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Membrane-associated molecules guide limbic and nonlimbic thalamocortical projections
F Mann1, V Zhukareva, A Pimenta
1Institut National de la Santé et de la Recherche Médicale, Unité 371, Cerveau et Vision, 69500 Bron, France.
Summary
Limbic system-associated membrane protein (LAMP) guides developing thalamocortical axons. Different thalamic fiber populations exhibit distinct responses to LAMP, with limbic axons preferring it and nonlimbic axons being repelled, ensuring precise projection targeting.
Area of Science:
- Neuroscience
- Developmental Biology
- Molecular Biology
Background:
- Thalamocortical projections form precisely during development.
- Membrane-associated signals in the developing cerebral cortex may guide axon target recognition.
Purpose of the Study:
- To investigate the role of membrane-associated signals in thalamocortical axon guidance.
- To test the hypothesis that limbic system-associated membrane protein (LAMP) mediates selective axon targeting.
Main Methods:
- Analyzing thalamic explant outgrowth on cortical membrane substrates.
- Using recombinant LAMP (rLAMP) in stripe assays.
- Employing antibodies against LAMP to block its function.
Main Results:
- Thalamic fibers discriminated between target and non-target cortical membranes.
- Limbic thalamic and cortical axons preferred rLAMP.
- Nonlimbic thalamic axons were repelled by rLAMP, inhibiting branch formation.
- Anti-LAMP antibodies blocked the discriminatory ability of limbic thalamic fibers.
Conclusions:
- LAMP acts as a selective guidance cue in the developing thalamocortical system.
- LAMP mediates differential responses in limbic versus nonlimbic thalamic axons.
- These findings elucidate molecular mechanisms of precise neural circuit formation.