Automatized actions in nicotine addiction: neural and behavioral correlates and their abstinence-induced plasticity

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In the course of addiction unconscious automatic processes which are encoded as "automatized action schemata", gain increasing control over the individual's behavior. They can be viewed as pathological habits, i.e. as strong stimulus-response-links, which are established during prolonged operant conditioning and are conveyed by interconnected subcortical structures as the amygdala, ventral and dorsolateral striatum as well as the ventral tegmental area. On the other hand, the frequent repetition of particular action sequences contributes to the quick, efficient and effortless performance of the strongly automatized action patterns. This aspect of the addiction schemata most probably involves the premotor cortex, superior parietal lobule and inferior temporal cortex/posterior middle temporal gyrus. In the current project the neural and behavioral correlates of action schemata are studied in nicotine addiction, where automatized mechanisms are of essential importance. The brain activation of smokers, non-smokers and former smokers shall be measured using functional magnetic resonance imaging (fMRI) while the participants complete two ecologically valid tasks reflecting the two main aspects of action schemata. Additionally, the connectivity within and between the assumed neural networks will be investigated. Important for the clinical relevance of the project is the question whether the neural and behavioral correlates of addiction-related automatisms can be fully eradicated by long-term abstinence, which will be examined by exploring the group differences between current and former smokers. Studying activation and connectivity differences between these three groups of participants could advance our knowledge about automatized action schemata in nicotine addiction and provide a first step towards the development of biomarkers for the severity of dependence and therapy success.