Zen-Brain Horizons

What Zen communicates is an awareness that is potentially already there but is not conscious of itself.

We observed how “no you” begins. It assigns, as a target for daily practice, every overemotionalized function that had served to reinforce our dominant sense of a personal Self. That’s the hard part. Next, the good news. It predicts that we will stop suffering when we drop these maladaptive limbic attachments from our usual repertoire.

The previous chapter identified its dual aspects. Starting with our tangible physical body, we observed that this somatic Self was represented chiefly among the upper parietal and frontal regions over the brain’s outside surface (see figures 2.1 and 2.2). We then noticed the overlappings that could help link the somatic aspects of our Self with the dorsal system of our attentiveness.

This chapter turns toward distinctly different regions. These regions sponsor the intangible Self of our psyche. Indeed, many key regions contributing to the psychic omni-Self are represented next to the midline. Here, they lie deep inside the medial prefrontal and posterior parietal cortex. Some of these regions confer our private sense of identity with that familiar person who is definable using the noun I and the pronoun Me. This same person owns possessions. If any possession falls within the clutching grasp of the adjective Mine, it must be defended.³ [ZB: 43–51] My political and religious opinions are especially sensitive.

But let’s start by exposing those problem layers of the I-Me-Mine that have even deeper roots. This means introducing four points about the neural levels of the Self. They often go unacknowledged.

1. Our soma and psyche are deeply rooted. They are not just represented up in the cortex. Each of these two big systems of high-level Self-generating functions is co-activated. This means that they share rapid oscillations with deep subcortical regions. These shared oscillations unite our cortical functions with those co-arising from (and usually anticipated milliseconds before by) corresponding sets of subcortical nuclei. Nuclei are large aggregates of many nerve cells.

2. Three subcortical nuclei play a crucial excitatory role in this regard. [SI: 85–121] These limbic nuclei are located down in the dorsal layer of the thalamus.

Because they serve to relay various emotionalized messages up from the limbic system. These messages then ascend through the limbic thalamus to activate our cortex. The resulting reverberations of the Self can cause big problems.

3. Fortunately, an inhibitory gate also surrounds the thalamus: the reticular nucleus. Its inhibitory transmitter is gamma-aminobutyric acid (GABA). When GABA is released and closes this gate, it shifts out of phase the usually well- synchronized timing of these fast, bi-directional thalamo ↔ cortical oscillations. This shift serves to interrupt and shut off those excessive contributions from the limbic system that would otherwise keep reverberating up and down from the cortex. [ZBR: 167–179] The resulting silence is selective. It has some analogies with what you hear, and what drops out, when you put on a set of noise-canceling headphones. [MS: 34–37].

4. Buddhist practices apply a comprehensive approach to long-term meditative training.⁴ In a variety of ways, many practices help diminish the upsetting impact that unwholesome cortico ↔ limbic emotional reverberations can have on the normal operational integrity of our psychic and somatic Self. [ZB: 141–145]

• How can a meditative practice help us let go of these maladaptive aspects of our Self?

Two important ways are by the training of (1) a fine-grained focal attentiveness, and (2) a clear, generalized global awareness. However, this dual approach, like all meditative training, must be lived daily. To be effective, it must be integrated in a balanced manner and actualized in how we behave in everyday life. In this regard, chapter 2 specified a basic normal function of our dorsal attention system: it serves to help us focus efficiently on tangible targets relatively close to our body. A standard term for this is concentrating. To concentrate means to be exclusive, to choose only one point on which to focus. The word has a Self-referential implication that is often lost sight of: we are the active agency. Our motivation has chosen, consciously or subconsciously, to devote our own attentive energy to focus on this single site.

For example, when we first sit down to meditate, we usually begin by using two techniques of concentrative meditation. First, we usually focus our gaze down in this one-pointed manner (because that is how we were taught to begin). Having chosen one spot, our two eyes converge on it, at an angle down some 30–45 degrees below the horizontal. [MS: 42–52] Second, we also focus attention on following our breath in and out. Again, we make a choice. We choose to follow either (1) the actual sensation of air flowing in and out, or (2) the proprioceptive messages that arise from the corresponding in and out movements far down in the lower abdomen. Clearly, this concentrative form of meditation is a voluntary, top-down, executive act, one that we refer to actual motor and sensory portions of our somatic (physical) Self. Concentration techniques can evolve into the absorptions when they are intensified (voluntarily or involuntarily). [ZB: 467–518]

Receptive meditation techniques are introduced during the next stage. [ZBR: 29–32; MS: 42–52, 203–204] They exemplify a more effortless, choiceless approach. Chapter 2 identified the attributes of openness and receptivity as among the key qualities infusing this kind of global awareness. Now the eyes are free to diverge slightly from their former inturned focus on one spot. Vision and hearing can open up, expanding into a bare spatial awareness that can become more universal in scope. This receptive approach to meditation evolves gradually. It becomes increasingly inclusive, involuntary, bottom-up, and other-referential. In the distant future, these several attributes may facilitate the shift into intuitive, insightful modes of consciousness. [ZB: 519–624]

It helps now to become familiar with another useful pair of Greek words. The first, ego, is in common use when we refer back to the axis of our Self. The second word, allo, points in the other direction. Indeed, it means “other.” Within this vast frame of allo-reference is everything in the outside environment beyond the surface of our skin. Our skin surface serves as both a tangible and a conceptual division. Beyond it, the rest of the whole other world expands into the endless space out there. [ZB: 34–47] Thomas Merton’s sentence in the chapter epigraph turns out to be a highly accurate description. The allo-perspective is already there. Because it operates subconsciously we don’t know it exists.

