task 4 - classical conditioning

Question 1

4 key pavlovian conditioning terms

Answer 1

1. Unconditioned stimulus (US) – Biologically significant stimulus that elicits a natural reflexive response.
2. Unconditioned response (US) – Natural reflex elicited by US.
3. Conditioned stimulus (CS) – Cue that was previously neutral but that through training (conditioning) becomes associated with US
4. Conditioned response (CR) –Learned response to CS that has been paired with US.

Question 2

Conditioned compensatory responses

Answer 2

→ Results in tolerance – Decrease in reaction to a drug (or something else), so that larger doses are required to have similar effect.
- It occurs primarily in body system that has mechanism for homeostasis –Tendency to gravitate towards state of equilibrium.

Question 3

Extinction

Answer 3

process of reducing a learned response to a stimulus, by stopping to pair that stimulus with a reward/punishment

Question 4

the associations for extinction

Answer 4

→There are two associations: CS –US and CS –no US.
- Context determines which response is retrieved → If CS –US is unlearned in one context, it will appear in original one.
- Previously extinguished CS will be re-acquired more rapidly than a new CS.
→ Association that became ‘inhibited’ following extinction training will not be lost in its entirety →In fact, learned response is not gone, just unexpressed.

Question 5

Compound conditioning

Answer 5

Simultaneous conditioning of two cues, usually presented at same time.
 Two cues compete against each other – Neither produces as much learning as it would have, had it been trained alone.
- Example – When trained with tone and light, tone alone will have less association with US than if it had been trained alone

Question 6

Overshadowing

Answer 6

Effect seen in compound conditioning when a more salient cue within a compound acquires mere association strength than less salient cue.
 They produce less learning if they are trained alone.

Question 7

Rescorla-Wagner Model of Conditioning

Answer 7

Amount of change that occurs in association between a CS and a US depends on prediction error.

Question 8

prediction error

Answer 8

Difference between whether animal expects the US and whether the US actually occurs. There are three key situations to consider in interpreting prediction error

Question 9

negative error

Answer 9

Unconditioned stimulus does not take place even if it is predicted

Question 10

error-correction rule

Answer 10

It is basically this model (equation 1 and 2), because over many trials of learning, it reduces, or corrects, likelihood of prediction error.
- Equation 1 → Prediction error = Actual US –Expected US →Result is positive.
- Equation 2→ Negative error = Actual US – Expected US. →Result is negative.
- When Actual US and expected US are equal →No error →No learning.

Question 11

3 assumptions of process of learning by error-correction

Answer 11

1. Each CS has association weight that describes strength of association between cue and US.
   - Associative weight–Value representing strength of association between CS and US.
   Before training–A.W. are 0, meaning that when potential CS appears, there is no expectation that any US will follow.
   With learning–Animal discovers which stimuli predicts US and thus has strong weights.
2. Animal’s expectation of US can be described by sum of weights of all cues that are presented during trial.
   - In phase 1, expectation of US is V(light) and in phase 2, expectation of US is sum of weights of both those cues: V(light) + V(tone).
3. On each trial, learning is proportional to difference between outcome expected by animal and what actually occurs–Prediction error.

Question 12

how can the Rescorla-Wagner Model of Conditioning explain the blocking paradigm?

Answer 12

It demonstrates the general conclusion that for a potential CS to become associated with US, the CS must provide valuable new information that helps animal or person predict future.

Question 13

Modulation of CS processing

Answer 13

Conditioning paradigm in which prior exposure to CS retards later learning of the CS –US association during acquisition training.
→ Reduction in learning about a stimulus (CS) to which there has been prior exposure without any consequence (no US)
- Example-Control group → No pre-exposure to potential CS / Experimental group →CS presented without US

Question 14

US modulation theory of learning

Answer 14

It argues that manner in which US is processed, determines what stimuli become associated with that US

Ability of US to promote learning is modulated by how unexpected the US is, given the potential CS preceding it

Question 15

CS modulation theories of learning

Answer 15

They propose that way in which different potential CSs are processed, determines which becomes associated with US.

Class of learning theories that focus on CSs, suggesting various mechanisms that modulate the ability of potential CSs to enter into associations

Question 16

Mackintosh theory

Answer 16

Based on observation that people and animals have limited capacity for processing incoming information. This limited capacity means that paying attention to one stimulus, diminishes ability to attend to other stimuli

View on blocking–Previously conditioned stimulus derives its salience from its past success, as a predictor of important events. This happens at expense of other co-occurring cues that do not get access to our limited pool of attention

Question 17

Cerebellum

Answer 17

responsible for conditioned response only – Not for unconditioned response.

→ Cerebellum has two main regions:
1. Cerebellar cortex – Contains large, densely branching neurons called Purkinje cells.
2. Cerebellar deep nuclei – Includes interpositus nucleus.

Question 18

CS input pathway

Answer 18

 CS pathways from elsewhere in brain first project to pontine nuclei in brainstem
- Pontine nuclei have different sub-regions, one for each kind of sensory information
 CS information travels up to mossy fibers (deep nuclei of cerebellum) that branch in two directions:
1. Contacts with interpositus nucleus:
2. Projects towards cerebellar cortex (by way of Granule cells), across parallel fibers, then connecting to dendrites of Purkinje cells

Question 19

US input pathway

Answer 19

 US (airpuff) to eye activates neurons in inferior olive (brainstem), which in turn activate interpositus nucleus
 Second pathway from inferior olive projects to cerebellar cortex by means of climbing fibers
- Each climbing fiber wraps around each Purkinje cell and they have strong excitatory effect on them ( = large arrowhead at synaptic junction)

Question 20

CR output pathway

Answer 20

 Starts at Purkinje cells and project down from cerebellar cortex into deep nuclei, where inhibitory synapse if formed with interpositus. Deep nuclei (including interpositus) project the only output from cerebellum
- Eyeblink responses – Activity in interpositus projects to muscles in eye to generate eyeblink CR.

Question 21

blocking

Answer 21

a two-phase training paradigm in which prior training to one cue in which prior training to one cue (CS1 → US) blocks later learning of a second cue when the two are paired together in the second phase of training (CS1 + CS2 → US)

• only when a cue is both useful and a nonredunant predictor of the future

Question 22

tolerance

Answer 22

a decrease in reaction to a drug so that larger doses are required to achieve the same effect

• the dogs body lowing the heart rate to compensate for the adrenaline (knowing it is on its way into the dogs body)