memory 2

Question 1

what does the neural network model of learning suggest?

Answer 1

that learning is a distributed code

neurons A, B, C respond to all 3 faces, responses of a single neuron not enough to learn/remember one face (not specific)

Question 2

what is the IT cortex?

Answer 2

• fired when presented with faces
• different neurons are selective for different faces
• neurons can change response to faces after multiple representations to acquire stimulus selectivity

Question 3

how does our brain recognize a face?

Answer 3

• as a distributed code/unique response across many neurons
• through a specific ratio of neuron activation

Question 4

what do changes in the synaptic strength indicate?

Answer 4

physical basis of information storage
- how memories are encoded

Question 5

what are the forms of synaptic modification?
how do they relate

Answer 5

• potentiation=strengthening
• depression=weakening

Question 6

how does information flow through the hippocampus?

Answer 6

1) Entorhinal cortex
2) dentate gyrus
3) CA3
4) CA1

Question 7

what is LTP? (long term potentiation)

Answer 7

high NMDA receptor activation

• a long lasting enhancement of the effectiveness of synaptic transmission

Question 8

what are LTP’s measured as?
how are they induced?

Answer 8

• they are measured as elevated EPSPs
• induced experimentally by tetanus (burst of high-frequency stimulation)
• brief tetanus can lead to prolonged LTP

Question 9

what 2 factors are necessary for LTP?

Answer 9

1) temporal summation of EPSPs
- caused by stimulation at high enough frequencies
2) cooperativity/ spatial summation
- enough co-active synapses need to be active to cause spatial summation of EPSPs (neurons that fire together wire together)

Question 10

how long does LTP last?

Answer 10

for years

Question 11

what are AMPA cells triggered by?
what do they release?

Answer 11

triggered by - binding glutamate

release - Na+

Question 12

what are NDMA cells triggered by?
what do they release?

Answer 12

triggered by
- depolarization which releases Mg+
- binding glutamate

release - Na+ & Ca++

Question 13

what does the release of calcium from NMDA receptors cause?

Answer 13

protein kinases to activate

Question 14

what do the protein kinase do?

Answer 14

• phosphorylate AMPA receptors to increase ion conductance of AMPA receptors
• insert new AMPA receptors to post synaptic membrane

Question 15

what is LDP?

Answer 15

long term depression
- prolonged decrease in the magnitude of the ESP

Question 16

what happens in LTD when there is low calcium?

Answer 16

weak NMDA activation
protein phosphatases are activated
- dephosphorilates
- internalization of AMPA receptors

Question 17

what is inhibitory avoidance an example of?

Answer 17

modification to an episodic memory

Question 18

how does protein synthesis coorelate with stimulation and salience?

Answer 18

salience leads to more stimulation which leads to increased protein transcription

Question 19

why do you remember what you had for breakfast on a traumatic day?

Answer 19

because weak events are consolidated if they occur proximal to strong ones

Question 20

how are long term memories sustained?

Answer 20

1) Protein Kinase M zeta - PKMZ is produced due to synaptic activation and RNA transcription
2) positive feedback which triggers additional synthesis of more proteins

Question 21

how are long term memories erased?

Answer 21

zip peptide will block Protein Kinase M zeta, which completely disrupts and blocks memory by disrupting the positive feedback loop