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28 Cards in this Set
- Front
- Back
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What are the 6 steps of forming a neural circuit?
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1) neural induction and patterning
2) specification of neural type 3) neuronal migration 4) neuronal polarization 5) circuit formation 6) circuit refinement |
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What 8 conditions are associated with malformation in synapses?
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1) autism
2) epilepsy 3)muscular dystrophy 4) congenital cranial dysinnervation disorders 5) fragile X 6) mental retardation 7) rett syndrome 8) angelman syndrome |
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What is a growth cone and what is its function?
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a growth cone is a sensorimotor organelle made of actin and tubulin
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What does actin do in the growth cone?
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actin sets the direction of the growth cone
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What does tubulin do in the growth cone?
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tubulin drives the outgrowth (forward and backward movement of the growth cone
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Is growth usually independent or dependent on the neuronal cell body?
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independent
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What are the two things that determine growth cone movement?
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1) Ca changes
2) attractive and repulsive cues 3) local translation of actin and tubulin |
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What are the 3 important components of the axon growth cone?
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1) poineer
2) followers/fasiculated growth cone 3) trophic growth factors |
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What are the four categories of axon guidance signals?
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1) ECM
2) CAMs 3) soluble ligands and receptors 4) repulsive cues |
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Are the axon guidance signals the same signals used for other biological functions such as angiogenesis and cell migration?
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yes
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What did John Langley demonostrate in his experiment where he cut cells in the sympathetic trunk?
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synaptic specificity
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What is the chemoaffinity process?
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chemical tags on target cells create an affinity for selective binding by receptive part of growth cone
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Is target selection activity dependent?
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no
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How does this relate to the formation of topographic maps in retina?
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retinal growth cones are attracted to specific parts of tectum
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What causes Congenital fibrosis of the extraocular muscles type 3?
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mutations in Tubb3 which is a trophic factor in the occulomotor nucleus
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What are the symptoms of the congenital fibrosis of the EOM type 3?
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stabismus
unilateral ptosis downward looking |
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What is the symptom of Duane's retraction syndrome?
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when you look downwards eyes diverge and close
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What is the cause of Duane's retraction syndrome?
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mutations in CHN1 which is a gene involved in axon pathfinding causing some axons to have stalled growth and others to be mistargeted
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How do trans synaptic signals direct synaptic differentiation?
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retrograde organizers and anterograde organizers such as CAMs, soluble factors, ECM and glial derived factors
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What are conditions related to synpatic differentiation problems? (5)
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1)muscular dystrophy
2) mental retardation 3) autism spectrum 4) OCD 5) epilepsy |
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What is an example of losing ability to form synapse at the NMJ?
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agrin deficiency which is required for postsynaptic apparatus in muscle, ie. no breathing
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How do neurons overcompensatate for synaptic differentiation possibly going wrong? (2)
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supernumerary neurons
supernumerary nerve terminals |
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What must happen after neurons find their targets?
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trophic support must be received from neuronal partners through neurotrophins
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What are some examples of neurotrophins?
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1)nerve growth factor NGF
2) brain derived neurotrophic factor BDNF 3) NT3 and 4 |
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what happens without trophic support in terms of symptoms?
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neurodegenerative diseases and memory deficits
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what happens to nuerons without trophic support?
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apoptosis
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What happens to neurons in terms of synaptic elimination, what are the steps?
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1) supernumeray inputs
2) polyneuronal innervation 3) synapse elimination |
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What drives synaptic refinement vs synapse elimination?
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synapse elimination - genetically driven
synapse refinement - activity driven |
