Development of the Nervous System

Development of the Nervous System

1. Structure of a Neuron

   • MotorNeuron
   • Sensory Neuron
   • Interneuron

2. Steps in Neural Development

   • Specification and Regional Subdivision of the Neurectoderm
     • Specification and Segregation of Neural Progenitors
       • Proliferation and Migration of Neural Progenitors
         • Neural Differentiation: Axon Pathfinding
     • Neurectoderm formation and neurulation in mouse embryo
       • What is the role of SoxB Expression in Mouse embryos?
         • SoxB genes are expressed in discrete subsets of vertebrate placodes
       • Neurectoderm Formation
         • Neural Crest
           • Sensory Placodes
           • Hedgehog Signaling
             • Notch Signaling (N)
               • Loss of Notch Signaling causes what?
                 • causes hyperplasia- too much cell proliferation
               • Function of Notch Signaling pathway in the Neural Primordium
                 • Distinction between two states: 1) maintain epithelial phenotype and remain undifferentiated/proliferatory 2) delaminate and differentiate as neuron, or committed neural progenitor
         • Morphogenesis of the Vertebrate Spinal Cord
       • Anterior-Posterior Subdivisions of the Neural Tube
         • What controls the Hox Gene Expression?
           • Signals from the Organizer (dorsal mesoderm)
           • Ectopic Expression of Hoxb1
             • We see that when a hoxgene is placed in a different area of the hindbrain, we see the nerve going to that Hox gene's specific brachial arch
       • Longitudinal Subdivisons of the Neural Tube
         • What do the alar plate and basal plate form?
           • the alar plate forms the sensory center and interneurons the basal plate forms interneurons and motor neurons
       • Shh and BMP Gradient Specify Neuronal Fate along the DV axis
         • Higher concentration of Shh  at  the Ventral  End=creating of  floor plate, ventral interneurons, motor neurons Higher concentration of  BMP at  dorsal end=  dorsalinterneurons
         • BMP-->Class I /----Shh---> Class II and Class I /-----/Class II
         • Ventral Fate
           • higher concentration of Shh
             • Creation of Floor plate
             • Shh signaling in the forebrain
               • What happens when there is a lack of Shh signaling in the forebrain?
                 • Disorders such as Alobar Holoprosencephaly and Cyclopia
       • Neurulation in Vertebrate and Drosophila
       • Proneural Clusters and Lateral Inhibition
         • Proneural genes encode TF of the basic helix-loop-helix class which are responsible for the development of neuroectodermal progenitor cells. 
         • Functions of Proneural genes?
           • integrate positional info and contribute to the specification of progenitor-cell identity - from the same ectodermal cells, neural or epidermal cells can develop based on interactions between proneural and neurogenic genes
           • Why are neurogenic genes given their name?
             • because loss of function mutants show an increase number of developed neural precursors.  On the other hand, proneural gene mutants fail to develop neural precursor cells
         • Use a laser to ablate a neuroblast and you will see a new neuroblast in its place
           • Lateral inhibition cell signaling used to ensure enough neuroblasts are made but not too many are produced

Images and files in the map