Download Neuroscience 5e

2016-01-10
신경발생 (Development of nervous system)
Neurulation (I)
•
Surface ectoderm
: Neural plate  Neural fold  Neural tube
1
2016-01-10
Neurulation (II)
•
•
•
Neural plate (신경판)
Neural fold (신경주름)
Neural tube (신경관)
•
•
•
•
Surface ectoderm
Neural groove (신경고랑)
Neural crest (신경능선)
Notochord (척삭)
Neurulation in the mammalian embryo
2
2016-01-10
The neural crest
Initial migratory route of
undifferentiated neural
crest cell
1.2, senosry & autonomic ganglions
3, adrenal medulla, melanocyte
4, sensory endings
Regional specification of the developing brain
3 flexure
1. Cephalic
2. Cervical
3. Pontine
3
2016-01-10
Sequential gene expression divides the embryo into regions and segments
Bicoid: anterior pole
Kruppel: ant-post axis
Hairy: mature segmented body
Wingless: individual segment
Hox genes (from an abbreviation of homeobox) are a group of related genes that control
the body plan of the embryo along the anterior-posterior (head-tail) axis
Spinal cord
•
•
•
Neuroepithelial layer
Mantle layer
Marginal layer
•
•
Roof plate
Alar plate
– Dorsal, posterior horn
Sulcus limitans
Basal plate
– Ventral, anterior horn
Floor plate
•
•
•
4
2016-01-10
Myelencephalon (숨뇌)
Metencephalon (뒤뇌)
소뇌
5
2016-01-10
Cerebellum (소뇌)
External granular layer
- 발생과정의 일과성 층
- 분열능력
- 생성된 세포는 속질로 이동
 과립층 형성
Mesencephalon (중간뇌)
6
2016-01-10
Diencephalon (사이뇌)
•
•
•
Basal plate: 퇴화
Roof plate: 송과체
Alar plate: 시상, 시상하부
Telencephalon (끝뇌)
•
•
•
대뇌반구: 가쪽벽의 팽대
줄무늬체
: 대뇌반구의 바닥부분
해마: 맥락틈새의 위
LGE
; Lateral Ganglionic Eminence
MGE
; medial ganglionic eminence
7
2016-01-10
Major inductive signaling pathways in vertebrate embryos
Cell lineage of developing CNS
8
2016-01-10
Neurogenesis: Where, When, and What
Where
When
Birthdate
Lineage
brdU
What
Differentiation
Acquire specific phenotypic or
molecular features
; specific identity of any
neurons
Regulation of
spinal cord development
•
•
SHH (sonic hedgehog)
BMP (bone morphogenetic
protein)
9
2016-01-10
Developmental property of OLG
•
OLG originates in a specialized
domain of the ventral ventricular
zone (VZ) in spinal cord
– Shh (Sonic Hedgehog)
– BMP (Bone Morphogenetic
protein)
D
V
Neural precursor cells undergo mitosis within the ventricular zone
Symmetric division
Asymmetric division
Red line: vertically oriented division
Dash line: ventricular surface
Arrows: radial process of cells
The radial processes are
retained once the cell has
divided
10
2016-01-10
Generation of cortical neurons
Inside first outside last
Delta-Notch signaling leads to neuronal differentiation
Delta binding cleavage
NICD
NICD translocation to nucleus
Binds to RBP-J
Activates bHLH
A stochastic increase in Delta ligands on a
particular cell leads to downregulation of Delth
in neighboring cells, while in the Deltaincreasing cell, bHLH gene expression is also
increased, and the cell becomes primed for
neuronal differentiation
11
2016-01-10
Molecular and cellular mechanisms that guide neuronal and glial differentiation
Migration and differentiation of the neural crest relies on regulation of gene expression and cell–cell
signaling
Neural crest+ cell
12
2016-01-10
Radial glia guide migrating neurons
Radially: arrows
Non-radially: *
Mixing it up: Long-distance neuronal migration
At first: Position was destiny
Laterly: Adult brain structures might be derived from a
broad range of embryonic brain subdivision
Radial
Tangential: GABAergic interneuron
but some GABAergic interneuron also are
genereated in the cortical rudiment
Cortical migration disorders: infant spasm
1. Reelin
2. DCX (doublecortin)
3. neuregulin, NCAM, DISC1-psychiatric disease
13
2016-01-10
Radial migration in the developing cortex
Axon growth and Guidance
Grasshopper
1.Ti1 Pioneer is aided by
guidespot or stepping stone cells
14
2016-01-10
The structure and action of growth cones
F-Actin : red
Microtubule: green; Lamellipodium
Filopodium
G-actin can be incorporated into Factin at the leading edge of
filopodium in response to atractive
cues.
Repulsive cues support
disassembly and retrograde flow of
G-actin toward the lamellipodium
By Ca via voltage-regulated Ca
channels as well as TRP channels
Several families of ligands and receptors constitute the major classes of axon guidance molecules
15
2016-01-10
Signals provided by the embryonic environment
Chemoattraction
Chemorepulsion
Growth cone-collapsing activity of semaphorin
depends on Ca signaling
Target-derived trophic support regulates survival of related neurons
16
2016-01-10
Hebb’s postulate and the development of synaptic inputs
Strenthening of synapse
Winner-takes-all”
The human brain changes significantly during postnatal life
17
2016-01-10
Birdsong
Foreing languate
In fact, many learned behaviors
are acquired during a critical
period in early life when
experence exerts an especially
potent influence on subseqent
behavior.
The sensitive period for song
learning
In short, intrinsic factors make
the nervous system of oscine
brids especially sensitive to
songs that are species-typical.
Similar biases may influence
human language learning.
Figure 24.11 Learning language
18
2016-01-10
19