Cortical Thickness Abnormalities in Cocaine Addiction—A Reflection of Both Drug Use and a Pre-existing Disposition to Drug Abuse?

Abstract

Summary The structural effects of cocaine on neural systems mediating cognition and motivation are not well known. By comparing thickness of neocortical and paralimbic brain regions between cocaine dependent and matched control subjects, we found that four of 18 a priori regions involved with executive regulation of reward and attention were significantly thinner in addicts. Correlations were significant between thinner prefrontal cortex and reduced keypresses during judgment and decision-making of relative preference in addicts, suggesting one basis for restricted behavioral repertoires in drug dependence. Reduced effortful attention performance in addicts also correlated with thinner paralimbic cortices. Some thickness differences in addicts were correlated with cocaine use independent of nicotine and alcohol, but addicts also showed diminished thickness heterogeneity and altered hemispheric thickness asymmetry. These observations suggest brain structure abnormalities in addicts are related in part to drug use, and in part to predisposition toward addiction.

Cannabis Use Is Quantitatively Associated with Nucleus Accumbens and Amygdala Abnormalities in Young Adult Recreational Users

“…Pending confirmation in other cohorts of marijuana users, the present findings suggest that further study of marijuana effects are needed to help inform discussion about the legalization of marijuana. These results extend prior studies showing that drugs of abuse that are known to elevate DA release are associated with structural abnormalities in the brain and related disruptions in behavior (Makris et al, 2004;Makris et al, 2008). The multimodal convergence of these findings also points to the salience of structural differences in the brain related to drug exposure and strongly argues that human addiction research, if not all psychiatric study, must move past a predominant focus on neurotransmission.…”

“…The largest of the nucleus accumbens and amygdala volumes was the left amygdala (1848 mm 3 ), which, divided by a minimum cluster size of five voxels (40 mm 3 ), suggested a correction of 0.05/46.2 ϭ 0.001 (z ϭ 3.3) as a significance level for all non-max voxels in a target cluster. These methods have been used previously (Breiter et al, 1997;Makris et al, 2008;Blood et al, 2010;Blood et al, 2012). To supply information for follow-up hypotheses by other investigators, all clusters outside of the nucleus accumbens and amygdala that met these two criteria were also tabulated in Table 3.…”

Increased Sensorimotor Gating in Recreational and Dependent Cocaine Users Is Modulated by Craving and Attention-Deficit/Hyperactivity Disorder Symptoms

“…Marked structural and functional alterations in striatal and prefrontal regions have been reported in dependent cocaine users (DCU) (5)(6)(7)(8)(9). Furthermore, reduced striatal DA D2 receptor availability and blunted striatal DA release have repeatedly been shown to be associated with chronic cocaine use in humans using PET imaging (10)(11)(12)(13).…”

MAO A VNTR polymorphism and amygdala volume in healthy subjects

“…In fact, there are few morphological studies that, using voxel-based morphometry (VBM), indirectly investigated the association of this genotype with amygdala volume, and these studies produced contrasting findings (Meyer-Lindenberg et al, 2006;Cerasa et al, 2008b). VBM is a morphological technique that performs a statistical mapping of differences in brain morphology voxel-byvoxel, which produces grey matter "density" or "concentration" measures, or volume differences between two groups, respectively; however, these are relative measures and not absolute volumes (Eckert et al, 2006;Makris et al, 2008). Alternatively, manual/ automatic volumetry is a quantitative measurement of specific brain regions in individual brains.…”