Synaptic refinement Flashcards
What is Donald Hebb’s rule of plasticity
Co-ordinated activity of a presynaptic terminal and a post synaptic neuron strengthen the synaptic connections between them
Neurons that fire together wire together
What is the postsynaptic response resulting from increasing stimuli
With increasing stimulus comes more afferents - increase postsynaptic potential at a steady rate - quantal increase
How do climbing fibres change in the developing cerebellum
Initially 4 climbing fibres per purkinje cell - 1 to1 in mature
Climbing fibres also reorganise - initially synapse with the soma - mature with dendrites - Post synaptic response recorded in mature soma has varied time response due to different distances of dendrites away from the soma
How was ocular dominance used to show connection focusing
Cortical layer 4 presents ocular dominance bands - where input to an individual neuron is from a single eye
One eye is blocked - near complete loss of functional connectivity from the deprived eye to the visual cortex
What was the result of both eyes being closed on ocular dominance
Had very little effect on the ocular dominance of cells in the visual cortex - proves that it is not caused by visual deprivation but by an imbalance in activity between both eyes
What is the role of the CA1 region of the hippocampus and what neurons come into it
Memory formation - Schaffer collaterals come up into this area - strength of the synapse varied according to synaptic activity
What does tetanic stimulation cause
Increases the postsynaptic response but stays enhanced for months/years - long term potentiation
What is the mechanism of LTP
tetanic stimulation causes the voltage dependent Mg block of the NMDA receptor to be removed - causes a calcium influx at the postsynaptic terminal - this causes an increase in AMPA receptors becoming available at the postsynaptic membrane - AMPA receptors are much more responsive to glutamate.
