Weaker Brain Network Connectivity in Abstinent Smokers
Reduced resource allocation index predicts abstinence-induced cravings to smoke
MONDAY, March 17, 2014 (HealthDay News) -- Abstinent smokers show weaker brain inter-network connectivity between the salience, executive control, and default modes, according to a study published online March 12 in JAMA Psychiatry.
Caryn Lerman, Ph.D., from the University of Pennsylvania in Philadelphia, and colleagues conducted a within-subject functional magnetic resonance imaging study to compare resting-state functional connectivity coherence strength after 24 hours of abstinence and after smoking satiety. The correlations between abstinence-induced changes in the resource allocation index (RAI; reflecting the combined strength of interactions among the networks) and alterations in subjective, behavioral, and neural functions were examined for 37 healthy smoking volunteers, aged 19 to 61 years.
The researchers found that, in the abstinent versus the smoking satiety states, the RAI was significantly lower (left RAI, P = 0.002; right RAI, P = 0.04), indicative of weaker inhibition between the default mode and salience networks. Reduced RAI predicted abstinence-induced smoking cravings (P = 0.007) and less default mode activity suppression during subsequent working memory task performance (ventromedial prefrontal cortex, P = 0.003 and posterior cingulate cortex, P = 0.001).
"Alterations in coupling of the salience and default mode networks and the inability to disengage from the default mode network may be critical in cognitive/affective alterations that underlie nicotine dependence," the authors write.
One author disclosed financial ties to Pfizer.