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Plasticity Notes

Medicine Notes > Neurology Notes

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.

The following is a more accessble plain text extract of the PDF sample above, taken from our Neurology Notes. Due to the challenges of extracting text from PDFs, it will have odd formatting:

Lecture 43 Plasticity




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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