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Term IV: Neuro > Neurodevelopment > Flashcards

Flashcards in Neurodevelopment Deck (15):

Critical events in neurodevelopment and timeline

1. Neurulation: done by 4 wks
2. Segmentation and cleavage: done by 8 wks
3. Proliferation and migration: 8 weeks-birth


Three major events occur in neurulation:

1. Differentiation: neuroectoderm and neural crest
2. Establish axes of symmetry: cephalic to caudal, ventral to dorsal
3. Signal molecule gradients


Closure of the neural tube results in formation of which axis?



What three segments form? And what do they split into?

1. Prosencephalon (forebrain)
- Telencephalon (basal ganglia, cortex)
- Diencephalon (thalamus, hypothalamus)
2. Mesencephalon (midbrain)
3. Rhombencephalon (hindbrain)
- Metencephalon (pons, cerebellum)
- Myelencephalon (medulla)


Three major events in proliferation & migration

1. Evolution of computational capacity
2. Neuroectodermal precursors
3. Migration


Which neural tube defects are involved with the anterior neuropore?

- Anencephaly (most severe)
- Encephalocoele


Which neural tube defects are involved with the posterior neuropore?

- Meningomyelocoele
- Meningocoele
- Spina bifida occulta (least severe)


Which neural tube defect involves both anterior and posterior neuropore?

Arnold chiari malformation


How can neural tube defects be detected in utero? Which neural tube defect cannot be detected in utero?

Measure maternal serum alpha fetaprotein (AFP) with confirmation of dysraphia by US

Spina bifida occulta


What are well-documented risk factors for neural tube defects

- Folate deficiency
- Retinoic acid administration for acne
- Valoproate for seizures


What is a Dandy Walker malformation

Segmentation/cleavage problem - Sites where CSF flow out of ventricle get blocked, blows hole in midline of cerebellum


What is Holoprosencephaly? What chromosomal defect is it associated with?

Spectrum of defects of segmentation between prosencephalon into telencephalic hemispheres

Trisomy 13 Patau's and trisomy 18


What is most minimal lesion of holoprosencephaly

Arrhinencephaly - "no nose brain"


What is most severe lesion of holoprosencephaly

Alobar holoprosencephaly with cyclopia and other midfacial defects


What three types of defects of proliferation and migration are there?

1. Axonal migration - agenesis of corpus callosum
2. Gyral pattern formation
- Lissencephaly - smooth brain - intellectual disability assoc. with seizures (defect of migration)
- Polymicrogyria - "many small gyri" - only two layers (molecular and neuronal)
3. Cortical organization - Band heterotopia: double cortex, Focal cortical neuronal heterotopia