BMS248 Lecture 9 - Learning and Memory Flashcards
What is the acquisition of information?
Learning
What is the storage of learned information?
Memory
What is the reacquisition of stored information?
Recall
What is known as the physical embodiment of a memory
The engram
What is explicit memory?
Memory that can be consciously recalled - declarative memory
What is declarative memory?
Facts and events available to the conscious mind - can be encoded in symbols and language
What is implicit memory + what are the 3 types?
Memory that cannot be consciously recalled:
1. Procedural memory
2. Classical conditioning
3. Priming
What is procedural memory?
Skills and associations largely unavailable to the conscious mind - e.g. juggling
What is classical conditioning
Associating a stimuli with positive/negative reward
What is priming?
Exposure to one stimulus influences the response to another subsequent stimuli
What are the two simple forms of memory?
- Habituation
- Sensitisation
What is habituation?
Amplitude of responses reduces with repeated stimulus
What is sensitisation?
Amplitude of responses increases with repeated stimulus
What is the Aplysia gill withdrawal reflex?
Touch/water jet causes gill withdrawal.
Habituation to repeated stimuli - reduces the reflex
What kind of circuit is involved in this reflex?
Typical reflex circuit - glutamatergic
Where in the reflex circuit does the habituation occur?
Between the presynaptic sensory neuron and the postsynaptic motor neuron
What is the molecular basis of habituation?
Reduced glutamate release leads to the depletion of the readily releasable pool (RRP) in subsequent firing of the neuron - reduced synaptic strength as there is less available synaptic vesicles
What leads to sensitisation (increased) of the gill withdrawal reflex?
Tail/head pinch or shock
Where does the sensory neuron (L29) that detects this stimulus bind?
To the other sensory neuron, at the pre-synaptic input of the motor neuron
What activates a G-protein at this synapse?
Serotonin (5-HT): serotonin-ergic feedback
The G-protein leads to activation of pkA (via adenylyl cyclase + cAMP) - what effect does this have? - What is the molecular basis of sensitisation?
pkA phosphorylates and inactivates K+ channels - therefore longer depolarisation means more vesicular release - therefore amplitude of response increases with repeated stimuli
What occurs when the weak siphon touch (CS) is paired with the strong shock (US)? - Pavlovian like Associative learning
Ca2+ influx from the conditioned stimulus (siphon touch), synergises the 5-HT effect from the unconditioned stimulus (shock) - MORE cAMP - greater siphon withdrawal
Long term sensitisation and conditioning involve what?
The nucleus - changes in gene and protein expression
In early stages of sensitising and conditioning what kinases are involved?
- PKA
- CamK II
- PKC
