Cross-Sensory Consciousness
Unmasking the Neural Mysteries of Transcendent Experience
Spring 2014
Consciousness is one of the greatest unsolved mysteries in science. The 17th-century French mathematician and philosopher René Descartes famously said “I think therefore I am”, introducing the notion of mind-body dualism- which proposes that the immaterial world of the mind, or soul, is fundamentally separate from the world of the body, or physical brain. Are there essential constituents of reality and minds that we that we can experience, but not objectively measure? The very act of doubting one’s own existence arguably proves the reality of one’s own existence, or at least one’s own thought. Yet nobody knows how exactly chemical and electrical brain signaling give rise to the overarching sense of one’s own existence within reality.
In his major work ‘Critique of Pure Reason’, philosopher Immanuel Kant endeavored to revise previously held notions in metaphysics and skeptical empiricism by synthesizing a fundamental framework about the transcendental principles of nature. Emphasizing the limitations of the human mind, Kant proposed there is greater reality past what can be gathered through sensory information; however, we may only understand it as it appears to us.1 If one were born without the ability to perceive using any of the senses, would it negate the existence of an external world? Except for a few radical idealist thinkers, most of us answer ‘yes’ to the hackneyed ‘When a tree falls in the forest..’ question. Using the same logic, how can we be sure that our brains are discerning actual, objective events and not just a speculative idea of them? Is there more to be known that we are normally unaware of? Perception cannot determine reality, only our mental model of it.
Mankind has pondered ontological concepts of nature and being throughout history. Attitudes towards these questions have played a significant role in guiding and shaping spirituality in religions, values in cultures, and personal belief systems about humanity’s purpose in individuals. However only recently have neuroscientists begun exploring these notions systematically. Correlations between neural phenomena and subjective experiences during altered states of consciousness have further advanced our understanding of the brain’s powerful perceptive capabilities. By examining research throughout this field, we may soon come to appreciate a new perspective on not only the beautifully intricate organization of the human brain, but perhaps something fundamental about the ornate workings of the universe itself.
Not one person, even an identical twin, will perceive stimuli the same exact way. Such rich diversity in brain anatomy and wiring stems from both our genetic encoding and differing environments. However, some people are unique in their ability to experience two or more different types of stimuli simultaneously across modalities.2 These extraordinary sensors have a neurological condition called synesthesia. There are many different forms of synesthesia which may involve any modality. For example, sounds might produce sights of different colors, (a dog’s bark may produce the color green, or the note C# could appear pink) the touch of certain objects may produce colors, or the names of people and objects could produce tastes, sounds, or smells. Neurologist Richard Cytowic has even studied a case of a man who can perceive geometric shapes sweeping down his shoulders and fingertips when he tastes or smells flavors of foods. The synesthete reports that he can vividly feel the objects’ weight and texture as if he is actually grasping it while eating.3
Synesthetes have irregular sprouting of neural connections within the brain that leads to a breakdown of the boundaries that normally exist between the senses. Diffusion tensor imaging (DTI) validated that the degree of white matter hyperconnectivity in the inferior temporal cortex was responsible for the intensity of the multi-modal sensations.4 In addition, DTI studies have demonstrated extensive bilateral white matter abnormalities in temporal lobe epilepsy that extend far beyond the temporal lobe- and these patients report very salient synesthesia-like experiences.5
Cytowic also proposes a disinhibited feedback theory, a reduction in the amount of inhibition along normally existing feedback pathways. In a normal brain, excitation and inhibition should be balanced. If regular feedback were not inhibited as usual, signals sending back from later phases of multi-sensory processing might affect earlier phases such that sounds can activate vision.6,7 Since complex interaction between brain systems enables us to perceive the external world as unified whole, a theory which relies on preexisting neural connections may explain why certain drugs can induce cross-sensory perception.8
Psychedelic drugs such as Lysergic acid diethylamide (LSD), psilocybin (psychedelic mushrooms) and dimethyltryptamine (DMT) heavily influence the transmission of serotonin (5-HT), which is well-known to regulate mood and arousal. Highly abundant in the dorsolateral prefontal cortex, where sound and visual input are integrated, are postsynaptic 5HT2a receptors. 9,10 Hallucinogenic molecules strongly agonize these receptors which are located on apical dendrites of pyramidal cells in layer V cortex.11,12 Pyramidal cells are known to play a critical role in complex object recognition within the visual processing and have diverse intracortical projections mediating multiple pathways of sensory and perceptual feedback analysis, implicating them in binding sensory perceptions into a discrete event.13
Though we can see a neural link between the two, reports of psychedelic experiences reach destinations far beyond that of synesthesia. Roland Griffiths, Ph.D., a professor at the Johns Hopkins departments of Psychiatry and Behavioral Sciences and Neuroscience conducted a study investigating the psychological effects of psilocybin on test subjects in comfortable, supportive conditions. About the experiences, he described: “There’s a dimension of awesomeness, of profound humility, of the self being stripped bare. In the psychology of religion, mystical experience is well-described–unity, transcendence of time and space, noetic knowledge, sacredness, ineffability… the sacred dimension of revelation.”14
There are many accounts similar to his, albeit documented by less ‘certified’ experimenters. Their journeys often begin with enhanced sensory integration, then crescendo into deep noetic insights and overwhelming awe for the whole essence of reality, consciousness, and their intertwinement. One “psychonaut” describes “Conscience moves on different layers, melts with memories, visions, reality, and imagination. I have all kinds of visions: …gold rings with turquoise, jade and lapislazuli whirling.. the union of these rings gives me complete comprehension of everything, the absolute conscience.”15 Another reported “Everything regarding the self becomes the earth and all my perceptions are the stars… I have seen every part through my observations and how they fit together, so I was worthy to view the Gestalt, the whole form, one singularity.”16
It has been proposed that the newborn baby is a ‘super-synesthete’. In this hypothesis, newborns fail to differentiate input from different senses because connections between cortical areas are pruned and inhibited later in development. The senses are not separate, but rather sights, sounds, feelings, and smells are one sensual “bouillabaisse”.17,18,19 Could newborns, due to their complete unmasking of sensory boundaries, be feeling a mergence with the ‘all-encompassing absolute’ that philosophers, artists, mystics, and scholars across religions and cultures strive to understand?
