Neuronal signalling 6 (3rd lecture) Flashcards
Can neurons have different axons that have excitatory and inhibitory effects?
Ye
How are v complex circuits formed in the nervous system?
Neurons can have thousands of inputs, and themselves give inputs to thousands of other cells/neurons
Two main types of synaptic modulation?
Simple/short term
Complex/long term
Short term ways of modulating a synapse?
Facilitation, depression and temporary potentiation
Long term mechanisms of synaptic modulation?
Long term potentiation and long term depression
What is facilitation?
Two or more APs reach the presynaptic terminals in a short period of time, leading to more NT released per AP
Postsynaptic effect of facilitation?
Postsynaptic change is stronger–> increased postsynaptic response
How does a postsynaptic response become stronger?
A larger change in depolarisaiton
Relationship between amount of differentiation and interval between stimuli?
Larger interval = less likely facilitation is to occur
What is a tetanic train?
A rapid succession of action potentials
What is the response to a tetanic train?
Depression, NT deletion, decreased NT release
What is the effect to a synapse following a depression?
Depression causes change in calcium dependent processes
Synaptic vesicles available per incoming action potential increase.
What is a post-tetanic potentiation?
Larger effect occurring after a tetanic train
Two short term ways to change the behaviour of a postsynaptic cell of a synapse?
depression and facilitation
What do a lot of short term effects affect?
Calcium
Is short term synaptic plasticity specific for neurons?
No it is specific for synapses–> same neuron can have multiple synapses that have diff types of synaptic plasticity
What is post-tetanic potentiation?
A high rate of stimulation of the presynaptic neuron
A gradual increase in the amplitude of the postsynaptic potential
What does post-tetanic potentiation represent?
storage of information about previous activity
How long can a post-tetanic potentiation last?
It can lasts minutes but can persist for an hour.
What is the hebbian synapse?
Coordinated inputs into a single cell will favour one pathway into that cell
I.e. pathway becomes “remembered”
How does a Hebbian synapse come about?
a form of co-ordinated activity for a series of neurones connected together that would strengthen specific pathways
What sort of change is the hebbian synapse?
Long term
Which long term synaptic effect leads to larger changes in calcium?
Long term depression
What does long term potentiation lead to?
Increased activity of a synapse
What does long term depression lead to?
results in reduced activity of a synapse
What are LTP and LTD the basis of?
memory
Long term glutamate example mechanism?
NMDA receptors which usually arent used (AMPA are used instead) are now used
Which specific molecules are involved in LTP formation?
NMDA, Ca/calmodulin dependent protein kinases and changes in protein synthesis
