Cortical-striatal integration of cocaine history and prefrontal dysfunction in animal modeling of dual diagnosis.
BACKGROUND
High rates of substance disorders in schizophrenia and other mental illnesses may reflect biological vulnerabilities to the addiction process. Interactions between addictive drug effects and mental illness involving circuits that generate motivated behavior may underpin this vulnerability.


METHODS
We examined separate and combined effects of neonatal ventral hippocampal lesions (NVHLs)-a neurodevelopmental model of schizophrenia (vs. SHAM-operated control animals)--and a behaviorally sensitizing cocaine history (15 mg/kg/day x 5 days vs. saline injections) on acute cocaine-induced neural activation signaled by c-Fos expression. Stereological assessment of activation densities spanned six ventral to dorsal cortical-striatal compartments.


RESULTS
Cortically, NVHLs showed hypoactivation and decreased volume of the ventral medial prefrontal cortex. In contrast, cocaine history was only expressed subcortically and as a hyperactivating effect in the dorsal striatum where significant NVHL-induced hyperactivation also emerged. Across all subjects and brain regions, only dorsal striatal activation was correlated with differences in sensitized locomotion. However, this activation was tightly correlated to a simple multiplicative function of ventral medial prefrontal hypoactivation and cocaine history-related increases in striatal activation.


CONCLUSIONS
These findings suggest drug history and developmental temporal limbic abnormalities associated with prefrontal dysfunction produce compounding effects within cortical-striatal circuits as mechanistic basis for dual diagnosis.
Chambers
R Andrew
RA
Laboratory for Translational Neuroscience of Dual Diagnosis & Development, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA. robchamb@iupui.edu
Sentir
Alena M
AM
Conroy
Susan K
SK
Truitt
William A
WA
Shekhar
Anantha
A
D000465:Algorithms; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology / Q000503:physiopathology*; D019970:Cocaine-Related Disorders / Q000473:pathology / Q000503:physiopathology*; D017831:Diagnosis, Dual (Psychiatry); D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects; D017072:Neostriatum / Q000473:pathology / Q000503:physiopathology*; D009434:Neural Pathways / Q000187:drug effects / Q000473:pathology / Q000502:physiology; D017397:Prefrontal Cortex / Q000473:pathology / Q000503:physiopathology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D016760:Proto-Oncogene Proteins c-fos