The psychopharmacology behind these subjective states is still not well understood, although more so than similar phenomena which may occur even without drugs or a preexisting neurological condition. For example, the flickering Ganzfeld Experiment is a sensory deprivation technique in which a subject receives homogeneous and unpatterned sensory stimulation, typically in the form of white noise paired with halved ping-pong balls over the eyes.20 It elicits vivid colors, complex geometrical patterns, dream-like imagery- even whole scenes. One study hypothesized that mystical experiences were evoked by transient microseizures in the temporal lobe via unusual electrical coherence. It is supposed these induced rhythms generate such out-of-body experiences, space-time distortions, intense meaningfulness, and dreamy scenes.21 Interestingly, the flickering Ganzfeld creates deep states of relaxation, concentration, and altered states similar to those obtained through transcendental meditation in Indian Yoga and Zen Buddhism- techniques which can alter the brain’s electrical wave nature.22,23 Moreover studies have shown that regular meditators commonly report synesthesia, and it has been shown that sense-merging can be cultivated through long-term meditative practice.24
Perhaps the most astonishing of all narratives is that of academic neurosurgeon Dr. Eben Alexander III, who has taught at Brigham’s and Women’s Hospital, Harvard Medical School, and other prominent universities In his account “Proof of Heaven: A Neurosurgeon’s Journey into the AfterLife” Dr. Alexander asserts that while in a seven day coma brought on by a menigitis-induced seizure, he had undergone a “hyper-vivid and completely coherent odyssey”, impossible according to global cortical involvement documented by his neurological exams.25 He chronicles seeing holy beings on millions of radiant butterflies, meeting angels, and hearing the voice of God. In his book he writes, :“ [there were] waterfalls, pools of water, indescribable colors, and above there were these arcs of silver and gold light and beautiful hymns coming down from them. Indescribably gorgeous hymns. I later came to call them “angels,” those arcs of light in the sky.” 26 He goes on to express, like the psilocybin users, his new revelation of undivided unity throughout the universe, and how the concept is exactly what quantum physics is furiously attempting to unravel. He says “beneath the surface, every object and event in the universe is completely woven up with every other object and event. There is no true separation. Before my experience these ideas were abstractions. Not only is the universe defined by unity, it is also—I now know—defined by love.” 27
An extremely high dose of psilocybin would likely be almost identical to the effects to DMT, as it breaks down into psilocin (4-OH-DMT), which is very structurally similar to DMT. Though unlike any other psychoactive compound known, DMT has inspired users to report vehement transportation into grand alternate dimensions, where many claimed to have seen intelligent alien beings or prominent religious figures (often outside one’s culture) that do not appear to be projections of their subconscious or memories.28 The report of Dr. Alexander and the account of this DMT user (as well as the psilocybin accounts) are shockingly alike: “..with rainbow colors I felt myself morphing into various species. I was experiencing the unfolding of life itself, and realizing.. life is directed by a simple life force of pure energy which operates on the smallest of conscious, sentient levels…the entire universe is conscious and connected…and we are nothing more than containers of that pre-existing everlasting all-pervading consciousness. The energy, the confidence, the power, the love in me began to surge, I felt it expand around me, encompassing everyone.”29
Dr. Alexander claims that there was absolutely no explanation as to how a surreal adventure of that magnitude could be experienced while his cortex was entirely non-functional. Is the renowned Harvard neurosurgeon missing something here? His story and many others’ raise the question: is the sensation of what people call the spiritual a form of awareness created by brain chemistry, or is brain chemistry a necessary conduit to transcend into higher planes of spiritual existence? The empirical investigation into the mysteries of consciousness and metaphysics is not complete if it omits crucial parts of the human subjective experience of transcendence. Spirituality can be studied as an effort to understand the general principles of the inner world’s own access to reality, and this new frontier in neuroscience continues to grow. Changed by his near-death experience, Dr. Alexander vows to spend the remainder of his life investigating the true character of consciousness and reality, continually professing to both colleagues and the public that we are “more, much more, than our physical brains.”30
- Kant, Immanuel. Critique of Pure Reason. New York, NY: Cambridge University Press. 1998.
