An extensive body of scientific literature exists describing the many neurological correlates and consequences of addiction and addiction-related behavior. However, whole-brain network scans are a more novel approach and, according to the authors of a recent study in NeuroImage: Clinical, may be able to reveal important disruptions during certain psychological processes in addicted and abstinent individuals.
The study examined the brains of 68 control individuals and 83 currently abstinent individuals. Substances used in the second group included alcohol, cocaine, and opiates. The authors used a monetary incentive delay task to measure brain activity while waiting for a reward, a psychological process with demonstrated abnormalities among addicted and recovering individuals.
While the two groups were well-matched in terms of their performance in the task, the abstinent individuals showed significant disruptions at a global level, with reduced clustering and higher path length.
In network analysis, clustering coefficient is a key measure of connectivity, increasing with the average number of connections between nodes (in this case, brain sites). Path length refers to the minimum distance in a network that information has to travel to get from one point to another; the more connected a network, the lower the path length. Thus, low clustering coefficients and high paths lengths indicated an overall reduced state of inter-region connectivity.
The findings are particularly significant in that they demonstrate the degree to which substance abuse affects neurophysiology and, downstream, psychology and behavior, but also because whole-brain techniques provide a novel way for understanding and perhaps combating these consequences. Network analysis, for example, demonstrated disruptions in reward-related connectivity in the addiction-group, touching on cognitive, striatal and limbic regions.
Despite the vast body of literature already dedicated to the neurology and psychology of addiction, there is still much that remains unknown and, importantly, few interventions that are truly long-lasting and effective. Novel approaches like the present study thus represent a key opportunity for developing more effective interventions.