Increased local and decreased remote functional connectivity at EEG alpha and beta frequency bands in opioid-dependent patients

Abstract

Although researchers now have a working knowledge of key brain structures involved in realization of actions of substance abuse and addiction, deeper understanding will require examination of network interactions between cortical neuronal assemblies and their subcortical tails in the effects of opioid dependence. Given that repeated exposure to opiates initiates a widespread reorganization of cortical regions, we predict that opioid dependence would result in a considerable reorganization of local and remote functional connectivity in the neocortex. We applied the novel operational architectonics approach that enables us to estimate two local and remote functional cortex connectivities by means of electroencephalogram structural synchrony measure. In 22 opioid-dependent patients, we found the evidence that brain functional connectivity was indeed disrupted by chronic opioid abuse (i.e., the local functional connectivity increased and remote functional connectivity decreased in opioid abusers). This significant difference between "opioid" and "control" populations was the same for alpha and beta frequency bands. Additionally, significant negative relations between duration (years) of daily opioid abuse and the number/strength of functional connections in the posterior section of the cortex were found.