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Ergebnisse 3 Einträge
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Zusammenfassung Nachdem positive Wirkungen von Meditation auf die Gesundheit lange Zeit im Fokus der Forschung standen, liegen inzwischen auch Studien vor, die unangenehme Nebenwirkungen (adverse effects) von Meditation untersucht und dokumentiert haben. Dieser Beitrag gibt eine Übersicht über (1) das Spektrum solcher Nebenwirkungen, die von Schlafstörungen über Ängste und Depressionen bis hin zu Psychosen reichen können, (2) ihre Häufigkeit in klinischen und traditionellen Praxiskontexten und (3) Risikofaktoren, die ihr Auftreten begünstigen können, wie etwa psychische Erkrankungen in der Vorgeschichte, fehlende Begleitung oder eine intensive Praxis im Rahmen von Retreats. Die vorgestellten Forschungsergebnisse unterstreichen die Wichtigkeit, potenzielle Nebenwirkungen von Meditation eingehend zu erforschen, um an Meditation interessierte Menschen über die Risiken aufzuklären und darüber zu informieren, was beachtet werden sollte, um die Meditationspraxis so sicher wie möglich zu gestalten.
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Goal: We aimed to identify electroencephalographic (EEG) signal fluctuations within independent components (ICs) that correlate to spontaneous blood oxygenation level dependent (BOLD) activity in regions of the default mode network (DMN) during eyes-closed resting state. Methods: We analyzed simultaneously acquired EEG and functional magnetic resonance imaging (fMRI) eyes-closed resting state data in a convenience sample of 30 participants. IC analysis (ICA) was used to decompose the EEG time-series and common ICs were identified using data-driven IC clustering across subjects. The IC time courses were filtered into seven frequency bands, convolved with a hemeodynamic response function (HRF) and used to model spontaneous fMRI signal fluctuations across the brain. In parallel, group ICA analysis was used to decompose the fMRI signal into ICs from which the DMN was identified. Frequency and IC cluster associated hemeodynamic correlation maps obtained from the regression analysis were spatially correlated with the DMN. To investigate the reliability of our findings, the analyses were repeated with data collected from the same subjects 1 year later. Results: Our results indicate a relationship between power fluctuations in the delta, theta, beta and gamma frequency range and the DMN in different EEG ICs in our sample as shown by small to moderate spatial correlations at the first measurement (0.234 < |r| < 0.346, p < 0.0001). Furthermore, activity within an EEG component commonly identified as eye movements correlates with BOLD activity within regions of the DMN. In addition, we demonstrate that correlations between EEG ICs and the BOLD signal during rest are in part stable across time. Discussion: We show that ICA source separated EEG signals can be used to investigate electrophysiological correlates of the DMN. The relationship between the eye movement component and the DMN points to a behavioral association between DMN activity and the level of eye movement or the presence of neuronal activity in this component. Previous findings of an association between frontal midline theta activity and the DMN were replicated.
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Our focus of attention naturally fluctuates between different sources of information even when we desire to focus on a single object. Focused attention (FA) meditation is associated with greater control over this process, yet the neuronal mechanisms underlying this ability are not entirely understood. Here, we hypothesize that the capacity of attention to transiently focus and swiftly change relates to the critical dynamics emerging when neuronal systems balance at a point of instability between order and disorder. In FA meditation, however, the ability to stay focused is trained, which may be associated with a more homogeneous brain state. To test this hypothesis, we applied analytical tools from criticality theory to EEG in meditation practitioners and meditation-naïve participants from two independent labs. We show that in practitioners-but not in controls-FA meditation strongly suppressed long-range temporal correlations (LRTC) of neuronal oscillations relative to eyes-closed rest with remarkable consistency across frequency bands and scalp locations. The ability to reduce LRTC during meditation increased after one year of additional training and was associated with the subjective experience of fully engaging one's attentional resources, also known as absorption. Sustained practice also affected normal waking brain dynamics as reflected in increased LRTC during an eyes-closed rest state, indicating that brain dynamics are altered beyond the meditative state. Taken together, our findings suggest that the framework of critical brain dynamics is promising for understanding neuronal mechanisms of meditative states and, specifically, we have identified a clear electrophysiological correlate of the FA meditation state.
Erkunden
Team
Eintragsart
Thema
- absorption (1)
- Adult (1)
- Attention/*physiology (1)
- Brain/*physiology (1)
- Brain Waves/*physiology (1)
- Cohort Studies (1)
- criticality (1)
- default mode network (1)
- EEG (1)
- EEG independent component clustering (1)
- Emotions/physiology (1)
- Female (1)
- fMRI (1)
- Humans (1)
- independent component analysis (1)
- long-range temporal correlations (1)
- Male (1)
- Meditation (1)
- *Meditation (1)
- meditation (1)
- Middle Aged (1)
- Nebenwirkungen (1)
- Practice, Psychological (1)
- Rest (1)
- Risiken (1)
- Signal Processing, Computer-Assisted (1)
- Thinking/physiology (1)
- Time Factors (1)
- Übersichtsarbeiten (1)
- Young Adult (1)