Interplay between laminar specificity and activity-dependent mechanisms of thalamocortical axon branching.

Full Abstract

Target and activity-dependent mechanisms of axonal branching were studied in the thalamocortical (TC) projection using organotypic cocultures of the thalamus and cortex. TC axons were labeled with enhanced yellow fluorescent protein (EYFP) by a single-cell electroporation method and observed over time by confocal microscopy. Changes in the firing activity of cocultures grown on multielectrode dishes were also monitored over time. EYFP-labeled TC axons exhibited more branch formation in and around layer 4 of the cortical explant during the second week in vitro, when spontaneous firing activity increased in both thalamic and cortical cells. Time-lapse imaging further demonstrated that branching patterns were generated dynamically by addition and elimination with a bias toward branch accumulation in the target layer. To examine the relationship between neural activity and TC branch formation, the dynamics of axonal branching was analyzed under various pharmacological treatments. Chronic blockade of firing or synaptic activity reduced the remodeling process, in particular, branch addition in the target layer. However, extension of branches was not affected by this treatment. Together, these findings suggest that neural activity can modify the molecular mechanisms that regulate lamina-specific TC axon branching.

Author information

Author/s: Uesaka, Naofumi (N); Hayano, Yasufumi (Y); Yamada, Akito (A); Yamamoto, Nobuhiko (N);

Affiliation: Neuroscience Laboratories, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience (J Neurosci), published in United States. (Language: eng)

Reference: 2007-May; vol 27 (issue 19) : pp 5215-23

Dates: Created 2007/05/14; Completed 2007/06/22;

PMID: 17494708, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Action Potentials - physiology
Animals
Animals, Newborn
Bacterial Proteins - genetics
Cell Communication
Cell Differentiation - physiology
Cells, Cultured
Cerebral Cortex - cytology; embryology; physiology
Coculture Techniques
Cues
Electroporation
Excitatory Amino Acid Antagonists - pharmacology

Growth Cones - physiology; ultrastructure
Luminescent Proteins - genetics
Microscopy, Confocal
Neural Pathways - cytology; embryology; physiology
Neuronal Plasticity - drug effects; physiology
Organ Culture Techniques
Rats
Rats, Sprague-Dawley
Sodium Channel Blockers - pharmacology
Staining and Labeling - methods
Synaptic Transmission - drug effects; physiology
Thalamus - cytology; embryology; physiology

Associated Chemicals: Bacterial Proteins (0) ; Excitatory Amino Acid Antagonists (0) ; Luminescent Proteins (0) ; Sodium Channel Blockers (0) ; yellow fluorescent protein, Bacteria (0)

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