Typical Neurological Development
- Morphological and Functional Development
- Development of the CNS is highly coordinated and complex.
- Morphological disorders (CNS malformations) can arise due to genetic or external factors such as inflammation and maternal substance abuse.
- Traditional classifications of CNS malformations are based on phenotypical and temporal criteria (proliferation, migration, organization).
- Recent classifications incorporate aetiological (especially genetic) factors.
- Timing of injury influences morphological outcomes significantly, e.g. in cerebral palsy.
- Brain maturation continues postnatally, extending into adulthood.
- Brain plasticity and reorganization are inherent to immature brains, facilitating recovery post-injury.
- Language and motor areas can reorganize functionally, depending on lesion timing and extent.
Main Stages of CNS Development
- Interaction between genetic and environmental determinants shapes infant motor activity.
- Motor pattern selection from abundant variations occurs at specific ages relevant to each function.
- see Neuronal Group Selection Theory (NGST)
Typical Developmental Milestones
- 2 weeks: Neural plate formation (enterogenous cysts, fistulae).
- 3−4 weeks: Dorsal induction/neurulation (blastopathies: anencephaly, encephaloceles, spina bifida, meningoceles).
- 4−7 weeks: Caudal neural-tube formation (diastematomyelia, Dandy-Walker syndrome, cerebellar hypoplasia).
- 5−6 weeks: Ventral induction (holoprosencephaly, median cleft face syndrome).
- 8−16 weeks: Neuronal/glial proliferation (microcephaly, megalencephaly).
- 12−20 weeks: Migration (lissencephaly, heterotopias, agenesis corpus callosum).
- 24 weeks onwards: Organization (polymicrogyria, cortical dysplasias).
- 24 weeks to 2 years post-term: Myelination (dysmyelination, white matter damage, cortical-subcortical damage).
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