Lecture 9 Flashcards
What is learning?
the process by which experiences change our NS
Changes associated with learning are referred to as?
memories
What are memories?
changes in the circuits that participate in perceiving, performing, thinking and planning
Explain the Hebb Synapse
The persistence or repetition of a reverberatory (something that keeps coming back) activity (or “trace”) tends to induce lasting cellular changes that add to its stability
- a connection between 2 neurons (anatomical connection) takes place only if bother neurons are firing at the same time
= Simultaneous activation
Explain the Hebb Rule
How and when will the brain change to represent a memory?
- if a synapse becomes repeatedly active at about the same time the post synaptic neutron fires, changes will take place in the structure or chemistry of the synapse that will strengthen it
E.g.
puff of air to the eye –> neuron of somatosensory system –> synapse P –> blink
1000 Hz tone –> neuron in auditory system –> synaps T –> blink
puff of air + tone –> eye blink; test: tone –> eye blink??
- during conditioning tone and blink neurons are active at the same time (not sequential; happening simultaneously)
What type of learning is involved with habituation and sensitization?
Repetition learning
- not associative
Is Hebb’s law specific to associative learning?
Yes
- associating two things at a time
What is non-associative learning?
repeat stimulation/lack of stimulation (not associating S-S or S-R)
- all about amount of usage
Explain topographical maps
- change with the use of afferent (input) pathways
- details vary between individuals
- E.g. increased use of fingers –> enlarged image of fingers
- intense disuse of a hand produces enlargement of cortical areas neighbouring the hand (e.g. face)
- evidence that these maps change with experience
–> repeated stimulation of one synapse
What is synaptic enhancement?
Pre-synaptic action potentials leave an after-effect that alters the release of neurotransmitters in response to subsequent action potentials
- If the after-effect increases the amount of neurotransmitters released by successive action potentials = synaptic enhancement
What is synaptic depression?
Pre-synaptic action potentials leave an after-effect that alters the release of neurotransmitters in response to subsequent action potentials
- if the after-effect educes the release of neurotransmitters by subsequent action potentials = synaptic depression
Explain facilitation
1 pre-synaptic action potential in a burst of stimulation
- 1 second duration of enhancement
Explain augmentation
A few hundred action potentials in a burst of stimulation
- 10 second duration of enhancement
Explain potentiation
A few thousand action potentials in a burst of stimulation
- 5 minute duration of enhancement
Explain what tetanus is
Form of synaptic potentiation that was first described at a neuromuscular junction
- because of this, potentiation follows a sustained, high frequency burst of action potentials = post-titanic potentiation