I left off in my previous post by mentioning that I would raise some of the physiological aspects occurring simultaneously with the near-death experience (NDE).
To set the stage, a review of the medical literature shows that there are no particular disease states or events predominantly associated with NDEs. Among the many clinical circumstances reported to be associated with NDEs are cardiac arrest in myocardial infarction, shock in postpartum loss of blood or in perioperative complications, anaphylactic and septic shock, electrocution, coma resulting from traumatic brain injury, intracerebral hemorrhage or cerebral infarction, attempted suicide, near-drowning or asphyxia, apnea, and serious depression.
Several retrospective analyses have been conducted which have identified a number of interesting physiological correlates of NDEs. According to a 2001 study, the physiology of an NDE in patients with cardiac arrest usually includes elevated partial O2 pressure relative to other patients with cardiac arrest.
In September 2008 it was announced that an international study conducted in 25 UK and US hospitals would examine near-death events in 1,500 patient-survivors of heart attacks. The 3-year AWARE study — a follow-up to an earlier 18-month pilot study — is being coordinated by Dr.Sam Parnia of Southampton University. The goal of the study is to determine whether individuals can have an OBE with veridical (ie, real-world) visual perceptions in the absence of a heartbeat and brain activity. (As a side note, one of the simple but quite elegant fine points of the study is the inclusion of pictures visible only from the ceiling on shelves in the hospital rooms. Thus, if a patient’s spirit truly leaves the body and ascends toward the ceiling, they may be able to describe these heretofore unseen items.)
Some researchers and commentators tend to emphasize a naturalistic, neurobiological basis for the experience, while not necessarily trying to debunk NDEs. These include Susan Blackmore (1991), Birk Engmann at the Univeristy of Leipzig, and the founding publisher of Skeptic Magazine, Michael Shermer (2010). Among the explanations invoked have been destabilized temporal lobes in the brain creating NDE-prone personalities, psychopathological symptoms secondary to severe brain malfunction resulting from the stoppage of cerebral blood circulation, and other concrete scientific explanations awaiting discovery.
In my next post, we’ll take a look at some of the data that don’t fit so neatly into the purely neurobiological “box” of explanations.
Showing posts with label scientific. Show all posts
Showing posts with label scientific. Show all posts
Monday, June 14, 2010
Thursday, May 27, 2010
Near-death experiences - the real afterlife or just a hallucination?
Coming back to the theme of consciousness that I touched on a few weeks ago, I’ve been looking into the scientific literature on near-death experiences (NDEs) and out of body experiences (OBEs). I find it absolutely fascinating to consider the possibility that a person’s consciousness could exist separately from the body, even for a finite period of time. There are also some intriguing tie-ins with remote viewing, but that’s a topic that will have to wait for a post of its own. Even NDEs and OBEs as individual topics merit much more than a brief post.
An NDE by definition is an experience or any of a collection of experiences by an individual associated with impending physical death. These experiences consist of a range of phenomena which may include separation from the body, a sense of floating or levitating, feelings of calm/security/warmth, and the presence of an all-encompassing light. The majority of these phenomena are reported when the individual in question is either very close to death or once he or she has actually been pronounced clinically dead. Ironically enough, there have been a significant number of NDEs reported by individuals who have not experienced life-threatening circumstances.
Modern interest in NDEs can be traced to the publication of Life After Life
by Raymond Moody, MD, PhD in 1975. For many people, this was their first exposure to a broad review and discussion of over 100 cases of clinical deaths and subsequent resuscitations. The interest sparked by this book led to the foundation of the Association for the Scientific Study of Near-Death Phenomena (now the International Association for Near-Death Studies) in 1978 by Moody, John Audette, MS, Ken Ring, PhD, Bruce Greyson, MD, and Michael Sabom, MD. Since that time, these individuals and others with an interest in NDEs have been involved with the founding of a number of similar research groups and programs, including the Near Death Experience Research Foundation and the Human Consciousness Project.
As with most other paranormal phenomena, the scientific community as a whole is divided on the issue of NDEs and what they represent versus what they actually are. Opinions vary from the entire experience being a hallucination brought on by the stress of the NDE at one extreme all the way to the experience being a definitive demonstration of the existence of an afterlife.
In my next post, I’ll examine the physiological correlates of the NDE and some of the pro- and con- afterlife viewpoints.
In the meantime, as always, I welcome your opinions on the subject!
