Cellular Learning & Memory Flashcards
What is Habituation (Non-Associative Learning) using snail example.
Repeated light touches to the syphon makes the Aplysia respond less to touch
What is Sensitization (Non-Associative Learning) snail example.
Painful intense electrical shock makes the Aplysia respond more to touch
What is the Gill withdrawal reflex in the snail?
Touching the syphon of the Aplysia leads to retraction of the gill
How does the siphon effect the gill (snail example)?
Repeated Light touch
Sensitivity to touch: no change
Excitability of the neuron: decreased (fewer a.p. in response to touch)
Then: Connection between sensory and motor neurons: weakened
Excitability of the neuron: no change
Connection between motor neuron and gill: No change
Decreased Response of the gill
How do you Change the strength of a synapse: LTP & LTD
If you stimulate a presynaptic neuron at…
High Frequency (100Hz for 1s)
Get Long Term Potentiation (LTP)
➡️ strengthen connection
If you stimulate a presynaptic neuron at…
Low Frequency (1Hz for 10min)
Get Long Term Depression (LTD)
➡️ Weaken
To induce LTP (strengthen the connection) you need:
• Neurotransmitter release
• Depolarization of the postsynaptic cell
How does a cell know Neurotransmitter release and Depolarization of the postsynaptic cell happens at the same time?
Stimulation of presynaptic cell only. The one that gets blocked by magnesium and is opened by glutamate.
NMDA receptor
▪ Ionotropic Glutamate Receptor
▪ Coincidence detector
▪ Need both glutamate release +
postsynaptic depolarization to let Ca2+ in the cell
What is LTP in 4 steps?
- Presynaptic side releases glutamate
- Glutamate binds to the NMDA receptor. If the cell is depolarized, the NMDA receptor will let Ca2+ flow in the cell.
- Ca2+ activates CAMKII (enzyme)
- CAMKII leads to an increase in AMPA receptors on the post-synaptic side
-AMPA receptors are ionotropic excitatory glutamate receptor
-Increase AMPAr = increased response to glutamate release
Pavlov’s dogs / classical conditioning, rat example? (Associative learning: behaviour)
▪ If you blow an air puff into the eye of a mouse -> Will reflexively blink
▪ Play a tone every time you blow the air puff -> after some time the mouse will associate the tone with the air puff, and blink to the even when no air puff is presented.
How does the brain pair a neutral stimulus with an aversive stimulus?
When neuron 1 is activated by the air puff, it depolarized the post synaptic cell
▪ Neuron 2 was activated by the tone at the same time -> since the post synaptic
cell was already depolarized by the neuron 1, the synapse will be strengthened !
By having the two stimulus’s together, the bonds between both of the neurons will strengthen. Which leads to the neutral stimulus having the same reaction as the aversive stimulus?
Fun little phrase
Neurons that fire together wire together
