CCL

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001-es BibID:BIBFORM033346
Első szerző:Kisvárday Zoltán (biológus, neurobiológus)
Cím:Orientation-specific relationship between populations of excitatory and inhibitory lateral connections in the visual cortex of the cat / Zoltán F. Kisvárday, Éva Tóth, Martin Rausch, Ulf T. Eysel
Dátum:1997
ISSN:1047-3211
Megjegyzések:The topography of lateral excitatory and lateral inhibitory connections was studied in relation to orientation maps obtained in areas 17 and 18. Small iontophoretic injections of biocytin were delivered to the superficial layers in regions where orientation selectivity had been mapped using electrode recordings of single- and multi-unit activity from various cortical depths. Biocytin revealed extensive patchy axonal projections of up to 3.5 mm in both areas while labelled somata occurred chiefly at the injection site, indicating that the labelling was primarily anterograde. Two types of boutons could be clearly distinguished: (i) putative excitatory boutons either en passant or having a short stalk and (ii) inhibitory boutons which were invariably of the basket-type. Three-dimensional reconstructions of all labelled boutons showed that the excitatory and the inhibitory networks had a distinctively different relationship to orientation maps. The overall distribution of connections showed that 53-59% of excitatory and 46-48% of inhibitory connections were at iso-orientation, +/-30 degrees; oblique-orientation, +/-(30-60) degrees, was shown by 30% of excitatory and 28-39% of inhibitory connections; cross-orientation was shown by 11-17% of excitatory and 15-24% of inhibitory connections. Although excitatory patches occupied mainly iso-orientation locations, interpatch regions representing chiefly non-iso-orientations (oblique + cross orientation) were also innervated. There was considerable overlap between the excitatory and inhibitory network. Nonetheless, inhibitory connections were more common than excitatory connections with non-iso-orientation locations. There was no significant difference between the orientation topography of area 17 and area 18 projections. The results suggest that in general the lateral connectivity system is not orientation specific, but shows a moderate iso-orientation preference for excitation and an even weaker iso-orientation preference for inhibition. The broad orientation spectrum of lateral connections could provide the basis for mechanisms that requiring different orientations, as for example in detecting orientation discontinuities.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
külföldön készült közlemény
Megjelenés:Cerebral Cortex. - 7 : 7 (1997), p. 605-618. -
További szerzők:Tóth Éva Rausch, Martin Eysel, Ulf T.
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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2.

001-es BibID:BIBFORM033347
Első szerző:Yousef, Tagrid
Cím:Topography of orientation centre connections in the primary visual cortex of the cat / Tagrid Yousef, Éva Tóth, Martin Rausch, Ulf T. Eysel, Zoltán F. Kisvárday
Dátum:2001
ISSN:0959-4965
Megjegyzések:The functional topography of lateral connections to orientation-centre zones was studied by optical imaging of intrinsic signals in combination with tracer injections (fluorescent beads and biocytin) and electrophysiological recordings. Three-dimensional reconstruction of anterogradely labelled axon terminals and retrogradely labelled somata revealed a uniform distribution across all orientations in a non-patchy manner. The overall lateral extent of the labelling was 3-4 mm in layer 3, that is about half of the extent observed for orientation domain connections in the same layer. These bulk injection data are in contrast with the reportedly sharp orientation tuning of neurons of centre zones and suggest that orientation specificity here does not require highly specific connections. Nonetheless, another plausible scenario is that orientation centre connections are orientation specific but their specificity present at the single cell level cannot be revealed by bulk labelling due to their large spatial overlap.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
külföldön készült közlemény
Megjelenés:Neuroreport. - 12 : 8 (2001), p. 1693-1699. -
További szerzők:Tóth Éva Rausch, Martin Eysel, Ulf T. Kisvárday Zoltán (1957-) (biológus, neurobiológus)
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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