Manipulating the Nature of Internal Stimuli Through Conditioning
About the Project
Shifting motivational value is a fundamental biological phenomenon that enables flexible adaptive behavioural modifications in response to alterations of an animal’s state. In particular, an internal, or interoceptive state can be learned to be appetitive or aversive depending on the context in which it is typically experienced. That is, learned valuation of an internal stimulus can make the perception of said stimulus appetitive or aversive and thereby alter the pattern of behaviour performed in that interoceptive state. The long term goals of my research program are to determine the behavioural and neural mechanisms by which the effects of differential learned experiences can shift motivational values of interoceptive stimuli.
In my laboratory, my trainees and myself use drugs that alter interoceptive state to assess the impact associative learning history on the value of that interoceptive state. This is done by explicitly creating associations between drug experience with appetitive or aversive unconditioned stimuli and measuring the impact on the reinforcing and reward efficacy of the drug. There are early data indicating that the motivational value of an interoceptive stimulus is enhanced by prior pairing with an appetitive sucrose stimulus, and I have shown that an interoceptive stimulus can acquire conditioned inhibitory properties by virtue of being explicitly unpaired with an appetitive stimulus. Furthermore, I have demonstrated that the interoceptive stimulus successfully competes with an exteroceptive conditioned stimulus for control of appetitive behaviour, a finding in keeping with Pavlovian literature focusing only on competition between exteroceptive stimuli for behavioural control.
In the next five years, my trainees and I will begin systematically testing the shifting in reinforcement value valence of a range of inherently differentially-motivational interoceptive stimuli by training drugs as conditioned stimuli and/or occasionsetters for appetitive or aversive associations by assessing subsequent changes in patterns of self-administration and place conditioning. The specific objectives of my research program over the next five years include 1) determining the behavioural impact of interoceptive conditioning history on value for distinct interoceptive states and underlying associative behavioural structures; 2) determining the effects of competitive extinction of an interoceptive drug stimulus element of a compound interoceptive/exteroceptive conditioned stimulus on the subsequent stimulus value; and 3) beginning to elucidate the neural circuitry underlying the perception of an interoceptive stimulus and how such manipulations alter its acquired appetitive or aversive value. Our research cuts across the boundaries of neuropsychopharmacology and learning theory and will advance our understanding of the behavioural and neural mechanisms underlying behaviour motivated by interoception.