Synaptic Plasticity/LTP Flashcards
Who was HM and who was responsible for the research on him?
Henry Molson had a biking accident and had to eventually have his hippocampus and part of his amygdala removed, and Brenda Milner did research on him and he had no ability to generate new memories
What did Hebb propose?
That memory comes from synaptic modification
What are the two presented examples of nonassociative learning?
Habituation and sensitization
What is associative learning?
Classical conditioning, putting causal relationships between things that are otherwise random
Why are invertebrates used for models of synapse learning?
Small nervous systems
Large/Identifiable neurons
Identifiable circuits
Simple genetics
What happened in the experiment with Aplysia?
There was a gill-withdrawal reflex that the slug was showing in response to an electric shock that it was habituated with using a puff of water - This was physically found to be associated with presynaptic modification in an area
What two areas of the brain have been studied to have synaptic modification during learning?
The cerebellar cortex and the hippocampus
What are two features of Purkinje Cells?
The dendrites only extend into the molecular layer, and cell axons synapse on deep cerebellar nuclei neurons
What are the two major inputs on postsynaptic Purkinje cells?
The climbing fiber and the parallel fibers
When stimulating parallel fibers and then the climbing fibers conjunctively, what happens to the Purkinje cell response?
The next time the parallel fibers fire, the response stays lower (learns)
What is the cerebellum responsible for?
Adjustment of motor coordination
What receptors do parallel fibers activate?
Glutamate receptors:
AMPA Receptors + Metabotropic Receptor
What happens in the metabotropic g-protein pathway in synaptic plasticity?
The g-proteins activate DAG, which releases a kinase (PKC) into the Purkinje cell
What two things activate the PKC together in the Purkinje fiber?
Influx of Calcium (from the climbing fiber) + G-protein activation(DAG) from the parallel fiber at the same time
What happens when the Purkinje Fiber PKC is activated?
It closes down AMPA receptors so the next response is weaker
What is long term potentiation?
After repeated exposure to a firing of an axon, the synapse gets stronger
What synapse is the most studied in the hippocampus?
The CA1 syanpse
How does learning physically affect the magnitude increase of neuronal activity in relation to vesicles in the synaptic cleft?
It increases your probability of release, or it increases the number of AMPAR receptors. (presynaptic or postsynaptic findings)
What is the role of magnesium in the learning process?
It is the coincidence detector, it opens the NMDA receptor when there is a lot of repolarization of the AMPA receptor and lets in a bunch of calcium for secondary reactions
How is magnesium blockage in the NMDA receptors inhibited in the learning process?
With high amplitude exposure, there is enough depolarization to activate the NMDA channel
What variable affects whether long term potentiation or long term depression occurs according to BCM theory?
The amount of NMDA activation (calcium presence), low activation leads to LTD, high activation LTP
What did the lecturer demonstrate in his studies?
He activated synapses with a laser, and the synapses actually got bigger on a microscope
What is Hebb assembly and how does it relate to grandma cells?
A cell pattern that generates a sensory image as a whole of a grandmother is completed when only a few of the stimulus are present
