Zeroing in on specific brain regions when studying drug and alcohol abuse simplifies research but may leave out important insights. In fact, the landscape of the entire brain reorganizes during withdrawal, potentially hindering communication between regions, according to new research in mice published in eNeuro.
Kimbrough et al. administered psychostimulant drugs to mice (cocaine, methamphetamine, or nicotine) for one week then measured their neuronal activity during withdrawal. For all three drugs, the withdrawal brain state displayed increased functional connectivity — a measure of synchronized activity and communication between brain regions —compared to the control brain state. Withdrawal, however, shuffled which brain regions activated at the same time. The control brains displayed normal modularity, where small groups of brain regions activate together. The brains undergoing withdrawal, on the other hand, possessed large groups of coactivated brain regions, representing decreased modularity. This also occurs during traumatic brain injury and Alzheimer's disease and implies impaired neural communication. These results indicate changes in brain modularity may be a universal effect of different types of addictive drugs.
