Theta activity and meditative states: spectral changes during concentrative meditation

Brain oscillatory activity is associated with different cognitive processes and plays a critical role in meditation. In this study, we investigated the temporal dynamics of oscillatory changes during Sahaj Samadhi meditation (a concentrative form of meditation that is part of Sudarshan Kriya yoga). EEG was recorded during Sudarshan Kriya yoga meditation for meditators and relaxation for controls. Spectral and coherence analysis was performed for the whole duration as well as specific blocks extracted from the initial, middle, and end portions of Sahaj Samadhi meditation or relaxation. The generation of distinct meditative states of consciousness was marked by distinct changes in spectral powers especially enhanced theta band activity during deep meditation in the frontal areas. Meditators also exhibited increased theta coherence compared to controls. The emergence of the slow frequency waves in the attention-related frontal regions provides strong support to the existing claims of frontal theta in producing meditative states along with trait effects in attentional processing. Interestingly, increased frontal theta activity was accompanied reduced activity (deactivation) in parietal–occipital areas signifying reduction in processing associated with self, space and, time.     

The exploration of meditation in the neuroscience of attention and consciousness

Many recent behavioral and neuroscientific studies have revealed the importance of investigating meditation states and traits to achieve an increased understanding of cognitive and affective neuroplasticity, attention and self-awareness, as well as for their increasingly recognized clinical relevance. The investigation of states and traits related to meditation has especially pronounced implications for the neuroscience of attention, consciousness, self-awareness, empathy and theory of mind. In this article we present the main features of meditation-based mental training and characterize the current scientific approach to meditation states and traits with special reference to attention and consciousness, in light of the articles contributed to this issue.     

Meditative introspection promotes the First-person's science of consciousness via intuitive pathways: A hypothesis based on traditional Buddhist and contemporary Monist frameworks

What forms the basis for validating any knowledge? Should it be always verified based on the objective and analytical methods that we adapt according to our progressive advancements in science or is there any other way of conceiving knowledge? This is the context where modern sophistication should embrace an ancient perspective. Recently, there have been great advancements in the science of consciousness and meditation. Meditation received much attention as a practice for wellbeing and as a tool for cognitive enhancement. Even though, hundreds of objective studies have been conducted on different practices of meditation across different traditions, there is one essential element missing in almost all of these studies: the discussion of the subjective experience of meditation. Embracing the traditional insights on meditation, we study this element by defining meditation based on the concept of introspection. In addition, we hypothesize that introspective meta-awareness associated with the non-conceptual experience of meditation may result in the conceptual understanding of natural phenomena via pathways of intuition. The proposed advancement bears implications for the ontological and epistemological basis of experiential knowledge, as well as, for developing introspection and meditation-based interventions for self and consciousness disorders.     

Meditation and the scope of mental action

While philosophers of mind have devoted abundant time and attention to questions of content and consciousness, philosophical questions about the nature and scope of mental action have been relatively neglected. Galen Strawson’s account of mental action, the most well developed extant account, holds that cognitive mental action consists in triggering the delivery of content to one’s field of consciousness. However, Strawson fails to recognize several distinct types of mental action that might not reduce to triggering content delivery. In this article, we argue that meditation provides a useful model for understanding a wider range of types of mental action than heretofore recognized. Conclusions yielded by two distinct bodies of current psychological research on meditation and cognition, and meditation and introspection, buttress meditation’s suitability for this role.     

Meditating selflessly at the dawn of a new millennium

Increasingly open to question are the efficacies and timing of some traditional, conventional and current meditative techniques. Recent brain research emphasizes that it is important to distinguish between the Self-centred (egocentric) and other-centred (allocentric) streams of processing. It also proves useful to view as complementary the assets of the concentrative and receptive styles of meditation, especially when one's practices cultivate an appropriate balance between their top-down and bottom-up systems of attentive processing. From this neural perspective, Part I ventures a small sample of empirical suggestions. Some of these could help practitioners engage in more open, effortless, choiceless, varieties of receptive meditation–indoors and outdoors. Part II discusses recent research that illuminates issues arising at the interface between Self and other. The evidence suggests how a balanced attentiveness might enable long-term meditators to enhance mindfulness of the present moment, while simultaneously becoming much less fearful and, ultimately, freer to openly express their most objective, innate instincts of selfless compassion.

