development of the mammalian nervous system neu257 1-11-11
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Development of the mammalian nervous system
NEU257 1-11-11
-Thousands of cell types
-Trillions of synapses
-Precise connections
Cells & synapses Perception, cognition & behavior
-Billions of cells
Circuits
O’Conner, et al. Nature (2009)
Development sets the spatial and functional contraints that govern nervous system (dis)function
Disease
-within and between areas, structures, nuclei and layers
Approaches to study neural development
1. Descriptive ‘cellular events’A. Prepare tissue from different age specimens
B. Image the same specimen over time
2. Descriptive ‘molecular expression’
A. Protein expression: immunohistochemistry
B. mRNA expression: in situ hybridization
3. “Mechanistic” studies
C. Fate mapping
A. Ablation, transplants (swapping, adding cells/tissues)
B. Gene deletion, overexpression
1. Descriptive ‘cellular events’A. Prepare tissue from different age specimens
Mumm et al., Neuron (2008)
QuickTime™ and aSorenson Video 3 decompressorare needed to see this picture.
1. Descriptive ‘cellular events’B. Image the same specimen over time
Mumm et al., Neuron (2008)
Structures
1. Descriptive ‘cellular events’
C. Fate mapping
Cells
1. Descriptive ‘cellular events’C. Fate mapping
Price et al., JoVS (2009)
2. Descriptive ‘molecular expression’
A. Protein expression: immunohistochemistry
B. mRNA expression: in situ hybridization
Stacey and Wong, JCN (2003)
Shimogori and Grove, Nat Neurosci (2003)
3. “Mechanistic” studies
A. Ablation, transplants (swapping, adding cells or whole tissues)
Sadato labKrubitzer and Kaas, Curr Opin Neurobiol (2002)
B. gene deletion, overexpression3. “Mechanistic” studies
Shimogori and Grove, Nat Neurosci (2003)
The natural experiment of evolution
from: H. Karten
Establishing the raw materials
Cell divisions
Sperm meets egg...
Blastula (ball of cells)
Gastrula (conversion to 3 layers)
Ecto, endo, mesoderm
Nervous system, inner ear, eye
Musclesskeletongonads
circulatory system
liver, lungs, gut, GI tract
From a tri-laminar structure to a folded tube
Gilbert (Developmental Biology)
From a tri-laminar structure to a folded tube
Gilbert (Developmental Biology)
Neural plate, fold and tube in 3-dimensions
Gilbert (Developmental Biology)
Neural crest derivatives
Broad, early rostral-caudal regionalization of the neural plate
Rostral-caudal asymmetries in tube closure timing
Broad arealization of fore-, mid- and hindbrain and rhombomeres
Subdivisions of fore-, mid- and hindbrain, and spinal cord
Dorsal-ventral patterning of the spinal cord: sulcus limitans
Sulcus limitans: sensory versus motor
how far rostral? What does this mean about cortex?
Subdividing major structures into distinct circuits: genetic control: example: rhombomeres
Patterning the forebrain and spinal cord:similar themes
Cell division, migration and cortical expansion
Cell division, migration and cortical expansion
Birthdating (cellular fate mapping) in the neocortex“Inside-out” neurogenesis
Rakic
Tangential migration of interneurons from distant origins (in the same brain)
Combining approaches: molecular expression, fate mapping, anatomy and physiology
Miyoshi et al., J Neuroscience (2010)
Combining approaches: molecular expression, fate mapping, anatomy and physiology
Miyoshi et al., J Neuroscience (2010)
Connecting one area to the next
Axons in one brain area head toward their targets in another brain area via intermediate cues that can
be both attractive or repulsive
Once they find their targets, they know where to go within their targets according to gradients of
attractants and/or repellants
How they pick which overall targets or specific cells to connect to remains a mystery