The role of melanin-concentrating hormone in conditioned reward learning.

Published

Journal Article

The orexigenic neuropeptide melanin-concentrating hormone (MCH) is well positioned to play a key role in connecting brain reward and homeostatic systems due to its synthesis in hypothalamic circuitry and receptor expression throughout the cortico-striatal reward circuit. Here we examined whether targeted-deletion of the MCH receptor (MCH-1R) in gene-targeted heterozygote and knockout mice (KO), or systemic treatment with pharmacological agents designed to antagonise MCH-1R in C57BL/6J mice would disrupt two putative consequences of reward learning that rely on different neural circuitries: conditioned reinforcement (CRf) and Pavlovian-instrumental transfer (PIT). Mice were trained to discriminate between presentations of a reward-paired cue (CS+) and an unpaired CS-. Following normal acquisition of the Pavlovian discrimination in all mice, we assessed the capacity for the CS+ to act as a reinforcer for new nose-poke learning (CRf). Pharmacological disruption in control mice and genetic deletion in KO mice impaired CRf test performance, suggesting MCH-1R is necessary for initiating and maintaining behaviors that are under the control of conditioned reinforcers. To examine a dissociable form of reward learning (PIT), a naïve group of mice were trained in separate Pavlovian and instrumental lever training sessions followed by the PIT test. For all mice the CS+ was capable of augmenting ongoing lever responding relative to CS- periods. These results suggest a role for MCH in guiding behavior based on the conditioned reinforcing value of a cue, but not on its incentive motivational value.

Full Text

Duke Authors

Cited Authors

  • Sherwood, A; Wosiski-Kuhn, M; Nguyen, T; Holland, PC; Lakaye, B; Adamantidis, A; Johnson, AW

Published Date

  • October 2012

Published In

Volume / Issue

  • 36 / 8

Start / End Page

  • 3126 - 3133

PubMed ID

  • 22775118

Pubmed Central ID

  • 22775118

Electronic International Standard Serial Number (EISSN)

  • 1460-9568

Digital Object Identifier (DOI)

  • 10.1111/j.1460-9568.2012.08207.x

Language

  • eng

Conference Location

  • France