Summary
Neurons are generated, migrate, extend axons and form synapses guided by chemical cues.
In depth
Neural tube forms from ectoderm; neurogenesis, migration, axon guidance by growth cones (netrins, semaphorins), synaptogenesis and pruning follow. Many neurons die by apoptosis, and use-dependent refinement shapes circuits in critical periods.
Activity-dependent refinement strengthens used synapses. Critical periods close when inhibition matures. Early deprivation has lasting effects.
Key idea: the brain is wired by genes and refined by experience.
Steps: neural induction (by organiser signals such as noggin and chordin inhibiting BMP), neural tube closure (failure causes spina bifida and anencephaly, reduced by folic acid), proliferation of progenitors, migration (radial glia guide neurons to build the cortex inside-out), differentiation, axon guidance (chemoattractants, repellents and contact cues), synapse formation, and refinement by activity-dependent pruning and apoptosis, with about half of neurons dying.
Critical periods: Hubel and Wiesel (Nobel Prize 1981) showed that covering one eye in kittens during a sensitive period caused permanent loss of vision in that eye (amblyopia), a principle applied to treating children's squint. Language learning is easier in childhood. Enriched environments support development; deprivation, toxins (alcohol, lead) and infection (Zika) can harm.
Frequently asked questions
What is Neural Development?
Neurons are generated, migrate, extend axons and form synapses guided by chemical cues.
Which area of biology covers Neural Development, and how advanced is it?
Neural Development is one of the 54 topics in Neuroscience. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Excitatory and Inhibitory Synapses, Glial Cells, Neurodevelopmental Disorders.
Why does Neural Development matter?
Errors in development underlie many neurodevelopmental conditions.
Can you give an example of Neural Development?
Amblyopia arises from lack of visual input in childhood.
What should I learn before Neural Development?
Work through the Beginner topics in Neuroscience first, such as Nervous System, Neuron, Central and Peripheral Nervous Systems, then return to Neural Development. Intermediate topics assume the Beginner vocabulary.
What topics are related to Neural Development?
The closest topics to Neural Development are Excitatory and Inhibitory Synapses, Glial Cells, Neurodevelopmental Disorders, Synaptic Plasticity. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Neural Development?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Neural Development. To practise the whole of Neuroscience, use the Neuroscience quiz.
How is Neural Development different from Excitatory and Inhibitory Synapses?
Neural Development: Neurons are generated, migrate, extend axons and form synapses guided by chemical cues. Excitatory and Inhibitory Synapses: Excitatory inputs depolarise the postsynaptic cell while inhibitory ones hyperpolarise it. Read both side by side and note what each one explains.
How should I study Neural Development step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Excitatory and Inhibitory Synapses and explain the difference aloud. Finally, take the Neuroscience quiz and come back to this page for any question you miss.