Biophotons in near-death
News: Bókkon I, Mallick BN and Tuszynski JA (2013). Near death experiences: A multidisciplinary hypothesis. Front. Hum. Neurosci., 11 September 2013 | doi: 10.3389/fnhum.2013.00533
Here is the link for full text download: http://www.frontiersin.org/Human_Neuroscience/10.3389/fnhum.2013.00533/abstract
Hypothesis about brilliant lights by bioluminescent photons in near death experiences
István Bókkon 1,2 Vahid Salari 3,4
Medical Hypotheses DOI: 10.1016/j.mehy.2012.03.028
1Doctoral School of Pharmaceutical and Pharmacological Sciences, Semmelweis University, Hungary
2Associate professor at Vision Research Institute, 25 Rita Street, Lowell, MA 01854 USA
3Kerman Neuroscience Research Center (KNRC), Kerman, Iran
4Afzal Research Institute, Kerman, Iran
In near death experiences (NDEs), seeing a brilliant light may arise in the recovery period following cardiac arrest, but the subjects can think that these experiences had happened during the actual period itself. Here we hypothesize a biophysical explanation about the encounter with a brilliant light in NDEs. Accordingly, meeting brilliant light in NDEs is due to the reperfusion that induces unregulated overproduction of free radicals and excited biomolecules among them in numerous parts in the visual system. Unregulated free radicals and excited species can produce a transient increase of bioluminescent photons in different areas of the visual system. If this excess of bioluminescent photon emission exceeds a threshold, they can appear as (phosphene) lights in our mind. In other words, seeing a brilliant light in NDEs may due to bioluminescent photons simultaneously generated in the recovery phase of numerous areas of the visual system and the brain interprets these intrinsic bioluminescent photons as if they were originated from the external visual world. Although our biophysical explanation about brilliant light phenomenon in NDEs can be promising, we do not reject further potential notions.
Near death experiences (NDEs) refer to a broad range of subjective experiences associated with forthcoming death. During NDEs, subjects are unconscious, without heartbeats and breath, and with a flat electroencephalogram. NDEs can include some recurring elements such as out-of-body experience (separation of consciousness from the physical body), going through a dark tunnel, encounter with a brilliant light, meeting deceased loved ones, relatives, friends, encounter with guardian spirits and mystical beings, sensing a border or limit, going back into the body voluntary or involuntary [1-4]. Children NDEs are similar to adult NDEs, and the characteristics of NDEs are similar worldwide.
Several physiological and neurochemical mechanisms have been suggested to explain NDEs such as cerebral hypoxia, activation of the limbic system, abnormal activity in the temporal lobes, serotonin pathways, release of endorphin hormones, atypical NMDA receptor activation etc. In addition, NDEs are proposed to arise as hallucination, psychosis, imagination, fear of death etc. However, any of proposed physiological, neurochemical and psychological ideas by itself could not elucidate all the common characteristics of NDEs. Although some features of NDEs may be attributed to neural processes or to psychological phenomena, nevertheless, we have not a satisfactory explanation about some features of NDEs.
Free radial generation during reperfusion in the brain and the retina
Unsaturated fatty acids with many double bonds are very vulnerable to oxidation (lipid peroxidation). The retinal photoreceptors have one of the highest demands for oxygen per square millimeter of any tissue in the body. In addition, the retina (photoreceptor outer segments contain rhodopsin) and the brain (neuronal membranes, synapses) have the highest concentration of polyunsaturated fatty acids (PUFA) [5,6].
After cardiac arrest during post-ischemic reperfusion, significant over production of oxygen free radicals has been demonstrated mainly by membrane lipid peroxidation in the brain that play important roles in the pathogenesis of the cardiac arrest-related cerebral neurochemical mechanisms and the increased mortality [7,8]. In addition, in the retina increased free radical generation has been demonstrated during the early phase of reperfusion following ischemia [9,10].
Phosphenes are perceived sensation of flashes of light in the absence of external visual stimulation. Phosphenes can be points, spots, bars or chaotic structures of colorless or colored light . Phosphenes can be elicited by various stimuli (mechanical, electrical, magnetic, etc.) of cells in the visual pathway as well as random firing of cells in the visual system. Phosphenes are an early symptom in a variety of diseases of the retina or of the visual system, but healthy individuals can spontaneously perceive them as well . Phosphenes can also be associated with drugs, emotional factors, alcohol, stress, fever or psychotic conditions. Induction of phosphenes is dependent on the type of stimulation (electrical or magnetic stimulation), stimulation parameters, and the neural structure of individuals .
