Cellular basis of learning

Question 1

habituation (general terms)

Answer 1

-when a stimulus is repeated over a period of time, the response diminishes

“decreasing response to a sensory stimulus”

Question 2

sensitization (general terms)

Answer 2

-an increased response to the same stimulus that previously underwent habituation

“increasing response to a sensory stimulus”

Question 3

molecular basis of habituation

Answer 3

• repeated stimulation
• depletes the supply of NT (Glu)
• less Glu is released
• less depolarization
• motor neuron is not stimulated
• decreased gill withdrawal reflex

Question 4

molecular basis of short term sensitization

Answer 4

• shock
• interneuron releases 5HT
• sensory neuron phosphorylates proteins (pka)
• K+ and Ca++ channels on sensory neurons open up
• influx of Ca++ causes release of NT (Glu)
• motor neuron is stimulated again

Question 5

molecular basis of long term sensitization

Answer 5

• multiple repeated shocks
• interneuron releases 5HT
• sensory neuron phosphorylates proteins (pka)
• PKA triggers PROTEIN SYNTHESIS (changes genes)
• change in gene expression supports a long-lasting increase in NT release

Question 6

types of learning

Answer 6

• habituation
• sensitization
• associative conditioning

Question 7

associative conditioning

Answer 7

• associating two sensory stimuli
• aka Pavlovian conditioning
• leads to formation of an associative memory

-when remove the natural stimulus, the artificial stimulus still brings the response

Question 8

removal of hippocampus

Answer 8

-no ability to form new memories

Question 9

synapses in hippocampus

Answer 9

• dentate gyrus to CA3 pyramidal cell
• to CA1 pyramidal cell
• to cortical regions
• this section focuses in CA1 region

Question 10

LTP is induced by __________

Answer 10

LTP is induced by HIGH FREQUENCY STIMULATION

Question 11

NMDA receptor channel only opens when post-synaptic neuron is ________

Answer 11

NMDA receptor channel only opens when post-synaptic neuron is DEPOLARIZED

Question 12

molecular basis of the trigger of LTP

Answer 12

• stimulation of AMPA receptors allows Na+ to flow into cell
• Mg+ blocks NMDA receptor
• with repeated stimulation, there are larger, stronger reactions to Na+
• Mg+ is expelled from NMDA receptor
• Ca++ enters cell
• signalling cascade
• LTP

Question 13

molecular mechanisms underlying EARLY LTP

Answer 13

• increase in Ca influx (due to opened NMDA receptors)
• activation of protein kinases (PKC, calmodulin)
• phosphorylation of receptors (AMPA)
• phosphorylated AMPA is inserted into membrane to increase

PROTEIN PHOSPHORYLATION

Question 14

early LTP

Answer 14

• lasts 1 to 2 hours
• caused by single 100 Hz high frequency stimulation
• cellular basis of short term memory

Question 15

late LTP

Answer 15

• lasts days to weeks
• caused by multiple high frequency stimulations
• cellular basis of long term memory

Question 16

molecular mechanisms underlying late LTP

Answer 16

• increase in Ca influx (due to opened NMDA)
• activation of protein kinases (variety)
• phosphorylate CREB (transcription factor)
• increased gene expression and protein synthesis
• –proteins go to synapse: support, make it larger (larger SA = more AMPA)

PROTEIN PHOSPHORYLATION
PROTEIN SYNTHESIS

Question 17

molecular basis of ASSOCIATIVE LTP

Answer 17

• food synapse has strong depolarization, triggers AP for salivation
• bell synapse alone has weak depolarization, no AP for salivation
• when food and bell stimuli presented together, food causes expulsion of Mg+ from food synapse AND from bell synapse receptors
• bell synapse is strengthened, sufficient to cause salivation on its own

Question 18

________ receptors are essential for associative learning

Answer 18

NMDA receptors are essential for associative learning

Question 19

diseases resulting from insufficent LTP

Answer 19

• alzheimers

- intellectual disability

Question 20

diseases resulting from too much LTP

Answer 20

epilepsy