Training attention for conscious non-REM sleep: The yogic practice of yoga-nidrā and its implications for neuroscience research

Functional connectivity changes in meditators and novices during yoga nidra practice

Yoga nidra (YN) practice aims to induce a deeply relaxed state akin to sleep while maintaining heightened awareness. Despite the growing interest in its clinical applications, a comprehensive understanding of the underlying neural correlates of the practice of YN remains largely unexplored. In this fMRI investigation, we aim to discover the differences between wakeful resting states and states attained during YN practice. The study included individuals experienced in meditation and/or yogic practices, referred to as 'meditators' (n = 30), and novice controls (n = 31). The GLM analysis, based on audio instructions, demonstrated activation related to auditory cues without concurrent default mode network (DMN) deactivation. DMN seed based functional connectivity (FC) analysis revealed significant reductions in connectivity among meditators during YN as compared to controls. We did not find differences between the two groups during the pre and post resting state scans. Moreover, when DMN-FC was compared between the YN state and resting state, meditators showed distinct decoupling, whereas controls showed increased DMN-FC. Finally, participants exhibit a remarkable correlation between reduced DMN connectivity during YN and self-reported hours of cumulative meditation and yoga practice. Together, these results suggest a unique neural modulation of the DMN in meditators during YN which results in being restful yet aware, aligned with their subjective experience of the practice. The study deepens our understanding of the neural mechanisms of YN, revealing distinct DMN connectivity decoupling in meditators and its relationship with meditation and yoga experience. These findings have interdisciplinary implications for neuroscience, psychology, and yogic disciplines.

Yoga Nidra, a Nonpharmacological Technique in Management of Insomnia and Overall Health in Postmenopausal Women

Yoga Nidra is a promising technique through which body is consciously simulated into a profound relaxation state similar to attained during naturally occurring deep sleep. It is aimed to attain complete emotional, physical, and mental relaxation of body and mind. In postmenopausal phase of life, regular practice of Yoga Nidra at home preferably in morning, can help in reduction in anxiety and pain associated with early morning awakenings. This nonpharmacological technique has a therapeutic potential to improve sleep quality and quantity, and overall well-being.

Conscious entry into sleep: Yoga Nidra and accessing subtler states of consciousness

Human sleep is a dynamic and complex process comprising sleep stages with REM and NREM sleep characteristics that come in cycles. During sleep, there is a loss of responsiveness or a perceptual loss of conscious awareness with increasing thresholds for wakefulness as sleep progresses. There are brief bursts of wakefulness or Wake After Sleep Onset (WASO) throughout a nocturnal sleep. Conscious experience during nocturnal sleep is known to occur during lucid dreaming when one is aware during dreams when the dream is occurring. Most cultures have known lucid dreaming since antiquity. However, conscious experience during dreamless sleep is relatively lesser known. Nevertheless, selected Indo-Tibetan meditation literature has documented it since antiquity. Minimal Phenomenal Experience (MPE) research describes lucid dreamless sleep as its target phenomenology. "Conscious entry into sleep" posits tonic alertness is maintained post sleep onset through the sleep stages for sustained durations of time until an eventual loss of conscious awareness. Entering sleep consciously and being aware during dreamless sleep, including Slow Wave Activity, is plausibly to be in the state of "Yoga Nidra" or Yogic sleep. An attentive sleepful state provides access to subtler states of consciousness and significantly deepens the levels of silence. It is phenomenologically distinct from hypnagogic hallucinations and lucid dreaming. Unfortunately, sleep studies validating this phenomenology are yet to be done. Therefore, an experimental methodology akin to those used in lucid dreaming experiments is described.

Qualitative Impressions of a Yoga Nidra Practice for Insomnia: An Exploratory Mixed-Methods Design

Introduction: Insomnia affects up to half of the U.S. population, and due to limitations of current treatments, there is a growing interest in mind-body practices to reduce insomnia. To understand how a guided meditation practice, Yoga Nidra, may affect relaxation and align with current descriptions of nonpharmaceutical practices that could improve sleep, qualitative and quantitative methods were used to explore participant experience of a single Yoga Nidra practice, administered in a group setting. Methods: Current insomnia (Insomnia Severity Index), sleep practices, and mood (positive and negative affect schedule [PANAS]) were measured at intake. After 30 min of Yoga Nidra practice, the PANAS was readministered. In a focus group that followed, participants discussed their experience before, during, and after the practice and the likelihood of repeating it. Six groups were conducted. All interested adults were welcome to join. Results: In the final sample of 33 individuals (79% female), 80% of participants reported insomnia at intake and 45% reported a regular mind-body practice, supporting the prevalence of insomnia in the society as well as the interest in mind-body practices. After the Yoga Nidra intervention, mean negative affect decreased 5.6 ± 4.5 points, a 31% decrease from baseline, and positive affect decreased 3.5 ± 9.7 points, a 13% decrease. Three major themes were identified from focus group discussions: response to the practice (relaxation, perceived sleep, and sense withdrawal); factors that affect engagement (delivery method and intrapersonal factors); and potential as a clinical intervention (for conditions including sleep, anxiety, and pain). Conclusion: Yoga Nidra appeared tolerable within the sample, and descriptions suggest it may be useful for enhancing relaxation, facilitating sleep, easing anxiety, and reducing pain. Results from this study will inform the design of future studies of Yoga Nidra for insomnia and related conditions.

