Jhāna Consciousness

On this webpage, several of the figures from chapter 12 of Jhāna Consciousness—which show excerpts from EEG recordings of meditators participating in a neuroscience study—are reproduced in color and can be examined more closely than is possible in the book. In addition, four short videos with voice commentary give a dynamic sense of the meditators’ real-time EEG recordings, which cannot be conveyed in still images. Together, the figures and videos illustrate some of the remarkable characteristics of brain activity during jhāna meditation that I explore in Jhāna Consciousness. These characteristics are:

  1. Disruption of the brain’s attention networks, evidenced by “spindle” EEG activity in the majority of the subjects studied. As meditators turn their attention inward, toward a mind-based meditation object, they progressively disengage from the outer world and their default sensory consciousness. This shift indicates the approach to the first rūpa jhāna.
  2. Development of very slow (infraslow) brain wave rhythms as meditators progress beyond the first rūpa jhāna. In some cases, these infraslow waves reach intensity levels unprecedented in EEG studies.
  3. The development of a “vertical axis” of jhāna consciousness that is distinct from brain activity patterns found in default sensory consciousness. As meditators progress to the higher jhānas and become more withdrawn from the sensory world, brain activity becomes concentrated primarily at the crown of the head and downward into the body via the brain stem.
  4. The responsiveness of the brain to meditators’ willed intention.
  5. The ability of some meditators to arouse high-energy states reminiscent of epileptiform or seizure activity, but with no discomfort and under full control.

Spindles

Figure 33 Chapter 12_webpage version

Figure 33. Spindles during samatha meditation.

EEG spindles are well known in neuroscience as occurring in the early stages of sleep. My research shows that spindles also occur in jhāna meditation and correspond to a disruption of the brain’s sensory-consciousness attention networks brought on as meditators direct attention inward to the breath while remaining fully alert. The EEG recording and enlarged extract in Figure 33 shows the characteristic “wave-packet” appearance of spindles (highlighted in yellow for clarity). For all the meditators who exhibited spindles, the spindle activity occurred at least partly at the back of the head. Because the visual cortex is located at the back of the brain, I posit the spindle activity in meditation to be related to an effect on the sense of “I/eye” subjectivity.

Video clip 1 compares an extract from the original EEG recording for Figure 33 with a short recording of a meditator showing much more widespread spindles across the head, which could indicate the subtly different ways individuals use their brains to aim toward similar outcomes. In this case, the first meditator may be unconsciously drawn to focus their disengagement from sensory consciousness on the “I/eye” subjectivity networks of the occipital visual cortex at the back of the head, while the second meditator might instinctively attempt to suppress all sensory consciousness activity across more widely distributed networks.

Infraslow Waves (ISWs) and the Vertical Axis of Jhāna Consciousness

While spindles were observed to some degree for most of the meditators in the study, the next most common feature of strong, rhythmic, slow brain waves was observed in only about half of the cohort of twenty-nine. Some of these slow waves, which I call infraslow waves (ISWs), were significantly slower and more rhythmic than other examples seen in neuroscience research. Five of the meditators recorded in this study developed ISWs of very high intensity unprecedented in neuroscience, which I believe is likely related to development of the third and fourth rūpa jhānas.

Figures 42 (also shown as Figure 35 in the book)  and 43 show how ISWs can develop as a meditator gains experience—in this case over an interval of three years, from 2014 to 2017. This can be seen most clearly in the inset intensity maps corresponding to the start and end points of the individual slow waves highlighted in yellow. The intensity maps show how activity is distributed throughout the brain. Note how the focused “hot spot” near or just posterior to the crown of the head (vertex) in the 2014 recording becomes almost entirely dominant in the 2017 recording, indicating increasing proficiency with jhāna meditation over the course of years of practice.

Figs 42_43 Chapter 12_webpage version

Figures 42 and 43. Subject 5 2014 (upper panel) and 2017 (lower panel).

This is illustrated in another form by the 3D cortical maps of Figures 37 and 44a. The nine plots of Figure 37 show the mean underlying cortical sources of brain activity from seven independent EEG recordings (2014–2017) of the five meditators who showed the clearest and strongest examples of ISWs. The middle three plots of Figure 37 show that a mean 44.4% of brain activity was focused at the vertex, which can be compared to the greater-than-95% focus at the vertex for subject 5 of this group in the lower panel, Figure 44a. (This figure is based on the detailed quantitative analysis described in the book, summarized in Table 4, chapter 12.) The overwhelming dominance of vertex activity in subject 5—as opposed to the more distributed brain activity indicative of ordinary sensory consciousness—is entirely consistent with Buddhist understandings of the fourth rūpa jhāna, in which the meditator reaches total equanimity and a complete withdrawal from ordinary sensory consciousness. As a group, the five subjects represent around 25% of the total group studied and are believed from the overall evidence to be at various stages of developing the second, third, and fourth rūpa jhānas.

