Your Self, Your Brain, and Zen

As you read these words, suppose that someone you respect were to bow politely and inquire gently of you, “Do you know who you really are? Where you are? And what time it is?” Continue to suppose that, Zen-like, you were unperturbed by this intrusion. Choosing to reply, you would answer with certainty. Each response would feel correct, because it would draw on your strong, stable sense of selfhood. This inside self would feel in touch with both your autobiographical past and each new event that has just transpired in the world outside. But would you be as certain if next you were asked, “Could you still fully experience this other, outside world if you had lost every last subjective sense of your inside self?” Or would such an interior vacancy of self leave you senseless, in a state resembling coma?

Before 1974, I had little appreciation of how pivotal was this interface where self meets other. But then, on sabbatical in Japan, I happened to meet a remarkable Zen master. In his Kyoto temple, Kobori-roshi introduced me to the practice of Zen meditation. My experiences as a meditator would teach me how ignorant I was about three key questions: Where in the brain had my own constructs of self developed? Could long-range Zen Buddhist training transform the way I thought, felt, and behaved? And, if so, how?

Before learning to meditate in Japan, I would not have believed it possible briefly to lose all sense of self. Nor could I have regarded that experience as desirable. Hadn’t my teachers emphasized, early in medical school, that our patients were very abnormal if they did not know who they were, or what time it was? So how could any state of “no self” help clarify the normal operations of one’s brain?

As it turned out, two very different kinds of loss of self occurred on my long path of Zen. The first experience was superficial: my physical sense of self dropped off temporarily—a “dearth of self,” so to speak. Years later, I briefly lost all sense of my psychic self and its bodily attachments. During this “death of self,” deep insightful realizations occurred.

For millennia, people in various cultures have reported brief experiences of deep insight. Some of these episodes appear to arise spontaneously; some are triggered by events in nature; others surface in an overtly religious context. In Zen, such deep realizations are referred to as kensho or satori. Among the names given to these “peak” states are spiritual awakening, enlightenment, flashes of insight, and existential wisdom.

In Buddhism, wisdom implies being liberated from all delusive fictions that separate one from being an integral part of the world at large. Zen seeks total, inclusive comprehension of being and responding within the web of the whole universe. Zen also emphasizes personal commitment to a long process of intuitive realizations, insights that plumb depths unreachable by ordinary concepts, thoughts, or words. Yet, trainees are cautioned that any insightful awakenings must still become integral to their daily life.

I view these brief moments of profound realization as alternate states of consciousness. They can become life’s defining moments, going on to transform our behavior and attitudes. Similar moments are reasonably common in the population at large; we need not think of them as states that are altered, abnormal, or anomalous. True, their wordless flash of existential insight does arrive unexpectedly. But this is more likely to reflect the culmination of a series of subtle biological events, not a simple random occurrence, or the intervention of some outside agency. The minutes after emerging from a state of kensho are a time of deep reflection, all prior reference to my self having vanished. When every self-referent impulse drops out of the picture, what processes sustain awareness?

In this state, an impression arises of “all other things as they really are.” There is, I believe, an overlooked category of normal brain function, non-self circuits we can call “other-referring” that perceive the outside world directly. And when these other-referent, innate brain circuitries are left free-standing, they can begin to register experience in an absolutely clear, fresh, and objective way.

On the Path of Zen

The Kyoto temple where Kobori-roshi introduced me to Zen was founded in 1327. At our first meeting, he emphasized the critical importance of prajna. This Sanskrit term stands for an awesome flashing insight, symbolized by a sword. I began by learning to meditate for longer periods each day. Sometimes I followed the path of receptive meditation: an awareness that was open, unfocused, and inclusive. At other times I adopted the more intensive techniques of concentrative meditation, focusing my attention in ways that were more one-pointed and exclusive. All the while, I was practicing the elusive art of applying a quieter, mindful, introspective approach to the troublesome realities of everyday life. Nothing came easily, but gradually the path of Zen became more practical, less baffling.

Then, one evening in Kyoto, during the third period of sitting meditation, and preceded by stress related to my whole left leg falling asleep, I experienced my first substantial “opening.” It turned out to be a startling wake-up call for this neurologist.

