Neurological Correlates of Transformational Experiences
Douglas G. Richards, Ph.D.
A variety of experiences - visions, near-death experiences,
mystical and numinous experiences - may lead to transformation of the personality,
resulting in greater compassion, altruism, and universal love. Cognitive
science has explored the reasoning capacities of the human mind/brain,
but has heretofore paid little attention to these higher functions. There
has been previous work on the role of the temporal lobe of the brain in
such experiences (e.g., that of Michael Persinger), as well as some neuroimaging
on the areas of the brain involved in meditation (e.g., that of Andrew
Newberg). My approach here is to extend this work in several ways to explore
the neurological correlates of transformational experiences: (1) better
quantitative assessment of experiences, going beyond descriptive phenomenology,
(2) more diversity of experiences, comparing spontaneous experiences to
induced experiences, and particularly exploring the factors involved in
positive vs. negative experiences (3) focusing specifically on neuroimaging,
with near-death experiences as a model, and (4) using the results of neuroimaging
to design experiments to induce experiences for controlled study. This
approach has the potential to show coherent mechanisms for these experiences
(as opposed to pathology caused by biological deterioration), encouraging
further exploration to gain an understanding of their role in human existence.
Central to the concept of higher human functioning
is a capacity for feeling connected with a higher or universal power. For
some this may take the form of a mystical or numinous experience, for others
an intuitive insight. Eastern traditions speak of "contemplative" knowledge,
at a level higher than that of ordinary reasoning. In contemporary Western
society, near-death experiences may lead to transformation of the personality,
resulting in greater compassion, altruism, and universal love. Cognitive
science has explored the reasoning capacities of the human mind/brain,
but has heretofore paid little attention to these higher functions. Here
I propose a research program to study these phenomena using the tools of
neurobiology. My specific aim is to systematically explore the neurological
correlates of positive, transformational experiences.
The major focus in studies of mystical and related
experiences has been on the temporal lobe of the brain, an area containing
a variety of structures related to perception, cognition, memory and emotion.
Much of our knowledge of these temporal lobe correlates has come from the
observations of neurologists and psychiatrists working with populations
suffering from pathology (Saver & Rabin, 1997). People with temporal
lobe epilepsy often report visions, contact with spirit beings, and revelations,
and can become focused on religious themes. The link with pathology has
been difficult to overcome, as most of the medical literature has treated
this association as evidence against the reality or value of these types
However, two research groups stand out for taking
a different approach: those of Michael Persinger (e.g., 1993a, 1999) and
of Eugene d'Aquili and Andrew Newberg (e.g., 1999, 2001). Both have gone
beyond speculation on the relationship between neurobiology and religious
experience based on pathological examples, by conducting experimental studies
using either normal individuals, in the case of Persinger, or experienced
meditators, in the case of d'Aquili and Newberg.
Persinger's work has the strength that it explores
the phenomenology of a diversity of experiences, and that it has confirmed
observational data by experimentally inducing experiences. But its weakness
is that it has focused on the temporal lobe to the exclusion of a more
complete model of brain activity, and has no imaging data to support the
hypotheses regarding specific brain areas. D'Aquili and Newberg's work
has the strength that it offers an integrated model of brain activity,
backed up by imaging experiments. Its weakness is that although the model
is wide-ranging, the experiments have dealt only with experiences induced
by meditation, and the applicability of the model to a greater diversity
of transformational experiences is not yet known.
My approach here is to build on the work of Persinger
and d'Aquili and Newberg, extending it in several ways to explore the neurological
correlates of transformational experiences: (1) better quantitative assessment
of experiences, going beyond descriptive phenomenology, (2) more diversity
of experiences, comparing spontaneous experiences to induced experiences,
and particularly exploring the factors involved in positive vs. negative
experiences (3) focusing specifically on neuroimaging, with near-death
experiences as a model, and (4) using the results of neuroimaging to design
experiments to induce experiences for controlled study.
I take the position that neurobiology alone cannot
make a determination of the "reality" of the experiences or of the insights
that may result from them. By analogy, demonstrating neurological correlates
of the perception of a chair provides no evidence for or against the reality
of a chair outside the brain. In the same way, demonstrating neurological
correlates of a mystical or near-death experience cannot be taken as evidence
that such experiences are "nothing but" brain states, or conversely that
they are proof of God or life after death. The value of the neurobiological
approach is that it has the potential to show coherent mechanisms for these
experiences (as opposed to pathology caused by biological deterioration),
encouraging further exploration to gain an understanding of their role
in human existence.