- Cytowic, R. Psychophysical relations in the synesthesia of geometrically shaped taste and colored hearing. Brain and Cognition. 1(1): 36-49. 1982.
- ibid.
- Rouw, R., Scholte, HS. Increased structural connectivity in grapheme-color synesthesia. Nature Neuroscience. 6(10): 792-797. 2007.
- Gross, DW. Diffusion tensor imaging in temporal lobe epilepsy. Epilepsia. 4(32): 1528-1167. 2011.
- Hubbard, EM., Ramachandran, VS. Neurocognitive mechanisms of synesthesia. Neuron. 48(3): 509-520. 2005.
- Hubbard, EM & Ramachandran, VS. Synaesthesia: A window into perception, thought and language. Journal of Consciousness Studies 8 (12): 3–34. 2001.
- ibid.
- Heim, R. Synthesis and pharmacology of potent 5-HT2A receptor agonists which have a partial N-2-methoxybenzyl structure. PhD Thesis, Institutional Repository of the Freie Universität Berlin. 2003.
- Hansen, M. Design and synthesis of selective serotonin receptor agonists for positron emission tomography imaging of the brain. PhD Thesis, University of Copenhagen. 2011.
- Jones, EG.Synchrony in the interconnected circuitry of the thalamus and cerebral cortex. Disorders of Consciousness: Ann NY Acad Sci. 1157(1): 10-23. 2009.
- Jones, EG.Thalamic circuitry and thalamocortical synchrony. Philos Trans R Soc Lond B Biol Sci. 357(1428):1659-1673. 2002.
- Elston, GN. Cortex, cognition and the cell: new insights into the pyramidal neuron and prefrontal function. Cereb. Cortex. 13(11): 1124–1138. 2003.
- Griffiths, RR & Richards WA.. Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance. Psychopharmacology. 187(3):268-83. 2006.
- Andrash. 2005, September 30. First Trip in Chiapas: Experience with Mushrooms. Retrieved from http://erowid.org/exp/19711
- FantomeCiel. 2010, March 23. Juxtaposition of All Selves into Singularity: Experience with Mushrooms. Retrieved from http://erowid.org/exp/8142
- Maurer, D. Neonatal synesthesia: implications for the processing of speech and faces. Developmental Neurocognition. 69: 190-124. 1993.
- Maurer, D., Mondloch, CJ. Neonatal synesthesia: a reevaluation. Synesthesia: Perspectives From Cognitive Neuroscience. 193-207. New York: Oxford University Press. 2005.
- Neville, H. Developmental specificity in neurocognitive development in humans. The New Cognitive Neurosciences. Cambridge, Massachusetts: The MIT Press. 219–234. 1995.
- Wackermann, J. Ganzfeld-induced hallucinatory experience, its phenomenology and cerebral electrophysiology. Cortex. 44: 1364-1378. 2008.
- Persinger, M. Religious and mystical experiences as artifacts of temporal lobe function: a general hypothesis. Perceptual and Motor Skills. 57:1255-1262. 1983.
- Herbert, R., Lehmann, D. Theta bursts: an EEG pattern in normal subjects practising the transcendental meditation technique. Electroencephalography and Clinical Neurophysiology. 42(3): 397-405. 1977.
- Gellhorn, E., Kiely WF. Mystical states of consciousness: neurophysiological and clinical aspects.Journal of Nervous and Mental Disease. 154: 399-405. 1972.
- Walsh, R. Can synaesthesia be cultivated?: Indications from surveys from meditators. Journal of Consciousness Studies. 12: 5-17. 2005.
- Eben, A. Proof of Heaven: A Neurosurgeon’s Journey into the Afterlife. New York, NY: Simon & Schuster. 2012.
- ibid.
- ibid.
- Rodriguez, MA. A methodology for studying various interpretations of the N,N-dimethyltryptamine-induced alternate reality. Nat. Neuroscience. 21: 67-84. 2007.
- Netrunner. 2004, July 7. The Power and The Glory: Experience with Harmaline, 5-MeO-DMT & DMT. Retrieved from http://erowid.org/exp/34866.
- Eben, A. Proof of Heaven: A Neurosurgeon’s Journey into the Afterlife. New York, NY: Simon & Schuster. 2012.