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1.

001-es BibID:BIBFORM033348
Első szerző:Beaulieu, Clermont
Cím:Quantitative distribution of GABA-immunopositive and -immunonegative neurons and synapses in the monkey striate cortex (area 17) / C. Beaulieu, Z. Kisvarday, P. Somogyi, M. Cynader, A. Cowey
Dátum:1992
ISSN:1047-3211
Megjegyzések:The number of GABA-immunoreactive [GABA(+)] neurons and synapses was determined in functionally distinct subregions delineated as rich and poor in cytochrome oxidase (CO) in the visual cortex of adult macaque monkeys. The average numerical density (number per unit volume, Nv) of GABA(+) neurons and synapses was not significantly different between the CO-rich and -poor regions. Twenty percent of the total number of cortical neurons and 17% of the synapses were GABA(+). On average, each visual cortical neuron receives 3900 synapses, 660 of them being GABA(+). The latter were distributed on the target cell in a pattern that predicts the site of GABA influences in cortex. The major targets of GABA(+) synapses were dendritic shafts, comprising nearly two-thirds of the postsynaptic elements. About every fourth and every eighth GABA(+) synapse was devoted to dendritic spines and to neuronal somata, respectively. Axon initial segments, although the exclusive targets of GABA(+) cells, comprise less than 0.1% of structures postsynaptic to GABA(+) boutons. From this distribution, we estimate that in each cubic millimeter of striate cortex there were about 20 million GABA(+) synapses on dendritic spines, 47 million on dendritic trunks, 9 million on somata, and fewer than 0.1 million on axon initial segments. The sites of influences of GABA-immunonegative [GABA(-)] synapses were different in that they target mainly dendritic spines and dendritic trunks. About two-thirds of GABA(-) synapses were on dendritic spines, and the remainder were devoted to dendritic trunks. Only a minute fraction innervate somata. We estimate that in 1 mm3 of striate cortex there were about 235 million GABA(-) synapses on spines, 133 million on dendrites, and about 2 million on somata. The proportions of GABA(+) neurons and synapses and their target distribution did not appreciably differ from those of the visual cortex of the cat even though the numerical density of neurons was 2.5 times higher in the monkey.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
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Megjelenés:Cerebral Cortex. - 2 : 4 (1992), p. 295-309. -
További szerzők:Kisvárday Zoltán (1957-) (biológus, neurobiológus) Somogyi Péter Cynader, M. Cowey, Alan
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2.

001-es BibID:BIBFORM033414
035-os BibID:PMID:3540723 WOS:A1986F055800006
Első szerző:Kisvárday Zoltán (biológus, neurobiológus)
Cím:Synaptic relationships of a type of GABA-immunoreactive neuron (clutch cell), spiny stellate cells and lateral geniculate nucleus afferents in layer IVC of the monkey striate cortex / Z. F. Kisvárday, A. Cowey, P. Somogyi
Dátum:1986
ISSN:0306-4522
Megjegyzések:The precise stimulus specificity of striate cortical neurons is strongly influenced by processes involving gamma-aminobutyric acid (GABA). In the visual cortex of the monkey most afferents from the lateral geniculate nucleus terminate in layer IVC. We identified a type of smooth dendritic neuron (clutch cell) that was immunoreactive for GABA, and whose Golgi-impregnated dendrites and axon were largely restricted to layer IVC beta. The slightly ovoid somata were 8-12 micron by 12-15 micron and the dendritic field was often elongated, extending 80-200 micron in one dimension. The axonal field was 100-150 micron in diameter and densely packed with large bulbous boutons. Although mainly located in IVC beta both the dendritic and axonal processes entered IVC alpha. Fine structural features of GABA-immunoreactive and-impregnated clutch cells and impregnated spiny stellate cells were compared. Clutch cells had more cytoplasm, more densely packed mitochondria and endoplasmic reticulum, and made type II as opposed to type I synapses. A random sample of 159 elements postsynaptic to three clutch cells showed that they mainly terminated on dendritic shafts (43.8-58.5%) and spines (20.8-46.3%), rather than somata (10-17%). The majority of the postsynaptic targets were characteristic of spiny stellate cells. This was directly demonstrated by studying synaptic contacts between an identified GABA positive clutch cell and the dendrites and soma of an identified spiny stellate cell. The termination of clutch cells mainly on dendrites and spines of spiny stellate cells suggests that they interact with other inputs to the same cells. Following an electrolytic lesion in the ipsilateral lateral geniculate nucleus we examined the distribution of degenerating terminals on three identified spiny stellate neurons in layer IVC beta. Out of eight synapses from the lateral geniculate nucleus one was on a dendritic shaft, the rest on spines. Only a small fraction of all synapses on the cells were from degenerating boutons. A clutch cell within the area of dense terminal degeneration was not contacted by terminals from the lateral geniculate nucleus. The results show that layer IVC in the monkey has a specialized GABAergic neuron that terminates on spiny stellate cells monosynaptically innervated from the lateral geniculate nucleus. Possible functions of clutch cells may include inhibitory gating of geniculate input to cortex; maintenance of the antagonistic subregions in the receptive fields; and the creation from single opponent of double colour opponent receptive fields.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
egyetemen (Magyarországon) készült közlemény
Megjelenés:Neuroscience. - 19 : 3 (1986), p. 741-761. -
További szerzők:Cowey, Alan Somogyi Péter
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Intézményi repozitóriumban (DEA) tárolt változat
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3.

