memory

Question 1

advantages of using invertebrates to learn about memory etc?

Answer 1

advantages:

Neuron size, circuit complexity, temperature-dependence, mapping (developmental, genetics, stereotypy)

Question 2

2 simple forms of memory

Answer 2

Habituation: depletion of the synaptic vesicle pool

Sensitisation: serotonin-ergic feedback from other sensory neuron

Question 3

examples of habituation in humans

Answer 3

Habituation of eye blink reflex
Habituation of repetitive non-harmful stimulus presentation (e.g. living on a noisy road)
Habituation of visual attention
Habituation of emotional response

Question 4

Describe the aplasia reflex

Answer 4

Gill and siphon withdrawal reflex:

Water jet or touch to the siphon elicits gill withdrawal

Habituation – repeated stimuli (10 - 15 at 10 - 60s intervals) reduce the reflex

Occurs at abdominal ganglion synapse

Question 5

what is habituation a result of

Answer 5

• reduced synaptic strength
• reduced transmitter release
• > 50% lower quantal release

Question 6

what is the Mechanism of Sensitisation - use the simple bear model

Answer 6

serotonin release activates aenylyl cyclase

activates cAMP activating PKA

pkA phosphorylates and inactivates K+ channels

Longer depolarization means more vesicular release

Question 7

Define a Hebbian synapse

Answer 7

Coordinated activity of a presynaptic terminal and a postsynaptic neuron strengthen the synaptic connections between them.

Question 8

describe the simplified hippocampal circuit

Answer 8

Entorhinal to dentate (perforant)

Dentate to CA3 (mossy fibres)

CA3 to CA1 (Schaffer collaterals)

Output via fornix and subiculum

Question 9

what is long-term potentiation

Answer 9

the long-lasting increase of synaptic strength

Question 10

how does LTP occur

Answer 10

LTP could occur by pre-synaptic changes.
Evidence suggests often a post-synaptic event.
Most indicates a critical role for Ca2+

Question 11

mechanism of NMDA receptors

Answer 11

have a voltage-dependent Mg2+ block.

need to be indirectly pre-activated by a separate depolarising input

Question 12

mechanism of NMDA receptors

Answer 12

have a voltage-dependent Mg2+ block.

need to be indirectly pre-activated by a separate depolarising input (glutamate)

so calciumand sodium flow in and K+ out

Question 13

declarative vs non declarative memory

Answer 13

declarative - can be consiously recalled

non - explicit, no conscious thought

Question 14

name 3 SNAREs and what is the overall role

Answer 14

synaptobrevin
SNAP25
Syntaxin

role- to regulate presynaptic release in the active zone

Question 15

what is synaptotagmin

Answer 15

Ca2+ sensor synaptotagmin-1 (Syt1) plays an essential function in synaptic exocytosis

Question 16

3 different types of vesicles in pre synaptic

Answer 16

readily releasable, proximal pool, reserve pool

Question 17

three types of glutamate receptors, and the kind of transmission, what they are selective too

Answer 17

NMDA - Ca2+ ionotropic glutamate receptors
AMPA - N+ and K+ ionotropic glutamate receptors
Metabotropic GluR - metabotropic glutamate receptors inhibit adenylyl cyclase, reducing the cell cAMP

Question 18

what is dynamic, how can you test its role

Answer 18

Dynamin is a GTPase responsible for endocytosis in the eukaryotic cell

test using temp sensitive mutations - paralyse fly at high temp