The art of Progress is to preserve order amid change and to preserve change amid order. (Alfred North Whitehead 1861–1947)     

Mindfulness training modifies subsystems of attention

Mindfulness is defined as paying attention in the present moment. We investigate the hypothesis that mindfulness training may alter or enhance specific aspects of attention. We examined three functionally and neuroanatomically distinct but overlapping attentional subsystems: alerting, orienting, and conflict monitoring. Functioning of each subsystem was indexed by performance on the Attention Network Test (ANT; Fan, McCandliss, Sommer, Raz, & Posner, 2002). Two types of mindfulness training (MT) programs were examined, and behavioral testing was conducted on participants before (Time 1) and after (Time 2) training. One training group consisted of individuals naive to mindfulness techniques who participated in an 8-week mindfulness-based stress reduction (MBSR) course that emphasized the development of concentrative meditation skills. The other training group consisted of individuals experienced in concentrative meditation techniques who participated in a 1-month intensive mindfulness retreat. Performance of these groups was compared with that of control participants who were meditation naive and received no MT. At Time 1, the participants in the retreat group demonstrated improved conflict monitoring performance relative to those in the MBSR and control groups. At Time 2, the participants in the MBSR course demonstrated significantly improved orienting in comparison with the control and retreat participants. In contrast, the participants in the retreat group demonstrated altered performance on the alerting component, with improvements in exogenous stimulus detection in comparison with the control and MBSR participants. The groups did not differ in conflict monitoring performance at Time 2. These results suggest that mindfulness training may improve attention-related behavioral responses by enhancing functioning of specific subcomponents of attention. Whereas participation in the MBSR course improved the ability to endogenously orient attention, retreat participation appeared to allow for the development and emergence of receptive attentional skills, which improved exogenous alerting-related process.     

Meditation-specific prefrontal cortical activation during acem meditation: an fMRI study

Some of the most popular meditation practices emphasize a relaxed focus of attention in which thoughts, images, sensations, and emotions may emerge and pass freely without actively controlling or pursuing them. Several recent studies show that meditation activates frontal brain areas associated with attention focusing and physical relaxation. The objective of the present study was to assess whether brain activation during relaxed focusing on a meditation sound could be distinguished from similar, concentrative control tasks. Brain activation was measured with functional magnetic resonance imaging (fMRI) in experienced practitioners of Acem meditation. Bilateral areas of the inferior frontal gyrus (BA47) were significantly more activated during repetition of a meditation sound than during concentrative meditation-like cognitive tasks. Meditation-specific brain activation did not habituate over time, but increased in strength with continuous meditation bouts. These observations suggest that meditation with a relaxed focus of attention may activate distinct areas of the prefrontal cortex, with implications for the understanding of neurobiological correlates of meditation.     

Meditation states and traits: EEG, ERP, and neuroimaging studies

Neuroelectric and imaging studies of meditation are reviewed. Electroencephalographic measures indicate an overall slowing subsequent to meditation, with theta and alpha activation related to proficiency of practice. Sensory evoked potential assessment of concentrative meditation yields amplitude and latency changes for some components and practices. Cognitive event-related potential evaluation of meditation implies that practice changes attentional allocation. Neuroimaging studies indicate increased regional cerebral blood flow measures during meditation. Taken together, meditation appears to reflect changes in anterior cingulate cortex and dorsolateral prefrontal areas. Neurophysiological meditative state and trait effects are variable but are beginning to demonstrate consistent outcomes for research and clinical applications. Psychological and clinical effects of meditation are summarized, integrated, and discussed with respect to neuroimaging data.     

Transcendence and psychological health: studies with long-term participants of the transcendental meditation and TM-Sidhi program

We investigated the nature of the relationship between experiences of transcendental consciousness and psychological health. In Study 1, three groups with different levels of experience in transcendental meditation (TM) and in the TM-Sidhi program (techniques that have been shown to produce experiences of transcendental consciousness) were studied, using the self-investigation method of Hermans (1976). We employed blind interviewers and raters with various attitudes toward TM to minimize the possible impact of a variety of artifacts. Cross-sectionally, experience with TM and the TM-Sidhi program was positively related to a general measure of psychological health (p = .002); longitudinally, the meditating groups improved more than the control group on the psychological health measure (p less than .03). In Study 2, two contrast groups of long-term participants were similar on several confounding variables but differed on physiological indicators of experiences of transcendental consciousness. The groups with the positive physiological indicators showed a trend toward higher scores on the psychological health factor (p = .092), indicating that psychological health may be developed through the systematic cultivation of transcendental meditation and the TM-Sidhi program.     

