Module 1: L5-6 + 8-9 - development Flashcards
Development
Describe the neural tube.
The neural tube is formed by neurolation in week 3-4 by bending the neural plate, which is tissue differentiated from the ectoderm, dorsally. The two ends eventually joins at the neural plate borders (the neural crest). The closure of the neural tube disconnects the neural crest from the epidermis.
What consequences are there of neural tube defects?
- Anencephaly: baby born without parts of the brain and skull
- Open/closed spina bifida: incorrect closure of the neural tube
- Encephalocele: sac-like protrusion and projection of the brain and membranes that cover it through an opening in the skull
When does proliferation dominate during the formation of the neocortex? Describe the process of proliferation.
The process of cell growth and division –> two daugther cells. Dominate in the embryonal/early fetal phase.
When does migration dominate during the formation of the neocortex? Describe the process of migraiton.
Inside first –> outsider last. The cells climb on radial glial cells to the correct place. Dominate in the midfetal fetal phase
When does differentiation dominate during the formation of the neocortex? Describe the process of differentiation.
The process where cells become the specific cell type they’re meant to be. Dominate in the late fetal phase
When does synaptogenesis/pruning dominate during the formation of the neocortex? Describe the process of synaptogenesis/pruning.
Dominate in the late fetal phase and in childhood (pruning takes place at different times in different regions).
Synaptogenesis is the formation of synapses. Pruning is the elimination of weak/unnecessary synapses.
When does myelination dominate during the formation of the neocortex? Describe the process of myelination.
Dominate in the late fetal phase and childhood.
Describe the homeobox genes and their overall role in brain development.
Master development control genes:
Genes that encode proteins, that typically switch on transcription cascades of other genes by binding to their promoter region. The homeobox is a well-defined 180 bp sequence, that encode a highly conserved 60 aa motif
Hox family homeobox genes play a role in the morphogenesis
Describe the order in which different brain regions are myelinated.
Starts in the brain stem around the 20th gestational week
The cerebrum is myelinated in a caudo-cephal direction beginning at the 2nd half of pregnancy and continue into late adolescence
How does the grey matter volume change during development?
The volume of grey matter decrease during development
How is the development of hippocampus different from the neocortex?
Differentiation and synaptogenesis takes place later in hippocampus (one of the last brain areas to achieve the majority of neurons)
What does the neural crest cells differentiate to form?
Most of the PNS
Define general maturational trends in grey and white matter structure during childhood and adolescence
From grey to white: apperent cortical thickness related to age
Describe general sex differences in brain maturation
Overall cortical volume: males have larger volumes
Age of peak: females peak earlier (in FA and MD)
Characterize how the grey and white matter matures in a regional specific pattern.
Visual, sensory and motor cortices mature earlier than higher order association cortices
