Nicht-invasive Vagusnervstimulation fördert kooperatives Verhalten im Gefangenendilemma, bei Patient/-innen mit Epilepsie

Previous studies have shown that there is a significant influence of transcutaneous vagus stimulation on different neurocognitive skills. Animal and clinical studies have shown that transcutaneous vagus stimulation leads to an increase in reward learning. This is due to the influence of vagus stimulation on dopamine release in the central nervous system. It is known that transcutaneous vagus stimulation is used as a treatment option for drug refractory depression. It has been shown that vagus stimulation promotes a positive effect on patient mood. Although there is evidence of positive effects on cognitive and emotional influences, less is known about stimulation effects on social interaction. To prove if there is an influence of vagus stimulation on social interaction, cooperative behaviour was analysed in a repeated prisoner’s dilemma. 19 epilepsy patients played several rounds of the prisoner’s dilemma against putative human opponents and computers. Measurements took place on two test days, with subjects receiving sham stimulation on one day and transcutaneous vagus nerve stimulation on the other day. The order of stimulation was randomized. In a repeated measure ANOVA, as well as a logistic regression analysis, consistent results showed a stimulation effect. It was proven that subjects cooperated more often under vagal stimulation compared to the sham condition, in addition a significantly higher rate of cooperation when playing against humans was detected. Using the drift diffusion model in an extended analysis of the decision making process mainly early processes were influenced. These results suggest that stimulation leads to a shift in expectancy. Subjects tend to cooperate under stimulation before knowledge about the opponent of the current round could be accumulated. A shift in tendency and an increase in cooperation under stimulation suggests that transcutaneous vagus stimulation promotes intuitive prosocial behaviour patterns. Previous studies have shown that vagus stimulation influences brain regions that are relevant for attention, reward and emotions, but which transmitter system has the greatest influence remains open. Future studies using imaging and EEG data may reveal closer correlations. A better understanding of neuromodulation could help to establish transcutaneous vagus stimulation as a treatment option for neuropsychological disorders. The goal would be not only to influence behaviour, but also to reduce the use of side-effect-rich drugs. In conclusion, our clinical study provides evidence for a direct influence of transcutaneous vagus stimulation on social behaviour.