Altered neural dynamics in people who report spontaneous out of body experiences

I thought this EEG study from last year, investigating the Altered neural dynamics in people who report spontaneous out of body experiences was worth posting.

They show a difference between OBE'ers vs Non-OBE'er-Controls where OBE'rs...

1) P1 event related potential deflection is reduced compared with controls,
2) Alpha-band phase locking between trials is reduced compared to controls, and
3) A reduction in the mean power spectrum calculated across all channels compared to controls (which they later seem to suggest is insignificant).

There are a lot of assumptions and speculative discussions by the authors about what these results might mean, but the actual measurements themselves look OK, and quite interesting to me, considering they found reductions, which appear inversely correlated with a the likelihood of having a spontaneous OBE.

Abstract

It has been suggested that individual differences in cortical excitability leading to disruption of the timing and integration of sensory information processing may explain why some people have out of body experiences (OBE) in the absence of any known pathological or psychiatric condition. Here we recorded EEG from people who either had, or had not experienced an OBE in order to investigate the neural dynamics of OBE in the non-clinical population.

A screening questionnaire was completed by 551 people, 24% of whom reported having at least one OBE. Participants who were free of any psychiatric or neurological diagnoses, including migraines, were invited to take part in subsequent EEG recording. EEG data were obtained from 19 people who had had an OBE and 20 who had not. Amplitude of the visual P1 ERP deflection and consistency of alpha-band phase locking were significantly reduced in the participants who had had an OBE. We did not find any group differences in resting state power or in visually induced gamma oscillations. These results provide support for the claim that cortical differences, particularly with respect to the timing of visual information processing, may give rise to OBE in clinically healthy individuals. To our knowledge, this study is the first to compare EEG variables obtained from people who have, and have not, had an OBE.

If I'm reading this right, they are taking measurements from two groups, a control group, and a group of those who have reported at least one OBE in the past. It doesn't look as though there were any OBEs at the time of the measurement?

If I'm reading this right, they are taking measurements from two groups, a control group, and a group of those who have reported at least one OBE in the past. It doesn't look as though there were any OBEs at the time of the measurement?

Yes, that’s right. They wanted to investigate, using EEG, any general differences between those who report having had an OBE in the past, verses those who do not report having an OBE.

It sounds reasonable that if OBES are real something must be happening in the brain too. Maybe the different structure allows for an OBE without a NDE.

If I understand this correctly (I've only been able to read the abstract so far) - the basic finding is that certain brain functions related to processing visual and auditory information are reduced in people who have OBEs?

If that is the case, then I would be surprised - if one went with a purely brain-based explanation of OBEs, I would expect the visual processing, at least, to be more developed, to allow for collecting enough detail to be able to construct images from unusual vantage points.

If I understand this correctly (I've only been able to read the abstract so far) - the basic finding is that certain brain functions related to processing visual and auditory information are reduced in people who have OBEs?

If that is the case, then I would be surprised - if one went with a purely brain-based explanation of OBEs, I would expect the visual processing, at least, to be more developed, to allow for collecting enough detail to be able to construct images from unusual vantage points.

Reduced power, reduced ERP deflection, reduced Alpha band consistency between trials for OBEer’s seems to be in the right sort of direction.

If it were the other way round I’d be scratching my head, because when the brain has substantially reduced power during cardiac arrest, people do recall having OBE’s apparently containing imagery from the same period as their cardiac arrest.

We also have ERP dropout opening up holes in the brains endogenous EM field which in my view are creating somewhat similar conditions for OBE’s to occur, under different physiological conditions (ie not cardiac arrest), but things like fear death.

That is, the brains networks appear vulnerable to external fields. Higher consistency for Alpha-band phase locking, increased power, increased ERP deflection would all seem to reduce the general vulnerability of an individuals brain to external fields.

Whether the results are surprising or not depends I suppose on what sort of model is adopted to (try to) explain OBEs.

I'm not actively involved right now, decades ago I set out to see whether it was possible to achieve an OBE, which involved for me a form of relaxation and meditation so that the body begins to fade from awareness, this is the preliminary preparation.

More recently I had a bad reaction to some prescribed medication, with hindsight I was slow to realise what was happening, I felt dizzy and nearly collapsed in the street - a dangerous situation since it was caused by drugs. At night time I was aware that my heart rate was disturbed, it would beat very fast and very slow, and I felt the same sensations as during the OBE preparation, I was right on the edge of leaving my body. I had to shake myself into alertness to prevent this from happening, I was seriously worried that If I did separate from the body in those circumstances I might not return.

