Blockade of action potential activity alters initial arborization of thalamic axons within cortical layer 4.
AUTOR(ES)
Herrmann, K
RESUMO
In the formation of connections during the development of the nervous system, it is generally accepted that there is an early phase not requiring neural activity and a later activity-dependent phase. The initial processes of axonal pathfinding and target selection are not thought to require neural activity, whereas the later fine-tuning of connections into their final adult patterns does. We report an apparent exception to this rule in which action potential activity seems to be required very early in development for thalamic axons to form appropriate patterns of terminal arborizations with their ultimate target neurons in layer 4 of the cerebral cortex. Blockade of sodium action potentials during the 2-week fetal period when visual thalamic axons initially grow into the primary visual cortex in cats prevents the normally occurring branching of lateral geniculate nucleus axons within layer 4. This observation implies a role for action-potential activity in cerebral cortical development far earlier than previously suspected, weeks before eye-opening and the onset of the well-known process of activity-dependent reorganization of axonal terminal arbors that leads to the formation of ocular dominance columns.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=40608Documentos Relacionados
- Coupling of the cortical hemodynamic response to cortical and thalamic neuronal activity
- Perinatal development of action potential propagation in cat rubrospinal axons.
- Hyperglycaemic hypoxia alters after-potential and fast K+ conductance of rat axons by cytoplasmic acidification.
- Action potential propagation and threshold parameters in inhomogeneous regions of squid axons.
- Palmitoylation alters protein activity: blockade of G(o) stimulation by GAP-43.