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1.

001-es BibID:BIBFORM029495
Első szerző:Birinyi András (anatómus, neurobiológus)
Cím:The extent of the dendritic tree and the number of synapses in the frog motoneuron / Birinyi A., Antal M., Wolf E., Székely G.
Dátum:1992
ISSN:0953-816X
Megjegyzések:Frog motoneurons were intracellularly labelled with cobaltic lysine in the brachial and the lumbar segments of the spinal cord, and the material was processed for light microscopy in serial sections. With the aid of the neuron reconstruction system NEUTRACE, the dendritic tree of neurons was reconstructed and the length and surface area of dendrites measured. The surface of somata was determined with the prolate - oblate average ellipsoid calculation. Corrections were made for shrinkage and for optical distortion. The mean surface area of somata was 6710 microm2; lumbar motoneurons were slightly larger than brachial motoneurons. The mean length of the combined dendritic tree of brachial neurons was 29 408 microm and that of lumbar neurons 46 806 microm. The mean surface area was 127 335 microm2 in brachial neurons, and 168 063 microm2 in lumbar neurons. The soma - dendrite surface area ratio was 3 - 5% in most cases. Dendrites with a diameter of </= 1.0 microm constituted approximately 75% of the combined dendritic length in most of the neurons. Unlike in the cat, there was no correlation between the size of stem dendrites and the extent of daughter branches. From the synaptic density estimated in earlier electron microscope investigations of frog motoneuron dendrites (Antal et al., J. Neurocytol., 15, 303 - 310, 1986; 21, 34 - 49, 1992), and from the present data, the number of synapses on the dendritic tree was calculated. The calculations indicated 26 949 synapses on the smallest and 61 519 synapses on the largest neuron if the synaptic density was multiplied by the length of the dendritic tree. If the synaptic density was multiplied by the surface area of the dendritic tree the calculation yielded 23 337 synapses for the smallest and 60 682 synapses for the largest neuron. More than 60% of the combined surface area of dendrites was >600 microm from the soma. This suggests that about two-thirds of the synapses impinged upon distant dendrites >600 microm from the soma. The efficacy of synapses at these large distances is investigated on model neurons in the accompanying paper
Tárgyszavak:Orvostudományok Természettudományok Biológiai tudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
egyetemen (Magyarországon) készült közlemény
Megjelenés:European Journal Of Neuroscience. - 4 : 11 (1992), p. 1003-1012. -
További szerzők:Antal Miklós (1951-) (orvos, anatómus) Wolf Ervin (1961-) (fizikus, neurobiológus) Székely György (1926-2017) (neurobiológus)
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2.

001-es BibID:BIBFORM037166
Első szerző:Stelescu András
Cím:Somato-dendritic morphology and dendritic signal transfer properties differentiate between fore- and hindlimb innervating motoneurons in the frog Rana esculenta / Stelescu András, Sümegi János, Wéber Ildikó, Birinyi András, Wolf Ervin
Dátum:2012
ISSN:1471-2202
Megjegyzések:BACKGROUND: The location specific motor pattern generation properties of the spinal cord along its rostrocaudal axis have been demonstrated. However, it is still unclear that these differences are due to the different spinal interneuronal networks underlying locomotions or there are also segmental differences in motoneurons innervating different limbs. Frogs use their fore- and hindlimbs differently during jumping and swimming. Therefore we hypothesized that limb innervating motoneurons, located in the cervical and lumbar spinal cord, are different in their morphology and dendritic signal transfer properties. The test of this hypothesis what we report here.RESULTS: Discriminant analysis classified segmental origin of the intracellularly labeled and threedimensionally reconstructed motoneurons 100% correctly based on twelve morphological variables. Somata of lumbar motoneurons were rounder; the dendrites had bigger total length, more branches with higher branching orders and different spatial distributions of branch points. The ventro-medial extent of cervical dendrites was bigger than in lumbar motoneurons. Computational models of the motoneurons showed that dendritic signal transfer properties were also different in the two groups of motoneurons. Whether log attenuations were higher or lower in cervical than in lumbar motoneurons depended on the proximity of dendritic input to the soma. To investigate dendritic voltage and current transfer properties imposed by dendritic architecture rather than by neuronal size we used standardized distributions of transfer variables. We introduced a novel combination of cluster analysis and homogeneity indexes to quantify segmental segregation tendencies of motoneurons based on their dendritic transfer properties. A segregation tendency of cervical and lumbar motoneurons was detected by the rates of steady-state and transient voltageamplitude transfers from dendrites to soma at all levels of synaptic background activities, modeled by varying the specific dendritic membrane resistance. On the other hand no segregation was observed by the steady-state current transfer except under high background activity.CONCLUSIONS: We found size-dependent and size-independent differences in morphology and electrical structure of the limb moving motoneurons based on their spinal segmental location in frogs. Location specificity of locomotor networks is therefore partly due to segmental differences in motoneurons driving fore-, and hindlimbs.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Bmc Neuroscience [electronic resource]. - 13 : 1 (2012), p. 68. -
További szerzők:Sümegi János Wéber Ildikó (1972-) (biológus, neurobiológus) Birinyi András (1960-) (anatómus, neurobiológus) Wolf Ervin (1961-) (fizikus, neurobiológus)
Pályázati támogatás:K67747
OTKA
Internet cím:DOI
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3.

