3. Synpatic Transmission Part 2

Question 1

refers to the ability of the synapse to change its properties depending on its level of activity

Answer 1

synaptic plasticity

Question 2

synaptic plasticity is thought to be the basis of:

Answer 2

learning and memory

Question 3

when brief tetanic stimuli were given in the dendate gyrus, each tetanus caused an increase in the:

Answer 3

amplitude of the synaptic response (eventually lasting for hours)

Question 4

only the combined tetanus of two distinct groups of presynaptic fibers in the _____ can produce long term potentiation

Answer 4

Schaffer collateral/ commissural pathway

Question 5

part of the brain involved in aspects of spatial memory

Answer 5

the hippocampus

Question 6

what is the major principle of the Hebbian synapse?

Answer 6

neurons that fire together, wire together; those that don’t, won’t

Question 7

what are the three main phases of long-term potentiation (LTP)?

Answer 7

• early - induction phase
• medium - expression phase
• late - maintenance phase

Question 8

how long does long term potentiation (LTP) last?

Answer 8

days to weeks

Question 9

phase of LTP characterized by NMDA receptor activation and calcium dependence

Answer 9

early - induction phase

Question 10

phase of LTP characterized by changes to receptors and release machinery as well as local protein synthesis

Answer 10

medium - expression phase

Question 11

phase of LTP characterized by genomic involvement, is translation dependent, and has possible anatomical changes

Answer 11

late - maintenance phase

Question 12

when measuring LTP, synaptic currents are larger in:

Answer 12

amplitude (after tetanic stimulation)

Question 13

which receptor is critical for induction of LTP?

Answer 13

the NMDA receptor

Question 14

describe the double-gated properties of the NMDA receptor

Answer 14

• ligand dependent (requires glutamate binding)
• voltage dependent (requires depolarization to remove Mg++ block of channel pore)
• activation requires BOTH elements

Question 15

Ca++ entry through the NMDA channel is critical for the _____ of synaptic changes

Answer 15

induction and expression

Question 16

large changes in intracellular [Ca++] induces:

Answer 16

long term potentiation (LTP)

Question 17

acts as both an ion and a signalling molecule (intracellular second messenger)

Answer 17

Ca++

Question 18

a large post synaptic increase in Ca++ triggers an increase in post-synaptic responsiveness via:

Answer 18

• an increase in AMPA receptors (postsynaptically)
• an increase in neurotransmitter release (presynaptically)
• an increase in synaptic contacts

Question 19

Ca-MKII is a key enzyme in the:

Answer 19

induction of LTP

Question 20

LTP is absent in mutant mice that do not express:

Answer 20

Ca++/calmodulin kinase

Question 21

a synapse in which the postsynaptic membrane only expresses NMDA receptors; the NMDA receptors are not activated due to the Mg++ block

Answer 21

silent synapse

Question 22

a type of receptor which is inserted into silent synapses during LTP

Answer 22

AMPA receptors

Question 23

receptors can be inserted into the membrane, or retrieved, depending on the induction of:

Answer 23

long term potentiation (LTP) or long term depression (LTD)

Question 24

for medium-term expression of LTP, local signalling mechanisms suffice, however, _____ may be necessary

Answer 24

local protein synthesis

Question 25

for long-term maintenance of LTP, nuclear involvement is necessary via:

Answer 25

genomic translation

Question 26

in long term depression (LTD), lower concentrations of calcium entry in the postsynaptic cell elicit:

Answer 26

changes which oppose synaptic enhancement

Question 27

long term depression (LTD) is evoked by:

Answer 27

both NMDA receptors and voltage-dependent Ca++ channel activation

Question 28

long term depression (LTD) is likely to include both pre and postsynaptic elements:

Answer 28

- a decrease in postsynaptic AMPA receptors - a decrease in presynaptic release of glutamate - a decrease in synaptic contacts