What happens to the brain when thoughts almost disappear, the familiar sense of time and body recedes, and awareness itself remains?
It is precisely this state that researchers attempted to study in experienced practitioners of transcendental meditation. The study involved 33 meditators and a comparable control group, which performed mental counting instead of meditating. The scientists simultaneously recorded EEG and collected detailed reports of the participants' subjective experience.
Particular attention was directed at the state that the authors call pure awareness: an experience in which the usual content diminishes, yet wakefulness and the very presence of consciousness are preserved.
The results showed that at that moment the brain by no means shifts into a simple "silence" mode.
The researchers analyzed the temporal entropy of the signal, aperiodic activity, complexity, and functional connectivity between brain regions. And they found that different characteristics become important depending on which state the meditation is compared with.
When compared with mental counting, changes in temporal entropy and aperiodic dynamics proved especially noticeable. And when meditation was compared with ordinary rest in the same practitioners, low-frequency functional connectivity came to the fore.
In other words, the researchers did not find a single "rhythm of pure consciousness."
Instead, a more interesting picture emerged: the state manifested as a complex, distributed configuration of brain dynamics that cannot be reduced to the activity of a single region or a single frequency.
The participants' subjective reports also proved important. The practitioners described the state of pure awareness as more pronounced and more variable over time than the participants in the control group did. At the same time, its intensity did not directly depend on the number of years of practice.
For research on consciousness, one point is especially important here.
The minimum of the content of consciousness turned out to be by no means equal to the minimum of neural activity.
When the stream of thoughts grows quieter, the brain does not simply "turn off the sound." It reorganizes the very way it is organized.
One can imagine an orchestra that has stopped playing a familiar melody. The musicians remain on stage, the interaction continues, but the music acquires a different structure.
That is precisely why this work is interesting not only as a study of meditation. It raises a more fundamental question: what in the brain is connected with the specific content of consciousness — thoughts, sensations, images — and what may be connected with the very presence of awareness?
For now, the study does not allow us to speak of a universal biomarker of "pure consciousness." One form of meditation was studied, and the EEG patterns found have yet to be tested in other practices and independent samples.
But one conclusion already looks especially curious: when the content of consciousness almost disappears, the brain does not become empty. It begins to work differently.
And perhaps it is precisely in this difference between what we are aware of and the very fact of awareness that one of the keys to understanding the nature of consciousness lies hidden.