The Temporal Lobe and Transformational Experience
The most popular linkage of brain structure with
transformational experience has been via the temporal lobe and associated
limbic system. Persinger has done by far the most extensive work on experiences
related to temporal lobe activity. Following such researchers as Dewhurst
and Beard (1970) and Bear and Fedio (1977), Persinger (1983) developed
a general hypothesis that mystical and other transformational experiences
are artifacts of microseizures in the deep structures of the temporal lobe.
Important in his hypothesis was the concept of a continuum that ranges
from "early morning highs" to recurrent bouts of conversion and dominating
religiosity. The different basic themes (e.g., space-time distortions,
intense meaningfulness, out-of-body experiences, etc.) reflect the inclusion
of different amygdaloid-hippocampal structures and adjacent cortices. Later
work (e.g., Persinger & Makarec, 1987, 1993) demonstrated the existence
of a continuum of temporal lobe lability from normal populations to epileptic
clinical populations, using extensive questionnaires of experiences based
on those evoked by electrical stimulation of the temporal lobes. Persinger
(1992, 1993b, et al., 1994) has further elaborated his model of temporal
lobe involvement, focusing on left/right asymmetry, with the right temporal
lobe as the source of experiences attributed to sources outside the self.
For example, Munro and Persinger (1992) measured increased theta EEG activity
over the right compared to the left temporal lobe in people with a history
of "sensed presences" (e.g., spirits), who also felt "detached from the
body," and reported fear. Persinger (1993a) also made a distinction between
subcortical processes that may generate paranormal-like experiences, and
right hemisphere cortical processes that involve the sense of self and
Persinger has not done neuroimaging to objectively
identify specific areas of temporal lobe involvement. Instead, Persinger's
most interesting work has involved experimental induction of temporal lobe
experiences. Persinger's induction experiments are based on the concept
that stimulation of the temporal lobe by weak, external magnetic fields
can induce experiences. For example, Cook and Persinger (1997) induced
the feeling of a sensed presence in normal subjects and in an exceptional
subject with a history of religious experiences. Persinger, Tiller and
Koren (2000) induced a "synthetic ghost" and "rushes of fear" in a man
using magnetic stimulation. Other experiments (Richards, Koren, & Persinger,
1992) have succeeded in inducing negative affect (apprehension, anxiety)
with magnetic stimulation.
But, while these induced experiences appear to have
some of the sensory and emotional components of transformational experiences,
they do not yet replicate the complete phenomenology, suggesting that we
will have to explore the roles of other regions of the brain. In particular,
the positive emotional effects and transcendent insights (the cognitive
component) have been neglected.
Emotions and Transformation
The notable prevalence of negative emotions in reports
of temporal lobe epilepsy and these stimulation experiments has led researchers
coming from a mental illness perspective to focus on the negative aspects
of what they classify as "religious" experience. For example, Persinger
(1997) did a study of factors that would lead to endorsement of the statement,
"If God told me to kill, I would do so in his name," and found elevated
temporal lobe signs and history of a religious experience to be significant
predictors. Carrazana et al. (1999) discuss the relationship of epilepsy
and Voodoo spirit possession. Joseph (2001) dwells on the role of the temporal
lobe and limbic system in raw experience and emotion, focusing on the linkage
of experiences of "Gods," voices, etc. to the negative emotional
correlates of some religious behavior: rage, murder, aggression, and sexuality.
These views stand in sharp contrast to the reports
of mystical experiences emphasizing universal oneness and peace. None of
these researchers address the positive aspects of religion such as inspiration,
love, oneness, and service, and what brain activity might mediate the emotional
tone of experiences in a positive or negative direction. While the "dark
night of the soul," a feeling of separateness from God, is a common experience
among mystics, the significance of transformational experiences lies in
these higher qualities as well. To understand the full range of human potential
and transcendence, we need to go beyond the temporal lobe and raw experiences.
We need to address the complex interconnectedness of the brain, and look
at brain activity in other areas that might explain the diversity of experiences
and emotional responses to the experiences, to develop an integrated model.
Beyond the Temporal Lobe: Integration and Control of Experiences
at Higher Levels
D'Aquili and Newberg (1999), and Newberg, d'Aquili,
and Rause (2001) have gone considerably beyond the temporal lobe hypothesis
to develop a model for transformational experience that addresses the entire
They identify four important brain areas. These include
(1) the limbic system, which generates and modulates emotions, (2) the
sensory areas (e.g., hearing and vision) and in particular the sensory
association areas where there are higher levels of abstraction and integration,
(3) the orientation association area in the posterior superior parietal
lobe, where the self-world and self-other identity distinction is made,
and (4) the attention association area in the prefrontal cortex, which
is important in intention, will, and modulation of emotion.