First came a sustained, involuntary heightening of attention, a hyperawareness of the immediate point of NOW. My vision expanded globally, encompassing in every direction endless space, blacker than black lacquer and absolutely soundless. This silent black vacuum of endless space admitted a small hallucination, a vivid red maple leaf— an image I had photographed weeks earlier. A plenum of aesthetic rapture infused the black void in which this leaf briefly hung suspended, a feeling replaced later by blissful emotional warmth.

No impression of my physical body remained. The witnessing center was empty. Nobody was there. My perception had undergone an extraordinary change. A shift toward interior consciousness had bypassed external vision, generated visual percepts in some kind of heightened interior mind’s eye, blocked all external hearing, and cut off the sensory input that nourished my usual physical self-image. Notice that these sensory changes are both excitatory and inhibitory in nature. When each is considered in relation to the underlying hyper-aware state, they provide clues that will help point us toward the roots of our physical self.

A Taste of Kensho

In England, eight years later, I experienced a very different alternate state of consciousness, the deep insights of which differed from the phenomena during that earlier episode of absorption. On a balmy Sunday morning in March, I was en route to the second day of a two-day meditation retreat. As I stood quietly on the empty platform of a train station in London, the view of a drab skyline instantly took on three qualities that I would later describe imperfectly as absolute reality, intrinsic rightness, and ultimate perfection.

A second wave of wordless realizations flooded in: This is the eternal state of affairs; nothing more remains to be done; there is absolutely nothing to fear. No physical or psychic self, but only a kind of anonymous mirror was witnessing the scene, which was briefly pervaded by moonlight. A buffer zone so wide as almost to be tangible further distanced the witness from any sense of possessive contact with outside events. Then a third wave of insights welled up. Now, some vague, diminutive lower-case “i” faintly noted that no conceptual framework existed to describe this event. Nor could this emerging “i” take seriously any prior notion of being a personal self. A sense of absolute release, freedom, and deep peace had overcome any residual sense of “me.” Later a surge of enormous gratitude filled me at having tasted that immanent, eternal reality pervading all things.

Were I now to summarize, in one sentence, the differences between these two experiences, I would say that the absorption resembled the enthusiasms of my high school years (transient, but memorable); whereas the later experience of kensho felt as though I had been emancipated, suddenly, by the essence of a college-level education.

I, Me, and Mine: Psychological Imperatives of Selfhood

In the view of psychologist and philosopher William James, the countless sensory messages coming in from our heads and bodies confirm our unshakable sense of a physical self. These sensory messages provide a basic physiological framework for various layers of the psychic self. Think of “psychic” as a kind of shorthand for our usual blend of two functions: cognitive and affective.

The cognitive side of this psychic pair is constantly subjected to emotional or affective influences, both positive and negative, called valences. They are attributable to the functions of our emotional brain, meaning both our limbic system and its closely related (paralimbic) systems. We tend to overlook the potent ways that such valences, enhanced by hormones, affect our higher thoughts and loftier concepts. Yet most of us sense, at least by adolescence, that our individual psychic self has evolved into a turbulent blend of cognitive, emotional, instinctual, and sensorimotor behavioral elements.

Surveying the dynamic nature of this “omni-self” at the level of descriptive psychology, one can visualize three major interactive components in operation: I-ME-MINE.

The operations of this triad have survival value, but selfhood creates problems, as well. Arrogance, for example, often expresses the attitudes of our sovereign “I,” that side of our self that can become aggressive. Simultaneously, its vulnerable partner, the fearful “ME,” is the aspect of our self that may feel emotionally besieged, if not physically battered. Finally, the possessive self, the “MINE,” is easily captured by its own greedy cravings. It can clutch at other persons, covet material goods, cherish each of its own biased opinions.

Zen is a change agent, but arrogant, besieged, craving selves resist change. Can mental imaging and letting go during meditation cut off these deep, tangled roots of the dysfunctional self? No. Roots regrow. But when regular meditative practice is reinforced during meditative retreats, the human brain does seem more likely to shift into short-lived extraordinary states. Only the insights of the deeper states, such as kensho, lay bare the dysfunctions of the psychic self. Then some degree of character transformation may occur, both in the surge of this wordless wisdom and in its reflective aftermath. But this is only the beginning. The Zen trainee requires decades of introspective daily practice to discern and discard selfish habits. Progress is glacial, but emerging out of the long, exacting process of introspection will be a simpler, more stable human being, slowly becoming more adaptable, buoyant, and compassionate.

