Neurodevelopment and Developmental Plasticity
From neural tube to mature circuitry
Developmental logic
Neural development proceeds through specification, proliferation, migration, differentiation, axon guidance, synaptogenesis, pruning, and myelination. These processes are orchestrated by gene regulatory programs and activity-dependent refinement.
Critical periods
There are developmental windows during which experience has disproportionate effects on circuit formation and behavior.
Which process is most directly responsible for activity-dependent refinement of neural circuits?
Pruning removes weaker or less-used connections during development.
Correct answer: Synaptic pruning
What is meant by neural migration?
Migration is essential for lamination and proper circuit assembly.
Correct answer: The movement of newly generated neurons to their final positions in the developing nervous system.
Developmental disorders
Disruption of developmental programs can produce malformations, intellectual disability, epilepsy, autism-spectrum phenotypes, or motor syndromes. Advanced interpretation requires distinguishing primary developmental defects from secondary network consequences.
Developmental stages and vulnerabilities
| Stage | Representative vulnerability |
|---|---|
| Neurulation | Tube closure defects |
| Migration | Cortical malformations |
| Synaptogenesis | Circuit miswiring |
| Myelination | Slowed conduction and cognitive delay |
Why are critical periods important in neurodevelopment?
They define phases of heightened plasticity and vulnerability.
Correct answer: Because experience can strongly and sometimes irreversibly shape neural circuits during these windows.
Myelination most directly improves which property of axonal transmission?
Myelin increases conduction velocity by enabling saltatory conduction.
Correct answer: Conduction velocity