It is rare that mystical experiences will occur at
a predictable enough time and space to study them, so the challenge has
been to go beyond the theoretical model and demonstrate this process in
the laboratory. Newberg et al. (2001) in their most recent experimental
paper, tested their model with SPECT imaging in Tibetan meditators. Notably,
they were able to capture the moment of the peak experience by having the
meditators signal for the neuroimaging. In contrast to Persinger's work,
Newberg et al. found activity in a variety of cortical structures: the
cingulate gyrus, inferior and orbital frontal cortex, dorsolateral prefrontal
cortex, and the thalamus, with reduced activity in the left superior parietal
lobe (the orientation association area). They relate these changes to an
increase in attentive focus and an altered sense of space experienced during
meditation. They emphasize that there are intricate central nervous system
interactions in this complex neurocognitive task, needing much further
The importance of this work is that it goes beyond
the simple "religious experience = temporal lobe" approach, and sees the
brain as an interacting system of structures and processes. However, by
focusing on meditation, D'Aquili and Newberg have not addressed the diversity
of experiences dealt with in Persinger's work, nor have they explored the
longer-term process of transformation.
A More Comprehensive Approach to Transformational Experience
My extension of Persinger's and Newberg and d'Aquili's
work has three components: (1) a more in-depth, quantitative assessment
of phenomenology, (2) a more extensive use of modern imaging technology,
and 3) a more sophisticated approach to induction of these experiences
based on the phenomenological and imaging data. I have chosen the near-death
experience as an example for this discussion, since it is one of the most
significant transformational experiences in human life, and has been touched
on by both Persinger and Newberg and d'Aquili.
Phenomenology and Psychological Measurement
One of the temptations in neurobiological work is
to oversimplify the complex phenomenology of mystical experiences in favor
of generalizations like "temporal lobe symptoms," which has led to the
perception of these experiences as pathology. In contrast, Varela (1996)
discusses some of the issues in what he calls "neurophenomenology." He
emphasizes the importance of disciplined first person accounts as elements
of a neurobiological proposal. Observers need to have some sophistication
in the dimensions of consciousness; such aspects as consciousness of time
and body image, and emotion.
For example, Newberg and d'Aquili's work focuses
on Tibetan meditators, who have practiced a discipline of observing consciousness.
They have made the wise choice of using only experienced meditators. But
nowhere in their books do they discuss the diverse varieties of meditative
experience (e.g., Goleman, 1977), or psychological assessment tools that
might be able to differentiate the experiences of the Tibetan meditators
from those of meditators in other traditions. For the purpose of neuroimaging
studies there needs to be a way to quantitatively assess the dimensions
of the experience.
Brown and Engler (1980) took steps toward this goal
by validating the concept of stages of practice and enlightenment in Theravada
Buddhist meditators. They used a 600-item questionnaire designed to discriminate
different types of meditation as well as different levels within the same
type of meditation. Their methodology, of phenomenological investigation
followed by development of assessment instruments, can yield quantitative
estimates of changes in consciousness for comparison with neuroimaging
These methods can be extended to Christian or other
forms of transformational experience as well. My own work (Richards, 1991)
has included a study of verbal prayer, in which I identified 19 different
types of prayer, with two major dimensions of experience: relationship
to God or a higher power and action or perceived outcome, and psychological
correlates of those dimensions (e.g., absorption, locus of control).
Below I will discuss in detail the application of
phenomenology and assessment tools to near-death experiences.
The basis of functional neuroimaging is that the
psychological experiences and behaviors of a person are correlated with
the portions of the brain that are the most metabolically active at the
time of the experience. This metabolic activity can be localized to specific
areas of the brain with such technologies as positron emission tomography
(PET), single positron emission computed tomography (SPECT), and functional
magnetic resonance imaging (fMRI). The modality chosen in a particular
research project may depend on practical considerations of cost and availability.
The major tradeoff is between temporal and spatial
resolution. Electroencephalograms (EEG) offer very fine temporal resolution
of brain electrical events, and have been especially useful in cognitive
and perceptual studies where a stimulus is presented at a precise time.
PET, SPECT, and fMRI measure brain activity more indirectly, looking at
metabolic activity or blood flow. They have poorer time resolution than
EEG, but good spatial resolution. SPECT has the lowest spatial resolution,
but has the advantages of portability, cost, and allowing the brain activity
at a given point in time to be "frozen" for subsequent measurement. Newberg
et al. (2001) took advantage of this feature of SPECT to have meditators
signal at the time of the most intense experience. PET has better spatial
resolution, but is more expensive and less convenient. fMRI has the best
spatial resolution, but the noise from the machine can interfere with the
states of consciousness. Dale and Halgren (2001) recommend an integration
of multiple imaging modalities, which can now generate estimates of brain
activation with high spatial and temporal resolution.
