Samatha Meditation - EEG Study

Lilies
Buddha and EEG
Buddha

Over 40 years ago during the time of the first Samatha meditation classes in London and Cambridge, Nai Boonman suggested we might someday carry out research into the effects of meditation on the brain. At that time, electroencephalograph (EEG) equipment was extremely expensive, and would probably have filled a small room. Since then technology has advanced enormously, and prices fortunately have dropped. In July 2010 a 19-channel EEG system was purchased and the first recordings of Samatha meditators in this tradition were made during an intensive retreat at the Samatha Trust’s National Centre in Wales during August 2010. Further recordings have been made since then at the Manchester Centre, and in London.

In 2017 a preliminary draft paper on the EEG study of Jhana meditation was completed. A link to a pdf copy of ths paper can be found in the Downloads menu at the bottom right of this page. A more detailed paper for one of the neuroscience peer-reviewed journals is in preparation.

Over the last 30 years there have been many EEG studies of meditation, but most of these have been of more open relaxation modes of practice, with very few studies of focused meditation, or Samatha, comparable to our own tradition. Recordings typically take 30 mins, although the analysis may take much longer. Individual meditators’ identities are kept confidential.

Rūpa and arūpa jhāna

Above is a recording of a meditator practicing rūpa jhāna from the early pilot study using the 19-channel EEG system. Each electrical trace on the left is from an electrode pair on the meditator’s head, and the 2-dimensional plots on the right show the intensity maps looking down on the head, and from the side, for the two low-frequency bands Delta (1.0 –4.0 Hz) and Theta (4.0–8.0 Hz). For this meditator, activity is focused in the left frontal cortex, in the Theta band (4.0–8.0 Hz), known to be associated with deep relaxation. (Higher frequency, Alpha and Beta, activity is not shown as it is effectively suppressed during deep meditation). Theta activity tends to come at the borders of sleep, but in meditation it develops as part of a highly alert state. This meditator was giving attention to a strong visual mental image, nimitta.

When this same meditator moved into developing arūpa jhāna, letting go of attending to the nimitta, electrical brain activity shifted to the right parietal lobe – see below - which is known to be involved in integrating spatial representations. The intense energisation has also now spread into the lowest-frequency (0–4 Hz) Delta band, as well as the Theta band. Delta activity is normally mostly found in deep sleep, but here it occurs as part of the highly aware meditative state.

Energisation / piti / “psychic power” practice

Below is an historic picture – the first recording of an experienced meditator demonstrating the deliberate arousing of a high-energisation state, related to piti, and sometimes referred to as “psychic power” practice. The surprise on seeing this was to notice the similarity to EEG recordings of some epileptic seizures, although in this case under complete control in entering and leaving that state, and with no discomfort.

A big problem in analysing a recording such as the above, is to separate the movement or muscle artifacts from the actual brain EEG activity. More careful recordings suggest that arousing piti and subsequently tranquilising the energised state, leads to a deepening of the meditators degree of absorption.

These pilot results have been sufficiently exciting that more advanced equipment has now been purchased (July 2012) with the help of very generous donations by Samatha meditators. The new 32-channel system will enable recordings to be made up to much higher frequencies than the pilot study so-far, and we hope will give more detailed information on the ways that different brain regions are affected by willed acts of attention in meditation, and will help to shed light on the more subtle processes, including the nature of consciousness itself.

A study of samatha meditation and neurofeedback can be downloaded here or from the download menu to the right of this page.

As a home for this study, a website has been set up at www.samadhieeg.org.uk

This website will take a cross-discipline approach that aims to bridge meditation/spirituality, neurology and mental health, as well as insights from physics and particularly quantum physics. The site will be regularly updated as new results become available.

Click here for details of residential courses for beginners and more experienced meditators.