L11 - modern questions in memory and learning

Question 1

what is the evaluator module

Answer 1

memories stored in specific locations in the brain, written by the evaluator module, so when something good happens get a change in synaptic connections. When see stimulus again activate certain parts of the brain previously modified. Modifies that part of the brain to a certain motor action

Question 2

outline Pavlov’s dog exp

Answer 2

bell + food - dog learned to salivate when bell rang due to conditioned learning
bell = neutral stimulus before conditioning, after conditioning it is a conditioned stimulus - predicts reward

Question 3

outline conditioning in flies

Answer 3

pair door with sugar reward or electric shock

flies have a choice between odours - go towards odour associated with reward

Question 4

what is a Kenyon cell

Answer 4

intrinsic neurons of the mushroom body

Question 5

outline properties of Kenyon cells

Answer 5

receive multiple projection neurons

require multiple simultaneous inputs to fire

Question 6

what do different Kenyon cells respond to

Answer 6

different odours

Question 7

why do Kenyon cells fire selectively

Answer 7

as they require multiple simultaneous inputs to fire

Question 8

outline the olfactory associative memory in drosophila

Answer 8

receives reward/punishment, activates different dopaminergic neurons and simultaneous co-activation of an odour specific subset of Kenyon cells, leads to synaptic plasticity at the output synapses of Kenyon cells activated by the odour. This changes the outward synapse of Kenton cell leading to another neuron
changes the behavioural output

Question 9

what does the GAL4/UAS system allow

Answer 9

to artificially express arbitrary transgenes in specific cells

Question 10

what is GAL4

Answer 10

transcription factor expressed in yeast

Question 11

how can it be put into the fly genome

Answer 11

combine with an enhancer that will be active within certain cells in bodu
can be done randomly or specifically

Question 12

what does GAL4 bind to

Answer 12

the upstream activating system (UAS)

Question 13

what happens when GAL4 binds to UAS

Answer 13

recruits RNA polymerase, which induces upstream transcription of anything following UAS

Question 14

what does the split-GAL4 system allow

Answer 14

greater specificity in which cells express our transgene

Question 15

how to get enhancer specific to small populations of neurons

Answer 15

take Gal4 and cut into 2 pieces - DNA binding domain and activation domain.
Take the halves and express under control of different promotors. Only cells in where both halves are active will you have both halves of GAL4 being expressed
add zipper domain on each half and then In cells with both being expressed the 2 zipper domains will join up

Question 16

what binds the UAS sequence

Answer 16

DNA binding domain

Question 17

what recruits the RNA polymerase

Answer 17

activation domain

Question 18

what is the mushroom body made up of

Answer 18

Kenyon cells

Question 19

what is the relationship between output neurones (MBONs) and dopaminergic neurons (DANs)

Answer 19

1-1 matching

Question 20

what was expressed in the flies in the behaviour chamber

Answer 20

CsCrimson

Question 21

what did the flies with CsCrimson do ?

Answer 21

approached the light

Question 22

what does having reward dopaminergic neurons in the same compartment as avoid output neurons do / punishment with approach output

Answer 22

weaken connections

Question 23

what happens if shocked then get odour

Answer 23

the odour is positive as it indicates end of the pain

Question 24

what happens if get odour then shock

Answer 24

avoid odour as it predicts pain

Question 25

in forward and backward pairing experiments, how is the connection modulated

Answer 25

artificial stimulation of the dopaminergic neuron by using an ATP receptor (P2X2) apply different stimulation protocols

Question 26

what happens if dopamine stimulation comes before

Answer 26

strengthen synapse

Question 27

what are the 2 dopamine receptors in Kenyon cells

Answer 27

DOPR1 and DOPR2

Question 28

what is DOPR1

Answer 28

signals through Gs pathway - signals production of cAMP - important for forward learning (odour precedes reward/potentiating synapse)

Question 29

what is DOPR2

Answer 29

signals through Gq pathway - results in ER Ca2+ release - backward pairing (depressing synapse)

Question 30

what is EPAC

Answer 30

sensor for cAMP

Question 31

what is ER-GCaMP

Answer 31

measure calcium in the endoplasmic reticulum

Question 32

what happens when dopamine comes before the odour

Answer 32

get a calcium release from the ER

Question 33

what are projections neurons onto Kenyon cells in humans

Answer 33

mossy fibres onto granule cells in cerebellum

Question 34

what do mossy fibres form

Answer 34

parallel fibres which are intersected by purkinje cells

Question 35

what depresses synapses between granule cells and purkinje cells

Answer 35

signals coming from the climbing fibres

Question 36

what drives motor learning

Answer 36

LTD between granule cells and purkinje cells

Question 37

function of the electro sensory lobe of weakly electric fish

Answer 37

actively emits electric pulses to detect prey using an electric field

Question 38

how does it ignore its own electric pulse

Answer 38

active granule cell cancelled out by the matching efferent copy by depressing the synapse between the granule cell and the purkinje cell