An NDE by definition is an experience or any of a collection of experiences by an individual associated with impending physical death. These experiences consist of a range of phenomena which may include separation from the body, a sense of floating or levitating, feelings of calm/security/warmth, and the presence of an all-encompassing light. The majority of these phenomena are reported when the individual in question is either very close to death or once he or she has actually been pronounced clinically dead. Ironically enough, there have been a significant number of NDEs reported by individuals who have not experienced life-threatening circumstances.
Modern interest in NDEs can be traced to the publication of Life After Life
by Raymond Moody, MD, PhD in 1975. For many people, this was their first exposure to a broad review and discussion of over 100 cases of clinical deaths and subsequent resuscitations. The interest sparked by this book led to the foundation of the Association for the Scientific Study of Near-Death Phenomena (now the International Association for Near-Death Studies) in 1978 by Moody, John Audette, MS, Ken Ring, PhD, Bruce Greyson, MD, and Michael Sabom, MD. Since that time, these individuals and others with an interest in NDEs have been involved with the founding of a number of similar research groups and programs, including the Near Death Experience Research Foundation and the Human Consciousness Project. As with most other paranormal phenomena, the scientific community as a whole is divided on the issue of NDEs and what they represent versus what they actually are. Opinions vary from the entire experience being a hallucination brought on by the stress of the NDE at one extreme all the way to the experience being a definitive demonstration of the existence of an afterlife.
In my next post, I’ll examine the physiological correlates of the NDE and some of the pro- and con- afterlife viewpoints.
In the meantime, as always, I welcome your opinions on the subject!
Friday, May 21, 2010
Mapping the psychic mind
Over the past week or so I’ve spent a lot of time thinking about what it might mean to be psychic in any sense of the word. Aside from the odd anomalous experience, I can’t really say that I know what it feels like. I’ve seen the odd psychic here and there, as well as a couple famous mediums in action. As a consequence I can say that I’m still open to the possibility despite not having had any direct personal experiences. Thinking about psychics and psi raised a lot of questions for me. Is everyone psychic to some extent or are only certain people? Can a person learn to be psychic? How could someone learn and how would they practice?
While there may be no satisfactorily objective answers to the above questions, another one occurred to me. From the standpoint of neuroscience and neurochemistry, what does the psychic brain look like and more to the point, where in the brain does psychic activity occur?
Empirical studies measuring psi activity are in remarkably short supply in the main body of medical literature. While some of this is likely because of the perceived fringe nature of this field, another possibility is the challenge imposed by knowing what and how to measure psi-related processes in the brain. After a reasonably stringent search for publications on the National Library of Medicine’s database, PubMed, I came up with a pair of recent articles using 2 different techniques with 2 very different results.
The first of these was “Using Neuroimaging to Resolve the Psi Debate” by Samuel T. Molton and Stephen M. Kosslyn.1 These researchers utilized functional magnetic resonance imaging (fMRI) to search for activity in the brains of pairs of biologically or emotionally related participants. The participants were shown emotional stimuli while in separate rooms with one participant acting as a “sender” and another playing the role of “receiver” while monitored by fMRI. According to Moulton and Kosslyn, “psi stimuli and non-psi stimuli evoked indistinguishable neuronal responses – although differences in stimulus arousal values of the same stimuli had the expected effects on patterns of brain activation.” In other words, the investigators found no evidence in support of psi using this method.
The second paper was “The Transliminal Brain at Rest: Baseline EEG, Unusual Experiences, and Access to Unconscious Mental Activity” by Jessica I. Fleck and colleagues. In order to understand this one better, I needed to look up the definition of transliminality which is, “a reflection of individual differences in the threshold at which unconscious processes or external stimuli enter into consciousness.” Among the characteristics reported for people high in transliminality are 1) belief in the paranormal and 2) reported occurrences of mystic experiences. While not examining psychic functioning directly, the investigators used electroencephalography (EEG) to measure the resting brain activity of individuals reportedly high or low in transliminality. The study revealed significant differences in 3 areas: the left posterior association cortex, the right superior temporal region, and the frontal-midline region. Aside from the similarities to schizotypy, this study demonstrates some fundamental functional/processing differences in the brains of individuals more open to the idea of the paranormal.
Of course neither of the above papers is an end result in and of itself with respect to the question of whether psi exists and where in the human brain it can be found. What they do serve to illustrate is the pronounced challenges and complexities inherent in investigating these phenomena. The methods and the choices of subjects for each study leave some questions unanswered. Were any of the participants in either study self-professed psychics? Why fMRI as opposed to diffusion weighted or diffusion tensor imaging? Would a 3-tesla magnet or an EEG monitor be expected to interfere with psi activity or reception? Would magnetoencephalography (MEG) provide better resolution that EEG?
