Ultrastructure of giant and small thalamic terminals of cortical origin: a study of the projections from the barrel cortex in mice using Phaseolus vulgaris leuco-agglutinin (PHA-L)

Détails

ID Serval
serval:BIB_41699A368ED4
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Ultrastructure of giant and small thalamic terminals of cortical origin: a study of the projections from the barrel cortex in mice using Phaseolus vulgaris leuco-agglutinin (PHA-L)
Périodique
Experimental Brain Research
Auteur(s)
Hoogland  P. V., Wouterlood  F. G., Welker  E., Van der Loos  H.
ISSN
0014-4819 (Print)
Statut éditorial
Publié
Date de publication
1991
Volume
87
Numéro
1
Pages
159-72
Notes
Journal Article
Research Support, Non-U.S. Gov't
Résumé
By means of tracing with the lectin Phaseolus-vulgaris leucoagglutinin (PHA-L), we examined in the thalamus of the mouse, the axon terminals of fibers originating in the barrel cortex. Vibratome sections of the brain were subjected to PHA-L immunocytochemistry and processed for light and electron microscopy. We observed small (0.5-0.8 microns in diameter) varicosities of labeled fibers in the nucleus ventrobasalis (VB) and the nucleus posterior (PO) as well as labeled giant terminals (3-5 microns in diameter) in PO. The analysis involved examination of serial sections and computer-aided reconstruction of several terminals. The small varicosities in VB appear to be small axon terminals forming distinct asymmetric synapses with small dendritic profiles. Some labeled terminals are apposed to, but not synaptically related with, the cell bodies of neurons in VB that are retrogradely labeled with PHA-L. The small varicosities seen with the light microscope in PO are terminals forming asymmetric synapses with dendritic shafts. The giant terminals in PO appear as large, vesicle-filled profiles forming part of synaptic glomeruli, i.e. complexes of one corticothalamic terminal engulfing several excrescences of a single dendrite. A giant terminal forms several asymmetric synapses (about 8) with these excrescences, as well as numerous (up to 15) puncta adhaerentia. The glomeruli are enveloped in glial lamellae, and they are often found at the bifurcations of primary dendritic segments. We suggest that the small terminals in VB are in the service of feedback signalling from the barrel cortex to its principal thalamic relay nucleus; the functional importance of this projection may reside in increased spatio-temporal discrimination. We interpret the giant terminals in PO as elements serving feed-forward processing, allowing the barrel cortex to influence, via PO, parts of the motor pathway modulating the animal's ongoing behavior.
Mots-clé
Animals Axonal Transport Axons/*ultrastructure Cerebral Cortex/anatomy & histology/*ultrastructure Female Immunohistochemistry Mice Mice, Inbred BALB C/*anatomy & histology Microscopy, Electron Microscopy, Immunoelectron Models, Neurological Nerve Endings/*ultrastructure Phytohemagglutinins Somatosensory Cortex/anatomy & histology/*ultrastructure Thalamus/anatomy & histology/*ultrastructure
Pubmed
Web of science
Création de la notice
24/01/2008 15:41
Dernière modification de la notice
03/03/2018 16:33
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