ELM 9.2

Question 1

Which intracellular signalling molecule is involved in the actions of serotonin in Aplysia gill reflex sensitization?

a.	 cAMP

b.	 Calcium

c.	 DAG

d.	 IP3

Answer 1

a

serotonin increase production of cAMP which then activates protein kinase A - pKA may well act to phosphorylate potassium channels and inactivate them - this depolarizes the presynaptic membrane, leading to increased neurotransmitter release

Question 2

Which of the following statements about the Aplysia nervous system is correct?

a.	 Aplysia has a relatively large central brain

b.	 All of its ganglia are paired

c.	 The abdominal ganglion controls its heart rate

d.	 The cerebral ganglion is located just above the animal's spinal cord

Answer 2

c

the abdominal ganglion controls heart rate - this ganglion is not paired - aplysia does not really have a central brain - its equivalent of a brain is the anterior nerve ring - its neurons are actually very big - it is an invertebrate so by definition does not have a spinal cord

Question 3

Ivan Pavlov conducted a classic series of condition experiments in dogs. At the end of Pavlov’s experiment:

a.	 The bell is the conditioned stimulus

b.	 The bell is the unconditioned stimulus

c.	 Food is the conditioned stimulus

d.	 The dog is the unconditioned stimulus

Answer 3

a

Question 4

Sensitisation of the gill withdrawal reflex of Aplysia involves:

a.	 a decrease in active synaptic zones at the sensory-motor neuron interface

b.	 activation of the cAMP cascade in the presynaptic (sensory) cell

c.	 release of glutamate by the facilitating interneuron

d.	 the sensory neuron running out of neurotransmitter

Answer 4

b

this process involves activation of the cAMP cascade in the presynaptic (sensory) cell

Question 5

What is the mechanism for synaptic depression that underlies habituation of the gill withdrawal reflex in Aplysia?

a.	 Desensitization of postsynaptic neurons

b.	 Inadequate repolarisation of the presynaptic neuron

c.	 Reduced calcium influx in the presynaptic neuron

d.	 The sensory neuron running out of neurotransmitter

Answer 5

c

this is due to a reduction in the Ca2+ influx per action potential leading to reduced transmitter release

Question 6

how many neurons do aplysias have?

Answer 6

20000

Question 7

there are two types of learning in aplysia. what are they?

Answer 7

non-associative learning
associative learning

Question 8

three things under non-associative learning

Answer 8

• habituation : loss of response because of repeated stimulus
• dishabituation : recovery of innate response
• sensitization : response stronger than normal

Question 9

what is under associative learning

Answer 9

classical conditioning

Question 10

define non-associative learning

Answer 10

change as a function of experience - doesn’t matter when the stimulus is in order to elicit a response

Question 11

unconditioned stimulus in regards to pavlov’s experiment

Answer 11

giving food without bell

Question 12

unconditioned response in pavlov’s experiment

Answer 12

bell - no response

Question 13

conditioned stimulus in pavlov

Answer 13

bell + food - salivation

Question 14

conditioned response

Answer 14

bell no food - salivation

Question 15

backwards pairing

Answer 15

unconditioned stimulus comes before the conditioned stimulus

Question 16

forward pairing

Answer 16

conditioned stimulus comes before unconditoned stimulus

Question 17

aplysia’s NS consists of _______________ and these communicate through ____________. as well, they are arranged in _____________________

Answer 17

ganglia
connectives
bilaterally symmetrical pairs

Question 18

the abdominal ganglion in an aplysia are ________, and their function is to control ____________ (3). they contain __________________________, ___________________, and __________________ involved in the ___________ withdrawal reflex

Answer 18

unpaired
heart rate, blood circulation, and respiration
primary sensory neurons, interneurons and motor neurons involved in the gill and siphon

Question 19

serotonin, when present, temporarily _______

Answer 19

closes potassium channels (s current) in sensory neuron

Question 20

when serotonin is present, repolarization of membrane potential is ___________
then there is an increase in _______ influx
and therefore an increase in ________ release and enhanced ______

Answer 20

slowed
calcium
transmitter
excitability

Question 21

cAMP acts as a ________ and activates _____

Answer 21

second messenger
PKA

Question 22

active PKA _______ substrate proteins

Answer 22

phosphorylates