Plasticity Notes

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This is an extract of our Plasticity document, which we sell as part of our Neurology Notes collection written by the top tier of Bristol University students.

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Lecture 43 Plasticity

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General o Need to be able to adapt our environment and store information
? Development
? Learning & memory
? Disease & addiction o Plasticity relates to the idea that the nervous system is modifiable o What can we change?
? Action potentials

* 'All or nothing' so can't change size

* Could possibly change probability of AP being fired
? Synaptic transmission

* Can reduce amount of NT release & thus change EPSP Synaptic plasticity, development and memory o Cell death and synapse elimination/re-organisation
? Establishing correct synaptic connections is essential to neuronal survival. Neurones lose in competition and fail to survive (keep important ones)
? Neurons appear to have target synaptic activity (max. number of synapses) o Mechanisms of pathway formation
? Large-scale reduction in neurons and synapses o Development of brain function
? Balance between genesis and elimination of cells and synapses o Apoptosis: programmed cells death o Start off with more neurons than need, but during development, lose these Activity-dependent synaptic rearrangement o Synaptic rearrangement
? Change from one pattern to another
? Consequence of neural activity/synaptic transmission before and after birth
? Critical period
? Example

* A & B both have some amount of post-synaptic connections (3)

* B is driven more & has stronger connections & is more in tune with target cell. Makes more connections & keeps other connections (5) o Synaptic segregation
? Refinement of synaptic connections
? Segregation of retinal outputs

* Retinal waves (in utero)- activity of two eyes not correlated?
segregation in LGN

* Process of synaptic stability (Hebbian modifications)

* Plasticity at Hebb synapses

* "Winner takes all" o Hebbian synaptic modification
? Hebb synapse=strength changes when pre/postsynaptic neurons act together

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