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Cell type Sensory Autonomic Schwann Pigment Smooth Neurons Neurons cells cells Muscle FIGURE 4.14 Different neural crest fates are promoted by a distinct set of extracellular signaling molecules. After Dorsky et al., 2000 Cell type Sensory Autonomic Schwann Pigment Smooth Neurons Neurons cells cells Muscle FIGURE 4.14 Different neural crest fates are promoted by a distinct set of extracellular signaling molecules. After Dorsky et al., 2000 mine them toward a sensory fate. It appears that the...

Dorsal Neural Tube And Neural Crest

Neural Tube Tion

The experiments of Harrison and others showed that removal of the notochord resulted in a neural tube without much dorso-ventral polarity. This implies that the dorsal neural tube is in some way the default condition, whereas the ventral structures require an additional signal to develop their fates. However, in the last few years it has become apparent that the dorsal neural tube also requires signals for its appropriate development. Before the neural tube closes, the future dorsal neural tube...

The Growth Cone

Ramon Cajal Growth Cone

Growth cones were recognized more than a hundred years ago by the famous Spanish neuro-anatomist, Ramon y Cajal, as expansions at the tips of axons in fixed embryonic material. He imagined the growth cone as a sort of soft battering ram that extending axons used to force their way through the packed cells of the embryonic brain Ramon y Cajal, 1890 Figure 5.6A . In 1910, Ross Harrison took pieces of embryonic neural tube and put them into tissue culture where he saw axons tipped with growth...

Conservation Of Neural Induction

Chordin Noggin Follistatin

Even more fascinating than the identification of three candidate neural-inducing factors in a relatively short period of time is that these three factors may all act by a related mechanism and that this mechanism appears to be at least partially conserved between ver FIGURE 1.21 Dissociation of animal cap cells prior to gastrula-tion causes most of them to differentiate into neurons in culture. Animal caps can be cultured intact left or dissociated into single cells by removing the Ca 2 ions...