Phosphenes by bioluminescent photons in the retina and the visual cortex
Recently, we have proposed that the phosphene phenomenon is due to the intrinsic perception of induced (mechanical, electrical, magnetic, ionizing radiation, etc.) or spontaneous increased bioluminescent biophoton emission of cells in various parts of the visual system (from retina to cortex) . Namely, we argued that phosphenes could arise from unregulated overproduction of free radicals and excited biomolecules in various parts of the visual system. Unregulated overproduction of free radicals and excited species can generate a brief increase of bioluminescent biophotons (Figure 1) in different regions of the visual system, and if this excess of bioluminescent biophoton emission exceeds a threshold, they can appear as phosphene lights in our mind. In other words, the brain interprets these retinal bioluminescent photons as if they originate from the external world.
Our prediction about one kind of retinal phosphenes (i.e. retinal phosphenes during space travel) was experimentally supported by Narici et al. . According to this study, free radicals induced by ionizing radiation (cosmic particles) can produce chemiluminescent photons via lipid peroxidation. Chemiluminescent photons are then absorbed by the photoreceptors and start the photo-transduction cascade, which results in the perception of phosphenes. In other words, during space travel, phosphene perception can be due to the transient increase of bioluminescent biophoton emission generated by ionizing particle induced free radicals.
Later, we presented the first experimental in vitro evidence of the existence of spontaneous and visible light induced ultraweak photon emission from freshly isolated whole eye, lens, vitreous humor and retina samples from rats . These results suggest that the photochemical source of retinal discrete noise, as well as retinal phosphenes, as predicted by Bókkon and Vimal , may originate from natural bioluminescent photons within the eyes (Figure 2). In addition to electric and chemical signals propagating in the neurons of the brain, signal propagation may take place in the form of biophoton production [17,18].
Catala  has shown that radicals from lipid peroxidation of the photoreceptors outer segments of the retina can generate (bio)chemiluminescent photons (bioluminescence is a type of chemiluminescence, which naturally occurs in living organisms) in the visual spectrum. Besides, there is biochemical evidence for the plasma membrane as the primary source of bioluminescent photons . Since phosphenes can also be elicited by direct stimulation of visual cortex without retinal photo-transduction cascade, it suggests that retinal and visual cortical phosphenes generated by similar mechanisms, and both may due to the transiently and locally increased ultraweak photons.
Hyphothesis: Lights during near death experiences by excess bioluminescent photons
A typical feature of NDEs as seeing a brilliant light may arise during the recovery period following cardiac arrest, but the patient can think that these experiences had occurred during the actual period itself. Several studies demonstrated that during post-ischemic reperfusion, there is considerable over production of oxygen free radicals generated in the brain and the retina. During the recovery phase, the overproduction of free radicals and excited species, among them, in the visual areas can produce significant bioluminescent photons via lipid peroxidation. In addition, phosphenes can be elicited by direct stimulation (electric, magnetic) of visual cortex without retinal photo-transduction cascade. It suggests that during the recovery phase, phosphenes (i.e. intrinsic bioluminescent photons) can be emerged simultaneously in numerous visual areas, which may cause the experience of an intrinsic brilliant light.
One might argue that in NDEs persons who have been born blind or become blind very early in their infancy can in fact “see” in a near death state. First we should make difference between seeing things during NDEs experience such as deceased relatives, angeles etc. or looking down and seeing the doctors standing over their bodies (i.e. out-of-body experience, OBE) and seeing brilliant lights. The former is not the matter of this paper and here we deal with a biophysical explanation about the encounter with a brilliant light in NDEs.
However, phosphenes can be induced in both sighted and blind subjects. In addition, phosphene-like lights may be seen by congenitally blind , but exact evidence is lack. We should also consider that congenitally blind people may lack the terminology and experience in conceptualizing the perception of (phosphene) lights.
Testing the hypothesis
Testing our hypothesis about bioluminescent photonic idea of brilliant light in NDEs will require a converging methods approach. It is well known that during natural metabolic processes, in all types of living systems, lasting spontaneous photon emission has been detected without any external excitation. In addition, recently, Dotta et al.  found significant increases in bioluminescent biophoton emissions from the right hemisphere while volunteers who imagined a white light in a dark room were compared to those who engaged in simple casual thinking. Namely, there was a cognitive coupling with biophoton emission in the brain during subjective visual imagery and biophoton emission is strongly correlated with the EEG activity and action potentials of axons.
So, in vitro and in vivo increases of ultraweak bioluminescent photon emission should be measured from the right and the left hemisphere in animal experiments before, during and the recovery period in experimental cardiac arrest.
In 1926, Heinrich Klüver  scientifically studied the effects of hallucinogenic mescaline on the subjective experiences of its users. Klüver observed that mescaline produced recurring geometric visual patterns in different users. He termed these recurring patterns form constants (reproducible phosphene patterns) and grouped them into four types such as: lattices, cobwebs, tunnels, and spirals. He proposed that the reproducible geometry visual patterns can reflect elementary visual mechanisms. In the 1950s, Max Knoll  grouped electrically produced and reproducible phosphene patterns into 15 form groups. Reproducible phosphene patterns could be changed by varying the frequency of pulses as subjects reported.
