What is the Aim of this project?

To record electroencephalogram (EEG) and physiological data (eye movements, breathing rate, ECG, GSR, etc) from practitioners of different types of meditation techniques and compare with their age and gender-matched controls. Although we will compare several neural and physiological features, our focus is on stimulus-induced gamma oscillations.

What are stimulus-induced gamma oscillations?

The effect of meditation on various endogenous brain rhythms such as alpha (8-12 Hz) and gamma (30-80 Hz) has been studied for a long time. However, gamma oscillations can also be induced in the brain by simply viewing certain stimuli such as bars or gratings. These are called “stimulus-induced” gamma rhythms. We have found that these stimulus-induced gamma rhythms weaken with healthy aging (Murty et al., 2020, Neuroimage; more details here) and are substantially weaker in subjects with mild cognitive impairment (MCI) or early Alzheimer’s Disease (AD) as compared to their age and gender-matched healthy controls (Murty et al., 2021, eLife; more details here). While these oscillations vary substantially from one individual to another, they remain remarkably similar for a given individual (Kumar et al., 2022, Cerebral cortex communications). Overall, these stimulus-induced gamma oscillations could be a reflection of finely tuned excitation-inhibition balance in the brain, which could be disrupted with aging and mental disorders and potentially be a general biomarker of brain health.

Our primary goal is to study whether these stimulus-induced gamma rhythms are different in long-term meditators. 

In general, gamma oscillations are not only related to behavior (attention, meditation) but also have been linked to specific processes such as excitation-inhibition balance and gain control, which gets compromised in mental disorders. These oscillations have also been modeled thoroughly at a very detailed circuit level. Gamma oscillations could, therefore, hold the key to linking a complex high-level behaviour such as meditation to specific neural mechanisms and their detailed circuit-level description.

Why should we study meditation scientifically?

Nowadays, a variety of meditative techniques exist, with the aim of calming and focusing the mind. However, this is not the primary aim of meditation; it is rather a useful byproduct. The primary aim of meditation is related to the metaphysical concept of ultimate reality or Brahman in the Indian Philosophical System. In simple terms, the goal of life is to find the ultimate reality, but this answer lies within oneself, not outside. Therefore, the mind needs to be trained and focused inwards. Yoga sutras describe an eight-fold path to achieve this; meditation or "dhyana" is the seventh step, one step before samadhi to achieve moksha (liberation). Different Indian philosophies have their own definitions and processes for achieving moksha, which has led to a rich diversity in the meditative practices that we find today.

It is important to note that some concepts in the Indian Philosophical System may not be amenable to rigorous scientific inquiry. For example, consciousness is considered to have an independent existence of its own; it is not a byproduct of the mind or the brain. It therefore may not be feasible to study consciousness by studying EEG which reflects some sort of aggregate electrical activity of the physical brain. So, why study EEG?

First, the “byproduct” of meditation – amelioration of mental health conditions such as stress, anxiety, and potentially some mental disorders, and improvement in the overall well-being and quality of life – is an important goal on its own and is amenable to rigorous scientific inquiry. Gamma has been shown to be compromised in mental disorders such as autism, schizophrenia, and AD. Therefore, characterizing the potential therapeutic effect of meditation by studying its effect on brain waves has direct clinical relevance.

Second, while consciousness may be a harder question to tackle scientifically, concepts like attention and mind-wandering are well-studied scientific topics that are deeply rooted in brain physiology. For example, the effect of attention can be observed at the level of single neurons in animal models. Meditation can be considered an extreme form of focused attention, and therefore can be studied in the framework used to study attention.

Finally, even if consciousness has a metaphysical existence beyond the brain, it may be possible to study it partially by studying its interactions with the brain. We aim to create a large publicly available dataset involving various types of meditative practices so that questions related to consciousness can be studied in the future, although this is not our emphasis right now.

Although we have shown that stimulus-induced gamma weakens with aging and mental disorders, “more gamma” does not necessarily mean a better meditator or a more enlightened individual. Gamma varies considerably from person to person, which could simply be due to factors such as skin resistance, bone density, electrode position, etc, irrespective of their mental status. Therefore, our aim is not to rank meditative techniques or meditators per se based on their gamma power or some other metric. Instead, we simply aim to test whether different meditative techniques have different effects on brain signals, especially gamma power. For example, in our healthy subject database, some subjects have two gamma bands, others have gamma that builds over time, and some have gamma at low frequencies (see here). This reveals the diversity of the gamma signature, but there is no “rank” across subjects or “target gamma” that we want to get. One way to think about this is to study the physiques of athletes engaged in different sports, which vary considerably depending on the sport. We do not say that one sport is better than another. Nonetheless, studying the physique reveals important information about how the body develops to meet the demands of the sport.

For spiritual organizations, teaching meditation is not only a way to achieve moksha, but also to deal with stress and anxiety and improve the overall well-being of the practitioners. We aim to quantify these effects by studying the effect of meditative practices on brain signals. By being part of this study, spiritual organizations will be promoting a focused scientific objective of linking meditation with gamma oscillations, towards the common end goal of improvement in the overall well-being of people.

What is our study protocol?

Our first project (ongoing) is with the Brahmakumaris. The overall procedure that we followed is as follows:

1. Discuss our study protocol with the organization (e.g. Brahmakumaris) and modify certain protocols if needed based on their inputs. 

2. Get ethical clearance from IISc to conduct this study. Please note that as per the data confidentiality requirements, we will not share any data from a given individual with anyone, even with the parent organization. This is to ensure that the relationship between the individual and the organization is not affected in any way due to our study. All data will be made publicly available after removing all personal information.

3. Typically, the project is managed by three people – one person who coordinates with the organization to get the meditators, and two people to do the actual EEG recordings. For the BK study, Dr. Kanishka Sharma coordinated with the BK organization, while data collection was done by Mr. Ankan Biswas and Ms. Srishty Aggarwal, both PhD students at IISc.

4. The coordinator, with cooperation from the organization, circulates a survey form to collect basic demographic data from meditators who are interested in being part of the study. Some subjects, based on many factors such as age, gender, health, meditative practices, etc, are then selected for the EEG study. We tried to span uniformly over 20-65 years.

5. We select age and gender-matched control subjects (who have no experience in meditation) by circulating emails and pamphlets. In our experience, this step was the hardest.

6. The EEG study design (same for meditators and controls) is explained in English and Hindi. 

7. After the results are published, we will make all data (including codes) publicly available.

Going forward, we plan to make the following changes:

1. Going to various centers for short durations (~2 weeks) to collect EEG data from advanced meditators. We have made the entire data collection setup mobile. This will allow meditators to meditate in familiar settings.

2. Continuous data collection from control subjects to build a large repository of control subject data instead of doing selective matching with the meditators.

How can I be part of this effort?

1. Be a subject: we are actively looking for healthy volunteers as control subjects. Click here. 

2. Donate to the study (link will be provided soon).