D'Aquili and Newberg (1999) discuss the need to explore
mystical experiences that can be attained spontaneously, not just by those
whose focused goal is to reach some higher state. They chose the near-death
experiences (NDE) as an example of a form of spontaneous mystical experience
that could be explored from a neuroscience perspective. The NDE is one
of the most compelling experiences that human beings can encounter. Those
who have undergone NDEs frequently report major life transformation, including
less fear of death, and more compassion and altruism. NDEs are reported
by 30-40% of individuals who have come close to death, or about 5% of the
adult American population (Greyson, 1993). Although d'Aquili and Newberg
speculate on how the NDE might fit into their framework for mystical experiences,
they provide no data or suggestions on how to go about studying NDEs.
Persinger (1999) has also addressed near-death experiences
in terms of his temporal lobe model. Many of the features of NDEs are the
features he has identified in people with high temporal lobe lability:
a sensed presence, religious insight, etc. Using magnetic stimulation,
he also claims to have simulated NDEs experimentally, eliciting the major
components (as well as many not typical of NDEs, such as odd tastes in
the mouth). However, he has not performed any imaging to verify that the
brain when magnetically stimulated is behaving in the same way it does
for an NDE.
Following a discussion of psychological measurement
considerations, here I propose some ways in which the neurobiological correlates
of NDEs can be studied.
Psychological Measurement Considerations in NDEs
The administration of psychometric instruments to
those who have recovered from near-brain-death would allow us to go beyond
treating the NDE as a unitary experience occurring in the temporal lobe,
and explore all of its cognitive, affective, sensory, and attentional aspects
in relation to relevant locations and processes in the brain. To address
the complexities of NDEs, Greyson (1983) developed a Near-Death Experience
Scale and collected reliability and validity data. The final version of
Greyson's scale includes 4 subscales based on inter-item correlations:
cognitive, affective, paranormal (including sensory-related and out-of-body),
and transcendental. These correspond well to the brain functions discussed
previously, in the cognitive, affective, attentional, and sensory realms.
Greyson (2000) in recent work has explored in depth the relationship between
out-of-body experiences and dissociation in NDEs, and Greyson (2001) has
also looked at emotionally negative aspects of NDEs and their relationship
to post-traumatic stress disorder. All these elements of NDEs are important
in understanding the relationship of the phenomenology to the brain mechanisms.
Assessing the positive and negative emotional aspects
of the near-death experience, in conjunction with neuroimaging, is especially
important. Greyson's scale is a first step, but considerable progress has
been made in what Richard Davidson calls "affective neuroscience," as a
parallel to cognitive neuroscience (Davidson & Sutton, 1995). Below
I will discuss some applications of Davidson's methodology to NDEs.
Neuroimaging During the Near-Death Process
The spontaneous nature of the NDE would at first
seem to preclude neuroimaging studies; one does not often have a PET scanner
handy during an auto accident. However, neuroimaging is in common use during
the dying process in one circumstance: determining brain death in organ
The most common form of imaging in use is SPECT,
the "gold standard" for determination of brain death (Kurtek et al., 2000).
It has the advantages of portability, does not require withdrawal of medical
therapy, and has lower cost than other imaging modalities (Reid et al.,
Recovery is rare in such patients, but as an example,
3 patients out of the 15 in the study by Reid et al. (1989) who were clinically
thought to be brain dead showed cerebral perfusion on the SPECT scan, and
survived the cerebral trauma. In a study specifically looking at the near-death
process, individuals with more signs of life might also be examined, increasing
the chances of imaging a patient who survives. This would allow an evaluation
of the hypothesis that oxygen deprivation of particular brain regions is
responsible for the NDEs (e.g., Persinger, 1999). It has the potential
for revealing more complex and interesting brain mechanisms.
MRI, although more difficult and expensive, has also
been recently used to determine brain death. Lovblad et al. (2000) used
a new technique of diffusion weighted imaging, a fast technique sensitive
to cerebral ischemia, to display changes related to brain death. Future
progress in functional imaging might make this and other high-resolution
techniques an alternative to SPECT.
Long-term Changes Following Near-Death Experiences
Those who undergo NDEs frequently report long-term
transformation of their entire being. Can this be confirmed by an integration
of psychological measurement and brain imaging? Persinger speculates that
transformation of the self is related to a loss of neurons due to the near-death
trauma. This could promote neuroplasticity - new connections to compensate
for the damage - that could be reprogrammed from the strong positive affect
in the experience.
