Image: Neuronal, physiological and brain-behavioural abnormalities in opiate-addicted individuals

Illustrated are the group level dorsal anterior cingulate cortex (dACC) BOLD activation maps and the spatial location of the volume localized proton-MRS (superimposed in blue) on a sagittaly oriented structural MR image (MNI, Talairach brain) for healthy controls (panel a) and opiate-dependent subject (panel b). While both groups activated the dACC to comparable levels, the opiate-using group (i) failed to show the expected correlations between dACC physiological activity and behavioural measures of control (that is, response errors) shown by the control group, (ii) had significantly increased task-related activation of fronto-parietal and cerebellar regions to achieve a comparable level of behavioural control as healthy controls and (iii) exhibited significantly reduced concentrations of N-acetylaspartate (NAA) and glutamate/glutamine (Glx) within the dACC (panel c; horizontal bars represent mean values). Taken together, these findings suggest that neuronal abnormalities and a breakdown of normal brain–behaviour relationships within the dACC of opiate addicted individuals may result in the recruitment of a compensatory network of brain regions in situations requiring behavioural control. For more information on this topic, please see the article by Yucel et al. on pp 691–702.