Cerebral perfusion abnormalities in abstinent cocaine abusers: a perfusion MRI and SPECT study

246

202

Brain imaging studies find evidence of prefrontal cortical dysfunction in cocaine-dependent subjects. Similarly, cocaine-dependent subjects have problems with behaviors related to executive function and impulsivity. Since prefrontal cortical axonal tracts cross between hemispheres in the corpus callosum, it is possible that white matter integrity in the corpus callosum could also be diminished in cocainedependent subjects. The purpose of this study was to compare corpus callosum white matter integrity as measured by the fractional anisotropy (FA) on diffusion tensor imaging (DTI) between 18 cocaine-dependent subjects and 18 healthy controls. The Barratt Impulsiveness Scale (BIS-11) and a continuous performance test: the Immediate and Delayed Memory Task (IMT/DMT) were also collected. Results of the DTI showed significantly reduced FA in the genu and rostral body of the anterior corpus callosum in cocainedependent subjects compared to controls. Cocaine-dependent subjects also had significantly higher BIS-11 scores, greater impulsive (commission) errors, and reduced ability to discriminate target from catch stimuli (discriminability) on the IMT/DMT. Within cocaine dependent subjects there was a significant negative correlation between FA in the anterior corpus callosum and behavioral laboratory measured impulsivity, and there was a positive correlation between FA and discriminability. The finding that reduced integrity of anterior corpus callosum white matter in cocaine users is related to impaired impulse control and reduced ability to discriminate between target and catch stimuli is consistent with prior theories regarding frontal cortical involvement in impaired inhibitory control in cocainedependent subjects.

Section: Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Reduced Anterior Corpus Callosum White Matter Integrity is Related to Increased Impulsivity and Reduced Discriminability in Cocaine-Dependent Subjects: Diffusion Tensor Imaging

Moeller

Hasan

Steinberg

et al. 2004

246

202

“…Although these findings indicate that the frontal lobes are a major target for cocaine's effects, prior functional brain-imaging studies in cocaine-dependent subjects noted impairments in other brain areas including the cerebellum (Gottschalk and Kosten, 2002) as well as in prefrontal and limbic cortex (Ernst et al, 2000;Volkow et al, 1988). An animal study has also reported cocaine-induced microscopic lesions in cerebellum (Barroso-Moguel et al, 2002).…”

Section: Introductionmentioning

confidence: 82%

Cerebellar Gray Matter Volume Correlates with Duration of Cocaine Use in Cocaine-Dependent Subjects

Sim

Lyoo

Streeter

et al. 2007

167

119

This study was conducted to explore differences in gray and white matter volume between cocaine-dependent and healthy comparison subjects using optimized voxel-based morphometry (VBM). Brain magnetic resonance imaging (MRI) and neuropsychological function tests were performed for 40 cocaine-dependent subjects (41.476.9 years, 27 men) and 41 healthy age-and sex-matched comparison subjects (38.778.8 years, 26 men). Optimally normalized whole brain MR images were segmented, modulated, smoothed, and compared between groups with statistical parametric mapping. The cocaine-dependent group had lower gray matter volumes in bilateral premotor cortex (Brodmann area (BA) 6, 8; 16.6%), right orbitofrontal cortex (BA 10, 15.1%), bilateral temporal cortex (BA 20, 38; 15.9%), left thalamus (12.6%), and bilateral cerebellum (13.4%) as well as lower right cerebellar white matter volume (10.0%) relative to the comparison group at a corrected po0.05 for multiple comparisons. Duration of cocaine use negatively correlated with right and left cerebellar gray matter volumes (r ¼ À0.37, r ¼ À0.39, respectively). In cocaine-dependent subjects, lower cerebellar hemispheric gray and white matter volumes were correlated with deficits in executive function and decreased motor performance. This study reports that cocaine-dependent subjects have lower gray matter volumes in cerebellar hemispheres as well as in frontal, temporal cortex, and thalamus. These findings are the first to suggest that the cerebellum may be vulnerable to cocaine-associated brain volume changes, and that cerebellar deficits may contribute to neuropsychological deficits and motor dysfunction frequently observed in cocaine-dependent subjects.

“…Gender differences in cerebral perfusion and metabolites of frontal white matter have also been reported in those who abuse cocaine, an addictive psychostimulant like MA. Male cocaine users have decreased rCBF and NAA/creatine ratio, while female cocaine users had increased rCBF and higher myoinositol/creatine ratio in frontal white matter, compared to their gender-matched comparison subjects (Chang et al, 1999;Ernst et al, 2000b;Tucker et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

Frontal Glucose Hypometabolism in Abstinent Methamphetamine Users

Kim

Lyoo

Hwang

et al. 2005

111

Changes in relative regional cerebral glucose metabolism (rCMRglc) and their potential gender differences in abstinent methamphetamine (MA) users were explored. Relative rCMRglc, as measured by 18 F-fluorodeoxyglucose positron emission tomography, and frontal executive functions, as assessed by Wisconsin card sorting test (WCST), were compared between 35 abstinent MA users and 21 healthy comparison subjects. In addition, male and female MA users and their gender-matched comparison subjects were compared to investigate potential gender differences. MA users had lower rCMRglc levels in the right superior frontal white matter and more perseveration and nonperseveration errors in the WCST, relative to healthy comparison subjects. Relative rCMRglc in the frontal white matter correlated with number of errors in the WCST in MA users. In the subanalysis for gender differences, lower rCMRglc in the frontal white matter and more errors in the WCST were found only in male MA users, not in female MA users, relative to their gender-matched comparison subjects. The current findings suggest that MA use causes persistent hypometabolism in the frontal white matter and impairment in frontal executive function. Our findings also suggest that the neurotoxic effect of MA on frontal lobes of the brain might be more prominent in men than in women.