Questions notwithstanding, these studies represent an encouraging effort in legitimate scientific research into psi. I encourage anyone interested in learning more about these 2 fascinating studies to obtain copies of the papers and have a read. Enjoy!
References
1. Molton ST, Kosslyn SM. Using neuroimaging to resolve the psi debate. J Cognitive Neurosci. 2008;20:182–192.
2. Fleck JI, Green DL, Stevenson JL, et al. The transliminal brain at rest: Baseline EEG, unusual experiences, and access to unconscious mental activity. Cortex. 2008;44:1353–1363.
While there may be no satisfactorily objective answers to the above questions, another one occurred to me. From the standpoint of neuroscience and neurochemistry, what does the psychic brain look like and more to the point, where in the brain does psychic activity occur?
Empirical studies measuring psi activity are in remarkably short supply in the main body of medical literature. While some of this is likely because of the perceived fringe nature of this field, another possibility is the challenge imposed by knowing what and how to measure psi-related processes in the brain. After a reasonably stringent search for publications on the National Library of Medicine’s database, PubMed, I came up with a pair of recent articles using 2 different techniques with 2 very different results.
The first of these was “Using Neuroimaging to Resolve the Psi Debate” by Samuel T. Molton and Stephen M. Kosslyn.1 These researchers utilized functional magnetic resonance imaging (fMRI) to search for activity in the brains of pairs of biologically or emotionally related participants. The participants were shown emotional stimuli while in separate rooms with one participant acting as a “sender” and another playing the role of “receiver” while monitored by fMRI. According to Moulton and Kosslyn, “psi stimuli and non-psi stimuli evoked indistinguishable neuronal responses – although differences in stimulus arousal values of the same stimuli had the expected effects on patterns of brain activation.” In other words, the investigators found no evidence in support of psi using this method.
The second paper was “The Transliminal Brain at Rest: Baseline EEG, Unusual Experiences, and Access to Unconscious Mental Activity” by Jessica I. Fleck and colleagues. In order to understand this one better, I needed to look up the definition of transliminality which is, “a reflection of individual differences in the threshold at which unconscious processes or external stimuli enter into consciousness.” Among the characteristics reported for people high in transliminality are 1) belief in the paranormal and 2) reported occurrences of mystic experiences. While not examining psychic functioning directly, the investigators used electroencephalography (EEG) to measure the resting brain activity of individuals reportedly high or low in transliminality. The study revealed significant differences in 3 areas: the left posterior association cortex, the right superior temporal region, and the frontal-midline region. Aside from the similarities to schizotypy, this study demonstrates some fundamental functional/processing differences in the brains of individuals more open to the idea of the paranormal.
Of course neither of the above papers is an end result in and of itself with respect to the question of whether psi exists and where in the human brain it can be found. What they do serve to illustrate is the pronounced challenges and complexities inherent in investigating these phenomena. The methods and the choices of subjects for each study leave some questions unanswered. Were any of the participants in either study self-professed psychics? Why fMRI as opposed to diffusion weighted or diffusion tensor imaging? Would a 3-tesla magnet or an EEG monitor be expected to interfere with psi activity or reception? Would magnetoencephalography (MEG) provide better resolution that EEG?
Questions notwithstanding, these studies represent an encouraging effort in legitimate scientific research into psi. I encourage anyone interested in learning more about these 2 fascinating studies to obtain copies of the papers and have a read. Enjoy!
References
1. Molton ST, Kosslyn SM. Using neuroimaging to resolve the psi debate. J Cognitive Neurosci. 2008;20:182–192.
2. Fleck JI, Green DL, Stevenson JL, et al. The transliminal brain at rest: Baseline EEG, unusual experiences, and access to unconscious mental activity. Cortex. 2008;44:1353–1363.
Wednesday, April 28, 2010
Update to the blog
I've been scouring the web for the past week or so, trying to find the academic institutions and their offshoots who are researching paranormal phenomena of every stripe. Not surprisingly, the legitimate institutions (i.e., the ones making a fair attempt at employing the scientific method and rigorous scientific principles in their research) are few and far between. However, I have managed to cull together quite a few links of interest and have begun posting them. Over the coming days and weeks I will continue to add more as I find them. In the meantime, please feel free to contact me with suggestions for sites that may be of interest. Until then - enjoy!
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