Dissolving the Sense of Physical Self

Following my experience of internal absorption in Kyoto, I became curious: Which kinds of physiological changes had caused my physical self-image to disappear? To answer this question, we need to simplify the brain’s functional anatomy. A provisional notion might suggest that the circuitry in our brain’s back half, represents most of this ordinary physical self-image within its countless modules and networks.

But before the elementary sensory messages from the head and body (our “soma”) can rise up to inform the cortex, they must first pass through a crucial gate at the back of the thalamus, a structure deep within the brain that processes all the signals entering from the outside world. Indeed, it seems likely that most elementary percepts and notions about our physical self-image enter the margins of our consciousness only when the back parts of our thalamus engage in a lively dialogue with the parietal somatosensory cortex and with the many special sensory-association regions behind it.

Neurophysiological research pioneered by Mircea Steriade and his colleagues in Quebec informs us that many such interchanges occur in the course of intricate electrophysiological oscillations. These “shimmerings” are synchronized at different frequencies and amplitudes.¹ Coming together, they help to refine and integrate a series of perceptions across the two sides of the self/other interface. One large set enables us to hear, see, taste, touch, and feel ourselves move, as though from one private source inside. Another set attends closely to salient events happening outside our skin.

What can close this gate over the back of the thalamus to self/other perception? Stressful events can, including sensory overload created during hyper-intense concentration. Even the nightly act of dropping off to sleep stops sensory impulses from rising through the thalamus. Could differing conditions of practice during meditation invoke similar kinds of gate-closing?

It is stressful, mentally and physically, to sit and sustain attention through long, repeated periods of meditation. Meditators do become drowsy, sooner or later. Extended retreats test one’s endurance skills, destabilize biorhythms, and create shifts in one’s prior sleep/waking cycles. Soon, arousals and drowsy periods enter at unusual times. Physiological systems that had once seemed to mesh smoothly in support of ordinary consciousness may begin to split off, as it were. Odd sensations and strange experiences surface when their components recombine in unusual configurations, but in Zen neither illusions nor hallucinations have spiritual significance.

Zen training entails a carefully calibrated series of stressful circumstances that can prompt the brain to release both its fast-acting (primary) and slower metabolic (secondary) messenger molecules. Stress responses lead to extra releases of biogenic amines inside the brain itself. These messengers (norepinephrine, dopamine, and serotonin) further enhance the shifts in attention and emotion. For example, the release of norepinephrine sets off a cascade of stimulating responses in key peptide nerve cells deep within the hypothalamus. There, corticotrophin-release-factor (CRF) cells send excitatory pulses of the CRF through the thalamus, hypothalamus, and brain stem. The CRF surges set off secondary pulses of two coexisting molecules, ACTH and its slow-acting partner, the opioid Beta-endorphin. Other hypothalamic cells enhance the release of oxytocin.

The earlier the cerebral cortex participates in the total buildup of reverberating waves of activation and affective arousal, the more it releases glutamate, its major fast-acting excitatory transmitter. However, brain circuits have ways to block excessive excitatory states driven by glutamate and norepinephrine.¹ For example, down in the thalamus the reticular nucleus can release its fast inhibitory transmitter, GABA, which acts like a “shield” covering the back of the thalamus. No longer can the sensory nuclei there relay an excess of incoming sensory signals up to the cortex to overstimulate it. This is a plausible explanation for some key features of the kind of deep internal absorption I first experienced in Kyoto.

In London came that deeper state of stark, insightful awakening. What mechanisms cause the psychic self to drop away during kensho?

Dissolving the Veils of the Psychic Self

The higher-level associative processes of our psychic self also depend on reciprocal interactions between the cortex and deeper subcortical assemblies of neurons. These regions include both the limbic system and other (para-limbic) structures rich in limbic connections.

