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I M Gabibov

Publications and source records attributed to I M Gabibov.

12 recordsLinked to original sources
PubMed1992

[The size of the neuronal receptive fields of the cat prestriate cortex in the left and right hemispheres].

Sizes of neurons' receptive fields (RFs) were studied in area 21 using as a stimulus the light bar 2.5 x 45 degrees C. The RFs were found to be larger than in areas 17-19 and LS cortex. Means sizes of the RFs were found to be larger in the left hemisphere (45 degrees) as compared with the right one (30 degrees). The whole visual field seems to be formed in area 21 in the cats.

Animals↗
PubMed1992

[The spatial-frequency characteristics of the neuronal receptor fields in area 21 of the cat visual cortex].

21 area's neurons of the visual cortex revealed obvious low-pass frequency characteristics ranging from 0.05 to 3.5 c/deg in cats. Responses of the neurons to different frequencies ranged from 0.05 to 0.89 c/deg in the left hemisphere and from 0.11 to 3.5 c/deg in the right one. The data obtained suggest that the RF's neurons of the area 21 make low-pass spatial-frequency description of visual images, the left hemisphere making a lower spatial-frequency description of the image than the right one.

Animals↗
PubMed1987

[Relation between the size of the receptive fields of field 21 neurons of the cat cerebral cortex and eccentricity].

The interrelationship between the size of receptive fields and the eccentricity in areas 21, 19 and 7 of both hemispheres was studied on immobilized cats. Correlation between the receptive fields size and the eccentricity in area 21 in the both hemispheres was low (R = 0.15; P greater than 0.05). In areas 19 and 7 the correlation of the size fields and eccentricity was higher: for area 19 R = 0.9; P less than 0.0001 and for area 7 R = 0.5; P less than 0.01. The fact determined before that the receptive fields size in the left hemisphere are larger than in the right hemisphere was confirmed.

Animals↗
PubMedDate not supplied

[Effect of gamma-aminobutyric acid on audiogenic seizures and conditioned reflexes in the rat].

The influence of GABA injection (intraperiotoneal) on the sensitivity to sound and behaviour was studied on KM line rats, in which a strong sound produces epileptiform seizures, and on sound-resistant Wistar line rats. It was shown that in the KM line rats the previously elaborated motor alimentary conditioned reflex was impaired for several hours after the seizures. The two first GABA injections to the rats of both lines reduce the number of adequate reactions to a signal stimulus. As GABA injections are repeated, conditioned activity is restored. A four-time GABA injection results in blocking of the audiogenic seizures in a number of rats of the KM line and in the maintenance of normal behaviour after the action of the epileptogenic stimulus.

Acoustic Stimulation↗
PubMedDate not supplied

[The functional organization of the spatial structures of the neuronal receptive fields in field 21 of the cat cerebral cortex].

In result study of structural organization of neural receptive fields (RFs) and their different zones on the prestriate cortex level was shown that neural RFs in this area have hypercomplex structure and consist of some spatial different excitatory zones. Orientation and velocity selectivity and spatial-frequency characteristics of the excitatory zones of the same RF may differ between zones. The number of zones in RFs correlate with RF sizes: the more RF size the more zones number in them (r = 0.05, P < 0.02). About 66% of zones in RFs have approximately identical sizes (12-16 deg) and sizes those zones an dependence as from their number in RFs (r = 0.03, P > 0.05) as from the eccentricity (r = 0.3, P > 0.05). Zones in RF were distributed so that distance their centres was between 56-65 degrees (an average across all 60 degrees). If two or three zones were tested simultaneously the neuron changed own frequency and orientation tuning. Consequently the functional organization of neural RFs of prestriate cortex depend upon number simultaneously tested zones in spatial information processing. Was shown that important properties of prestriate cortex neurons is their ability to integrate and complex processing of spatial information across wide area of the visual field; in the prestriate cortex thus violate of straight retinotopical representation principle of visual field, characteristics of all investigated areas of visual system. The results represented in this review allow suppose that the structural and functional unit of cortex which make integration of spatial information from different compose this information is prestriate cortex neurons and not is no striate cortex modules. Consequently combined of neurons which make images description from different parts of visual field out of dependence of cortical area in turn integrate in neuron networks. Is known that neurons of any level have characteristics different of (from) characteristics of other levels visual system. The interaction of different elements of visual system form ultrastructure of RFs and their different zones in prestriate cortex, and ensure function of networks. So just on prestriate cortex neurons level appear whole system of surrounding world universe system of connections from different cortical areas which is morphological and functional base in process of spatial information integration RFs which have the central and peripheral representation.

Animals↗
PubMedDate not supplied

[Hemispheric interaction during the processing of spatial information].

As a result studying the features of single neurons of prestrial cortex (field 21) of a cat the interhemispheric differences are revealed. It is found that the sizes of receptive fields (RF) of the neurons of this region in the left hemisphere is 1.5 larger as in the right one. The RFs of the left hemisphere consist of zones (mainly 5-9) than the RFs of the right hemisphere which in turn consist of 1-4 zones. About 70% of neurons of the left hemisphere are invariant to a direction of the movement of stimulus, the similar number of the right hemisphere neurons are selective with respect to orientation of a stimulus. The study of the spatial-frequency characteristics of RTs of this region indicated that the left hemisphere neurons are tuned to more lower frequencies (0.05-0.89 cycle/grade) than neurons of the right hemisphere (0.11-3.5 cycle/grade). The study of an activity of the neurons of field 21 after commissurotomy has demonstrated that in this case the hemispheres are fully lost the possibility to receive information from contralateral semifield of the vision. The sizes of RFs are significantly less and become equal in the both hemispheres. The neurons of this region become selective to an orientation of stimulus both in the left and right hemispheres. On the basis of the results of clinical and psychophysical studies it is customary to assume that the two sides of the visual perception--concrete and abstract--to a certain extent are disintegrated between each other and are supplied chiefly by different hemispheres.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[Functional reorganizations of the neuronal structures of the cat associative cortex after total sectioning of the corpus callosum].

In given work results of researches functional organization of neural networks at associative cortex level in intact and after total corpus callosum section (Cc sec) of cat's brain. In result of the given researches is established, that after total Cc sec the brain is exposed significant morphological and functional changes. Is shown, that Cc sec is accompanied by infringements in act of reception of food and head orientation of the animal in space. A configuration and characteristics varies conducting ways, opportunity of an exchange the information between is lost by hemispheres, and accordingly, to receive the information from ipsilateral hemifield of vision. The structural and functional characteristics vary of neural structures of both hemispheres: asymmetry of hemispheres in size disappears, orientational and directional characteristics and decreases number of subzones in receptive fields (RF). In RF of this area occur extensive inhibitory zones. Arrangements RF in vision field main borrows contralateral hemifield of vision, in intact a brain large part RF pass in ipsilateral hemifield of vision. Thus in result of these researches is established, that the majority of neural functions of left and right hemispheres at level associative cortex, revealed on intact brain are formed for account transcallosal of connections. In conditions of isolated functioning both hemispheres there are the changes as in ways of the information processing, and in complementary ways of display of space. In result callosotomy of neuron networks in both hemispheres undergo essential changes: the hemispheres lose ability to integrate the set of the parties of subjects, disturbed an opportunity of invariant the descriptions of images, hence the description of the space information occurs on separate attributes of this information.

Animals↗