lecture 6

Question 1

aversive stimulus applied AFTER habituation results in

Answer 1

reflex responsiveness/vigour Is RESTORED

Dishabituation undoes the effects of prior habituation

Question 2

what happens to reflex responsiveness / vigour after aversive stimulation if is has NOT previously been habituated

Answer 2

responsiveness and vigour increases= reflex sensitisation

Question 3

sensitisation occurs mainly in

Answer 3

defensive reflexes , avoidance and related reflexed like orienting and startle reflexes

Question 4

sensitisation is the opposite effect

Answer 4

to habituation and is responsible for dishabituation - undoing the effects of habituation

Question 5

sensitisation differs from habituation

Answer 5

occurs quickly - reaches maximum quickly and fewer stimuli are needed
non specific - effects of habituation are confined to the elicited response but sensitisation affects all defensive avoidance and relatedness

Question 6

sensitisation exhibits both

Answer 6

short and long term forms

Question 7

short term

Answer 7

a SINGLE aversive stimulus may be sufficient to produce a short term sensitisation effect that lasts from a few minutes to a few hours

Question 8

more aversive stimuli are needed to produce a

Answer 8

noticeable effect

Question 9

long term

Answer 9

repeated sessions separated by several hours produce a long term effect that can last days/weeks

Question 10

dual process theory

Answer 10

2 simultaneously active process - habituation and sensitisation

Question 11

opposite effects -

Answer 11

habituation - reduces reflex responsiveness

sensitisation - increases reflex responsiveness

Question 12

the dual process theory proposes that

Answer 12

habituation is always engaged by an eliciting stimulus

sensitisation process may be engaged- depends upon how aversive/arousing the stimulus is

Question 13

when an eliciting stimulus is presented both processes

Answer 13

are engaged , depend on which process has the larger effect

Question 14

if the eliciting stimulus is NON AVERSIVE

Answer 14

the habituation process proceeds and the responsiveness of the reflex declines

Question 15

if the eliciting stimulus is AVERSIVE

Answer 15

habituation process is still automatically engaged but its effects are COUNTERACTED by a STRONGER SENSITISATION process- so responsiveness INCREASES

Question 16

No stimulation

Answer 16

neither process is engaged

Question 17

non aversive

Answer 17

habituation engaged

sensitisation weakly engaged

Question 18

aversive

Answer 18

sensitisation is strongly engaged

habituation weakly engaged

Question 19

what happens if both processes have equal strengths

Answer 19

both processes engaged but CANCEL each other out

reflex responsiveness does not change

Question 20

what is the neural basis of reflex habituation

Answer 20

habituation effects are observed in very simple neural circuits in simple animals like sea slugs and worms

Question 21

gill withdrawal reflex

Answer 21

reflex mediated by a simple neural circuit

connectivity is both mono and disynaptic

Question 22

Sensory neuron connects

Answer 22

monosynaptically with the motoneuron

interneuron disynaptically

Question 23

a brief tickle of the siphon elicits a

Answer 23

rapid gill withdrawal

Question 24

a few tickles repeated with an ISI inter stimulus interval will

Answer 24

quickly habituate the response

Question 25

what changes in the circuit as a result of repeated tickling

Answer 25

the effectiveness (strength) of the synaptic connections

Question 26

the synaptic terminals of the SN’S release

Answer 26

less transmitter substance in response to the arrival of AP’S - So less excitatory effect on interneuron and motor neuron

Question 27

this strength change only happens if the effects of the

Answer 27

previous transmitter are PRESENT when the next release occurs

Question 28

a short inter stimulus interneuron is needed if its too long

Answer 28

the effects of previous stimulus have worn off - no change

Question 29

long term habituation

Answer 29

if sessions of repeated tickling with short inter stimulus interneurons are repeated a long term effect is produced

Question 30

structural changes of habituation

Answer 30

reduced number of changes - pruning

reduction of efficacy/strength - homosynaptc depression

Question 31

gill withdrawal reflex

Answer 31

short term sensitisation
presynaptic connections cause increased neurotransmitter release - increase in withdrawal response strength
opposite of short term habituation

Question 32

long term sensitisation

Answer 32

produced by a series of sessions of shock delivery

associated with structural changes in the synaptic connections - increased in the number of connections

Question 33

short term sensitisation undoes the

Answer 33

changes associated with short term habituation but not long term habituation

Question 34

are all learned changes a result of habituation or sensitisation

Answer 34

no
person standing on an horizontal platform
it unexpectedly and rapidly tilts through- toes up direction - produces a quick stretch of the calf muscle
the stretch will evoke a stretch reflex response

Question 35

what happens when you make tilts a random intervals -

Answer 35

habitual protocol but it is not

Question 36

why is it not an habituation effect

Answer 36

reduction is only present if the person continues to stand up
if they sit or lie down , response is back to normal

Question 37

in a sitting position stretches of the calf muscle produces

Answer 37

no change in reflex response amplitude

Question 38

reduction cannot be

Answer 38

dishabituated by presenting aversive stimuli

Question 39

decline in calf muscle stretch reflex was due to

Answer 39

a contraction of the calf muscle when standing in this posture PULLS you backwards - destabilising effects on upright posture

Question 40

associative learning g

Answer 40

animal learns to suppress a reflex response that has unwanted consequences

Question 41

non associative learning

Answer 41

habituation and sensitisation = no consequences