Stimulated brains and meditative minds: A systematic review on combining low intensity transcranial electrical stimulation and meditation in humans

BackgroundLow intensity transcranial electrical stimulation (tES) and meditation are two promising, yet variable, non-pharmacological interventions. Growing research is investigating combined effects of both techniques on one's cognitive, emotional, and physical health.ObjectiveThis article reviews the current research that combines tES and meditation interventions in healthy and diseased participants. The review considers the intervention parameters and their effects in a well-organized manner.MethodA systematic search for clinical and experimental published studies was conducted in the PubMed, Cochrane, and transcranial direct current stimulation (tDCS) databases using common keywords for tES and for meditation techniques well defined by previous studies. Unpublished ongoing studies were identified with the ClinicalTrials.gov and DRKS.de clinical trial websites.Results20 published studies and 13 ongoing studies were included for qualitative analysis. 13 published articles studied patients with chronic pain, psychological disorders, cognitive impairment, and movement disorders. Anodal tDCS was the only tES technique while mindfulness meditation was the most common meditation type. Eight studies had a main group effect, with outcome improvement in the active combined intervention. However, most published studies showed improvements after at least one combined intervention with variable effects.ConclusionPairing anodal tDCS with meditation shows promising improvements of the physical, mental, and emotional aspects of daily life. Further studies are required to confirm the relevance of this combination in the clinic.     

AGNOSTIC MEDITATIONS ON BUDDHIST MEDITATION

I first attempt a taxonomy of meditation in traditional Indian Buddhism. Based on the main psychological or somatic function at which the meditative effort is directed, the following classes can be distinguished: (1) emotion‐centered meditation (coinciding with the traditional samatha approach); (2) consciousness‐centered meditation (with two subclasses: consciousness reduction/elimination and ideation obliteration); (3) reflection‐centered meditation (with two subtypes: morality‐directed reflection and reality‐directed observation, the latter corresponding to the vipassanā method); (4) visualization‐centered meditation; and (5) physiology‐centered meditation. In the second part of the essay I tackle the problem of the epistemic validity and happiness‐engendering value of Buddhist meditation. In my highly conjectural view, the claim that meditation represents an infallible tool for realizing the (Supreme) Truth as well as a universally valid method for attaining the highest forms of happiness is largely based on the crēdō effect, that is, a placebolike process. I do not deny that meditation may have some positive effects on mental and physical health or that its practice may bring changes to the mind. Meditation may be a valuable alternative approach in life and clinical treatment, but it is far from being a must or a panacea.     

Long-term concentrative meditation and cognitive performance among older adults

ABSTRACT

Background: The general consensus that cognitive abilities decline with advancing age is supported by several studies that have reported that older adults perform more poorly on multiple tests of cognitive performance as compared to younger adults. To date, preventive measures against this cognitive decline have been mainly focused on dietary, physical, and lifestyle behaviors which could allow older adults to maintain their cognitive abilities into late life. However, much less stress has been laid on evaluating meditation as a preventive measure in such cases in spite of the fact that the role of meditation on attention has been proved in several studies. In the current study, we extend this preliminary idea, examining the practice of concentrative meditation and the differences in the cognitive performance of older adults who have or have not employed this practice long term. Methodology: This was a cross-sectional study comparing the cognitive performance of meditators and non-meditators in the geriatric age group. Twenty (age > 55 years) long-term practitioners of Vihangam Yoga meditation (>10 years of practice) were recruited in the present study and were applied six paper–pencil neuropsychological tests for assessment of short-term memory, perceptual speed, attention, and executive functioning. The tests used were: (1) the Digit Span test, (2) the Stroop Color Word test, (3) the Trailmaking test, (4) the Letter Cancellation Task, (5) the digit symbol substitution test, and (6) the Rule Shift Card Test. All the tests were also applied to 20 age- and education-matched geriatric adults who have not practiced the meditation technique. Results: Vihangam Yogis showed significantly better performances in all these tests of attention (p < .05) except for the digit backward test, where a trend (p = .08) was found in favor of meditators. Conclusion: Long-term Vihangam Yoga meditators have superior cognitive abilities than non-meditators in the old age group. This technique should be studied further for its ability to prevent age-related cognitive decline.     