Limbic circuitry contributes countless instinctual and acquired emotional overtones to the psychic responses of our frontal and temporal lobes. The result is that rich admixture of swirling thought streams, quasi-cognitive concepts, emotion-laden memories, and biased interpretations that we accept as everyday consciousness.

Valenced messages from these networks do more than affect our attitudes. They mobilize our behaviors. Some messages leave us feeling positive toward an event and eager to approach and connect with it. Others fuel fear, causing us to withdraw, or anger, leading to aggressive action. Still others make us recoil with separate feelings of disgust and loathing.² Biases of limbic and paralimbic origin have been pulling and pushing each of us since birth, generating unfruitful longings, anxieties, hostile behavior, and loathings in countless unsuspected, over-conditioned ways.

Zen views such personal biases as layers of subjective veils that shut us off from a more objective view of reality and prevent us from reaching our mature potentials. Indeed, the world we inhabit is less a world of so-called self/other dualities than one obscured and distorted by a barrier of self-imposed “trialities,” as shown in the illustration above. Accordingly, our usual perceptions do not correspond with the objective reality of the OTHER world, in capital letters. Rather, they register a jumbled landscape, one dominated by the insertions of an overinflated, subjective SELF: S-o-ELF-ther.

From the Zen Buddhist perspective, this is a fundamental delusion. We are, instead, just one tiny wave rising in a vast ocean, a transient phenomenon in that whole vast universe of unconditioned unity wherein self equals OTHER. Only when the veils of the old, conditioned personal self drop away do we begin to liberate our capacity to see deeply into the reality of this outside world. Only during such an emancipation can what Zen calls our “original self” or our “true nature” register an extraordinary impression: things as THEY are, not what they had once seemed to be in our overconditioned imagination.

Kensho’s “death of the self” dissolves more than the emotional dysfunctions of the I-ME-MINE, with its selfish impulses. It also cuts deeply into some of cognition’s key premises, including a range of categorical yin/yang—black-white—distinctions. Previously, we had been convinced such distinctions were true: “This” was always separate from “that.” Moreover, we felt certain that we could always split personal time into its three familiar compartments: past, present, and future.

The table above suggests the kinds of direct realizations that flash in (wordlessly) when subjective veils vanish during kensho. The lowest row describes the state of egoless awareness that emerges. A state empty of self, but now infused with salient affirmative qualities, it comprehends each particular thing and its every interrelationship within one universal Unity. This is experienced with utmost clarity, and feels “realer than real.” It is also timeless, perfect, unconditioned, and beyond all fear. But the paradox remains: How can a human brain go on “experiencing” when its sense of self has dropped out of the picture?

Losing One’s Place

The global positioning system, or GPS, enables you to pinpoint your physical location—in two dimensions—on Earth’s vast grid of latitude and longitude. During the recent Decade of the Brain (the 1990s), a few neuroscientists began to explore analogous systems that help animals orient themselves in three dimensions. In primates, such a “GPS of the self” is more sophisticated than is the system of “place cells” used by rodents.³ It takes the form of a multi-modular neural network, poised to integrate two different frames of reference. One can help sustain our notion of having a tangible, responsive, physical axis inside our body. The other refers to the world of space.^1,3

Suppose a visual stimulus enters a monkey’s brain from the external world. Tiny electrodes, put in place days before, enable researchers to track the resulting impulses. These first speed through the early visual pathways, then spread through the posterior parietal and temporal lobes, the posterior hippocampus, and related regions. En route, these signals diverge; they appear to be processed in different cells of two kinds of functional channels.

One category of perceptual channel— the egocentric channel—is implicitly self-referring. In the monkey, even while this channel is relaying visual signals from a particular item out in external space, its various cells are also firing with special reference to where that monkey’s own head, eyes, and trunk are at that instant. Suppose you slightly shift the positions of these body parts, then redeliver exactly the same visual signal. Now these visual cells respond by changing their firing rates accordingly.^1,3

This kind of “seeing” is an egocentric, body-centered process. One of its benefits is helping to maintain a physical axis of self, responsive to the immediate needs of working memory of the world outside. The process is ready to become integrated into more ongoing, “self”-establishing, psychic layers of internal reference. These can set up the personal basis for remembering our conditioned response to some item or event in outside space.