Suffice to say, my model of brain activity during OBE is one of reduced activity, either through meditation or through reduced blood supply.

This is a relevant post I made on Skeptiko back in 2016...

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Interesting new paper where researchers attempt to test the idea that the right Temporo-parietal Junction may play a specific role in abnormal body perception (ABP) like out of body experience (OBE). They attempted to induce an OBE using repetitive transcranial magnetic stimulation (rTMS) of the brains right Temporo-parietal Junction (rTPJ), vs a Control Site (CS) located 5cm away.

"Effects of Transcranial Magnetic Stimulation on Body Perception: No Evidence for Specificity of the Right Temporo-Parietal Junction"

https://www.researchgate.net/publication...l_Junction

[Updated Link to full free version of the paper above]

Even though they failed to induce a full-blown OBE, I applaud the researchers for being so open minded and actually providing a realtime hidden target just incase they had been successful...

"...The aim of the present study was therefore to investigate in a larger sample, whether repetitive transcranial magnetic stimulation (rTMS) of the rTPJ in a healthy brain can induce ABP, and to explore neurophysiological correlates of ABP. We employed MRI-based neuronavigated TMS for exact localisation of the rTPJ. Following the design of previous research, a visual target was displayed out of sight of the participant. A laptop was placed above the participant with the screen turned to the ceiling. The screen displayed a series of 5-digit numbers that changed randomly every second. The participant was instructed that if he/she experienced an ABP and was able to see the target, he/she would have to recall it after the ABP. The participant’s electroencephalography (EEG) was monitored to allow the assessment of neurophysiological correlates of ABP...."

Highlights for me...

"...Thirteen participants (65 %) reported ABP when stimulated at the rTPJ and twelve (60 %) when stimulated atthe CS. Among the participants who reported ABP, none reported an OBE. Two participants had somatosensory tingling sensations in their arms or legs. Eight participants reported twitching sensations in their body parts (arms and/or legs). Most remarkably, three participants reported complete illusory movements of body parts. These participants did not see their body parts moving, but they felt illusory movements of body parts such as arm deflections and stretching legs..."

and...

"...Our neurophysiological data indicate that abnormal body perception (ABP) were related to a systematic (almost independently of the rTMS cortical site and rTMS frequency: in 3 out of 4 experimental conditions) decrease of the EEG power in all frequency bands at a common left anterior and left central cortical area according statistical results in 2 conditions (15 Hz rTMS at rTPJ and CS) and according to trends (Fig. 6) in a third condition (1 Hz rTMS at rTPJ). The EEG power decrease in all frequency bands could be interpreted as a specific type of cortical deactivation due for instance to EEG desynchronisation (Mun˜oz-Torres et al. 2011; Julkunen et al. 2008) or a reduced connectivity (Julkunen et al. 2008). At a neurofunctional level, ‘‘power decrease in all frequency bands is generally seen after arousal stimuli, during orienting reactions’’ (Gamma et al. 2000, p. 160) and EEG desynchronisation has been interpreted as reflecting the perception of an incongruence (Berlyne and McDonnell 1965). Thus, the power decrease in all frequencies could reflect an orientation mechanism to the presence of an incongruent body perception that we refer to as an ABP..."

Whether it's with drugs, cardiac arrest or event related desynchronisation etc, it seems to me that a common cause of localised OBE-type phenomena continues to be a reduction in power output of the brains endogenous EM field.

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Reduced power, reduced ERP deflection, reduced Alpha band consistency between trials for OBEer’s seems to be in the right sort of direction.

If it were the other way round I’d be scratching my head, because when the brain has substantially reduced power during cardiac arrest, people do recall having OBE’s apparently containing imagery from the same period as their cardiac arrest.

We also have ERP dropout opening up holes in the brains endogenous EM field which in my view are creating somewhat similar conditions for OBE’s to occur, under different physiological conditions (ie not cardiac arrest), but things like fear death.

That is, the brains networks appear vulnerable to external fields. Higher consistency for Alpha-band phase locking, increased power, increased ERP deflection would all seem to reduce the general vulnerability of an individuals brain to external fields.

I was playing devil's advocate, to an extent - if one assumed OBEs were "just" hallucinations, one might expect increased activity at the time, and perhaps expect heightened activity in certain areas at all times to allow for collecting and retaining enough information to construct certain images.