Occipital gamma activation during Vipassana meditation

Long-term Vipassana meditators sat in meditation vs. a control rest (mind-wandering) state for 21 min in a counterbalanced design with spontaneous EEG recorded. Meditation state dynamics were measured with spectral decomposition of the last 6 min of the eyes-closed silent meditation compared to control state. Meditation was associated with a decrease in frontal delta (1–4 Hz) power, especially pronounced in those participants not reporting drowsiness during meditation. Relative increase in frontal theta (4–8 Hz) power was observed during meditation, as well as significantly increased parieto-occipital gamma (35–45 Hz) power, but no other state effects were found for the theta (4–8 Hz), alpha (8–12 Hz), or beta (12–25 Hz) bands. Alpha power was sensitive to condition order, and more experienced meditators exhibited no tendency toward enhanced alpha during meditation relative to the control task. All participants tended to exhibit decreased alpha in association with reported drowsiness. Cross-experimental session occipital gamma power was the greatest in meditators with a daily practice of 10+ years, and the meditation-related gamma power increase was similarly the strongest in such advanced practitioners. The findings suggest that long-term Vipassana meditation contributes to increased occipital gamma power related to long-term meditational expertise and enhanced sensory awareness

MIND-BODY RESPONSE AND NEUROPHYSIOLOGICAL CHANGES DURING STRESS AND MEDITATION: CENTRAL ROLE OF HOMEOSTASIS

Stress profoundly impacts quality of life and may lead to various diseases and conditions. Understanding the underlying physiological and neurological processes that take place during stress and meditation techniques may be critical for effectively treating stress-related diseases. The article examines a hypothetical physiological homeostatic response that compares and contrasts changes in central and peripheral oscillations during stress and meditation, and relates these to changes in the autonomic system and neurological activity. The authors discuss how cardiorespiratory synchronization, which occurs during the parasympathetic response and meditation, influences and modulates activity and oscillations of the brain and autonomic nervous system. Evidence is presented on how synchronization of cardiac and respiratory rates during meditation may lead to a homeostatic increase in cellular membrane potentials in neurons and other cells throughout the body. These potential membrane changes may underlie the reduced activity in the amygdala, and other cortical areas during meditation, and research examining these changes may foster better understanding of the restorative properties and health benefits of meditation

Can enlightenment be traced to specific neural correlates, cognition, or behavior? No, and (a qualified) Yes

The field of contemplative science is rapidly growing and integrating into the basic neurosciences, psychology, clinical sciences, and society-at-large. Yet the majority of current research in the contemplative sciences has been divorced from the soteriological context from which these meditative practices originate and has focused instead on clinical applications with goals of stress reduction and psychotherapeutic health. In the existing research on health outcomes of mindfulness-based clinical interventions, for example, there have been almost no attempts to scientifically investigate the goal of enlightenment. This is a serious oversight, given that such profound transformation across ethical, perceptual, emotional, and cognitive domains are taken to be the natural outcome and principle aim of mindfulness practice in the traditional Buddhist contexts from which these practices are derived. If short-term interventions as short as a few sessions are now beginning to produce neuroplastic changes, it may be that even in secular contexts, practitioners are already developing states and traits that are associated with progress toward enlightenment. In order to carefully assess the potential effects of meditative interventions it is of singular importance to ask whether enlightenment can be traced to specific neural correlates, cognition, or behavior

Topological changes of brain network during mindfulness meditation: an exploratory source level magnetoencephalographic study

We have previously evidenced that Mindfulness Meditation (MM) in experienced meditators (EMs) is associated with long-lasting topological changes in resting state condition. However, what occurs during the meditative phase is still debated. Utilizing magnetoencephalography (MEG), the present study is aimed at comparing the topological features of the brain network in a group of EMs (n = 26) during the meditative phase with those of individuals who had no previous experience of any type of meditation (NM group, n = 29). A wide range of topological changes in the EM group as compared to the NM group has been shown. Specifically, in EMs, we have observed increased betweenness centrality in delta, alpha, and beta bands in both cortical (left medial orbital cortex, left postcentral area, and right visual primary cortex) and subcortical (left caudate nucleus and thalamus) areas. Furthermore, the degree of beta band in parietal and occipital areas of EMs was increased too. Our exploratory study suggests that the MM can change the functional brain network and provides an explanatory hypothesis on the brain circuits characterizing the meditative process

Study of the electroencephalographic correlates of mind wandering and meditation. Etude des corrélats électroencéphalographiques de la dérive attentionnelle et de la méditation

