EEG measures manifestations of nondual awareness

Berman, A. E., & Stevens, L. (2015). EEG manifestations of nondual experiences in meditators. Consciousness and Cognition, 31, 1-11. Abstract

Highlights • Nondual states of consciousness reflect the culminating meditation experience. • These resulting states are differentiated from method or type of practice. • EEGs were recorded during meditation and states of nonduality. • Results suggest nondual states are neurologically distinct from general meditation. • Differentiating method and state will contribute to a more comprehensive taxonomy.

The holistic experiential benefits of meditation among a widely ranging population have been well established within the empirical literature. What remain less clear are the underlying mechanisms of the meditative process. A large impediment to this clarity is attributable to the lack of a unified and comprehensive taxonomy, as well as to the absence of clear differentiation within the literature between method of practice and resulting state.

The present study discusses and then attempts to identify within our sample a theoretically universal culminating meditative state known as Nondual Awareness, which is differentiated from the method or practice state. Participants completed an in-lab meditation, during which neurological patterns were analyzed using electroencephalography (EEG).

Analyses indicated significantly higher EEG power among slower wave frequencies (delta, theta, alpha) during the reported nondual events. These events appear neurologically distinct from meditation sessions as a whole, which interestingly demonstrated significant elevation within the gamma range.

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Mindfulness in the brain

Fletcher, L. B., Schoendorff, B., & Hayes, S. C. (2010). Searching for mindfulness in the brain: A process-oriented approach to examining the neural correlates of mindfulness. Mindfulness, 1(1), 41-63. Full text.

Abstract. There has been great interest of late in trying to capture the benefits of meditation by scanning meditators’ brains. In this paper, we argue that a successful neuroscience of mindfulness needs to be based on an adequate psychological analysis.

We present a definition of mindfulness based on four psychological processes that are relatively well understood, and we show how this model may help organize neuroimaging research and create a bridge to clinical applications.

This framework provides an approach to neuroscience research grounded in psychological principles and theory. We propose that this is critical for advancing scientific endeavors such that the knowledge gained helps improve the human condition.

Interventions in mild cognitive impairment and Alzheimer’s disease

Larouche, E., Hudon, C., & Goulet, S. (2014). Potential benefits of mindfulness-based interventions in mild cognitive impairment and Alzheimer’s disease: An interdisciplinary perspective. Behavioural Brain Research. In Press. Abstract.

Highlights: • Hippocampal damage is central in MCI/AD and could be prevented or delayed by mindfulness-based interventions (MBI).  • MBI reduce MCI/AD adverse factors (stress, depression, metabolic syndrome).  • Multiple pathways could explain MBI’s effects on modifiable adverse factors.  • Effects seem based on neuro- endocrine, immune, and transmission regulation.  • MBI show great potential to prevent the neurodegenerative cascade leading to AD.

The present article is based on the premise that the risk of developing Alzheimer’s disease (AD) from its prodromal phase (mild cognitive impairment; MCI) is higher when adverse factors (e.g., stress, depression, and metabolic syndrome) are present and accumulate. Such factors augment the likelihood of hippocampal damage central in MCI/AD aetiology, as well as compensatory mechanisms failure triggering a switch toward neurodegeneration. Because of the devastating consequences of AD, there is a need for early interventions that can delay, perhaps prevent, the transition from MCI to AD.

We hypothesize that mindfulness-based interventions (MBI) show promise with regard to this goal. The present review discusses the associations between modifiable adverse factors and MCI/AD decline, MBI’s impacts on adverse factors, and the mechanisms that could underlie the benefits of MBI. A schematic model is proposed to illustrate the course of C specific to MCI/AD, as well as the possible preventive mechanisms of MBI. Whereas regulation of glucocorticosteroids, inflammation, and serotonin could mediate MBI’s effects on stress and depression, resolution of the metabolic syndrome might happen through a reduction of inflammation and white matter hyperintensities, and normalization of insulin and oxidation.

