Table of Contents
Development of the Central Nervous System
PPT Slide
PPT Slide
PPT Slide
PPT Slide
Lineage: The extent to which the characteristics of cells or groups of cells are determined by cell lineage -- genetics. Commitment: The extent to which cell characteristics are determined by environment.
PRODUCTIVE EVENTS
SUBTRACTIVE EVENTS
NEURAL PLATE -- Three Layers:
NEURAL PLATE Three Layers: Endoderm, Mesoderm, Ectoderm
The Development of the Neural Tube
DEVELOPMENTAL CHANGES IN THE PRENATAL BRAIN
STAGES OF NEURONAL DEVELOPMENT
PROLIFERATION
NEURONS AND GLIA ARE PRODUCED IN THE “PROLIFERATIVE ZONE”
A CROSS-SECTION OF THE PROLIFERATIVE ZONE
A SINGLE CELL UNDERGOING CELL DIVISION
NEURONS AND GLIA ARE PRODUCED IN THE “PROLIFERATIVE ZONE” (continued)
NEURONS AND GLIA ARE PRODUCED IN THE “PROLIFERATIVE ZONE” (continued)
TWO MODES OF NEURONAL CELL MIGRATION
TWO MODES OF NEURONAL CELL MIGRATION (contintued)
Neuron Migrating along a Radial Glial Cell
THE RADIAL UNIT HYPOTHESIS: The Radial Unit Hypothesis: Each proliferative unit produces all the neurons in a single cortical column. But there are different kinds of neurons within a single cortical column. How can DIFFERENT kinds of cells be produced from the same progenitor cells at different points in time. Some kind of external signal (not yet specified) tells the progenitors in a given region of the neural tube to start producing one kind of cell or another.
ILLUSTRATION OF THE RADIAL UNIT HYPOTHESIS
CELL DIFFERENTIATION
Subtractive Events in Brain Development: Naturally Occurring Cell Death
Natually Occurring Cell Death
Experimental Evidence that Resources Affect Rate of Cell Death
Subtractive Events in Brain Development: Synaptic Exuberance and Synapse Retraction
Subtractive Events in Brain Development: Synaptic Exuberance and Synapse Retraction (continued)
EVIDENCE FOR THE ROLE OF INPUT ON THE DEVELOPMENT OF BRAIN PATHWAYS: “Rewired Ferrets”
EVIDENCE FOR THE ROLE OF INPUT ON THE DEVELOPMENT OF BRAIN PATHWAYS: “Rewired Ferrets” (continued)
EVIDENCE FOR THE ROLE OF INPUT ON THE DEVELOPMENT OF BRAIN PATHWAYS: An Example in Humans
EVIDENCE FOR THE ROLE OF INPUT ON THE DEVELOPMENT OF BRAIN PATHWAYS: An Example in Humans (continued)
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