat with extreme malformation of the visual system, born in our breeding colony, rendered a good model system for investigating possible cross-modal...
Early blindness in humans and experimental visual deprivation in animal models are known to induce compensatory somatosensory
and/or auditory activation of the visual cortex. An abnormal hydrocephalic cat with extreme malformation of the visual system,
born in our breeding colony, rendered a good model system for investigating possible cross-modal...
Auditory activation of the primary visual cortex (area 17) and two extrastriate visual cortical areas - the anterolateral lateral suprasylvian area (ALLS) and anteromedial lateral suprasylvian area (AMLS), was investigated in visually impaired cats. Impairment was accomplished shortly after birth by bilateral eyelid suturing (binocularly deprived c...
In view of previous evidence that area 17 and 18 cells in cats represent the first level contour abstraction, we decided to study the specific response pattern of these cells to shapes enriched with contours, such as animated objects (AO). AO (cat's body whole contours) and 4 levels of AO degraded patterns were presented monocularly and repeatedly...
We have studied whether the presence of an artificial metal conductor in the visual cortex has an effect on the responsiveness pattern of the cells there. The physiological properties of single cells have been characterized in the mammalian primary visual cortex, following the acute and chronic implantation of silver wire electrodes. The Experiment...
Crustacean eyestalk ganglia are part of the protocerebrum and have been demonstrated to produce numerous neurohormones. 3H(2-D-Pen, 5-D-Pen)-enkephalin, 3H-(-)-ethylketocyclazocine and 3H(D-Ala2-NMePhe-Glyol5)-enkephalin were used as ligands for opioid receptors on neuronal membrane preparations of eyestalk ganglia under consideration of their ster...
We have previously shown that, cat simple cells respond linearly to edges of variable blur widths: cells with receptive fields (RFs) of even symmetry respond better to a luminance ramp (where Mach bands are observed); cells with RFs of odd symmetry respond better to a luminance step (where no Mach bands are perceived). Our evidence has also indicat...
We wished to study in detail the time course of changes in the electroretinogram (ERG) that occur following lesioning of the cat retina by photocoagulation. The superior-temporal quadrant of one eye of 15 adult cats was photocoagulated by argon laser. The ERG was recorded at baseline and followed for up to 13 weeks postlaser. The retina was also ob...
Whether restoration takes place in the visual cortex of neonates was physiologically studied in cortical cells of cats following their deafferentation. Deafferentation was performed by a parasagittal incision made in the visual cortex, separating the medial part of it from the thalamocortical and other visual fibers. Responsiveness (percentage of r...
The effects of cancellation of both interhemispheric callosal transfer and interocular interactions, were studied in early monocularly deprived cats. The main purpose of this study was therefore to prove whether unilateral hemispheric dominance would result under these conditions and to what extent each hemisphere will be functionally independent....
Mach bands are a visual illusion evoked by a luminance ramp dividing two luminance plateaux (blurred edges), but not by sharp edges. Recently, two physiology-based models have tried to cope with the psychophysical data concerning this phenomenon. The basic components of both models are neurons with even- or odd-symmetric receptive fields (RFs). Bot...
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We have studied the physiological properties of cells (N = 822) in visual cortex area 17 of seven adult cats transplanted with visual cortex xenografts from fetal (E15-E17) rats. The transplants were assumed to induce recovery of adjacent neurons partially deafferented from visual input. The control group (eight cats, 564 cells) had just analogous...
The contribution of the corpus callosum to binocularity of visual cortex cells and to their responsiveness was studied in cats. Electrophysiological recordings of the responses of single cells to visual stimulation was performed in the callosal projection zone, visual cortex area 17-18 boundary in callosotomized cats. Callosotomy was carried out by...
We have studied physiologically whether visual cortex cells in areas 17 and 18 of split-brain cats preserve their performance despite the blockage of both binocularity and of interhemispheric communication. The absolute majority of the cells in cats underwent split-brain surgery as kittens and adults and were driven by the ipsilateral eye, resultin...
This review covers intraocular transplantation of retinal tissue. This has importance both for theoretical understanding of retinal and neural development and for possible future clinical application. Transplantation sites have ranged from the anterior chamber through the retina to the subretinal space.
Transplanted tissue has ranged from whole ret...
The visual cortex of adult cats was studied physiologically following neonatal isochronic transplantation of grafts from areas 17,18, which were placed homotopically, in order to reveal their functional integration and thus possible repairing of damaged cortical neuronal circuits. Three homograft cats, in which transplantation was carried out betwe...