Now for a contrast. First we observed that the course of our egocentric processing stream overlaps the functions of our dorsal attention system as it rises upward on its parietal trajectory. We have just been informed that a second stream exists. Its specialty is the anonymous processing of visual and auditory information. It follows a lower, ventral pathway among the allocentric networks. This “other” frame of reference is more global in nature. Its visual course begins down in the lower occipital region. It runs forward through the temporal lobe, then flows on into the lower frontal lobe (see figure 3.1).

Figure 3.1 The inside surface of the right side of the brain, depicting the medial origins of the psychic Self as remote from the allocentric processing stream

Chapter 3 focuses on the functions of the two large white areas and the long gray, curving, arrowheaded line at the viewer’s right. Begin with this long, curving, arrowheaded line. It starts low down, in the lower occipital cortex at the back of the brain. Let this represent the major initial ventral trajectory of our allocentric (other-referential) processing stream. As its messages relay forward into the temporal lobe, notice that they will pass through the color sensitive region of the right fusiform gyrus (FG).

The two large white areas are located higher up, a substantial distance away. In front is the medial prefrontal cortex (mPFC). Its multiple connections normally contribute adaptive autobiographical and allied executive functions to our omnipresent psychic sense of Self. The larger white area is farther back in the medial posterior parietal cortex. Its connections serve to bring its topographical memories of events into useful links with the more executive agencies of our autobiographical Self. The resulting coalitions enable us to remember how to navigate within our environment. This figure cannot show (aside from its hint of the location of the amygdala (A) all the other origins of our overconditioned emotional longings and loathings. After these limbic messages have ascended through the deep limbic nuclei of the thalamus, their oscillations rise up to engage these two white medial regions. The small white numbers refer to the numbering system devised by Korbinian Brodmann to identify different cortical areas. [ZBR: 146–148] For example, area 19 identifies one part of the occipital association cortex as Brodmann area 19, abbreviated BA 19.

Some patients can suffer discrete damage to this lower network. Their resulting allocentric deficit of global visual processing involves objects in both the right and left halves of the visual field. Why is this called object-centered neglect?⁵ Because the patients neglect that particular half of any discrete object anywhere in outside space—to the left or right. And the neglected half of that object is on the side opposite their brain dysfunction.⁶ [SI: 64–70]

The parallel distributed pathways of allocentric visual processing are reasonably close to, and accessible by, the ventral attention system. They remain relatively distant from the regions representing the physical Self of our soma and the mental functions of our psyche. The primary modules of this lower attention system are chiefly within the right temporo-parietal junction (TPJ) and the right inferior frontal gyrus (iFG) (see figure 2.1). This right TPJ serves a circuit-breaker function. Its connections enable attention to disengage from its previous topic. Once detached, attention can then shift automatically to point toward the reprocessing of the next newly salient stimulus.

Notice that this right ventral system for our normal online alerting and reorienting functions is bilaterally aware. Within its basic level of global awareness, this system stands poised to serve a reflexive role. This means that it can react quickly when a relevant stimulus event arises on either side of our environment. This characteristic automatic reaction to such an unexpected stimulus occurs long before there is time to think any long discursive thoughts. [SI: 29–34] These facts help explain why centuries of Zen literature cite instances when a person’s brain, suddenly surprised by a bird call, is instantly triggered into a state of kensho (see chapter 6).

• How could such an abrupt, involuntary shift in attention coincide with the dropping out of the person’s sense of Self?

Now for another contrast. Neuroimaging research in this century has shown that an inverse relationship normally exists between the regions that represent our attention and those that participate in our Self-centeredness. [SI: 109–121] Especially when external attention networks suddenly turn on, many Self-referential regions will turn off. These simultaneous, reciprocal capacities are noteworthy. They enable each substantial, brisk activation of our attention systems to coincide with the deactivation of our innermost frontal and posterior parietal regions. Remember: some parts of these same medial regions could otherwise be contributing maladaptive degrees of the Self-centeredness that complicates our access to more useful psychic resources. This normal seesaw, negatively correlated relationship can be oversimplified visually as follows:

• But states of awakening are not just selfless. Why are they also infused by an impression of reality? Why is this impression so meaningful and perfect that it transfigures the appearance of what had seemed, only an instant earlier, to be the ordinary outside world?