The contrasting category of sensory channels is called allocentric, allo meaning “other.” It implies that the senses are attuned to that other world of space outside oneself. Does a stimulus from this other-referent world have the same primary obligation to consult first with any obvious part of the viewer’s body? No, it seems to have been hard-wired to register a sense of this world directly. So, for example, when the networks of allo-spatial view cells process the visual data they receive from events “out there,” their codes convey an initially selfless view of exterior things. Their percepts convey an impersonal, anonymous version of space and its contents.³ In 1998, Lawrence Snyder and colleagues found more of these “worldreferenced” nerve cells in area 7A of the posterior parietal cortex of primates, dsitinct from their “body-referenced” neighbors.

Under ordinary conditions, the two types of neural networks work together. When they merge and interact seamlessly, one’s body seems both to “own” parts of itself and to occupy its central place inside our private version of the outside world. As you began reading this article, when you reached back into your various memory levels and linked them into your personal GPS, you knew precisely where your own body was located in space.

Hughlings Jackson said, a century and a quarter ago, that he didn’t “pretend to know” which specific anatomical pathways among “our highest nervous arrangements” served either subject or object consciousness. Today we are only beginning to edge beyond what he called “admittedly imperfect hypotheses” in specifying those precise points at which all of our egocentric categories of processing diverge from their allocentric counterparts. But several intriguing leads tend to point more toward the front of the brain as at least one major source for our egocentric consciousness.

In the forward half of the brain, two good candidates for a key role in egocentric consciousness are the amygdala and hippocampus, both located in the most medial areas of the anterior temporal lobe. Pierre Gloor and his colleagues in Montreal delivered discrete electrical stimuli to the amygdala or hippocampus during their studies of patients whose seizures began in the temporal lobe. Stimuli here often yield vivid experiential phenomena having the compelling immediacy that patients describe as “being there.” For example, the intimate resonances of fear are common, as are visual illusions and déja vu experiences.

Many other studies confirm that the amygdala in particular is not only pivotal to the ways we process the complex emotion of fear,² but that it is also a key module in the networks of our limbic system and its paralimbic extensions. Could many of the depersonalizations of the I-Me-Mine during kensho be part of a larger series of other inhibited functions? If so, would such losses within the psyche first be affecting the limbic system per se (amygdala, hippocampus, hypothalamus, cingulate gyrus, septal region, and so on) or its paralimbic extensions, such as the three thalamic nuclei and the cortex of the insula?

Limbic and Paralimbic Considerations

The three paralimbic nuclei down in the thalamus normally influence our higher cognitive-emotional functions in several ways. First, the medial-dorsal nucleus. The largest of these nuclei is an essential partner in many of our so-called frontal lobe functions, as is suggested by the large area of the frontal lobe surrounding the letters MD in the smaller figure on the next page.

Next is the anterior thalamic nucleus. Its cortical partner is the vast expanse of the cingulate gyrus, a major constituent of the original “limbic system,” a still-evolving concept. Lying just behind this anterior nucleus is the small lateral dorsal nucleus (LD). It is involved in the emotional functions of cortex around the back end of the cingulate gyrus.

Given the suggestive evidence that the reticular nucleus, a thin cap of GABA nerve cells, shields the back of the thalamus during internal absorption, one is now led to inquire: Could the forward reaches of this nucleus also inhibit these paralimbic nuclei up front in the thalamus and interfere with their co-sponsoring higher-level emotional functions? The answer is yes, though only in 1998 did specialists on the primate thalamus, such as Edward Jones, report that the front of the reticular nucleus does extend its inhibitory cap over all three paralimbic nuclei. These recent findings suggest a second potential way that kensho might subtract vital higher-level cognitive and emotional functions, namely, those arising within the medial frontal region and around the cingulate gyrus. The limbic cortex of this gyrus lies hidden from view in the cleft between the two hemispheres. It spans a long deep arc, and would stretch back a length longer than that of the thalamus.

