Wilson presentation

Human Brain Development *Neural Tube Formation

*Brain Growth

*Synapse Formation

By Cheryl Wilson, Belmont High School

http://commons.wikimedia.org/wiki/File:Neuron_with_mHtt_inclusion.jpg

QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.


http://commons.wikimedia.org/wiki/File:Brain_090407.jpg

QuickTime™ and aTIFF (Uncompressed) decompressor

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http://en.wikipedia.org/wiki/Brain_development






http://commons.wikimedia.org/wiki/File:Fetus.jpg

1. Neural Tube Formation-induction, proliferation & shape changes

2. Brain Formation-Proliferation, differentiation & migration




QuickTime™ and a decompressor


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Life Sciences-HHMI Outreach. Copyright 2009 President and Fellows of Harvard College.



3. Wiring the Brain & Nervous SystemEach neuron, once in place, must send axon connections to exactly the correct target!

http://upload.wikimedia.org/wikipedia/commons/b/ba/Nervous_system_diagram.png



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White matter-neuronal axon (connections)

Gray matter-neuronal cell bodies (brownish when fixed)

Some neurons have axons 3 feet long!!!

Finding the proper target to make a connection with is a highly complex process!

http://commons.wikimedia.org/wiki/File:Complete_neuron_cell_diagram_en.svg

Growth, differentiation, development and normal functioning of the nervous system (like all organ systems) requires:

Correct Gene Expression at the Correct Time and Place.

Early Neural CrestNeural Tube

Neural Crest

Neural Tube

Skin

Body Cavity

Neural Tube

Neural CrestCentral Canal

Neural Tube Formation in the Human Embryo-Cross Section

Ectoderm

Mesoderm

Endoderm

Neural Plate

Neural Fold

Notochord & Somites

Neural Groove


Cephalic End

Caudal End

Neural Tube (neurons and glia)



http://en.wikipedia.org/wiki/Brain_developmentLife Sciences-HHMI Outreach. Copyright 2009 President and Fellows of Harvard College.

Central Canal (will be spinal canal and ventricles)

Longitutinal Cross Section of Early Embryo



http://commons.wikimedia.org/wiki/File:Encephalon.pngand edited by CW

http://commons.wikimedia.org/wiki/File:4_week_embryo_brain.jpg

The 3-Vesicle Stage of Embryonic Brain Development


http://commons.wikimedia.org/wiki/File:Encephalon.png



http://commons.wikimedia.org/wiki/File:6_week_embryo_brain.jpghttp://commons.wikimedia.org/wiki/File:Encephalon.png



Mylencephalon

Metencephalon

and edited by CW

The 5-Vesicle Stage of Embryonic Brain Development




http://upload.wikimedia.org/wikipedia/en/1/1b/Development_of_nervous_system.pngand edited by CW





1. Neural Tube Formation

2. Brain Formation

3. Wiring the Brain & Nervous System


http://commons.wikimedia.org/wiki/File:Brain_bulbar_region.svg

Overview of Brain Development





http://upload.wikimedia.org/wikipedia/en/1/1b/Development_of_nervous_system.png

Cephalic End

Caudal End

Neural Tube (neurons and glia)

Neural Tube Cross-Section



http://en.wikipedia.org/wiki/Brain_developmentLife Sciences-HHMI Outreach. Copyright 2009 President and Fellows of Harvard College.

Central Canal (will be spinal canal and ventricles)

Cut

Longitutinal Cross Section of Early Embryo

Inside Out Brain Growth in the Human Embryo-

Neural Tube (early CNS)Central Canal (early spinal cord or brain ventricles)

Most neurons migrate radially from the ventricular zone towards the marginal zone, following glial cell fibers.

The next wave of migrating neurons goes past the previously-settled cells.

Again.

Again.

Again.

Neurons proliferate on the ventricular side of the neural tube Neurons migrate towards the marginal side in waves Each wave of neurons travel past the earlier layers

Ventricular zone (inner)

Marginal zone (outer)




http://en.wikipedia.org/wiki/Brain_developmentWith labelling by CW


1. Ventricular zone-Where proliferation/cell division occurs

2. Cells migrate past the last wave of cells to deposit

3. Once neurons have reached their final destination, they must now send out their axons to make connections with the correct target and be responsive to receive the correct signals.

Correct temporal-spatial gene expression is critical for the correct neurons to find each other!




http://commons.wikimedia.org/wiki/File:Gray754.pngLife Sciences-HHMI Outreach. Copyright 2009 President and Fellows of Harvard College.

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Wilson presentation