Neural Correlates of Induced Light Experience during Meditation: A Pilot Hyperscanning Study
Peter Fenwick, Caroline Di Bernardi Luft, Andreas A Ioannides, Joydeep Bhattacharya
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Abstract
Certain individuals during deep meditative state can give out an aura or ‘light, which is perceived by others through some unknown connections, visual, telepathic or other. Despite various anecdotal, historical accounts of such induced light experience (ILE), its underlying neural mechanisms are not known. In this pilot study, we investigated the neural correlates of ILE by simultaneously recording the EEGs of an expert meditation Teacher, who is claimed to elicit ILE, and his Pupil (N=2) during joint meditation sessions under various instructions, given separately to the Teacher (transmit/do not transmit) and to the Pupil (receive/do not receive) and also during transmit/receive instruction but both wearing goggles, limiting the visual input. We observed a robust increase in the high frequency beta (12- 30 Hz) and gamma oscillations (30-70 Hz) in the Teacher’s brain whenever he was instructed to transmit. Electric field tomography analysis localized these effects over a multitude of brain regions including the fusiform gyrus, angular gyrus and the cerebellum. Finally, we found that the Teacher’s and Pupil’s brain responses were synchronized especially in the alpha band (8-12 Hz) during transmit/receive condition, and the information flow was directional, i.e. from the Teacher to the Pupil; interestingly, this enhanced interbrain synchrony disappeared with goggles. These results were interpreted in terms of heightened internally selective attention as manifested by high frequency betagamma oscillations and of joint attention as manifested by interbrain alpha synchrony. Altogether, our results provide first neuroscientific evidence underlying the phenomenological experience of induced light.
Introduction
Anecdotal accounts of individuals who see light surrounding their meditation teacher when meditating are not uncommon. In fact, the occurrence of such induced light experience (ILE) dates back to early history. Greek philosopher Parmenides and Plato both associated ‘truth’ with light. Since then there are many accounts in the esoteric literature of spiritual teachers who are able to radiate ‘light and energy’ when meditating. For example, St. Francis of Assissi was reported by other monks to have been surrounded by a cloud of white light, as was St. Theresa of Avila. Puhle, (2014) has summarized the history of light phenomena in over 750 individual accounts and shows the widespread nature of light experiences. Light has also been associated with the dying just days before death. The light is seen by the dying themselves, carers and relatives, however, there is a subjective component as not all the relatives may see it, and interestingly, any light experiences often end with death (Fenwick and Fenwick, 2012). In some cultures, subjective light experiences have been associated with the nature of the mind. For example, in the book, “Awakening the Luminous Mind”, Rinpoche, (2012) gives a number of Tibetan meditation practices to reveal this light of the mind.
Meditation has been shown to affect brain physiology. Numerous studies suggest robust structural changes, i.e. brain’s gray and white matter, associated with in the intense meditation training (Fox, Dixon et al., 2016). Further, changes in the functional brain responses are also widely reported during (Cahn and Polich, 2006). In a pioneering fMRI experiment, Beaureguard and Paquette, (2006) recorded the haemodynamic responses of Carmelite nuns, who often experience light and love in their meditation, while they were subjectively experiencing a state of union with God. A wide range of brain regions including right medial orbitofrontal cortex, right inferior and superior parietal lobules, right medial temporal cortex, left anterior cingulate cortex were activated during this mystical state. Further, high frequency gamma oscillations (> 30 Hz) are found to increase during meditation (Lehmann, Faber et al., 2001; Lutz, Greischar et al., 2004; Vialatte, Bakardjian et al., 2009; Cahn, Delorme et al., 2010). Gamma oscillations are widespread in human brain and generated out of the coordinated interaction between excitatory and inhibitory neuronal populations (Buzsáki and Wang, 2012); its functional roles are less specific as it is implicated with wide ranging cognitive and emotional processes in visual binding, selective attention, memory recall, to emotional arousal. However, to our knowledge, no study so far has connected the documented increase in occipital gamma during meditation with spontaneous visual imagery. Interestingly, the process of “seeing things” during meditation is a commonly reported phenomenon – “encounters with light” – amongst meditators (Lo, Huang et al., 2003, Lindahl, Kaplan et al., 2014). For example, Lindahl, Kaplan et al. (2014) wrote “Two practitioners also reported a proprioceptive dimension to their meditationinduced light experience. One practitioner explained that “my body just was breaking apart into sparkles and like electrical sparks being sent off everywhere in all directions”; the other “felt like I was radiating, like there were rays of light coming out of me.”
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