A Closer Look at Yoga Nidra: Sleep Lab Protocol

Extended sleep onset latency (SOL), or "sleep onset insomnia," can decrease total sleep time, increasing risk for many health conditions, including heart disease, stroke, and all-cause mortality. Sleep disorders persist in the United States despite current behavioral/pharmaceutical remedies, with 10% to 15% of the population suffering from insomnia. Mind-body therapies offer additional solutions, as meditation has been correlated with decreased SOL. More research on use of mind-body practices for insomnia is needed. This study investigates the guided meditation practice of Yoga Nidra (yogic sleep) as a promising intervention for sleep disorders because of its purported ability to induce mental, physical, and emotional relaxation. In this pilot study, we address the feasibility of Yoga Nidra for insomnia, appropriateness of our selected measurement systems, and effect of Yoga Nidra on brainwaves, sleep onset, and the autonomic nervous system. Our study sample includes 22 adults, ages 18-45, with insomnia. The design includes two clinic visits (V1, lying quietly for 90 min; V2, randomization to 90-min lying quietly vs. 30-min Yoga Nidra plus 60-min lying quietly), taking place 1 to 14 days apart. Outcomes measured during/after Yoga Nidra (vs. control) include sleep onset, electroencephalography (EEG) power, heart rate variability (HRV), and respiratory rate. Self-reported mood and anxiety will be measured before/after each visit. Resulting physiological, psychological, and feasibility data will be used to inform future clinical studies of Yoga Nidra for sleep and relaxation.

On the Neurobiology of Meditation: Comparison of Three Organizing Strategies to Investigate Brain Patterns during Meditation Practice

Three broad organizing strategies have been used to study meditation practices: (1) consider meditation practices as using similar processes and so combine neural images across a wide range of practices to identify the common underlying brain patterns of meditation practice, (2) consider meditation practices as unique and so investigate individual practices, or (3) consider meditation practices as fitting into larger categories and explore brain patterns within and between categories. The first organizing strategy combines meditation practices defined as deep concentration, attention to external and internal stimuli, and letting go of thoughts. Brain patterns of different procedures would all contribute to the final averages, which may not be representative of any practice. The second organizing strategy generates a multitude of brain patterns as each practice is studied individually. The rich detail of individual differences within each practice makes it difficult to identify reliable patterns between practices. The third organizing principle has been applied in three ways: (1) grouping meditations by their origin—Indian or Buddhist practices, (2) grouping meditations by the procedures of each practice, or (3) grouping meditations by brain wave frequencies reported during each practice. Grouping meditations by their origin mixes practices whose procedures include concentration, mindfulness, or effortless awareness, again resulting in a confounded pattern. Grouping meditations by their described procedures yields defining neural imaging patterns within each category, and clear differences between categories. Grouping meditations by the EEG frequencies associated with their procedures yields an objective system to group meditations and allows practices to “move” into different categories as subjects’ meditation experiences change over time, which would be associated with different brain patterns. Exploring meditations within theoretically meaningful categories appears to yield the most reliable picture of meditation practices.

Understanding Meditation Based on the Subjective Experience and Traditional Goal: Implications for Current Meditation Research

Owing to its benefits on various cognitive aspects, one's emotions, and well-being, meditation has drawn interest from several researchers and common public alike. We have different meditation practices associated with many cultures and traditions across the globe. Current literature suggests significant changes in the neural activity among the different practices of meditation, as each of these practices contributes to distinct physiological and psychological effects. Although this is the case, we want to find out if there is an underlying commonality among all these different practices. Thus, we ask the following questions related to different practices of meditation, the traditional goal of meditation and its significance-what is the central purpose of meditation? Do traditions define the final goal of all the practices of meditation? Are the purpose and goal of these practices different or is there a common goal to be attained through all these distinct practices? Embracing the traditional perspective, through this paper, we want to emphasize that, although these techniques and practices may appear different on the periphery, eventually, they seem to subject one to the same experience at the end, a natural meditative state (discussed in various spiritual traditions as the goal of meditation). In view of future studies on different meditation practices and also those exploring this subjective state, we offer some interesting ideas based on the traditional insights into meditation. In this context, we would also like to make a few comments on the way contemporary researchers view different practices of meditation.