Si l'on essaye de concentrer notre attention sur un objet physique ou mental donné, on s'aperçoit vite qu'elle ne peut pas rester indéfiniment fixée sur l'objet en question mais se ré-oriente rapidement vers d'autres pensées ou sensations, un phénomène appelé dérive attentionnelle. Fait intéressant, les anciennes traditions de pratiques de méditation ont développé une grande variété de méthodes visant à développer la prise de conscience des épisodes de dérive attentionnelle et à entraîner l'esprit à rester concentré. Il est important de souligner que la connaissance du contenu de l'attention est une information qui est personnelle au sujet et qui ne peut être évaluée qu'à l'aide de méthode prennant en compte la perspective à la première personne. Au cours de ma thèse, j'ai étudié à la fois la dérive attentionnelle et les états de méditation dans un effort pour mieux comprendre ce qui se passe dans le cerveau quand quelqu'un médite. Quelle que soit la tradition de méditation, les dérives attentionnelles sont omniprésentes pendant la méditation. Ce sujet constitue donc un point de départ idéal pour l'étude de la méditation. Ce phénomène de dérive attentionnelle n'est pas unique à la méditation mais est présent dès qu'une personne se concentre sur une tâche à l'exclusion de toute autre. En utilisant un protocole nouveau, nous montrons que les épisodes de dérive attentionnelle sont accompagnés par une amplitude accrue des basses fréquences EEG 1-3Hz delta et 4-7Hz theta ainsi qu'une réduction du traitement sensoriel pré-attentif, comme le montre l'analyse de potentiels évoqués. Ces résultats indiquent que la dérive attentionnelle est associée à un niveau réduit de vigilance, similaire aux premiers stades de la somnolence. Ceci est cohérent avec certains textes bouddhistes sur la méditation, qui représentent la dérive attentionelle comme un état de sommeil par rapport aux périodes où l'esprit est concentré. Puis, nous avons réalisé une étude comparative de l'activité EEG au cours de la méditation pour tenter de déterminer l'origine des résultats divergents de la littérature. Nous avons enregistré l'activité spontanée EEG de 3 groupes de méditants de 3 différentes traditions de méditation et d'un groupe de non-méditants en utilisant le même protocole. Nous avons montré que tous les groupes de méditants avaient une amplitude de fréquence gamma 60-110Hz plus élevée par rapport aux contrôles pendant la méditation, indiquant peut-être des processus attentionnels différents chez les méditants. Aucune différence n'a été trouvée entre l'état mental contrôle et l'état méditatif chez les méditants, ce qui suggère que les modifications dues à la pratique longue de la méditation sont plus robustes que les effets de l'état mental de méditation par rapport à un état contrôle. Dans l'ensemble, notre étude souligne la nécessité de mieux définir ce que pourrait être le meilleur état de contrôle mental pour la méditation. Au cours de ce travail j'ai également exploré les méthodologies pour recueillir des informations subjectives pertinentes. Notre travail apporte de nouvelles perspectives pour l'étude la conscience humaine, mais la route reste longue avant que nous ne comprenions parfaitement les mécanismes sous-jacents de notre vie intérieure.Trying to focus our attention on any given physical or mental object, we soon realize it cannot be kept indefinitely focused and soon drifts towards other thoughts or sensations, a phenomenon called mind wandering. Interestingly, ancient traditions of meditation practices have developed a large variety of methods aiming at developing the awareness of mind wandering episodes and training the mind to remain focused. It is important to point out that the knowledge of the focus of attention is a type of information that is private to the subject and that can only be assessed using methods that take into account first-person perspectives. During my thesis, I studied both the mind wandering and the meditation mental states in an effort to better understand what is happening in the brain when someone meditates. First, regardless of the meditation tradition, mind wandering is ever present during meditation and it seemed like an ideal starting point for studying meditation. It is also a phenomenon that is not unique to meditation and is present whenever a person attempts to focus. Using a novel EEG protocol, we show that mind wandering episodes are accompanied by increased amplitude at low frequencies in the delta (1-3Hz) and theta (4-7Hz) frequency bands as well as a reduction of pre-attentive sensory processing as shown by the analysis event-related potentials. These results indicate that mind wandering is associated with a lower vigilance level, resembling early stages of drowsiness. These results are consistent with some Buddhist texts on meditation, in which mind wandering is considered to be a state of relative sleep where the mind is not aware. Then, we realized a comparative study of EEG activity during meditation to attempt to sort out the origin of the divergent results found in the literature. We recorded the spontaneous EEG activity of 3 groups of meditators from 3 different meditation traditions in addition to a non-meditator group using the same protocol and equipment. We showed that all groups of meditators had higher 60-110Hz gamma amplitude when compared to the controls during meditation, possibly indicating different attentional processes in meditators. No differences were found between the mental control state and the meditative state in meditators, suggesting that we were observing trait rather than state effects of meditation. Overall, our study emphasizes the need to better define what could be the best control mental state for meditation. During this work, I also explored the methodologies allowing the collection of accurate subjective data. Our work brings new data in the field of consciousness, mind wandering and meditation study, but the road will be long before we fully understand the mechanisms underlying our inner life

