Extensions of Pavlovian Conditioning

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The cognitive chess game:

Excitation and Inhibition

Starting point for what would appears to be a highly complex set of learning rules. Not really that bad as long as you realize that from the Pavlovian point of view

all stimuli (CSs) have the potential to be inhibitory+or excitatory-, that is the stimulus signal response decrease if the CS is inhibitory and response increase if it is excitatory. This dual process is also true in other areas of learning, also true in the nervous system (excitatory and inhibitory potentials), vision (excitatory and inhibitory receptive fields.

Inhibition and Excitation.

Beyond CRs, SPC, HOC

I. Simple Conditioning: Trials consists of a tone (of light) followed by a shock. Trials continue until a substantial

CR (fear) is produced to the tone. Excitation to CS light

1)Excitation: Normal forward conditioning in which CS is paired with UCS and the CR resembles the UCR. CS elicits or Excites the production of the CR. Or the UCS is not presented

II.) Inhibition is a type of classical conditioning in which the conditioned stimulus (CS) becomes a signal for the absence of the unconditioned stimulus (UCS). In Pavlov's world all stimuli are excitatory or inhibitory depending on the history the CS has had with the UCS. EXAMPLES: Extinction

a)External Inhibition:

Temporary disruption of conditioned response (CR) due to presentation of external stimuli. (non-associative)

Example: Presenting a novel stimulus (noise, smoke, light) will immediately inhibit, albeit, temporarily the production of a CR. Novel stimulus inhibits CR.

b)Disinhibition (also non-associative) occurs when a novel stimulus occurs during extinction causing the opposite effect in 2a. A novel stimulus presentation during extinction increase the strength of the conditioned stimulus (CR).

Novelty inhibits inhibition and that is referred to as disinhibition.

c) Latent Inhibition:

often time called the stimulus pre-exposure effect. Reduced associability of familiar stimuli

Stage 1 CS 1 alone/zilch

Stage 2 CS1 > UCS

Stage 3 CS1 reduced relative to when no pre-exposure allowed.

Control group for Latent Inhibition

Stage 1 Nothing

Stage 2 CS1 > UCS

Stage 3 CS1 produces robust CR

d) Inhibition of delay:

Passage of time can produce an inhibitory process. Responding is suppressed or inhibited during the first part of a regularly spaced interval.

CS-a-----------------b-UCS

(trace) Present novel stimulus as a you get disinhibition or place novel stimulus a b yoou get inhibition

e) Blocking (Kamin) inhibition: Multiple Cues

To make the conditioning situation more realistic, we need to consider what happens when many contextual cues are present

simultaneously. The most important situation where many cues interact is in a blocking experiment (Kamin 1968). In this type of learing, CS1 is first paired with the US using any of the paradigms described until an association has been established.

On later trials, two cues, CS1 and CS2, are simultaneously paired with the US. Had the CS2 been paired on its

own, it would have established an association with the US, but when it is paired together with the CS1, the result is different. If the CS2 is later presented on its own, no CR will be produced, which means that no association has been formed between theCS2 and the US (or UR).

Kamin Blocking is also referred to as overshadowing inhibition.

1) CS1 > Shock CR fear

2) CS1 + CS2 > shock

3) test CS2/no CR

Overshadowing effect.

Folowing excitation conditioning of CS1, the failure to condition CS2.

f) Compound conditioning

CS1 + CS2 > UCS Will the CR occur to CS1 or CS2 or both or neither. Depends