The literature reviewed in this paper suggests that the main reach of MBI over MCI/AD development involves the management of stress, depressive symptoms, and inflammation. Future research must focus on achieving deeper understanding of MBI’s mechanisms of action in the context of MCI and AD. This necessitates bridging the gap between neuroscientific subfields and a cross-domain integration between basic and clinical knowledge.

Evidence from neuroimaging studies (lit review)

Marchand, W. R. (2014). Neural mechanisms of mindfulness and meditation: Evidence from neuroimaging studies. World Journal of Radiology, 6(7), 471-479. Full text.

mindimagesAbstract. Mindfulness is the dispassionate, moment-by-moment awareness of sensations, emotions and thoughts. Mindfulness-based interventions are being increasingly used for stress, psychological well being, coping with chronic illness as well as adjunctive treatments for psychiatric disorders. However, the neural mechanisms associated with mindfulness have not been well characterized. Recent functional and structural neuroimaging studies are beginning to provide insights into neural processes associated with the practice of mindfulness.

A review of this literature revealed compelling evidence that mindfulness impacts the function of the medial cortex and associated default mode network as well as insula and amygdala. Additionally, mindfulness practice appears to effect lateral frontal regions and basal ganglia, at least in some cases. Structural imaging studies are consistent with these findings and also indicate changes in the hippocampus. While many questions remain unanswered, the current literature provides evidence of brain regions and networks relevant for understanding neural processes associated with mindfulness.

Effect on brain structure (review & meta-analysis)

Fox, K. C., et al. (2014). Is meditation associated with altered brain structure? A systematic review and meta-analysis of morphometric neuroimaging in meditation practitioners. Neuroscience & Biobehavioral Reviews, 43, 48-73. Full text.

From the Abstract: Numerous studies have begun to address how the brain’s gray and white matter may be shaped by meditation. This research is yet to be integrated, however, and two fundamental questions remain: Is meditation associated with altered brain structure? If so, what is the magnitude of these differences? To address these questions, we reviewed and meta-analyzed 123 brain morphology differences from 21 neuroimaging studies examining ∼300 meditation practitioners.

Anatomical likelihood estimation meta-analysis found eight brain regions consistently altered in meditators, including areas key to meta-awareness, exteroceptive and interoceptive body awareness (sensory cortices and insula), memory consolidation and reconsolidation (hippocampus), self and emotion regulation (anterior and mid cingulate; orbitofrontal cortex), and intra- and interhemispheric communication (superior longitudinal fasciculus; corpus callosum).

Framework for understanding neurobiological mechanisms of mindfulness

Vago, D. R., & Silbersweig, D. A. (2012). Self-awareness, self-regulation, and self-transcendence (S-ART): a framework for understanding the neurobiological mechanisms of mindfulness. Frontiers in human neuroscience, 6.

Mindfulness—as a state, trait, process, type of meditation, and intervention–has proven to be beneficial across a diverse group of psychological disorders as well as for general stress reduction. Yet, there remains a lack of clarity in the operationalization of this construct, and underlying mechanisms.

Here, we provide an integrative theoretical framework and systems-based neurobiological model that explains the mechanisms by which mindfulness reduces biases related to self-processing and creates a sustainable healthy mind. Mindfulness is described through systematic mental training that develops meta-awareness (self-awareness), an ability to effectively modulate one’s behavior (self-regulation), and a positive relationship between self and other that transcends self-focused needs and increases prosocial characteristics (self-transcendence). >>> continue with full text

Brain changes following MBSR training

Lazar, S. (2014). Change in brainstem gray matter concentration following a mindfulness-based intervention is correlated with improvement in psychological well-being. Name: Frontiers in Human Neuroscience, 8, 33. Full text via Abstract.

Individuals can improve their levels of psychological well-being through utilization of psychological interventions, including the practice of mindfulness meditation, which is defined as the non-judgmental awareness of experiences in the present moment.

We recently reported that an 8-week Mindfulness-Based Stress Reduction (MBSR) course lead to increases in gray matter concentration in several brain areas, as detected with voxel-based morphometry of MPRAGE MRI scans, including the pons/raphe/locus coeruleus area of the brainstem. Given the role of the pons and raphe in mood and arousal, we hypothesized that changes in this region might underlie changes in well-being.