Meditation,mindfulness and cognitive flexibility

This study investigated the link between meditation, self-reported mindfulness and cognitive flexibility as well as other attentional functions. It compared a group of meditators experienced in mindfulness meditation with a meditation-naïve control group on measures of Stroop interference and the “d2-concentration and endurance test”. Overall the results suggest that attentional performance and cognitive flexibility are positively related to meditation practice and levels of mindfulness. Meditators performed significantly better than non-meditators on all measures of attention. Furthermore, self-reported mindfulness was higher in meditators than non-meditators and correlations with all attention measures were of moderate to high strength. This pattern of results suggests that mindfulness is intimately linked to improvements of attentional functions and cognitive flexibility. The relevance of these findings for mental balance and well-being are discussed.     

Meditation to fit the person: Psychology and the meditative way

Only lately having recovered their bodies and feelings, Western devotees of various meditative practices are in increasing numbers striving to transcend both. Is such a turning inward healthy for individuals and our society? A full response requires both a clarifying discussion of exactly what meditation is and a review of its effects. Meditation, essentially a way of life, is marked by four stages: preparation, attention, active reception, and higher consciousness. Even though the Western traditions aim finally at union with the Infinite and Eastern traditions seek primarily an internal unity through the negation of consciousness, both describe essentially the same four stages, reached through the meditative pathways of the intellect, emotions, body, and action. Present scientific research is only beginning to provide data on the effects of meditation upon the person. To date, most research findings point out psychophysiological changes during meditation, indicating a low-stress state. Meditative experience lends support to the conclusion that successful meditation also positively affects growth by touching man's inner life source, expanding his consciousness, and revealing personal life directions.     

不同冥想类型对创造性思维的影响及作用机制

冥想与创造性的关系正逐渐被关注,澄清冥想练习对创造性思维的影响效果和作用机制对个体创新潜能的培养与提升具有重要意义。不同冥想类型对创造性思维的影响具有特异性,专注冥想主要通过注意聚焦和提升自上而下的执行控制能力来对聚合思维产生积极影响;正念冥想引起的离焦的注意状态,以及对认知灵活性和积极情绪的促进,有助于发散思维。未来应加强不同冥想类型与创造性思维的整合研究,探讨冥想影响创造性思维的脑机制,以及冥想与其他干预训练对创造性思维的不同作用机制等。     

Mindfulness meditation and consciousness: An integrative neuroscientific perspective

Although mindfulness meditation has been practiced in the East for more than two millennia, Western scientific research and healthcare programs have only recently drawn their attention to it. Basically, the concept of mindfulness hinges on focusing on one’s own awareness at the present moment. In this review we analyze different hypotheses about the functioning and the cerebral correlates of mindfulness meditation. Since mindfulness is strictly associated with a particular state of consciousness, we also examine some of the most relevant theories that have been proposed as accounts of consciousness. Finally, we suggest that consciousness and mindfulness meditation can be integrated within a neuroscientific perspective, by identifying the brain areas which seem to play an essential role in both, namely the anterior cingulate cortex, posterior cingulate cortex, insula and thalamus.     

Mental Attention, Consciousness, and the Progressive Emergence of Wisdom

I discuss the mental–attentional mechanisms of consciousness, meditation, and the emergence of wisdom. A developmental (neoPiagetian), dynamic flash-light model of mental attention is used. I model the initial stages of consciousness in infancy, showing that the growth of consciousness is influenced by the number of schemes that attention can coordinate. I discuss ordinary consciousness in adults and the stages/levels of adult development in consciousness. Wisdom is defined as an expectable but often missed outcome of adult development. To accelerate access to wisdom, two complementary paths are mentioned: a natural life-experience path and a meditation path. Maturational organismic factors and the role of mental attentional mechanisms in these two paths are discussed, and a constructivist neuropsychological model of what happens in the brain during meditation, and in higher consciousness, is sketched. Processes involved in higher stages of consciousness are then examined from this perspective.     

正念机制的核心：注意还是态度？

注意与态度是正念的两个关键的工作机制,但关于这两个机制究竟哪个是核心机制却没有统一的定论。本文就针对这一争议存在的现状和原因进行了梳理和分析,认为正念的核心机制在于注意力的训练,并尝试从佛教与心理学两个角度在理论推导与实证支持两个层面上给予了阐释。