The paraventricular nucleus of the thalamus is differentially recruited by stimuli conditioned to the availability of cocaine versus palatable food

Addict Biol. 2017 Jan;22(1):70-77. doi: 10.1111/adb.12280. Epub 2015 Jun 19.


The paraventricular nucleus of the thalamus (PVT) is not traditionally considered part of the brain addiction neurocircuitry but has received growing attention with regard to a role in the modulation of drug-seeking behavior. This study sought to establish the pattern of neural activation induced by a response-reinstating discriminative stimulus (SD ) conditioned to either cocaine (COC) or a conventional reinforcer using a palatable food substance, sweetened condensed milk (SCM). Male Wistar rats were trained to associate one SD (S+ ; COC or SCM availability) and a distinctly different SD (S- ; non-reward; i.e. the availability of saline or the absence of SCM). Following extinction of COC- and SCM-reinforced responding, rats were presented with the respective S+ or S- alone and tested for the reinstatement of reward seeking. The COC S+ and SCM S+ elicited identical reinstatement, whereas the non-reward S- was behaviorally ineffective. PVT sections were obtained following completion of the reinstatement tests and labeled for Fos. The number of Fos+ neurons was compared among rats that were presented with the COC S+ , SCM S+ or S- . Rats that were presented with the COC S+ exhibited a significant increase in Fos expression compared with rats that were presented with the S- . Moreover, Fos expression was significantly correlated with the number of reinstatement responses that were induced by the COC S+ . In contrast, the SCM S+ and S- produced identical increases in Fos expression, without behaviorally relevant correlations. The findings implicate the PVT as an important site that is selectively recruited during COC-seeking behavior.

Keywords: Cocaine; discriminative stimulus; reinstatement.

MeSH terms

  • Animal Feed*
  • Animals
  • Behavior, Animal / drug effects*
  • Cocaine / pharmacology*
  • Conditioning, Operant / drug effects*
  • Cues
  • Dopamine Uptake Inhibitors / pharmacology
  • Drug-Seeking Behavior / drug effects*
  • Male
  • Models, Animal
  • Paraventricular Hypothalamic Nucleus / drug effects*
  • Rats
  • Rats, Wistar
  • Self Administration
  • Thalamus / drug effects


  • Dopamine Uptake Inhibitors
  • Cocaine