We have studied electrophysiologically by single cell recording in the visual cortex, whether modification of the visual system in developing and in adult cats by hydrocephalus has an effect on processing of visual information. One of our cats (H1) had developed a complete hydrocephalus and the others partial, as proved by either complete or partia...
We studied whether plasticity-induced callosal transfer exists after the critical period for sensitivity of visual cortex cells in kittens postnatally monocularly deprived and in which interocular competition was cancelled by chiasm transection during adulthood. Callosal transfer was studied acutely (n = 3 cats) and chronically (n = 7) following th...
Plasticity-induced interhemispheric transfer of visual information to cortical cells was studied in adult cats. The direct contralateral visual pathway was surgically eliminated permitting binocularity only by callosal transfer. In order to enhance the interhemispheric transfer, one hemisphere was made less visually active by depriving it chronical...
The possible involvement of the corpus callosum in binocular functions of the visual cortex was studied in adult cats. Unit recording was made in areas 17, 18 boundary following posterior or complete transection of the corpus callosum, acutely as well as chronically, after short (3-4 months) and long (5.5-39 months) survival periods. A considerable...
To differentiate between the resulting effect of disuse, developmentally induced by deprivation, and the binocular competition effect on cortical cells, visual split brain was performed concurrently with monocular deprivation in kittens. In the experienced hemisphere of the split brain deprived cats (ipsilaterally to the non-deprived eye), there we...
The geniculocortical pathways from the contralateral eye and the callosal pathway were interrupted in cats in order to study how cortical cells are influenced by changes induced in the interhemispheric transfer of visual information. Unit recording was carried out from areas 17 and 18 boundary, the callosal projection zone. The ocular dominance dis...
In order to study the ocular dominance and responsiveness of cells in the deafferented visual cortex, the geniculate and the callosal inputs were interrupted in adult cats by either simultaneous (OTCCX) or separate surgical transection of the optic tract (OTX) and the posterior corpus callosum (CCX). Unit recording was chronically carried out mainl...
A condition of asymmetrical activation in the visual system, induced by unilateral optic tract section (OTX) was examined in nine adult cats, four of which had been reared after early onset of monocular deprivation (MD-OTX) during the critical developmental period. Their results were compared to those of monocularly deprived (MD) and normal control...
Visual callosal transfer during development was studied in order to reveal plasticity-related compensation for the absence of direct contralateral inputs. The optic chiasm was midsagittally sectioned in 6-8 weeks old kittens (OCK) and for comparison, in adult cats (OCA). Unit recording was made during adulthood in the border area between visual cor...
The ocular dominance distribution and the excitability level of single cells in the callosal projection zone of the visual cortex (area 17-18 boundary), were electrophysiologically studied in acute and in chronic cats following simultaneous (OCX-CCX) and separate transections of the optic chiasm (OCX) and corpus callosum (CCX). Except for a few cel...
Physiologically, several different experimental approaches have been so far adopted in order to demonstrate the involvement of visual cortex cells in interhemispheric relationships. Of these approaches the main ones will be briefly described here.
Receptive field properties and the selectivity of cortical cells to visual stimulation were studied in the visual cortices (the boundary between areas 17 and 18) of both hemispheres following unilateral deafferentation in normal and in early monocularly deprived cats. Almost no visual activity was encountered in the deafferented hemisphere and a co...
The callosal transfer of information to the visual cortex following its unilateral deafferentation from its geniculate input was studied in both hemispheres. Deafferentation was performed in adult cats by sectioning the optic tract. Action potentials of single cortical cells and visual evoked potentials were recorded from area 17-18 boundary in acu...
Two experimental groups of domestic fowl chicks were reared in darkness. One group was normal (DR) and the second had unilateral lid closure (DRC). A control group was reared in normal illumination (LR). The optical components of the eye were examined by retinoscopy, keratometry and phacometry while physical measurements were made using ultrasonogr...
The ocular dominance, responsiveness level and receptive field properties of single cortical cells were studied in 12 acute and chronic split chiasm adult cats (729 cells) and in 13 normal controls (544 cells). Recording was made from the border between visual areas 17/18. Responsive cells in the operated cats were obtained exclusively (87.1%) foll...
To study whether early visual experience survives the absence of consequent visual stimulation during development, experimental kittens were reared in the dark for 5–13.5 months following monocular deprivation (MD) periods of 2–11 weeks which were initiated at the time of natural eye opening (MD-dark). For comparison, experimental kittens, normally...
