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001-es BibID:	BIBFORM033406
035-os BibID:	WOS:A1994PP97600012 PMID:7850026
Első szerző:	Kisvárday Zoltán (biológus, neurobiológus)
Cím:	Relationship between lateral inhibitory connections and the topography of the orientation map in cat visual cortex / Zoltán F. Kisvárday, Dae-Shik Kim, Ulf T. Eysel, Tobias Bonhoeffer
Dátum:	1994
ISSN:	0953-816X
Megjegyzések:	The functional and structural topography of lateral inhibitory connections was investigated in visual cortical area 18 using a combination of optical imaging and anatomical tracing techniques in the same tissue. Orientation maps were obtained by recording intrinsic signals in regions of 8.4-19 mm(2). To reveal the inhibitory connections provided by large basket cells, biocytin was iontophoretically injected at identified orientation sites guided by the pattern of surface blood vessels. The axonal and dendritic fields of two retrogradely labelled large basket cells were reconstructed in layer III. Their axonal fields extended up to 1360 mu m from the parent somata. In addition to single basket cells, the population of labelled basket cell axons was also studied. For this analysis anterogradely labelled basket axons running horizontally over 460-1280 mu m from the core of an injection site in layer III were taken into account. The distribution of large basket cell terminals according to orientation preferences of their target regions was quantitatively assessed. Using the same spatial resolution as the orientation map, a frequency distribution of basket cell terminals dependent on orientation specificity could be derived. For individual basket cells, the results showed that, on average, 43% of the terminals provided input to sites showing similar orientation preferences (+/-30 degrees) to those of the parent somata. About 35% of the terminals were directed to sites representing oblique-orientation [+/-(30-60)degrees], and 22% of them terminated at cross-orientation sites [+/-(60-90)degrees]. Furthermore, the possible impact of large basket cells on target cells at different distances and orientation preferences was estimated by comparing the occurrence of orientation preferences with the occurrence of basket terminals on the distance scale. It was found that a basket cell could elicit iso-orientation inhibition with a high impact between 100-400 and 800-1200 mu m, strong cross-orientation inhibition at similar to 400-800 mu m, and oblique-orientation inhibition between 300-500 and 700-900 mu m from the parent soma. The non-isotropic topography of large basket axons suggests a complex function for this cell class, possibly including inhibition related to orientation and direction selectivity depending on the location of the target cells and possible target selectivity.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	European Journal Of Neuroscience. - 6 : 10 (1994), p. 1619-1632. -
További szerzők:	Kim, Dae-Shik Eysel, Ulf T. Bonhoeffer, Tobias
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
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001-es BibID:	BIBFORM033439
Első szerző:	Kisvárday Zoltán (biológus, neurobiológus)
Cím:	Functional topography of horizontal neuronal networks in cat visual cortex (area 18) / Kisvárday Zoltán F., Bonhoeffer Tobias, Kim Dae-Shik, Eysel Ulf T.
Dátum:	1996
ISBN:	0-444-82046-9
Tárgyszavak:	Orvostudományok Elméleti orvostudományok könyvfejezet
Megjelenés:	Brain Theory - Biological basis and computational principles / eds. Aertsen, A., Braitenberg, V. - p. 97-122. -
További szerzők:	Bonhoeffer, Tobias Kim, Dae-Shik Eysel, Ulf T.
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM033353
Első szerző:	Yousef, Tagrid
Cím:	Orientation topography of layer 4 lateral networks revealed by optical imaging in cat visual cortex (area 18) / Tagrid Yousef, Tobias Bonhoeffer, Dae-Shik Kim, Ulf T. Eysel, Éva Tóth, Zoltán F. Kisvárday
Dátum:	1999
ISSN:	0953-816X
Megjegyzések:	The functional specificity of corticocortical connections with respect to the topography of orientation selectivity was studied by optical imaging of intrinsic signals and bulk injections of fluorescent latex beads (green and red) and biocytin into layer 4. The distributions of retrogradely labelled cells and anterogradely labelled axon terminals were histologically reconstructed from all cortical laminae, and the resulting anatomical maps compared with the optically imaged functional maps. Layer 4 injections produced extensive horizontal labelling up to 2-3 mm from the injection centres albeit without the clear patchy pattern described after layer 2/3 injections (Gilbert & Wiesel 1989, J. Neurosci., 9, 2432-2442; Kisvárday et al. 1997, Cerebral Cortex, 7, 605-618). The functional (orientation) distribution of the labelled projections was analysed according to laminar location and lateral spread. With regard to the former, no major difference in the orientation topography between supragranular- (upper tier), granular- (middle tier) and infragranular (lower tier) layers was seen. Laterally, proximal and distal projections were distinguished and further dissected into three orientation categories, iso- (+/- 30 degrees ), oblique- (+/- 30-60 degrees ) and cross-orientations (+/- 60-90 degrees ) with respect to the orientation preference at the injection sites. The majority of distal connections (retrograde and anterograde) was equally distributed across orientations (35.4% iso-, 33.7% oblique-, and 30.9% cross-orientations) that are equivalent with a preponderance to dissimilar orientations (oblique- and cross-orientations, 64.6%). In one case, distal excitatory and inhibitory connections could be morphologically distinguished. For both categories, a marked bias to dissimilar orientations was found (excitatory, 63.7%; inhibitory, 86.6%). Taken together, these results suggest that the long-range layer 4 circuitry has a different functional role from that of the iso-orientation biased (52.9%, Kisvárday et al. 1997, Cerebral Cortex, 7, 605-618) layer 2/3 circuitry, and is perhaps involved in feature difference-based mechanisms, e.g. figure ground segregation.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	The European Journal of Neuroscience. - 11 : 12 (1999), p. 4291-4308. -
További szerzők:	Bonhoeffer, Tobias Kim, Dae-Shik Eysel, Ulf T. Tóth Éva Kisvárday Zoltán (1957-) (biológus, neurobiológus)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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