Lecture 16: Brain Circuits Mediating Pavlovian-Instrumental Transfer

What is general PIT?

A stimulus that predicts an outcome ( e.g food) enhances performance that procures food. For example lunch time making you hungry and encouraging you to go and get some food.

What is a specific PIT?

A stimulus that predicts an outcome (e.g. food) that biases choice towards actions procuring that same food. For example, the golden archs encouraging you to go get maccas.

Describe how they test general PIT?

I

n general PIT, S1 - O1 is associated with food, and another S2 is associated with the absence of food in the first stage. In the instrumental stage, a lever is associated with another outcome. Then general transfer is measured at test, when rat stops responding to lever due to lack of outcome, outcome is reinstated, and lever response is measured to S1 or S2,
A general PIT effect is shown when the S1 response is more than S2 response.

Describe how they test specific PIT?

In a specific PIT, S1 is associated with food and S2 is associated with water. In the instrumental stage lever 1 is associated with O1 and lever 2 is associated with O2. At test, after ceasure of responding, each S1 and S2 is presented and the amount of conditioned response is demonstrated.
What is generally found in tests of specific PIT is that when S1 is on, there is more responding on A1 than A2, and when S2 is on, there is more responding on A2 than A1. In other words, a stimulus predicting a particular outcome increases performance on an action delivering that same outcome.

What is the graph associated with general PIT?

What is the graph associated with specific PIT?

Describe the 3 CS pit design?

Stimuli S1, S2, and S3 each predict a specific food outcome (O1, O2, O3). During the instrumental stage, Rats learn that two outcomes (O1 and O2) can be earned by performing specific actions (e.g., left and right lever presses) During the test phase, Lever pressing is measured during, Each of the three Pavlovian stimuli (S1, S2, S3) being presented and with a baseline period with no stimuli.

What does the 3 CS pit design find and why does this not make sense?

S1 and S2 both trigger specific PIT, that is, S1 increases A1 but not A2 whereas S2 increase A2 but not A1. responding on the same lever is greater than the difference lever, S3 generates general responding on both A1 and A2.
Begs the question, S3 (GENERAL RESPONDING) enhances performance on both A1 and A2, but why isn’t S1 or S2 enhancing performance on A2 or A1? —> suggest that there are two distinct phenomena driving these types of responses.

Explain the two types of Outcome Properties?

Motivational appetitive vs. aversive • Sensory specific food vs water. Question of if changing these outcome properties will change the way general vs. specific PIT is presented

How did they use the 3S design to test how changes in motivational states influence responding?

Used the same 3 stages, however, there are two transfer tests, one when the rat is hungry and one when the rat is stated.
In this case, the experiment found that during the hunger test - there was still evidence of the specific PIT as, the Same responding was more than the different responding, and evidence of general PIT, as the general was more that pre(noCS).
However during the stated test, there was evidence of specific pit.

Explain the model of outcome processing in the amygdala?

in this model,
The central amygdala (CeA) encodes the motivational value (valence) of the CS–US association and triggers preparatory conditioned responses (CRs), e.g approach or withdrawal.
The basolateral amygdala (BLA) encodes the sensory-specific details of the CS–US association and generates consummatory responses tailored to the specific outcome, e.g freezing
Thus, the CeA and BLA support different types of CRs based on motivation vs. specific sensory features of the expected outcome.

How did they test which portions of the amygdala are necessary for general vs. specific PIT?

They gave the rats lesions in either the BLA or the CeA, and performed the 3 x PIT test,
Found that BLA is necessary for specific PIT, but not general PIT and that CeA is necessary for general PIT but not specific PIT.

Which type of PIT is associated with habitual actions?

We have seen in the experiment involving a shift in motivational state that goal directed actions become insensitive to outcome value in specific PIT. This suggests that they may become habitual.

What does DLS and DMS inactivation in specific PIT do?

Recall that the DLS is critical for habits and the posterior DMS is critical for goal-directed actions.
In this study, rats were injected with muscimol in the DLS or DMS, this found that DMS is important for specific PIT, with cessation of effect with lesions, lesions in the DLS only influenced overall performance.

What is a specific PIT about?

Specific PIT is really about action selection and not performance.

What did core vs. shell inactivation of the nucleus accumbens do?

Same 3S test, found that shell is needed for specific PIT, and cores is critical for general PIT.

Give a general summary of general PIT?

A stimulus predicting food elevates performance on an action delivering food • A1 S1 > no S • Abolished by shifts in motivational states • Triggered by the general motivational properties of the outcome predicted by the stimulus • Relies on CeA, NAc Core

Give a general summary of specific PIT?

A stimulus predicting a particular food increases performance on an action earning the same food ◦ S1 { S2

A1 < A2 ◦ Survives shifts in motivational states and outcome devaluation ◦ Triggered by the sensory-specific properties of the outcome predicted by the stimulus ◦ Relies on BLA, pDMS, NAc Shell.