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001-es BibID:BIBFORM033344
Első szerző:Buzás Péter
Cím:Axonal topography of cortical basket cells in relation to orientation, direction, and ocular dominance maps / Péter Buzás, Ulf T. Eysel, Péter Adorján, Zoltán F. Kisvárday
Dátum:2001
ISSN:0021-9967
Megjegyzések:Abstract The axonal (bouton) distributions of a layer 4 clutch cell (CC), two layer 3 medium-sized basket cells (MBC), and a layer 3 large basket cell (LBC) to orientation, direction, and ocular dominance maps were studied quantitatively. 1) The CC provided exclusively local projections (<380 microm from the soma) and contacted a narrow "niche" of functional representations. 2) The two MBCs emitted local projections (75% and 79% of all boutons), which were engaged with isoorientations (61% and 48%) and isodirections, and long-range projections (25% and 21%, >313 microm and >418 microm), which encountered cross-orientation sites (14% and 12%) and isoorientation sites (7% and 5%). Their direction preferences were mainly perpendicular to or opposite those of local projections. 3) The LBC provided the majority (60%) of its boutons to long-range distances (>437 microm). Locally, LBC boutons showed a rather balanced contribution to isoorientations (19%) and cross-orientations (12%) and preferred isodirections. Remotely, however, cross-orientation sites were preferred (31% vs. 23%) and the directional output was balanced. 4) Monte Carlo simulations revealed that the differences between the orientation specificity of local and long-range projections cannot be explained by a homogeneous lateral distribution of the boutons. 5) There was a similar eye preference in the local and long-range projection fields of the MBCs. The LBC contacted both contra- and ipsilateral eye domains. 6) The basket axons showed little laminar difference in orientation and direction topography. The results suggest that an individual basket cell can mediate a wide range of effects depending on the size and termination pattern of the axonal field.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
külföldön készült közlemény
Megjelenés:The Journal of Comparative Neurology. - 437 : 3 (2001), p. 259-285. -
További szerzők:Eysel, Ulf T. Adorján Péter Kisvárday Zoltán (1957-) (biológus, neurobiológus)
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DOI
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2.

001-es BibID:bibEBI00019271
Első szerző:Buzás Péter
Cím:Model-based analysis of excitatory lateral connections in the visual cortex / Buzás P., Kovács K., Ferecskó A. S., Budd J. M. L., Eysel U. T., Kisvárday Z.F.
Dátum:2006
Megjegyzések:Excitatory lateral connections within the primary visual cortex are thought to link neurons with similar receptive field properties. Here we studied whether this rule can predict the distribution of excitatory connections in relation to cortical location and orientation preference in the cat visual cortex. To this end, we obtained orientation maps of areas 17 or 18 using optical imaging and injected anatomical tracers into these regions. The distribution of labeled axonal boutons originating from large populations of excitatory neurons was then analyzed and compared with that of individual pyramidal or spiny stellate cells. We demonstrate that the connection patterns of populations of nearby neurons can be reasonably predicted by Gaussian and von Mises distributions as a function of cortical location and orientation, respectively. The connections were best described by superposition of two components: a spatially extended, orientation-specific and a local, orientation-invariant component. We then fitted the same model to the connections of single cells. The composite pattern of nine excitatory neurons (obtained from seven different animals) was consistent with the assumptions of the model. However, model fits to single cell axonal connections were often poorer and their estimated spatial and orientation tuning functions were highly variable. We conclude that the intrinsic excitatory network is biased to similar cortical locations and orientations but it is composed of neurons showing significant deviations from the population connectivity rule.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:The Journal of comparative neurology. - 499 : 6 (2006), p. 861-881. -
További szerzők:Kovács Krisztina Ferecskó, Alex S. Budd, Julian M. L. Eysel, Ulf T. Kisvárday Zoltán (1957-) (biológus, neurobiológus)
Internet cím:DOI
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3.

