Vertebrate Brain: Neuronal Differentiation & Migration, Axon Outgrowth, Synapse Formation, Study notes of Neurobiology

Download Vertebrate Brain: Neuronal Differentiation & Migration, Axon Outgrowth, Synapse Formation and more Study notes Neurobiology in PDF only on Docsity! Lecture 10 Neuronal Differentiation -> Cell Movement and Migration 1. Neuronal Differentiation General Cells stop dividing Axonal outgrowth begins Cells become electrically excitable (axon first then soma) Axons contact target area Axons chose specific site to synapse Synapse formation Modulation of synapse strength (experience controlled) Vertebrate brain Neuronal precursors crudely defined at ventricular zone Indeterminate lineage divisions give rise to variable progeny Neurons migrate out radial glia Late dividing cells migrate past early dividing cells: "inside-out" pattern Plasticity of transmitter choice in sympathetic ganglion cells Normally become adrenergic Plus heart conditioned medium - become cholinergic Intermediates express both transmitters Intrinsic neuron branching pattern tendencies. Sensory - unipolar; Motor neurons; multipolar; pyramidal cells - triangular cell bodies apical and basal dendrites 2. Cell Migration - Postmitotic neurons: recap basic features including migration and axon outgrowth - Cell migration: Neurons move from one location to another. - Axonogenesis: Neurons send out processes: dendrites and axons San Diego to LA on I-5 analogy - General processes: Intrinsic initial cell polarity (recently divided fibroblasts; grasshopper limb sensory neurons) Intrinsic neuron branching pattern tendencies Sensory -unipolar; Motor neurons; multipolar; pyramidal cells - triangular cell bodies apical and basal dendrites Chemo-attractants: (chemotaxis) Cell surface and cell matrix guidance cues/Adhesion molecules - Dissociation/reaggregation experiments - Expression and function of various cadherins (N and E in neural tube) Mechanism of directional movement - Cells typically follow several redundant cues: e.g., laminin, fibronectin, collagen etc. Cell culture experiments on ECM need to block with antibodies to several cues to block migration. Neural Crest: Between neural tube and somites –> track along fibronectin path In vitro: block with single N.C migration with single anti-Fibronectin Ab In vivo: block migration with anti-Fibronectin Ab injection. Control side fine.