001-es BibID:BIBFORM033390
035-os BibID:PMID:3007194 WOS:A1986A521100008
Első szerző:Kisvárday Zoltán (biológus, neurobiológus)
Cím:The relationship between GABA immunoreactivity and labelling by local uptake of [3H]GABA in the striate cortex of monkey / Z. F. Kisvárday, A. Cowey, A. J. Hodgson, P. Somogyi
Dátum:1986
ISSN:0014-4819
Megjegyzések:An antiserum to GABA was used in the macaque monkey to determine whether neurons that accumulate exogenously applied [3H]GABA in vivo are also immunoreactive for GABA. Following the injection of [3H]GABA into different laminae of striate cortex in two untreated animals and in one animal treated with amino-oxyacetic acid, selective accumulation of the labelled amino acid was demonstrated in perikarya by autoradiography. Radiographically labelled neurons (n, 519) and their unlabelled neighbours were tested in consecutive 0.5 micron thick sections by immunocytochemistry for GABA immunoreactivity. Injection of [3H]GABA did not increase the number of neurons showing GABA immunoreactivity. On the contrary many of the cells that accumulated [3H]GABA were immunonegative. These neurons were mostly located in layers IVC and VA following [3H]GABA injection into layers II-III, and in layers upper III and II following injection into layers V and VI. A comparison of the position of these neurons with known local projection patterns in the striate cortex of monkey suggests that GABA-immunonegative neurons may nevertheless become labelled by [3H]GABA if most of their local axon terminals fall within the injection site. The interlaminar projection of GABA-immunopositive neurons, which probably contain endogenous GABA, could be deduced from the position of the [3H]GABA injection site that leads to their autoradiographic labelling. Although the present study confirmed our previous results on the interlaminar connections of neurons that accumulate [3H]GABA, it demonstrated that [3H]GABA labelling alone may not be a sufficient criterion to assess the GABAergic nature of neurons in the striate cortex of monkey.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
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Megjelenés:Experimental Brain Research. - 62 : 1 (1986), p. 89-98. -
További szerzők:Cowey, Alan Hodgson, Anthony J. Somogyi Péter
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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4.