Fear and Loathing

In the thalamus, shown expanded above, our perceptions are refined, integrated and “self” begins to meet “other.” As sensory messages rise toward consciousness in our cortex, they must first pass through the thalamus, where they are modified by our previous associations. But the gate of the thalamus can be closed temporarily, including by the stress of intense meditation, and then—as ordinary experience of self/other is blocked—deeper internal absorption may ensue. Cortical projections of three thalamic nuclei are shown at the top right (MD, LP, P).© 2003 Christopher Wikoff[/caption]

A century ago, William James noted that alternate-state experiences can include religious, spiritual, and similar mental phenomena. Today, we associate some of these phenomena with specific higher functions of the temporal lobe.¹ It is noteworthy that opioid and other neuropeptide receptors are concentrated both in the cingulate gyrus, related limbic and medial frontal regions, and cortical regions nearer the front half of this temporal lobe. These peptide-receptor systems are among the leading candidates to account both for some memorably warm, blissful additions to, and some cooler subtractions of, the psychic self that characterize deeper alternate states of consciousness.

For example, it is a curious fact that an opioid, enkephalin, so enhances the net effect of signals within the hippocampus that this region becomes more responsive, not less. This observation can help reconcile two key phenomena in kensho that otherwise present a paradox: the fact that this state registers as more memorable (not less), but is accompanied by a loss of fear. The first could be explainable on the basis of opoid-enhanced hippocampus functions, while the second could be attributed to opoid inhibition of the amygdala and/or its extensive connections.

More speculative are explanations for the loss of loathings and longings. Some of a person’s loss of abilities to evaluate loathings and to respond with feelings of disgust might reflect inhibition of paralimbic regions as high as the cortex of the insula and/or its deeper connections.² On the other hand, it might be necessary to inhibit several hypothalamic-cingulate-prefrontal and deeper connections to the septal region in order to dampen the driving energies that fuel a person’s habitual appetitive longings and approach behaviors.

Can Neurological Patients Lose their Autobiographical Sense of Self?

French psychologists, before James, were aware of a useful distinction: Brain diseases disrupted their patients’ recent, ongoing memories. These anterograde memories were lost to a much greater degree than were those older (retrograde) memories laid down in the remote past. Today it is a commonplace observation that patients with Alzheimer’s disease lose their recent memories first. They may lose their eyeglasses every day, yet remain capable of recounting detailed personal memories from childhood.

Not until 1992 did the case reports by Narinder Kapur draw attention to some unusual exceptions to this old clinical dictum. This new subset of patients showed the opposite pattern: a severe retrograde amnesia. They lost their old autobiographical memories, while retaining their recent memories and their fund of general factual information. Could a single, isolated lesion in the brain cause this inverse pattern of autobiographical memory loss? No, patients with this condition had lesions at several cerebral sites, often in both hemispheres, acting in combination.⁴

The locations of the lesions were sites where we either store or index our remote personal memories. They were also sites where a lesion could disconnect the storage or indexing functions from the mechanisms that help us retrieve our personal memories. These descriptors point to multiple vulnerable locations in the brain, and the same frontal and temporal lobe sites discussed earlier are among them. These particular modules and networks represent a variety of reciprocal limbic, paralimbic, thalamic and cortical connections. These enable us both to attach attention and infuse salient emotional resonances into our processes of evaluating and responding to our psychic selfhood.

Brain Imaging and the Search for the Origins of Self

Great strides have been made in the technical aspects of neuroimaging, but the resulting data, however good, must be matched with accurate clinical reports of personal experience and also correlated with relevant psychological and physiological measurements. Recent imaging studies confirm that normally the frontal and temporal lobes of our brain hemispheres do contribute—often asymmetrically—to our I-Me-Mine constructs.¹

In 1999, Michael Kopelman and his colleagues in London correlated the brain lesions they found using PET and structural MRI scans with the records of psychological testing on 44 neurological patients. The right frontal and right temporal cortex seemed to have contributed more than the left to the ways these patients had personalized, stored, and retrieved their private memories. A more recent report reinforces the greater role of the right anterior frontal lobe in concepts of selfhood.⁵ When Bruce Miller and his colleagues studied 72 patients with fronto-temporal dementia, they identified a small subset in whom the most selective (narrow) dysfunctions of the self had occurred. In these seven patients, the greater damage was on the right side. In six of the patients, the right frontal lobe showed the greater abnormalities; in the seventh patient, the right temporal lobe was more affected.

