developmental biology in the adult brain Flashcards
why does post-natal development of the brain occur?
to form memories
name the two regions where new neurones are generated in the adult brain
striatal subventricular zone (SVZ) and subgranular zone (SGZ)
what are stem cells in SVZ?
a type of astrocytes
what are protein markers for these SVZ astrocytes?
GAFP and Prominin-1
what additional function do these SVZ astrocytes have?
wafting cilia that wash away toxins in the brain as we sleep
where are SVZ astrocytes found?
in contact with the ventricle or directly below
asymmetric division of SVZ astrocyte occurs to form:
one stem cell and one transient amplifying cell
these SVZ transient amplifying cells divide to make:
neuroblasts and some oligodendrocytes
proteins markers for SVZ neuroblasts are:
PSA-NCAM
in rodent PSA-NCAM can be used to track SVZ neuroblasts to the:
olfactory bulb via the rostral migratory stream
what do SVZ neuroblasts produce? and what disease are these depleted in?
striatal inter-neurones
these are depleted in Huntington’s
what is Neurog2?
a pro-neural TF
why is new neurone production repressed in all but two regions of the brain?
reduces the risk of cancer
how many new neurones are made in a rat brain per day?
20,000 as smell and memory of these smells are very important
how do adult NCS progeny differ from embryonic?
- delayed firing
- more excitable
- deeper layer
what are NSC in the SGV?
a type of astrocyte/radial glia hybrid
what are protein makers for SGV NSC?
GFAP, nestin and Sox2
what neurones are formed from SGV NSC?
glutamatergic dendrite granule cells
TF changes are induced by signalling. give three examples of this signalling
- Wnt
- neurotransmitters
- miRNA
why does the hippocampus need new neurones from SGZ?
- spatial learning
- fear conditioning
- clearing memory traces
- navigation
how might depression be linked to the hippocampus?
in depression the hippocampus is less able to make new memories/disrupt old ones, locking in old memories
what factors affect neurogenesis?
exercise increases neurogenesis. stress and raised cortisol levels reduce neurogenesis in the hippocampus.
highly active dentate granule cells activate interneurons. what is leaks from interneurons to inform nearby SGZ NSC everything is ok?
GABA
what does the absence of GABA induce?
activation of SGZ NSC as this is an indication of diseased/damaged neurones
does the number of NSC decrease with age?
yes
how does the activity of NSC fair with age?
it decreases, NSC become quiescent
what reduces NSC efficiency?
age and reduced exercise
what is heterochronic parabiosis?
when a young and an old mouse blood circulation is linked
what happens in heterochronic parabiosis?
increased number of NSC and neuroblasts in old brain.
something in young blood that rejuvenates old brain degeneracy.