001-es BibID:BIBFORM033519
035-os BibID:PMID:4067011 WOS:A1985AUJ9500001
Első szerző:Kisvárday Zoltán (biológus, neurobiológus)
Cím:Synaptic connections of intracellularly filled clutch cells : a type of small basket cell in the visual cortex of the cat / Z. F. Kisvárday, K. A. C. Martin, D. Whitteridge, P. Somogyi
Dátum:1985
ISSN:0306-4522
Megjegyzések:Light and electron microscopic quantitative analysis was carried out on a type of neuron intracellularly filled with horseradish peroxidase. Two cells were studied in area 17, one of which was injected intra-axonally, and its soma was not recovered. One cell was studied in area 18. The two somata were on the border of layers IVa/b; they were radially elongated and received synapses from numerous large boutons with round synaptic vesicles. The dendrites were smooth and remained largely in layer IV. The cells can be recognised on the basis of their axonal arbor, which was restricted to layer IV (90-95% of boutons) with minor projections to layers III, V, and VI. Many of the large, bulbous boutons contacted neuronal somata, short collaterals often forming "claw"-like configurations around cells. The name "clutch cell" is suggested to delineate this type of neuron from other aspiny multipolar cells. Computer-assisted reconstruction of the axon showed that in layer IV the axons occupied a rectangular area about 300 X 500 microns, elongated anteroposteriorly in area 17 and mediolaterally in area 18. The distributions of synaptic boutons and postsynaptic cells were patchy within this area. A total of 321 boutons were serially sectioned in area 17. The boutons formed type II synaptic contacts. The postsynaptic targets were somata (20-30%), dendritic shafts (35-50%), spines (30%), and rarely axon initial segments. Most of the postsynaptic somata tested were not immunoreactive for GABA and their fine structural features suggest that they are spiny stellate, star pyramidal, and pyramidal neurons. The characteristics of most of the postsynaptic dendrites and spines also suggest that they belong to these spiny neurons. A few of the postsynaptic dendrites and somata exhibited characteristics of cells with smooth dendrites and these somata were immunoreactive for GABA. It is suggested that clutch cells are inhibitory interneurons exerting their effect mainly on layer IV spiny neurons in an area localised perhaps to a single ocular dominance column. The specific laminar location of the axons of clutch cell also suggests that they may be associated with the afferent terminals of lateral geniculate nucleus cells, and could thus be responsible for generating some of the selective properties of neurons of the first stage of cortical processing.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
külföldön készült közlemény
Megjelenés:Journal of comparative neurology. - 241 : 2 (1985), p. 111-137. -
További szerzők:Martin, Kevan A. C. Whitteridge, David Somogyi Péter
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
DOI
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4.

001-es BibID:BIBFORM033388
035-os BibID:PMID:3597830 WOS:A1987H469200001
Első szerző:Kisvárday Zoltán (biológus, neurobiológus)
Cím:Evidence for interlaminar inhibitory circuits in the striate cortex of the cat / Z. F. Kisvarday, K. A. C. Martin, M. J. Friedlander, P. Somogyi
Dátum:1987
ISSN:0021-9967
Megjegyzések:An interlaminar, ascending, and GABAergic projection is demonstrated in the striate cortex of the cat. We have examined a basket cell, with soma and smooth dendrites in layers V and VI, that was injected intracellularly with HRP in the kitten. Three-dimensional reconstruction of its axon revealed a horizontal plexus in layer V and upper VI, extending about 1.8 mm anteroposteriorly and 0.8 mm mediolaterally; a dense termination in the vicinity of the soma in layers V and VI; and an ascending tuft terminating in layers II and III in register above the soma and about 250 microns in diameter. Many boutons of this cell contacted neuronal somata and apical dendrites of pyramidal cells and subsequent electron microscopy showed that these boutons formed type II synaptic contacts with these structures. A random sample of postsynaptic targets (n = 199) in layers III, V, and VI showed that somata (20.1%), dendritic shafts (38.2%), and dendritic spines (41.2%) were contacted. The fine structural characteristics of postsynaptic