Since hallucinogenic drugs can induce phosphene patterns as well as over expression of free radicals and excited species, which are the main sources of biophotons [13,15], it should be tested if after intoxication by hallucinogenic drugs significant induction of bioluminescent biophoton emission from the hemispheres of volunteers occurs, and compare it with experimental cardiac arrest results.
Previously, we have proposed that the phosphene phenomenon is due to the intrinsic perception of induced or spontaneous increased biophoton emission of cells in various parts of the visual system. Explicitly, we argued that phosphenes could arise from overproduction of free radicals and excited biomolecules in diverse parts of the visual system. Unregulated overproduction of free radicals and excited molecules can create a brief increase of bioluminescent biophotons in the visual system, and if this excess of biophoton emission exceeds a threshold, they can appear as phosphene lights in our mind.
It is possible that blinding white light subjective experience in NDEs may occur in the recovery phase following cardiac arrest, but the patients can think that these experiences had happened during the actual period itself. Here we suggested that seeing brilliant lights in NDEs may due to bioluminescent biophotons simultaneously produced in the recovery period in many regions of the visual system and the brain interprets these intrinsic biophotons as if they were originated from the external visual world. In other words, brilliant light experience in NDEs is nothing else as simultaneously emerged phosphenes (i.e. intrinsic bioluminescent photons) in numerous visual areas during the recovery phase.
However, several investigations are needed to support our proposed biophysical notion about lights in NDEs in the future. Although our suggested biophysical mechanism about brilliant light phenomenon in NDEs may be promising, we do not eliminate further possible explanations.
We thank Prof Edward J. Tehovnik for helpful comments on the manuscript.
Conflict of interest statement
No conflict of interest exists.
 Youdim, K.A. Martin, A. Joseph, J.A. Essential fatty acids and the brain: possible health implications. Int J Dev Neurosci 2000;18:383–99.
 Basu S, Miclescu A, Sharma H, Wiklund L. Propofol mitigates systemic oxidative injury during experimental cardiopulmonary cerebral resuscitation. Prostaglandins Leukot Essent Fatty Acids 2011;84:123–30.
 Tehovnik EJ, Slocum WM, Carvey CE, Schiller PH. Phosphene induction and the generation of saccadic eye movements by striate cortex. J Neurophysiol 2005;93:1–19.
 Bókkon I. Phosphene phenomenon: a new concept. BioSystems 2008;92:168–74.
 Narici L, De Martino A, Brunetti V, Rinaldi A, Sannita WG, Paci M. Radicals excess in the retina: A model for light flashes in space. Rad Meas 2009;44:203–5.
 Wang C, Bókkon I, Dai J, Antal I. First experimental demonstration of spontaneous and visible light-induced photon emission from rat eyes. Brain Res 2011;1369:1–9.
 Bókkon I, Vimal RLP. Retinal phosphenes and discrete dark noises in rods: a new biophysical framework.J Photochem Photobiol B Biology 2009;96:255–9.
 Sun Y, Wang Ch, Dai J. Biophotons as neural communication signals demonstrated by in situ biophoton autography. Photochem Photobiol Sci 2010;9:315–22.
 Rahnama M, Tuszynski J, Bókkon I, Cifra M, Sardar P, Salari V. Emission of mitochondrial biophotons and their effect on electrical activity of membrane via microtubules. J Integr Neurosci 2011;10:65–88.
 Catalá A. An overview of lipid peroxidation with emphasis in outer segments of photoreceptors and the chemiluminescence assay. Int J Biochem Cell Biol 2006;38: 1482–95.
 Dotta BT, Buckner CA, Cameron D, Lafrenie RF, Persinger MA. Biophoton emissions from cell cultures: biochemical evidence for the plasma membrane as the primary source. Gen Physiol Biophys 2011;30:301–9.
 Gothe J, Brandt SA, Irlbacher K, Röricht S, Sabel BA, Meyer BU. Changes in visual cortex excitability in blind subjects as demonstrated by transcranial magnetic stimulation. Brain 2002;125:479–90.
 Dotta BT, Saroka KS, Persinger MA. Increased photon emission from the head while imagining light in the dark is correlated with changes in electroencephalographic power: Support for Bókkon’s Biophoton Hypothesis. Neurosci Lett 2012; doi:10.1016/j.neulet.2012.02.021.
 Klüver H. Mescal Visions and Eidetic Vision. Amer J Psychol 1926;37:502–15.
 Knoll M. Kügler J. Subjective light pattern spectroscopy in the electroencephalic range. Nature 1959;184:1823–4.