Slide 3 Flashcards
Which brain structure is responsible for explicit memory?
hippocampus
Which brain structure is responsible for emotional regulation of memory?
amygdala
Which brain structure is responsible for eye blink conditioning
cerebellum
Which brain structure is responsible for object recognition
rhinal cortex
Damage to what brain structure results in Korsakoff’s syndrome?
medial diencephalon (mediodorsal nucleus)
Damage to what brain structure results in alzheimers?
basal forebrain
Define neuroplasticity
- brain’s ability
- to modify synaptic connections
- as a result of experience
Name 4 mechanisms of learning and memory
- hebbian plasticity
- structural changes in synapses after learning
- long term potentiation
- habituation and sensitization in Aplysia
Describe the concept of Hebb’s postulate
- increase in synaptic strength
- arises from the presynaptic cell’s
- repeated and persistent stimulation
- of the postsynaptic cell
Which mechanism does this phrase describe:
‘neurons that fire together wire together’
Hebb’s postulate
Describe the concept of Hebbian plasticity
- If cell A
- Stimulates cell B
- The connection becomes stronger
What is an example of Hebbian plasticity used in learning?
Pavlovian conditioning
Before Pavlovian conditioning, the bell ______ elicit the salivation response
does not
Before Pavlovian conditioning, the food ____ elicit the salivation response
does
During Pavlovian conditioning, ___________ elicit the salivation response
- the food
- and
- the bell
After Pavlovian conditioning, _____ by itself is able to elicit the salivation response
-the bell
During Pavlovian conditioning, what must happen for learning to occur?
- CS neuron and UCS neuron
- both fire the CR neuron
- in the same place
- at the same time
- causing synaptic changes to occur
Why is timing critical for learning?
-CS must predict the UCS
Define coincidence detection
- neurons are able to detect changes
- that happen close together in time
How does coincidence detection occur?
- NMDA receptors bind glutamate
- NMDA receptors are normally blocked by magnesium ions
What must happen for NMDA receptors to respond maximally
- glutumate must bind
- AND
- neuron must be partially depolarized
What ion does NMDA allow in the cell
-Ca++
What effect does the entry of Ca++ have on the cell?
- activates enzymes
- called protein kinases
What are protein kinases?
- enzymes that influence many chemical reactions
- inside neurons
- eg. structural changes of neurons
Which stimulus results in glutamate release?
- conditioned stimulus
- eg. bell
What effect does the unconditioned stimulus have on the post synaptic cell and which ions does this affect?
- depolarizes post synaptic cell
- removes Mg ++ blockade
Learning results in a(n) ______ in the number of synapses
increase
What effect does learning have on existing synapses?
-changes the structure
What happens to the shape of the post synaptic membrane after learning?
- it becomes more dense
- increase in the number of AMPA receptors
What is the result of an increase in the number of AMPA receptors in the post synaptic membrane after learning?
- Na+ influx
- synaptic strength
What model is used to portray the process of learning?
electrophysiological
What is LTP?
- long term potentiation
- long lasting increase in synaptic strength
- following high frequency stimulation of a synapse
Does long term potentiaion = learning?
- no
- but evidence suggests that LTP like changes occur during learning
4 similarities between LTP and learning
- drugs preventing LTP also prevent learning
- LTP and learning use the same type of neural changes
- learning can produce LTP type changes
- LTP more readily observed in structures known to be involved in learning/memory
What is an example of a drug which prevents LTP and prevents learning?
-NMDA receptor antagonist
What is an example of a neural change common to both LTP and learning?
increase in AMPA receptors in postsynaptic membrane
What is a brain structure which is known to be involved in learning/memory in which LTP is more readily observed?
hippocampus
What role did Eric Kandel and co play in learning discoveries?
- characterized how nervous system changes
- during leraning
What did Eric Kandel choose to study in his research on learning?
-Aplysia
Why did Kandel choose to study Aplysia?
- fewer cells than vertebrates
- cells/connections virtually identical from animal to animal
- therefore easier to work out mechanisms in greater detail
What is habituation
- simplest form of learning
- decrease in response to a stimulus
- when that stimulus is presented repeatedly
How is habituation portrayed in Aplysia?
- gill withdrawal reflex
- stimulating siphon
- results in gill withdrawal
What is the neural basis of habituation?
- decrease in synaptic activity
- at sensory/motor neuron junction
- decrease in Ca++ influx
- therefore decrease in neurotransmitter release
What is sensitization?
increase in strength of response to a stimulus
How is sensitization portrayed in Aplysia?
- electric shock to Aplysia tail
- increases amplitude of gill withdrawal reflex
- to a mild stimulus
- that lasts several minutes
What is the best way to observe long term sensitization?
-spread out trials across several days
What have we learned from research on Aplysia?
- discovered neural circuit supporting this behavior
- discovered molecular and cellular mechanisms of learning/memory
Transcription factors
- in nucleus
- can make new protein