Figs 37_44a Chapter 12

Figures 37 (top panel) and 44a (lower panel).

The cross-section (sagittal) view of the brain (Fig. 44a) shows the position of the vertex source. The vertex area of the brain is highly connected to core regions of the brain and upper brain stem, which in turn are highly connected to the nervous systems of the body. This suggests strongly that the higher jhānas act as a bridge and may perform an integrating function between brain and body systems, creating what I call the vertical axis of jhāna consciousness.

Video clip 2 shows a portion of the original EEG recording from which the segment in Figure 43 and the 3D plots of Figure 44a are derived.

Responsiveness to Willed Intention

The concept of brain plasticity is often used in neuroscience to describe the ability of the brain to adapt to different conditions or to recover from injury. This study of jhāna meditation has revealed a property closely related to brain plasticity, which is the remarkable responsiveness of the brain to the willed intentions of a meditator. Figure 36 below is one among several examples. This meditator is beginning a practice with the direct intention of developing the higher jhānas immediately, without attending to a preliminary progression through lower stages. Within less than 40 seconds, very strong and extensive slow waves have developed, initially in the form of strong inhibitions.

The left-hand intensity map shows a quiet, normal-intensity EEG at the start of the yellow-highlighted section; leading to an annulus of intense inhibition reaching levels of over 2,000μV at the end of the yellow-highlighted section, shown in the right-hand intensity map.

Figure 36 Chapter 12_webpage version

Figure 36. Rapid onset of ISWs.

A rather different and even more striking example is given in the book, which is a recording of a meditator demonstrating the ancient technique of Bu Ddho meditation to develop the first rūpa jhāna. Historically, this practice has been used across Southeast Asia as a lead-in to the more detailed ānāpānasati (mindfulness of breathing) practice. Figure 31 shows the course of brain activity during the thirty seconds that follow the cue to begin practice, which is marked by the label BUDDHO, upper left below the time bar.

The effects on the temporal lobe (electrodes T3 and T4) and the frontal lobe (Fp1 and Fp2), as the meditator silently intones the syllables Bu and Ddho, are shown in Figure 31 and described in detail in chapter 12 of Jhana Consciousness. The scale of the response is marked by the two inset intensity maps for the start and end points of the yellow-highlighted section; a rapid increase in intensity of 2,000μV to the peak is followed by a slower decline with a total peak-to-trough change in intensity of over 3,000μV—levels rarely seen in neuroscience and a quite surprising effect of quiet, willed intention.

Video clip 3 shows real-time sequences from the original EEG recordings of this Bu Ddho practice.

Figure 31. Bu Ddho meditation

Pīti: Deliberate Arousal of High-Energy States

Related to the above are techniques in esoteric Buddhism to deliberately develop high-energy states, which are then deliberately calmed into deep tranquility and jhānic absorption. At their most intense, such practices can resemble grand mal seizures in terms of brain activity, yet practitioners experience no discomfort and can arouse and calm the states at will. These techniques date back to the early years of Buddhism, and perhaps even earlier, and are found both in Tibetan yoga (in the form of practices such as Tummo, or inner fire) and within the Yogāvacara practices of Southeast Asia described in Jhāna Consciousness. From a modern, scientific perspective, these practices are of great interest in relation to epilepsy, raising questions as to whether any aspects of these techniques might be adapted to mitigate the intensity or frequency of epileptic seizures.

Figure 39 was recorded in 2018 with the consent of an experienced meditator. The segment highlighted in yellow and enlarged in the lower panel shows the most intense part of the episode, which is localized in the posterior temporal region of the brain.

Video clip 4, from the original EEG recording, shows the episode unfolding in real time.

Figure 39 Chapter 12_webpage version

Figure 39. An example of the deliberate arousal of a state of high energy, Pīti.

Acknowledgment

I wish to acknowledge the contribution of Guy Healey, video consultant, long-term meditator, and meditation teacher, whose patient and thoughtful help in compiling these clips from the raw EEG recordings has been absolutely indispensable.