We studied the preservation of the early monocular deprivation effect by rearing kittens in complete darkness for long periods (9.5 to 20 months) after a monocular deprivation period of 4 weeks that was initiated at the age of 1 month (MDDR cats). For comparison, four groups of kittens were used: monocularly deprived as those described above and th...
Kittens reared in the dark with their eyelids sutured postnatally on one side have developed hypermetropia in the closed eye (average: +2.75 D for the horizontal meridian). This was significantly different (0.01 greater than p greater than 0.005) from the results of the open eye (+1.67 D; 180 degrees). The closed eye of light-reared kittens had sim...
In this review the effects of changes in the quality of the visual environment on the development of myopia during eye growth in various mammalian and avian species are described. The effect of changes in the light/dark cycle on myopia development has been studied only in the avian eye, mainly that of the domestic fowl. In the eyes of chicks reared...
Monocular closure surgically performed during development by suturing the eyelids induced less hyperopia in the closed eye of light reared kittens (+0.95 Diopters) in comparison to the closed eyes of lid sutured dark reared kittens (+2.61 D). The normal control cats were also slightly hypermetropic (+0.69 D). While a certain proportion of myopic ey...
The optic tract was unilaterally transected and receptive field mapping and unit recordings were made for cells in the boundary of areas 17-18 in the deafferented and in the intact visual cortex of adult cats monocularly deprived during the critical developmental period. Three groups of adult animals served as controls: normal cats, early monocular...
Single unit recording from visual cortex areas 17 and 18 and in the border region between them was performed on adult cats with unilateral optic tract section (OTX) either on the day of the operation (acute) or three to six months postoperatively (chronic). Visual activity from both hemispheres was analyzed with respect to the responsiveness level,...
Intoxication of the retina, caused by penetration of foreign metallic substances into the eye, induces pathological changes (Knave 1970; Schmidt and Strube 1972). Copper is one of the most dangerous and frequently found in such eye’s injuries. In order to find a simple criterion for justifying the need for emergency at operation, the electrophysiol...
1. Vision was investigated with behavioural and electrophysiological techniques in three groups of cats: ( a ) two normally raised kittens in which one eye was rotated at an age of 3 months, ( b ) three adult cats in which one eye had been rotated and the other closed 6 months prior to recording, ( c ) two adult cats in which first one eye had been...
1. In nine 4‐week‐old, dark‐reared kittens we sutured one eye closed and rotated the other surgically. The kittens then grew up in a normally lighted animal colony with adequate room to play.
2. For about two weeks after surgery their visual‐motor co‐ordination did not differ from that of kittens with conventional monocular deprivation; then severe...
Unit recording was carried out in the visual cortex of split chiasm and optic tract-sectioned adult cats. From the proportions of the visually responsive and unresponsive cells found in each hemisphere of the operated cats it was concluded that the indirect pathway via the corpus callosum becomes visually inactive under these conditions. However, t...
Five groups of kittens (N = 13) were dark reared for 9.5-20 months following normal binocular exposure of 0-85 days after natural eye opening and 1 month of monocular deprivation. For comparison, kittens monocularly deprived (MD) for 10 months (N = 2) and normal adult cats (N = 13) served as controls. The ocular dominance distribution of cortical c...
In kittens in which rotation of the visual field was performed, behavioral changes and changes in receptive field orientations for cells in the primary visual cortex were found. These changes reflect the conflict existing in these kittens between the vestibular and the visual input to the visual cortex with regard to the orientation of the body in...
Newly hatched chicks were dark reared continuously for maturity. The average pupillary size in these chicks was 2.6 mm in comparison to 4.5 mm in the normal controls. There was no change immediately after exposure to light and only a slight recovery several weeks later. Histology showed no morphological change in the iris, ciliary body or lens, thu...
It is generally accepted that in cases of hemianopsia macular sparing is frequent, especially if the lesion is caused in the center of the optic chiasm or higher up in the visual system (Duke-Elder 1971). Depth perception is thus preserved to a certain extent, although it is not known what kind of physiological mechanism is involved.
Following chronic (2-3 months) unilateral eye enucleation in cats, an increase was found in the proportion of diffuse (5.4%), orientation bias (8.3%) and non-oriented (9.6%) receptive fields of cortical cells above the normal level. A reduction in small size receptive fields (< 0.8 sq. degrees) and in cells with the smallest (< 22.5 degrees) range...
