The neural consequences of repeated cocaine exposure revealed by functional MRI in awake rats

Marcelo Febo, Annabell C. Segarra, Govind Nair, Karl Schmidt, Timothy Q. Duong, Craig F. Ferris

Research output: Contribution to journalArticle

78 Scopus citations

Abstract

The use of functional magnetic resonance imaging (fMRI) in animal models of cocaine addiction is an invaluable tool for investigating the neuroadaptations that lead to this psychiatric disorder. We used blood-oxygen-level-dependent (BOLD) MRI in awake rats to identify the neuronal circuits affected by repeated cocaine administration. Rats were given an injection of cocaine (15mg/kg, i.p.) or its vehicle for 7 days, abstained from injections for 1 week, and challenged with an intracerebroventricular cocaine injection during functional imaging. Acute cocaine produced robust positive BOLD responses across well-known monoamine-enriched brain regions, such as the prefrontal cortex, nucleus accumbens, dorsal striatum, sensory cortex, hippocampus, thalamus, and midbrain areas. However, repeated cocaine administration resulted in lower BOLD responses in the prefrontal cortex, agranular insular cortex, nucleus accumbens, ventral pallidum, and dorsomedial thalamus, among other brain regions. Reductions in BOLD intensity were not associated with variations in cerebrovascular reactivity between drug naïve rats and those repeatedly exposed to cocaine. Therefore, the lower metabolic activation in response to cocaine could reflect a reduced neuronal and/or synaptic activity upon repeated administration.

Original languageEnglish (US)
Pages (from-to)936-943
Number of pages8
JournalNeuropsychopharmacology
Volume30
Issue number5
DOIs
StatePublished - May 2005

Keywords

  • Awake rat
  • BOLD imaging
  • Cocaine
  • Drugs of abuse
  • Functional MRI
  • Reward circuitry
  • Sensitization

ASJC Scopus subject areas

  • Pharmacology
  • Psychiatry and Mental health

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