Linked Life Data

10096608

Source:http://linkedlifedata.com/resource/pubmed/id/10096608

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1999-5-4
pubmed:abstractText
The pulvinar nucleus is a major source of input to visual cortical areas, but many important facts are still unknown concerning the organization of pulvinocortical (PC) connections and their possible interactions with other connectional systems. In order to address some of these questions, we labeled PC connections by extracellular injections of biotinylated dextran amine into the lateral pulvinar of two monkeys, and analyzed 25 individual axons in several extrastriate areas by serial section reconstruction. This approach yielded four results: (1) in all extrastriate areas examined (V2, V3, V4, and middle temporal area [MT]/V5), PC axons consistently have 2-6 multiple, spatially distributed arbors; (2) in each area, there is a small number of larger caliber axons, possibly originating from a subpopulation of calbindin-positive giant projection neurons in the pulvinar; (3) as previously reported by others, most terminations in extrastriate areas are concentrated in layer 3, but they can occur in other layers (layers 4,5,6, and, occasionally, layer 1) as collaterals of a single axon; in addition, (4) the size of individual arbors and of the terminal field as a whole varies with cortical area. In areas V2 and V3, there is typically a single principal arbor (0.25-0.50 mm in diameter) and several smaller arbors. In area V4, the principal arbor is larger (2.0- to 2.5-mm-wide), but in area MT/V5, the arbors tend to be smaller (0.15 mm in diameter). Size differences might result from specializations of the target areas, or may be more related to the particular injection site and how this projects to individual cortical areas. Feedforward cortical axons, except in area V2, have multiple arbors, but these do not show any obvious size progression. Thus, in areas V2, V3, and especially V4, PC fields are larger than those of cortical axons, but in MT/V5 they are smaller. Terminal specializations of PC connections tend to be larger than those of corticocortical, but the projection foci are less dense. Further work is necessary to determine the differential interactions within and between systems, and how these might result in the complex patterns of suppression and enhancement, postulated as gating mechanisms in cortical attentional effects, or in different states of arousal.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9967
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
406
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
221-50
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Single axon analysis of pulvinocortical connections to several visual areas in the macaque.
pubmed:affiliation
Department of Neurology, University of Iowa, Iowa City 52242-1053, USA. rockland@blue.weeg.uiowa.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.