Lid fusion was surgically performed in newly hatched and grown-up chicks for various periods of up to three-and-one-half months. This led to an unusual enlargement of the eyeball in the first group of chicks in all equators, resulting in average myopia of −8.02 D. The value that was obtained in normal eyes was +0.42 D. Simultaneously, an antagonist...
During the first 2 weeks following unilateral severance of the 6 extraocular eye muscles in adult cats, the operated eye is partially immobile as shown by electrooculographic (EOG) recordings of horizontal eye movements. Although the motility of the operated eye improves with time (mainly in terms of amplitude but also with regard to direction and...
The physiological effects of inversion of vision were studied in the visual cortex of five adult cats following 180 ° surgical rotation of one eye for 2–3 months. The other eye was closed in order to prevent binocular conflicting visual input in the period between eye inversion and unit recording.
The distribution of neurons according to their ocul...
33 eyes of 18 cats raised in cages or in small rooms under conditions of near vision were compared with 22 eyes of 11 street cats. Refraction of the caged cats showed that three quarters of them were myopic (average:-0.8 D) while 87.5 percent of the street cats were hypermetropic (average: +1.4 D). The antero-posterior diameter was practically equa...
The period of susceptibility of the visual cortex of kittens to the effect of squint is limited to the first three postnatal months. The reduction of binocularity found in these kittens as reflected by the distribution of neurons according to their ocular dominance is especially emphasized in animals operated on between the ages of 4-7 weeks in com...
Unilateral eye rotation was surgically induced in 11 kittens during the period of susceptibility to visual deprivation, and in five cats after the termination of this period; five cats were used as normal controls. Single unit recording was carried out in the visual cortex of eight cats from the two age groups (100 units), and from the normal contr...
Ten out of 82 simple, complex and hypercomplex cells in areas 17 and 18 of the cat visual cortex responded with either rhythmic or nonrhythmic sustained firing patterns to movement stimulation. Sustained (X −) cells tended to show multimodal average response histograms with a dominant excitatory peak indicating organizational subdivision of their r...
In five normal cats, 70.7% of the neurons recorded from the visual cortex responded to binocular stimulation; only 27.2% of the neurons in 12 cats raised with convergent squint and 63.6% of neurons in four cats with divergent squint displayed binocularity. In cats with convergent squint, 15% of the neurons showed normal receptive fields through one...
Most receptive fields of neurons in the visual cortex (area 17) of rats could be mapped with moving and stationary stimuli. Neurons were most effectively driven by moving stimuli. They were classified s motion (37 per cent), orientation (11 per cent), or direction selective (4 per cent) and indefinite cells (41 per cent). Many cells had only a weak...
Substantial electrophysiological changes in the visual cortex and lateral geniculate nucleus of cats result from unilateral pattern deprivation. The question arises whether these changes are secondary to those occurring in the retina. When retinal responses (ERG’s) of visually deprived cats were examined, a diminution of the b-wave of the deprived...
The refraction of 12 street cats' eyes and of 11 caged cats was measured by retinoscopy, and the anteroposterior (axial) length of the eyeball was measured by ultrasound. While 87.5 per cent of eyes in street cats were found hypermetropic (average + 1.14 D), among cats caged for periods of 8.5-14.0 months under conditions of near vision. 68.2 per c...
The “deprived” cortex of monocularly deprived rats showed a considerable diminution in response to specific visual stimuli. Many neurons (57.7%) in the “deprived” cortex did not respond to any visual stimuli, and 29% reacted nonspecifically to any stimulus anywhere in the visual field (indefinite cells). In comparison, 7.4% neurons in the “nondepri...
We found a distinct group of simple and complex cells in cat visual cortex which responded to a moving stimulus in a rhythmic or nonrhythmic series of spike bursts. Each burst consisted of 2–12 spikes and 5–40 bursts were produced at each sweep. The regularity of the interburst intervals of rhythmic neurons depends on the velocity direction and ori...
Albino rats were monocularly deprived for 1.5–13.5 mo after which the electroretinogram was recorded from both the normal and the deprived eyes. The amplitude of the b-wave in the deprived eyes was much lower for most of the intensity range used. This difference results initially from temporary changes in the deprived retina which decrease with sti...
The approach to a neuron with a desired activity, to a distance at which it can be easily isolated, is controlled by an electronic device which divides the motion of one micron in a number of steps. This is done by applying 10–40 pulses to a DC motor which is built into a micro-electrode manipulator. The number of pulses per μ and the intervals bet...
In the present experiments we studied whether visual pattern deprivation affects the visual evoked potential (VEP) as has been assumed from modification of neuronal structures found in the rat cortex under this condition. The VEP of normal and of monocularly deprived rats is similar in waveform and composed of a small negative component at 40 msec,...
