A growth cone is a large actin-supported extension of a developing or regenerating neurite seeking its synaptic target. It is the growth cone that drives axon growth. Their existence was originally proposed by Spanish histologist Santiago Ramón y Cajal based upon stationary images he observed under the microscope. He first described the growth cone based on fixed cells as "a concentration of protoplasm of conical form, endowed with amoeboid movements" (Cajal, 1890). Growth cones are situated on the tips of neurites, either dendrites or axons, of the nerve cell. The sensory, motor, integrative, and adaptive functions of growing axons and dendrites are all contained within this specialized structure.
The morphology of the growth cone can be easily described by using the hand as an analogy. The fine extensions of the growth cone are pointed filopodia known as microspikes. The filopodia are like the "fingers" of the growth cone; they contain bundles of actin filaments (F-actin) that give them shape and support. Filopodia are the dominant structures in growth cones, and they appear as narrow cylindrical extensions which can extend several micrometres beyond the edge of the growth cone. The filopodia are bound by a membrane which contains receptors, and cell adhesion molecules that are important for axon growth and guidance.
In between filopodia—much like the webbing of the hands—are the "lamellipodia". These are flat regions of dense actin meshwork instead of bundled F-actin as in filopodia. They often appear adjacent to the leading edge of the growth cone and are positioned between two filopodia, giving them a "veil-like" appearance. In growth cones, new filopodia usually emerge from these inter-filopodial veils.
The growth cone is described in terms of three regions: the peripheral (P) domain, the transitional (T) domain, and the central (C) domain. The peripheral domain is the thin region surrounding the outer edge of the growth cone. It is composed primarily of an actin-based cytoskeleton, and contains the lamellipodia and filopodia which are highly dynamic.
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.
The course introduces students to a synthesis of modern neuroscience and state-of-the-art data management, modelling and computing technologies with a focus on the biophysical level.
The goal of the course is to guide students through the essential aspects of molecular neuroscience and neurodegenerative diseases. The student will gain the ability to dissect the molecular basis of
La neuroregénération est le renouvellement des neurones (uniquement artificiel dans toutes les zones du cerveau exceptés la zone sous-ventriculaire de l'hippocampe et le striatum chez l'homme et la plupart des autres mammifères), leur réparation ou la repousse du tissus nerveux (axones et synapses), endommagés par exemple par une maladie neurodégénérative, l'absence de sommeil, ou un neurotoxique. Les blessures du système nerveux affectent plus de par année, dont à la moelle épinière.
thumb|400px|Synapse entre deux neurones. La synapse (du grec , « contact, point de jonction », dérivé de , « joindre, connecter ») est une zone de contact fonctionnelle qui s'établit entre deux neurones, ou entre un neurone et une autre cellule (cellules musculaires, récepteurs sensoriels...). Elle assure la conversion d'un potentiel d'action déclenché dans le neurone présynaptique en un signal dans la cellule postsynaptique. On estime, pour certains types cellulaires (par exemple cellule pyramidale, cellule de Purkinje.
Le guidage axonal est une branche du neurodéveloppement. Elle étudie comment les axones parviennent à trouver leurs cellules cibles notamment grâce aux cônes de croissance. Le principe élémentaire du guidage axonal repose sur la chemoattraction et la chemorepulsion : Le cône de croissance est attiré par des molécules présentes dans le milieu extracellulaire et sécrétées par les cellules de sa zone de destination (ex: des facteurs de croissance).
Explore la réaction du corps étranger aux interfaces neurales et l'impact sur la performance de l'implant.
Explore la rigidité de flexion des interfaces neurales douces, y compris les axones et les sondes pénétrantes, avec des modèles géométriques idéaux et des gammes de modules élastiques.
Explore les composants du cytosquelette cellulaire, y compris les filaments d'actine et les microtubules, et discute de la dynamique moléculaire sans solvant et des simulations de Monte Carlo.
Here, we show that, in the developing spinal cord, after the early Wnt-mediated Tcf transcription activation that confers dorsal identity to neural stem cells, neurogenesis redirects beta-catenin from the adherens junctions to the nucleus to stimulate Tcfo ...
Spinal cord injury (SCI) interrupts axonal connections between the brain and the spinal cord, and is characterized by a spectrum of sensorimotor and autonomic impairments. While spontaneous recovery is limited, recent studies have shown that functional imp ...
The establishment of neuronal circuits requires neurons to develop and maintain appropriate connections with cellular partners in and out the central nervous system. These phenomena include elaboration of dendritic arborization and formation of synaptic co ...