Lecture 39- Cortex 2 Flashcards
What does the prosencephalon develop into?
telecephalon and diencephalon
What does the retina develop from?
optic vesicle (part of the diencephalon)
What is the first part of the telecephalon to develop into cortex called?
insula
Where is the insula found?
hidden by the temporal lobe- in the sylvian fissure
What are the two initial layers of the neuroepithelium?
Marginal Zone
Ventricular Zone
Which of the two initial layers of the neuroepithelium are in contact with the pial surface?
Marginal Zone
Where are the neuroblasts found in the developing neocortex?
Ventricular Zone
What type of tissue is the ventricular zone of the developing neocortex classified as?
pseudostratified epithelium
Where do neuroblast cells divide in the developing neocortex?
in the ventricular zone
Prior to dividing what does the neuroblast do?
translocates its nucleus through the cytoplasm into the marginal zone and then back down to ventricular margin where it will divide
What happens is the neuroblast divides vertically?
2 neuroblasts are created
How should you divide a neuroblast if you want to get two neuroblasts?
VERTICALLY
What happens when you divide a cell horizontally?
- Neuroblast
2. Neuron or radial glial cell
What is the plane of cleavage of a neuroblast important?
because it causes differential segregation of transcription factors
- VERTICAL=2 neuroblasts
- HORIZONTAL= 1 neuroblast & 1 neuron or glial cell
What do the first neuroblasts to develop become?
radial glia
What is the function of the radial glia?
they stretch from the ventricular margin to the pial surface and create a scaffolding for new neurons to migrate toward the cortical plate
What does the marginal zone become in the adult neocortex?
layer 1
Where do most of the new neurons stop and accumulate during development?
cortical plate
Which of the neuronal layers develops first in the cortical plate?
layer 6 (develops inside out)
What does the intermediate zone become in the adult neocortex?
subcortical white matter
What type of glia do the radlal glal cells become?
astrocytes
Where would the youngest cells be found in the cortical plate?
youngest cells of the cortical plate would be ON TOP
What part of the cortex is not fully developed until age 30?
myelination of axons
When are the bulk of glial cells developed?
postnatally
What will the lateral ganglionic eminence give rise to?
basal gangla
What do the basal ganglia develop from?
interneurons of the lateral ganglionic eminence
What happens to the cells of the medial ganglionic eminence?
they migrate to the cortex to become interneurons
Where do the interneurons of the cortex develop?
in the medial ganglionic eminence
Why do babies exposed to cocaine in utero often have seizures activity?
cocaine interrupted migration of the the interneurons from the medial ganglionic eminence to the brain- lack of interneurons in the brain
What is one area that animals have shown new neuronal development into adulthood?
hippocampus-dentate gyrus
What are the 2 theories of cortical area development?
- protomap
2. protocortex
What does the protomap theory posit?
that the fate of neurons is present very early even before they migrate into the cortex and that cells migrate to their designated areas by traveling along radial glia cells
What is one problem with the protomap theory?
it does not account for non-radial migration pathways such as cells from the ganglionic eminence
What does the protocortex theory posit?
that the fate of neurons is not preprogrammed but develops later as a result of anatomical inputs and functional activity
supported by radical rewiring experiments