Meditation states and traits in Australian Yoga practitioners: the effect of proficiency and practice on “sense of self”

The effects of meditation practice can be divided into changes occurring during the practice (state changes) and those persisting beyond the practice (trait changes), making permanent changes in self-perception and one’s ‘sense of self’. This project investigated both effects of Yoga meditation in ‘advanced’ Yoga teachers and students with ‘short-term’ experience from two Yoga traditions practised in Australia, Satyananda Yoga and Yoga in Daily Life. A qualitative study charted the personal journey of Australian Yoga practitioners in coming to meditation, their experiences in meditation and its effects on their daily life. Exact low resolution tomography (eLORETA) analysis of participants’ EEG data measured the location and frequency of brain activity during meditation and a calculation control condition. The major finding was a proficiency-related difference in location and frequency between the Satyananda teacher and student groups. The teacher group showed higher gamma band activity predominantly in the right temporal and right ventral prefrontal cortex, while the student group showed higher alpha1 band activity in the right somatosensory and right premotor cortex. These regions have been linked to alterations in one’s ‘sense of self’ derived from awareness of the body’s internal space. This is the first study to show enhanced gamma band activation in Western Yoga practitioners, converging with similar evidence from advanced Buddhist practitioners. The brain activity differences between the student and teacher groups were interpreted as reflecting the traditional Yoga stages of pratyahara and dharana, a difference also evident in the groups’ subjective descriptions of their meditation experiences. The results are interpreted as evidence of changes in meditation states and traits with increasing proficiency, leading alterations in one’s ‘sense of self’

Spontaneous eye movements during focused-attention mindfulness meditation

Oculometric measures have been proven to be useful markers of mind-wandering during visual tasks such as reading. However, little is known about ocular activity during mindfulness meditation, a mental practice naturally involving mind-wandering episodes. In order to explore this issue, we extracted closed-eyes ocular movement measurements via a covert technique (EEG recordings) from expert meditators during two repetitions of a 7-minute mindfulness meditation session, focusing on the breath, and two repetitions of a 7-minute instructed mind-wandering task. Power spectral density was estimated on both the vertical and horizontal components of eye movements. The results show a significantly smaller average amplitude of eye movements in the delta band (1\u20134 Hz) during mindfulness meditation than instructed mind-wandering. Moreover, participants\u2019 meditation expertise correlated significantly with this average amplitude during both tasks, with more experienced meditators generally moving their eyes less than less experienced meditators. These findings suggest the potential use of this measure to detect mind-wandering episodes during mindfulness meditation and to assess meditation performance

Neural Correlates of Induced Light Experience during Meditation: A Pilot Hyperscanning Study

Certain individuals during deep meditative states can transmitt and give out an aura or ‘light, which is perceived by others through some unknown connections, visual, telepathic or other. Despite various anecdotal, historical accounts of such induced light experience (ILE), its underlying neural mechanism is not known. In this pilot study, we investigated the neural correlates of ILE by simultaneously recording the EEGs of an expert Teacher, who is claimed to elicit ILE, and his Pupil (N=2) during joint sessions under various instructions, given separately to the Teacher (transmit/ do not transmit) and to the Pupil (receive/ do not receive). In a further condition both teacher and pupil wear opaque goggles during transmit/receive instruction, limiting the visual/outputinput. We observed a robust increase in the high frequency beta (12-30 Hz) and gamma oscillations (30-70 Hz) in the Teacher’s brain whenever he was instructed to transmit. Electric field tomography analysis localized these effects over several brain regions including the fusiform gyrus, angular gyrus and the cerebellum. Finally, we found that the Teacher’s and Pupil’s brain responses were synchronized, especially in the alpha band (8-12 Hz) during transmit/receive condition, and the information flow was directional, i.e. from the Teacher to the Pupil; interestingly, this enhanced interbrain synchrony disappeared with opaque goggles. These results were interpreted in terms of heightened internally selective attention as manifested by high frequency beta-gamma oscillations and of joint attention as manifested by interbrain alpha synchrony. Altogether, our results provide the first neuroscientific evidence underlying the phenomenological experience of induced light