Brain Development
93
Neural plate
Mesoderm
Neural ridge
(neural crest)
Notochord
Neurel crest cells
D
Epidermis
Somite
V
Endoderm
D
Roof plate
Alar plate
Sulcus limitans
Basal plate
Floor plate
V
D
Sensory inputs
White matter
Gray matter
Motor outputs
V
(a)
Cranial
Trunk
Pigment cells
Sensory neurons and glia
Sympathetic neurons
Adrenomedullary
and Schwann cells
Cartilage
and bone
Connective
tissue
Neurons and glia
of cranial ganglia
(b)
Normal condition
Notochord removed
Notochord grafted
Roof
plate
Roof
plate
Roof
plate
motor neurons
Floor plate
No motor
neurons
No floor plate
Ectopic
motor
neurons
Ectopic floor
plate
Grafted
notochord
Notochord
Notochord
(c)
Neural tube
Neurel tube
Fig. 3
Neurulation and D–V patterning of the neural tube. (a) Neurulation and D–V
patterning of the neural tube during vertebrate development. D, dorsal; V, ventral.
(b) Neural crest cells can differentiate into various cell types. Note that cranial neural
crest cells are different from trunk neural crest cells in generating a distinct set of cell
types
in vivo
. (c) The role of the notochord in the neural tube D–V patterning.
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