Citations
... However, all patients also had poor visual tracking function. 6 Townend et al. also studied the oculomotor function of 18 girls with Rett syndrome, and their work suggests that this function remains intact in Rett syndrome patients. 7 In the studies above that observed ocular structures in patients with Rett syndrome, all noted normal optic nerves. ...
... One would expect, then, that there would be very little input to the visual cortex from the ipsilateral eye and that binocularlydriven cells would be rare. However, the area of the visual cortex over which gross potentials can be evoked by stimulation of the ipsilateral eye is quite extensive (Adams and Forester 1968;Montero et al. 1973) and Shaw et al. (1974), admittedly on the basis of a small sample, showed that 60% of cortical cells in this binocular segment could be driven through both eyes. Also, Drfiger and Olson (1980) reported that in the binocular segment of the albino mouse's visual cortex, most cells are driven from both eyes. ...
![[object Object]](https://i1.rgstatic.net/ii/profile.image/273694584995881-1442265282826_Q64/Christopher-Shaw-8.jpg)
... In addition to the more severe case of full monocular deprivation via lid suturing, disrupted visual input has also been studied in cats with artificial squint or induced anisometropia. Such animals typically exhibit reduced numbers of binocularly responsive cells in early visual cortex 31 and altered sensitivity to spatial frequency. 32,33 As in earlier deprivation studies, these physiological effects are age-dependent, such that abnormal visual input early on (in the first 3 months of life) led to lasting structural changes, with the largest effects resulting from induced strabismus between 4 and 7 weeks. ...
... 157 and 158. They require activated brain states (162), require scanning of and interaction with the environment (163), and fail to occur when the available sensory evidence is in conflict with inborn response properties of the system (164,165). However, some of these network changes can be induced even under anesthesia when stimuli are presented repetitively (162,166). ...
... They have a lasting impact on perception psychology research up to the present day (cf. Bedford, 1993;Held & Hein, 1958;Held, 1965;Howard, 1974;Kornheiser, 1976;Lackner, 1981;Michel, 2016;Redding & Wallace, 1992Redding, Rossetti, & Wallace, 2005;Singer, Tretter, & Yinon, 1979;Striemer & Danckert, 2010;Taylor, 1962;Miaelian and Held, 1964;Werner & Wapner, 1955). ...
... Second, measurements of refractive error made after MD revealed a slight hyperopia for the deprived eye (+0.6 diopters), and this was largely unchanged after inactivation of the fellow eye (+0.5 diopters). This measured hyperopia in our study is consistent with previous measurements from normal light-reared cats that were also shown to be slightly hypermetropic (Belkin et al., 1977;Smith et al., 1980). In aggregate, results from this study support previous reports that MD in cats does not consistently produce a significant myopia in the deprived eye (Gollender and Thorn, 1979;Nathan et al., 1984). ...
![[object Object]](https://i1.rgstatic.net/ii/profile.image/272339682197512-1441942248167_Q64/Michael-Belkin-3.jpg)
... esistono elementi empirici in favore di questa ipotesi. il più convincente è probabilmente quello fornita dalla plasticità corticale (Hunt, Yamoah e Krubitzer 2006;likova 2012; ramachandran e rogers-ramachandran 2000; roe, garraghty, esguerra e sur 1993; roe, pallas, Kwon e sur 1992; Yinon 1977). in altri termini, non sembra esservi un piano rigido, né algoritmi strettamente codificati a livello innato nelle varie aree. ...
... 32,33 As in earlier deprivation studies, these physiological effects are age-dependent, such that abnormal visual input early on (in the first 3 months of life) led to lasting structural changes, with the largest effects resulting from induced strabismus between 4 and 7 weeks. 34 This pattern of results has also been found in more recent studies with non-human primates. (31,33) Early neuroanatomical and electrophysiological studies of disrupted visual input in animal models have guided the clinical understanding of amblyopia in humans. ...
... However, we were able to observe a reduction in the RF area during LED stimulation. In addition, similar RF areas were reported by other investigators for the rat visual cortex 22,36,37 . ...
... In addition to translational deviations, torsional misalignments of the visual images have significance for the maintenance of cortical binocularity (Blakemore et al., 1975;Yinon, 1975;Bruce et al., 1981). The photographic data also provided information about the torsional alignment of the eyes, as measured by extending the lines formed between the base and apex of each slit pupil upwards and determining the angle of intersection. ...