Other recent imaging research has correlated many subtle, individual attributes of the self with the innermost parts of the frontal lobe and with different regions of the cingulate cortex. The attributes include how each person appreciates humor, engages in self-reflective thought, intuits other persons’ thought processes, responds with pain relief to a placebo, or experiences degrees of negative affect. A recent fMRI study by Debra Gusnard and her colleagues is pertinent, because it focused on how two subregions of this medial prefrontal cortex normally engage in two contrasting evaluations of inside/outside events. The contrasts in this instance hinged on the way the subjects processed their own emotions as opposed to the way they made more impersonal evaluations about items in external space.⁶

These researchers studied 24 normal subjects whose first task was to judge how deeply moved they were when viewing pictures that were pleasant, neutral, or unpleasant. Here, the subjects’ emotional reaction served as their internal cue. For their second task they had only to decide whether any given picture had been taken indoors or outdoors. For this extrapersonal evaluation each picture served as the external cue.

In general, when the brain responds to any such tasks, it undergoes an array of changes, both excitatory and inhibitory. In the computer images, some brain regions signal their increased activities by “lighting up,” whereas others appear to “darken” as they undergo decreases. Even though these two kinds of imaging findings diverge, each can be meaningfully interpreted. In this respect, the inside/outside aspects of this fMRI study showed intriguing correlations with two separate subregions within the medial frontal cortex. The more dorsal of the two regions seemed more introspectively oriented and emotionally valenced; its activity increased during the self-referential tasks. In the ventral region, by contrast, activity dropped when a task demanded more attention. On these occasions the subjects also felt less emotionally involved.

Imaging the Meditating Brain

Meditation is not monolithic. There are different kinds, stages, and depths of meditation as well as subtle results that can be immediate or delayed. To clarify this complexity with brain imaging, a study must specify: What is the meditator experiencing as each successive phase evolves? Which meditative techniques—focused and concentrative, or openly receptive—are being used? For how many years has each meditator practiced, and with what degree of skill? Is the laboratory setting conducive? How well did each meditator actually perform during the entire period of the study? Have the experimenters designed a well-controlled program, measured changes in respirations, brain waves, and other physiological parameters, and subjected the data to appropriate statistical tests?

A study in 1999 by Hans Lou and his co-workers in Copenhagen documented brain wave and brain blood flow findings while nine experienced yoga teachers went through successive stages of meditation.⁷ In preparation for the tests, these meditators spent two hours in an intensive concentrative form of yoga meditation. Why? Because they had learned from experience that this would enable them later to “let go” into the deeper levels of will-less, genuinely passive meditation. These were the object of the study.

PET scans and other tests monitored the next periods of increasingly more relaxed meditation. Both to standardize the steps in this procedure and to help the meditators relax, they listened to a sequence of four external, voice-guided, taped messages. This took place over a 45-minute period (unlike the silent, interior approach used in Zen). The intent was to induce four different guided imagery steps, in succession, during this extended period of yoga “relaxation meditation.”

The subjects reported reaching a genuinely passive state described as loss of will. This loss was confirmed by the finding that theta wave power increased in all EEG leads. Moreover, successive PET scans during this relaxation showed that metabolic activity did fall substantially in the prefrontal and anterior cingulate regions on both sides of the brain. This decrease contrasted with the higher levels found during the subjects’ resting periods used as controls.

Research has shown that we normally increase the activity of our frontal and anterior cingulate cortex when we intend to willfully exercise our normal executive functions and do so. Moreover, test conditions that involve cognitive stress and/or physical discomfort further enhance brain activity in these same regions. It would seem that similar sets of circumstances could have attended the fMRI study of meditation by Sara Lazar and co-workers.⁸ Their five Kundalini yoga meditators sought to keep their attention focused on a twofold task: silently reciting one mantra while they breathed in, and repeating a second mantra while they breathed out. Increased fMRI signals were detected, bilaterally, involving both frontal-parietal-temporal and anterior cingulate regions. (One empathizes with both the subjects and the investigators. It is a difficult task, even for accomplished meditators, to stay fully concentrated during the loud, distracting noises inherent in fMRI recordings.)

