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

UMMS Affiliation

Psychiatry Department

Publication Date


Document Type



Animals; Biogenic Monoamines; Brain; Brain Chemistry; Carbon Dioxide; Cocaine; Hemoglobins; Injections, Intraventricular; Magnetic Resonance Imaging; Male; Oxygen; Oxygen Consumption; Rats; Rats, Sprague-Dawley


Life Sciences | Medicine and Health Sciences


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 (15 mg/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 naive 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.

DOI of Published Version



Neuropsychopharmacology. 2005 May;30(5):936-43. Link to article on publisher's site

Journal/Book/Conference Title

Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology

Related Resources

Link to Article in PubMed

PubMed ID