Synapse stabilisation Flashcards
What is the term for when motor neurons initially innervate multiple muscle fibres and each muscle fibre receives multiple inputs?
Polyinnervation
What happens in mature muscles?
Monoinnervation – each fibre innervated by a single motor neuron
Are the synapses eliminated randomly?
No
What is synaptic competition dependent on?
Activity
What is the primary determinant of survival?
Co-ordinated electrical activity between the pre and post synaptic cells
- Non-coordinated firing increases rate of synapse loss
What is expressed in neuromuscular junctions?
• BDNF, TrkB and p75-NTR
What are the 2 forms of BDNF?
proBDNF and BDNF
What does BDNF do?
triggers synaptic potentiation and maturation through TrkB (reward)
What does blockade of TrkB do?
Synapse elimination
What does proBDNF do?
supresses synaptic transmission and causes axonal retraction via p75-NTR
What cause proBDNF ==> BDNF?
matrix metalloproteases (MMP)
Therefore, what does synchronised activation do?
Increases MMP processing which then leads to synaptic strengthening through TrkB
What is Hebbian theory essentially?
Use it or lose it
what are ocular dominance columns?
segregation of inputs to layer 4 of visual cortex into eye specific columns
Which neuron inputs are not seperated but become apparent after eye opening?
LGN
