Dorsomedial striatum lesions affect adjustment to reward uncertainty, but not to reward devaluation or omission

Carmen Torres, Amanda C. Glueck, Shannon E. Conrad, Ignacio Morón, Mauricio R. Papini

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

The dorsomedial striatum (DMS) has been implicated in the acquisition of reward representations, a proposal leading to the hypothesis that it should play a role in situations involving reward loss. We report the results of an experiment in which the effects of DMS excitotoxic lesions were tested in consummatory successive negative contrast (reward devaluation), autoshaping training with partial vs. continuous reinforcement (reward uncertainty), and appetitive extinction (reward omission). Animals with DMS lesions exhibited reduced lever pressing responding, but enhanced goal entries, during partial reinforcement training in autoshaping. However, they showed normal negative contrast, acquisition under continuous reinforcement (CR), appetitive extinction, and response facilitation in early extinction trials. Open-field testing also indicated normal motor behavior. Thus, DMS lesions selectively affected the behavioral adjustment to a situation involving reward uncertainty, producing a behavioral reorganization according to which goal tracking (goal entries) became predominant at the expense of sign tracking (lever pressing). This pattern of results shows that the function of the DMS in situations involving reward loss is not general, but restricted to reward uncertainty. We suggest that a nonassociative, drive-related process induced by reward uncertainty requires normal output from DMS neurons.

Original languageEnglish
Pages (from-to)13-25
Number of pages13
JournalNeuroscience
Volume332
DOIs
StatePublished - Sep 22 2016

Bibliographical note

Publisher Copyright:
© 2016 IBRO

Keywords

  • extinction spike
  • partial reinforcement
  • reward devaluation
  • reward omission
  • reward uncertainty
  • successive negative contrast

ASJC Scopus subject areas

  • General Neuroscience

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