Moreover, several regions showed statistically significant decreases during this kind of deliberately induced absorption. Noteworthy decreases occurred in both superior parietal regions. As discussed earlier, decreases apparent in this region are consistent with the known inhibitory functions of the reticular nucleus in the thalamus down below. The decreases can block the transmission of sensory messages up through the lateral posterior (LP) thalamic nucleus and prevent them from reaching the superior parietal lobule. The decreases are also consistent with the proposals cited elsewhere¹ that an extension of this GABA inhibitory blockade was the origin of the total loss of my physical self-image that occurred, unintentionally, during the experience of internal absorption recounted earlier.

In addition, it turned out that the temporal lobe was the origin of the only other two sites where SPECT signals were decreased. One of these sites, the right lateral temporal gyrus, was found in an earlier PET scan report by E. Fink and his colleagues in 1996 to be one small part of that larger configuration contributing to our normal autobiographical sense of identity.

One may hope that future multidisciplinary studies of skilled Zen meditators will begin with more conventional periods of meditation: shorter and less strenuous, lasting only a half hour or so. Why? Because experienced meditators can also relax during shorter periods, let go of willful self-intent and of various other aspects of selfhood, yet still remain mindfully aware and receptive.

The Endless Path

In Zen, the states of internal absorption and kensho are regarded as nothing special. Formal Zen training looks beyond these, toward an exceptional stage of maturity in which positive changes in the person’s ongoing traits of character evolve. Observable over time should be permanent modifications in a person’s posture, attitudes, and conduct, not mere temporary shifts in cognition, affect, and behavior. It is true, though, that only the rare sage—one who lives a selfless, simplified life, fully engaged in the present moment, navigating each new situation with skillfully applied compassion—exemplifies this advanced level of personal transformation.

Which interacting brain systems has the egoless sage cast off? So far, I have mentioned pathways through the cerebrum, but some of their affective roots can probably be traced down to the brain stem. At a minimum, the basic networks of selfhood would seem likely to include the core of our ancient instincts for self-preservation. Our “self”-preservation core resides in a vital subcortical triad: the hypothalamus, amygdala, and central gray matter of the midbrain. Multiple emotion-generating pathways interconnect this triad with other limbic and paralimbic regions.¹

Why suggest the potential involvement of subcortical levels as low as the central core of gray matter in the midbrain? The answer is that we must try to explain why the endless path toward enlightenment implies a “lightening up,” letting go of selfhood’s heavy burden of dysfunctional habits, an extinction of greed, fear, and hatred. Once released from these habitual behaviors, other, latent, deeper instinctual circuits can express themselves, and as they take on their most fruitful forms, one observes them evolving into more genuine compassionate affiliations within the world at large.

In this regard, multiple lines of preclinical research have demonstrated that social affiliative behaviors do occur when the chemical messengers oxytocin, vasopressin, or Beta-endorphin are released into the subcortical regions of lower animal species. Although the various neuropeptides studied in these animal models are present in low concentrations, they now join the ranks of that long list of other messenger systems whose functions are waiting to be critically evaluated in the context of the more intricate human social equation.

Meanwhile, does it follow that all our human leanings toward compassion and altruism simply represent the result of outside cultural pressures? When we were children, were we forced toward virtue (if not into it) by authoritarian forms of social “brainwashing”? In closing, I would suggest instead that some of our most adaptive behaviors can arise from within, from ancient circuits already intrinsic to our brains. For centuries, the meditative practices within Zen and other spiritual paths, judiciously exposing their adherents to conditions alternately aversive and supportive, have watered the seeds of such innate affirmative behaviors, carefully cultivated their emergence, then gone on selectively to nurture them.

From this perspective, many of the resulting behaviors are our “native virtues,” to use Buddhist scholar D. T. Suzuki’s happy phrase. What do such behaviors express? Not the results of outside cultural pressures alone. Rather, they express the latent capacities of our deeper intrinsic circuitries. Once awakened, liberated, energized, and channeled appropriately, they can help each future generation aspire to evolve into a species of increasingly more humane beings.