001-es BibID:BIBFORM029492
Első szerző:Wolf Ervin (fizikus, neurobiológus)
Cím:Morphometric descriptors and cable modelling of dendritic arborizations based on 3-dimensional reconstructions / Wolf E., Birinyi A., Puskár Z.
Dátum:1996
ISSN:0236-5383
Megjegyzések:The main goal of this paper is twofold. First, to classify some of the quantitative morphological descriptors within a common theoretical framework and to illustrate their use in the neurobiological research. The second aim is to describe how the computer modelling of dendritic impulse propagation could be related to those high-fidelity morphological databases of dendritic arborizations that we had obtained by three-dimensional reconstructions. Most of the illustrative examples cited here were chosen from morphological and computer simulation studies published by our institute in the past few years. The selection of different morphological parameters in reliability tests of our newly developed 3DARBOR three-dimensional neuronal tree reconstruction system was also cited as an example. The advantages of the parallelled morphological and computational approach in the study of dendritic arborizations were discussed. A full flow chart that gives an outline of the methods we followed in setting up a morphologically accurate cable model was also presented.
Tárgyszavak:Orvostudományok Természettudományok Biológiai tudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
egyetemen (Magyarországon) készült közlemény
Megjelenés:Acta Biologica Hungarica. - 47 : 1-4 (1996), p. 427-439. -
További szerzők:Birinyi András (1960-) (anatómus, neurobiológus) Puskár Zita
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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4.

001-es BibID:BIBFORM029487
Első szerző:Wolf Ervin (fizikus, neurobiológus)
Cím:A fast 3-dimensional neuronal tree reconstruction system that uses cubic polynomials to estimate dendritic curvature / Wolf E., Birinyi A., Pomahazi S.
Dátum:1995
ISSN:0165-0270
Megjegyzések:The main goal of this work was to develop and test the accuracy of our 3DARBOR neuronal tree reconstruction system by comparing it with a very precise but time-consuming method of reconstruction (NEUTRACE). Comparison was performed by reconstructing 18 dendritic trees of frog spinal motoneurons from serial sections with both methods and comparing several morphological summaries of the two reconstructions. In 3DARBOR the planar projection of the dendritic trees was drawn and fed into an IBM-compatible PC through a graphic tablet. Dendritic coordinates along the perpendicular (focus) axis on the plane of drawing were estimated by an interpolation method. The interpolation was based on the lengths of projected dendrites and the coordinates of points where dendrites entered the next section. Focus axis coordinates of these points could automatically be calculated from the serial numbers and thicknesses of sections. 3DARBOR was tested by comparison of the distributions of characteristic points of dendritic trees, segment lengths and branching angles. Product moment analysis on dendritic trees was also performed. It was concluded that 3DARBOR is a fast enough reconstruction system without any systematical error of interpolation that can correctly supply the most morphological parameters and visualize the natural arborizations.
Tárgyszavak:Orvostudományok Természettudományok Biológiai tudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
egyetemen (Magyarországon) készült közlemény
Megjelenés:Journal Of Neuroscience Methods. - 63 : 1-2 (1995), p. 137-145. -
További szerzők:Birinyi András (1960-) (anatómus, neurobiológus) Pomaházi Sándor
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
DOI
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5.

001-es BibID:BIBFORM029497
Első szerző:Wolf Ervin (fizikus, neurobiológus)
Cím:Simulation of the effect of synapses : the significance of the dendritic diameter in impulse propagation / Wolf E., Birinyi A., Székely G.
Dátum:1992
ISSN:0953-816X
Megjegyzések:The effectiveness of synapses at various sites of the dendritic tree was studied using a segmental cable model with a program developed by Hines (Int. J. Biomed. Comput., 24, 55 - 68, 1989). The model rendered possible a high-fidelity simulation of the dendritic geometry of a frog motoneuron described in the accompanying paper (Birinyi et al., Eur. J. Neurosci., 1003 - 1012, 1992). The model was used in the passive membrane mode and the synaptic activity was simulated with current injections into large and small diameter dendrites at proximal and distal locations. Synaptic efficiency was defined by the charge transfer ratio expressed as the proportion of the injected current which appeared at the soma. The charge transfer ratio was determined with uniform and non-uniform distribution of specific membrane resistance over the soma - dendrite surface while the diameter of selected dendrite segments changed. The best charge transfer ratio was found with the largest dendrite membrane resistance, and the maximum efficiency of synaptic activity appeared at the original size of the dendrite segment stimulated. The amount of current that flowed in the proximal and distal directions from the segment stimulated depended on the diameter of that segment. The increase in diameter of proximal dendrites increased synaptic efficiency on distal dendrites, whereas the reverse caused a decline in synaptic efficiency on proximal dendrites. In addition to the diameter of dendrites, the arborization pattern also played a significant role in this mechanism. It is concluded that the cellulipetal increase in dendrite diameter greatly increases synaptic efficiency.
Tárgyszavak:Orvostudományok Természettudományok Biológiai tudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
egyetemen (Magyarországon) készült közlemény
Megjelenés:European Journal Of Neuroscience. - 4 : 11 (1992), p. 1013-1021. -
További szerzők:Birinyi András (1960-) (anatómus, neurobiológus) Székely György (1926-2017) (neurobiológus)
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
DOI
Borító:
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