001-es BibID:BIBFORM033366
035-os BibID:PMID:2537391 WOS:A1989T409800030
Első szerző:Kisvárday Zoltán (biológus, neurobiológus)
Cím:Interlaminar and lateral excitatory amino acid connections in the striate cortex of monkey / Zoltan F. Kisvárday, Alan Cowey, A. David Smith, Peter Somogyi
Dátum:1989
ISSN:0270-6474
Megjegyzések:The intrinsic excitatory amino acid pathways within the striate cortex of monkeys were studied by autoradiographic detection of retrogradely labeled somata following microinjections of D-3H-aspartate (D-3H-Asp) into different layers. The labeled amino acid was selectively accumulated by subpopulations of neurons and, to a small extent, by glial cells, the latter mainly in the supragranular layers. Immunocytochemical detection of neurons containing GABA showed that, apart from a few cells exclusively in layer I, GABAergic neurons do not accumulate D-3H-Asp. Several lines of evidence suggest that D-3H-Asp uptake occurred only at nerve terminals; thus, the pattern of perikaryal labeling allowed the delineation of interlaminar and lateral projections. Neurons in layer I probably project laterally, and layer I receives wide-ranging projections from layer IVB and layer V from cells up to 1300 microns laterally. Some neurons in layer II send a focused projection to lower layer VI. Some neurons in layers II/III project up to 1 mm laterally within their own layer, but relatively few neurons can be labeled in these projections. Similarly, in layers II/III few neurons can be retrogradely labeled from layers V and upper VI, and this projection is organized such that cells closer to the pia project deeper in layer V/VI. The connections of layer IVA could not be revealed separately because of the difficulty of confining injections to this thin sublamina. Neurons in layer IVB project up to 1300 microns within IVB itself. A small number of cells from IVB also project to layers III, IVC-alpha, V, and VI with much more restricted lateral spread. Neurons in upper IVC-alpha send axons to layer IVB with at least 600-800 microns lateral spread. Neurons in lower IVC-alpha/upper IVC-beta project to layer III with at least 300-500 microns lateral spread. The bottom 50-80 microns of layer IVC-beta contains neurons with a very focused projection, apparently exclusively to the layer III/IVA border region. Both layers IVC alpha and beta have rich connections within themselves, the beta sublayer having more restricted lateral connections. Some neurons in layer IVC-beta give a laterally restricted small input to layers IVC-alpha and IVB. Both IVC-alpha and -beta project to layers V and VI, and these projections are spread at least 400 microns laterally. Neurons in layer V project to all layers, but the projection to layers I-III and within layer V itself spread much further laterally than the projections to layers IV and VI.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
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Megjelenés:Journal Of Neuroscience. - 9 : 2 (1989), p. 667-682. -
További szerzők:Cowey, Alan Smith, A. David Somogyi Péter
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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5.

001-es BibID:BIBFORM033364
Első szerző:Kisvárday Zoltán (biológus, neurobiológus)
Cím:Direct and indirect retinal input into degenerated dorsal lateral geniculate nucleus after striate cortical removal in monkey : implications for residual vision / Kisvárday Zoltán F., Cowey Alan, Stoerig Petra, Somogyi Péter
Dátum:1991
ISSN:0014-4819
Megjegyzések:We removed the striate cortex of one cerebral hemisphere in a macaque monkey, causing almost total retrograde degeneration of the corresponding dorsal lateral geniculate nucleus (dLGN) and extensive transneuronal degeneration of ganglion cells in the corresponding hemi-retina of each eye. The rare surviving geniculate projection neurons were retrogradely labelled by horseradish peroxidase (HRP) from extra-striate cortex and retinogeniculate terminals were labelled by an intraocular injection of HRP. Retinal terminals in the degenerated dLGN made synaptic contact exclusively with the dendrites of interneurons immunopositive for gamma-aminobutyric acid (GABA) in both parvocellular and magnocellular regions of dLGN. As well as being post-synaptic to retinal terminals these vesicle-containing dendrites were pre- and postsynaptic to other similar dendrites, and presynaptic to relay cells. Surviving labelled projection neurons received retinal input indirectly, via both the GABA-immunopositive interneurons and GABA-immunonegative terminals characteristic of those from the superior colliculus. In the degenerated, as opposed to the normal dLGN, about 20% of retinal terminals were GABA-immunopositive and GABA-immunoreactivity was prominently elevated in the ganglion and amacrine cell layers of the degenerated half of the retina. The optic nerve also contained numerous GABA-immunopositive axons but very few such axons were found in a normal optic nerve processed in identical manner. The surviving pathways from the retina must underlie the visual abilities that survive striate cortical removal in monkeys and human patients and may involve the degenerated dLGN as well as the mid-brain.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
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Megjelenés:Experimental Brain Research. - 86 : 2 (1991), p. 271-292. -
További szerzők:Cowey, Alan Stoerig, Petra Somogyi Péter
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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6.