elements indicated that the majority originated from pyramidal cells. Direct identification of postsynaptic neurons was achieved by Golgi impregnation of four large pyramidal cells in layer V, which were contacted on their somata and apical dendrites by between three and 34 boutons of the HRP-filled basket cell. Layer IV neurons were not contacted. Golgi-impregnated neurons similar to the HRP-filled basket cell were also found in the deep layers. The axonal boutons of one of them were studied; it also formed type II synapses with somata and apical dendrites of pyramidal cells. Boutons of the HRP-filled neuron were shown to be GABA-immunoreactive by the immunogold method. This is direct evidence in favour of the GABAergic nature of deep layer basket cells with ascending projections. The existence of an ascending GABAergic pathway was also demonstrated by injecting [3H]GABA into layers II and III. The labelled amino acid was transported retrogradely by a subpopulation of GABA-immunoreactive cells in layers V and VI, in addition to cells around the injection site. The axonal pattern and mode of termination of deep basket cells make them a candidate for producing or enhancing directional selectivity, a characteristic of layer V cells.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
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Megjelenés:Journal Of Comparative Neurology. - 260 : 1 (1987), p. 1-19. -
További szerzők:Martin, Kevan A. C. Friedlander, M. J. Somogyi Péter
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DOI
Intézményi repozitóriumban (DEA) tárolt változat
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5.

001-es BibID:BIBFORM033363
Első szerző:Kisvárday Zoltán (biológus, neurobiológus)
Cím:Network of GABAergic large basket cells in cat visual cortex (area 18) : implication for lateral disinhibition / Zoltán F. Kisvárday, Clermont Beaulieu, Ulf T. Eysel
Dátum:1993
Megjegyzések:Anatomical and immunohistochemical data indicate that, in addition to pyramidal neurons, nonpyramidal cells are exposed to perisomatic inhibition mediated by gamma-aminobutyric acid (GABA)-containing terminals. However, no direct information is available as yet for the origin of GABAergic inputs to morphologically identified GABAergic neurons. In the present paper, we studied the topographical and synaptic relationship between identified GABAergic large basket cells and their immunohistochemically characterized target neurons revealed by parvalbumin-(PV) and GABA immunostaining in the same material. Extracellularly applied biocytin labelled a total of 36 and 9 large basket cells in layers III and V, respectively. Of these, the axonal arborizations of two basket cells, BC1 and BC2, were reconstructed. The axon of BC1 occupied an area of about 2.3 x 2.2 mm2 in layer III, providing a total of 2,755 terminals. The axon of BC2 showed an overall extent of 3.8 x 1.7 mm2 in layer V elongated in the anteroposterior direction, and gave off 1,599 terminals. Immunostaining for PV was carried out to reveal putative nonpyramidal targets for BC1 and BC2. It was found that in addition to immunonegative cells, they established an average of 4-6 perisomatic contacts onto each of 58 (BC1) and 33 (BC2) PV-immunopositive neurons. For electron microscopic verification, 23 terminals apposing the somata of 12 PV-immunopositive neurons were selected. Each terminal was found to establish symmetrical (type II) contacts with its targeted cell. Furthermore, the distribution of soma area of the targeted PV-immunopositive cells and of identified large basket cells showed remarkable similarity, implying that the two populations were actually the same. In addition, the average horizontal distance between neighbouring PV-immunopositive target cells was found to be about 100 microns both in layers III and V. The results suggest that in area 18 the same large basket cell provides direct inhibition to certain pyramidal cells and facilitation to other pyramidal neurons, by inhibiting their presynaptic large basket cells at regular intervals.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
külföldön készült közlemény
Megjelenés:The Journal of Comparative Neurology. - 327 : 3 (1993), p. 398-415. -
További szerzők:Beaulieu, Clermont Eysel, Ulf T.
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
DOI
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