Opioid withdrawal results in an increased local and remote functional connectivity at EEG alpha and beta frequency bands.

Withdrawal may be a natural model to study craving and compulsive drug seeking, since craving can be viewed as a conditioned dysphoric state. It has been suggested that functional connectivity between brain areas may be of major value in explaining excessive craving and compulsive drug seeking by providing essential link between psychological and biological processes. Considering that withdrawal initiates a widespread activation of cortical regions responsible for compulsive drug seeking and desire for the drug, we predict that withdrawal would result in a significant increase in functional cortical connectivity. We applied the novel operational architectonics approach that enables us to estimate both local and remote functional cortical connectivity by means of EEG structural synchrony measure. In 13 withdrawal opioid-dependent patients we found the evidence that local and remote cortical functional connectivity was indeed significantly enhanced (for both alpha and beta frequency oscillations). Additionally, statistical relationship between functional connectivity and the severity of opioid withdrawal has been found.