001-es BibID:BIBFORM033396
Első szerző:Somogyi Péter
Cím:Retrograde transport of gamma-amino[3H]butyric acid reveals specific interlaminar connections in the striate cortex of monkey / Péter Somogyi, Alan Cowey, Zoltán F. Kisvárday, Tamás F. Freund, János Szentágothai
Dátum:1983
ISSN:0027-8424
Megjegyzések:Several lines of evidence suggest that gamma-aminobutyric acid is an inhibitory neurotransmitter in the cerebral cortex. To study the intracortical projection of neurons that selectively accumulate this amino acid, we injected radioactive gamma-aminobutyric acid into the upper layers of the striate cortex of monkeys along tracks at an oblique angle to the pia. Sections from the injected area were then processed by a combination of autoradiography and Golgi impregnation to reveal the distribution of labeled neurons and their morphological characteristics. Labeled neurons always occurred around the injection site in each layer. In addition, a consistent radial pattern of perikaryal labeling was observed in layers IVc-VI below the injection track in layers I-IVa. The closer the injection track was to the pia the deeper the peak density of labeled cells appeared. After injection in layers IVa and the lower part of III, the highest number of labeled neurons was in layer IVc; after injection in the upper part of layer III, most labeled neurons were in layer V; and, after injection in layers I and II, the proportion of labeled neurons increased in the lower part of layer V and in layer VI. All these neurons in the infragranular layers are presumably labeled by retrograde axonal transport via the labeled fiber bundles that extended from upper to lower layers. Thirty-four Golgi-stained neurons of various types were also examined for retrograde labeling. Two were labeled, and both were aspiny stellate cells in layer V. The arrangement of these putative GABAergic neurones, with axons that ascend from lower to upper layers in a regular pattern and arborize locally, would enable them to mediate inhibition within cortical columns and between neighboring columns.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
egyetemen (Magyarországon) készült közlemény
Megjelenés:Proceedings Of The National Academy Of Sciences Of The United States Of America. - 80 (1983), p. 2385-2389. -
További szerzők:Cowey, Alan Kisvárday Zoltán (1957-) (biológus, neurobiológus) Freund Tamás F. Szentágothai János
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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7.

001-es BibID:BIBFORM033394
035-os BibID:PMID:6200348 WOS:A1984SB66300009
Első szerző:Somogyi Péter
Cím:Characterization by Golgi impregnation of neurons that accumulate 3H-GABA in the visual cortex of monkey / P. Somogyi, Z. F. Kisvárday, T. F. Freund, A. Cowey
Dátum:1984
ISSN:0014-4819
Megjegyzések:3H-GABA was injected into restricted regions of visual areas 1 and 2 (cortical areas 17 and 18) on the lateral surface of the occipital lobe in monkeys. The injected tissue was processed for Golgi impregnation and gold toning. Sections containing Golgi-impregnated neurons were re-embedded, sectioned at 1 micron, and prepared for autoradiography to reveal neurones that had selectively accumulated 3H-GABA. Golgi-impregnated pyramidal, spiny stellate and aspiny nonpyramidal neurons were examined for 3H-GABA accumulation. Out of 47 aspiny non-pyramidal neurons 16 were labelled by 3H-GABA. The other cell types did not accumulate the amino acid. Twelve of the labelled neurons were drawn. Eight were bitufted neurons with their dendrites oriented predominantly radially, three were small multipolar neurons, and one could be reconstructed only partially. One neuron had a locally arborizing axon in layer III. Two bitufted, Golgi-impregnated neurons in layer II and upper III of area 18 were labelled from GABA injection radially beneath in layer VI, providing evidence for earlier suggestions that in the monkey's visual cortex the cells in the upper layers which project radially and accumulate 3H-GABA are aspiny non-pyramidal cells. The results indicate the existence of different types of putative GABA-ergic interneurons.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
külföldön készült közlemény
Megjelenés:Experimental Brain Research. - 53 (1984), p. 295-303. -
További szerzők:Kisvárday Zoltán (1957-) (biológus, neurobiológus) Freund Tamás F. Cowey, Alan
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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