Experiments AF lectures Flashcards
mainly whats the point of all of them
What does birth dating show
which cells have exited the cell cycle at certain times
cells born at different times migrate to different layers of the cortex
What do heterochronic transplants show
early precursors have the ability to adopt many fates but this is lost in older precursors
for early precursors, something in the environment influences their fate
What does a reelin KO show
failure of seperation of CR and subplate cells
shows CR and reelin dictate layering
What do axon guidance experiments in the retina of adult frogs show
axons grow back but doesnt tell us much about development
axon guidance in chick embryos
axons migrate to their targets
grasshopper embryo lazer
growth cones respond to cues or labels in the environment
certain axons are looking for cues on other axons
grasshopper embryo pioneers lazer
pioneer gcs also look for specific things in the environment
F actin fluorescent labelling
new flow of actin from periphery into transition zone
attachment of of GC to substrate isnt enough to drive forward movement , need a stimulus
repelling GCs (retinal ganglia and sensory neurons)
GC collapse isnt to do with it not attaching
Permissive subtrates
stickiness of substrate has no effect on axon growth
gradients of morphogen re used
early patterning used to guide pioneer axons
open book experiment
c axons cross midline due to losing sensitivity to netrin
hindbrain they cross floorplate without turning
spinal cord they turn up towards the brain
genetic screen mutants of comm and robo
comm and low robo when crossing midline
high robo and no comm once crossed
stripe assay of tectum
temproal axons repell a factor in posterior stripes
limb bud in chick embryo
size of target correlates with amount of innervation
target influences how many neurons synapse
NGF chamber
need NGF for cel and neuron survival
NGF is tropic and trophic
GFP of synapses
can have preestablished or random adhesions
loss of netrin in presynapses
synapse sites can be dictated by axon guidance factors secreted from adjacent cells
weaver mouse
purkinje cells in cerebellum still produce dendritic spines, even when partners are missing
receptor clustering
in ACh KO, AChR clusters grow faster
activity plays a role in synapase stabilisation
punishment and reward proof
+ BDNF. supresses synapse elimination
-TrkB signalling accelerates elimination
-MMP prevents strengthening
+pro BDNF accelerates elimination
-p75-NTR prevents elimination
ocular dominance
activity is important in maintaining synapses in CNS
