The role of serotonin 1B in the representation of outcomes

Laura Corbit,Caroline Moul,Michael Kendig

doi:10.1038/s41598-019-38938-4

Laura Corbit, Caroline Moul + Show 1 more

Open Access

https://doi.org/10.1038/s41598-019-38938-4

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Abstract

Disrupted serotonin neurotransmission has been implicated in the etiology of psychopathic traits. Empirical research has found that people with high levels of psychopathic traits have a deficit in reinforcement learning that is thought to be linked with amygdala dysfunction. Altered serotonin neurotransmission provides a plausible explanation for amygdala dysfunction in psychopathic traits and recent research suggests that this may be associated with serotonin 1B (5-HT1B) receptor function. This research used an animal model to test the hypothesis that 5-HT1B receptors are involved in the encoding of the specific features of reinforcing outcomes. An outcome devaluation task was used to test the effect of the systemic administration of a selective 5-HT1B receptor agonist administered before encoding of “action-outcome” associations. Results showed that while administration of a 5-HT1B receptor agonist allowed rats to acquire instrumental responding for food, when the content of that learning was further probed using an outcome devaluation task, performance differed from controls. 5-HT1B agonism impaired learning about the specific sensory qualities of food rewards associated with distinct instrumental responses, required to direct choice performance when the value of one outcome changed. These findings suggest a role for 5-HT1B receptor function in the encoding of the specific features of reinforcing outcomes.

Highlights

Disrupted serotonin neurotransmission has been implicated in the etiology of psychopathic traits
We found that while peripheral administration of a selective 5-HT1B receptor agonist (CP94253) allowed rats to acquire instrumental responding for food, when the content of that learning was further probed using an outcome devaluation task, performance differed from controls
The results indicate that 5-HT1B agonism impairs learning about the specific sensory qualities of food rewards associated with distinct instrumental responses, required to direct choice performance when the value of one outcome has changed

Summary

Introduction

Disrupted serotonin neurotransmission has been implicated in the etiology of psychopathic traits. 5-HT1B agonism impaired learning about the specific sensory qualities of food rewards associated with distinct instrumental responses, required to direct choice performance when the value of one outcome changed. These findings suggest a role for 5-HT1B receptor function in the encoding of the specific features of reinforcing outcomes. One of the most informative tasks has been the response-reversal learning task These tasks typically begin with an acquisition phase in which stimuli are presented in pairs; one stimulus in each pair leads to reward when selected (e.g., win 100 points), and the other leads to a loss (e.g., lose 100 points). Their ability to associate a specific value with an arbitrary stimulus and judge this value relative to alternatives to optimize performance was impaired relative to the controls

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