Abstract (eng)
Meditation can be seen as a mental training, which supports the cultivation of well-being, awareness and other beneficial properties by improving cognitive traits, like attention and emotion. It is hypothesised that this long-term mental training may influence the mind and the body in a sustainable manner, subsequently leading to observable changes in the brain. A former study showed that the P3a brain potential – which is thought to be an index for attentional engagement – was decreased during a form of open monitoring meditation compared to a mind-wandering state in long-term meditators during distractor tone presentation. It is hypothesised that a more concentrative practice, like focused attention meditation, may facilitate a narrowing of the attentional focus in such a way that even stronger alterations in this P3a event-related potential amplitude can be expected. Therefore, meditators in this thesis were encouraged to perform focused attention and open monitoring meditation to account for P3a amplitude differences between both types of meditation and the two control conditions (active listening, mind-wandering), where no meditative state was to be reached. In addition, a control group was asked to perform the same tasks, to account for trait effects. A three-stimulus auditory oddball paradigm was presented to the participants to gain reliable ERP responses. Overall, no state effects in the form of lower P3a amplitudes during open monitoring and focused attention meditation compared to the mind-wandering condition were observed. However, a comparison to the active listening state revealed lower amplitudes for both types of meditation, but also for mind-wandering. Further, the comparison between the two types of meditation yielded no significant differences. These results suggest that the inducement of a meditative state does not affect attentional systems in the form of altered P3a amplitudes. Although no state effects were experimentally verified, it seemed that long-term mental training can lead to sustainable trait changes. In this regard, the comparison between the meditators and the control group revealed significantly lower P3a amplitudes during all conditions for meditators over central and posterior midline electrode sites. These results suggest that long-term meditation influences the brain in a way that unexpected and distracting auditory stimuli are processed differently, indicating less automated reactivity of the brain as a trait effect. As a consequence, gained results imply that meditation, practised over a long period of time, may induce neuroplasticity, in the form of altered brain processes.