Meaning does not materialize out of thin air. Meaningful impressions coalesce in association networks, especially in associations within the temporal lobe and their connections. Meanings spring from configurations that can also access our normal allocentric spatial processing pathways. [ZBR: 357–371; SI: 189–207] Allocentric spatial representations often link with activations of the right hippocampus in human subjects.⁷ Moreover, inherent coalitions of allocentric functions could become further enhanced, clarified, and sustained as the result of deep subcortical shifts at a thalamic level. These pivotal changes could serve to liberate this “other” frame of reference, freeing it from its prior domination by our weighty egocentric frame of reference.⁸ Now all things as they really are could seem especially real. Some of kensho’s direct sense of authenticity could also arrive when highly efficient degrees of fast processing accompany such an uncluttering of entanglements from our usual elaborate Self. [SI: 145–146]

• What could explain the way that a person’s usual discriminating word-thoughts and concepts vanish during a major state of awakening?

Eleven centuries ago, Master Huang-po was aware of this silence. His description for such powerful quieting translates as “the Stillness beyond all activity.” [ZB: 633–638] Meditators soon discover how much valuable, quiet, productive time they waste while generating useless trains of noisy word-thoughts. Why do we produce so many discursive thoughts? Mostly because our habitual Self-preoccupations are activating impulses in deeper striatal and limbic regions. These can keep rising up to agitate the language networks in our frontotemporal cortex (L>R).⁹

It’s not clear why so many language functions evolved on the brain’s left side, (or why the liver is over on the right side of our abdomen). Huang-po’s prescience as an early observer of silence is apparent, given how little was then known about brain physiology. Not until 1861 were we in the West enlightened about the fact that our normal language functions were dominant on the left side. Then, Pierre Paul Broca (1824–1880) reported that damage to the left inferior frontal region caused verbal silence. A lesion here blocked the (motor) articulation of his patient’s speech. And we waited until 1874 for Carl Wernicke (1848–1905) to show, again on the left side, that the superior temporal gyrus was our dominant region for decoding the meaning in receptive (sensory) speech (see figure 2.1).¹⁰

Let’s now review four key contrasts in chapters 2 and 3, with the aid of figures 2.1, 2.2, and 3.1:

1. The left upper temporal and lower frontal regions are dominant for these normal sensory and motor language functions. In contrast, corresponding temporal and frontal regions over on the right side are dominant for the ventral attention system’s capacities for spatial attentiveness. These ventral regions enable the brain to be aware of, and to react to, stimuli anywhere on either side of our environment (see figures 2.1 and 2.2)

2. The egocentric processing stream is overlapped by the dorsal attention system. This overlapping occurs over the upper and outer parts of the cortex. Up here, in the superior parietal lobule, our somatic Self’s sensory-motor association functions start to become integrated into the schema of our whole body. These parietal associations representing our physical Self are further refined in the inferior parietal lobule.

In contrast to these attentive regions over the outside of the brain, most autobiographical and topographical correlates of our psychic Self are represented elsewhere. These networking functions arise chiefly on the brain’s inside surface between the two hemispheres. Here, they are distributed among the medial prefrontal and posterior parietal regions (see figure 3.1).

3. The allocentric processing stream begins anonymously much farther down (see figure 3.1). This other-relational frame of reference pursues a lower trajectory. This permits it to be accessed relatively easily by the lower modules of the ventral attention system rather than by those distant, Self-entangled modules higher up in the dorsal attention system. Moreover, whereas the right side of this ventral system is dominant (R>>L), each side of our dorsal attention system directs its vanguard functions—to an equal degree (R=L)—toward the opposite side of the environment.

4. When attention is activated, deactivation occurs in the (mostly medial) frontoparietal regions representing the psychic Self, and vice versa.

• Do other important differences exist between the left and right sides of the brain?

Yes. For example, our left temporal lobe contributes especially to fine-grained semantic understanding of language. Semantic is another word for “meaning.” The temporal lobe’s tightly organized templates are coded to instantly identify, interpret, and infuse meaning into what we perceive. These basic categorizing functions enable us to understand and to express spoken, silent, and written forms of language in an orderly, accurate manner.

Skill sets of this kind are an essential prelude to comprehension in general. In this regard, the right temporal lobe helps instantly integrate more subtle kinds of nonverbal information in the form of ideas. Such an ideational approach to decoding enables us to formulate and interpret atmospheres of aesthetic appreciation in art and music. These are examples of the kinds of nuanced functions that could coalesce when intuitive forms of comprehension unfold into wordless insights of all sizes and depths.

It sometimes helps to remember a further qualification. Yes, the primary functions of our right and left hemispheres are complementary. Yes, in this respect, they do interact chiefly as allies. However, each side quietly maintains a subversive system of its own. These autopilots on one side serve silently to restrain and inhibit regions on the opposite side.¹¹ [ZB: 358–367]

These significant differences in the ways our lobes and two hemispheres function are a preamble for the themes to unfold in subsequent chapters. Once again we return to events that happened millennia ago.