Neuroimaging, together with detailed psychological
assessment of the changes, should reveal what specific areas of the brain,
if any, have changed as a result of the experience. Is there, for example,
permanent reduced activity in the left temporal lobe (as compared with
pre-NDE), allowing right hemisphere qualities to emerge?
Regarding the issue of the subject population, within-individual,
before/after neuroimaging could be conducted with volunteer cardiac patients,
of the sort interviewed by Bruce Greyson and Ian Stevenson in an ongoing
prospective study of phenomenology. With baseline imaging data on the whole
population, comparisons also could be made between those surviving near-death
reporting an NDE, those surviving near-death and not reporting an NDE,
and those recovering without a close brush with death.
Davidson and his collaborators have done the most
interesting work in neuroimaging of emotions. One way to explore transformation
of emotional response is with picture tests using emotionally charged memories,
pictures or video clips. For example, Lane et al. (1997) found neuroanatomical
correlates of happiness, sadness and disgust in different areas of the
prefrontal, frontal, and temporal cortex using PET imagery. Their work
challenges the simple model (for example, that used by Persinger), that
emotions are primarily a right hemisphere function. Employing PET as well,
Paradiso et al. (1997) were the first to explore emotional activation of
limbic circuitry in elderly normal subjects using emotionally-charged film
clips. Specific emotions produced different regional limbic activations,
as well as complex activation of other brain regions, suggesting that different
pathways may be used for different types of emotional stimuli. Such studies
could be extended with before/after measurements of NDEers.
Induction of NDE-like Experiences Under Non-Life-Threatening Conditions
The strength of Persinger's work is that he has developed
a means of magnetic stimulation to induce temporal-lobe-related experiences
in normal volunteers, including components of mystical and near-death experiences.
But there are three main weaknesses that need to be addressed. The first
is that the subjective reports do not show the coherent phenomenology or
the insights typically reported from spontaneous experiences, suggesting
that his approach is only tapping into a portion of the complete experience.
The second is that his target areas are entirely based on inference from
these subjective reports; he has no imaging data to show that the targeted
brain locations are, in fact, the relevant areas for the experiences, and
no imaging data to show that the magnetic stimulation is having the intended
effect. The third weakness is that his means of stimulation is very different
from conventional transcranial magnetic stimulation, and his work has not
been independently replicated. I propose that these weaknesses be addressed
by independent replication with the following improvements:
(1) Induction experiments must be preceded by and
accompanied by imaging; the imaging can serve to guide placement, form
and intensity of stimulation, and to evaluate the effects.
(2) The phenomenology of the induced experiences
must be documented and quantitatively assessed, and used as a guide to
modify stimulation parameters. Particularly important will be an exploration
of cognition and belief-related changes in response to these experiences,
and a comparison with spontaneous experiences and those induced by meditation
(3) The parameters for the ideal stimulus need research.
The vast majority of transcranial magnetic stimulation (TMS) research uses
very high intensity magnetic fields, on the order of 2 Tesla or more, with
simple pulsed patterns (Paulus et al., 1999). These have been shown to
affect both sensory and emotional experiences (e.g., in the suppression
of hallucinations in schizophrenia (Hoffman et al., 1999), and in the relief
of depression (George et al., 1999)). Persinger employs a far smaller magnetic
field (1 microTesla or one millionth of the usual intensity), and a very
complex temporal pattern unlike that used by other researchers.
Magnetic stimulation is by no means the only way
to induce experiences. For example, Schenk (1999) has used hypnotically-facilitated
"pseudo near-death experiences" for their transformative value in working
with clients. Neuroimaging could compare the patterns in these states with
those typical of actual NDEs. Acoustic stimulation may also be effective.
Robert Monroe has developed audio tapes that synchronize the left and right
hemispheres, and induce a variety of experiences. Masluk (1997) has done
extensive phenomenological work with these experiences and their potential
for personal transformation. Johnson and Persinger (1994) found that Monroe
"Hemi-Sync" tapes led to more intense experiences than Persinger's own
The program proposed here should take us well beyond
the current medical model of transformational experiences as a consequence
of brain pathology. Beginning with an integration of phenomenology, psychological
measurement, and neuroimaging, we can proceed to experimental investigation
of these states with techniques ranging from traditional meditation to
magnetic stimulation. Neurobiology can play a key role in the quest for
new insights about our capability for discovering the nature and meaning
of the universe.
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