New Nature study on enhanced consciousness

#2
They claim to have proved LSD and psilocybin produce states of enhanced conscousness:
https://www.nature.com/articles/srep46421
Interesting - this study directly contradicts a cornerstone of Bernado Kastrup's recent arguments.

http://www.bernardokastrup.com/2011/11/consciousness-and-memory.html
Psychedelic substances have been known to induce similarly profound hallucinatory and mystical experiences. It has always been assumed that they do so by exciting the parts of the brain correlated to such experiences, thereby causing them. Yet, a very recent and as-of-yet unpublished study has shown that at least one particular psychedelic, psilocybin (the active component of magic mushrooms), actually does the opposite: It dampens the activity of key brain regions.
I wonder if the study he is referring to was ever published.
 
#4
Interesting - this study directly contradicts a cornerstone of Bernado Kastrup's recent arguments.

http://www.bernardokastrup.com/2011/11/consciousness-and-memory.html
From a quick read I doubt it, but I might be wrong.
This study uses "empirical measures of conscious level" called PCI (perturbational complexity index), while the studies mentioned by Bernardo essentially took in consideration blood flow. They are two very distinct and different things, I fear.

More here: http://stm.sciencemag.org/content/5/198/198ra105

Cheers
 
#5
From a quick read I doubt it, but I might be wrong.
This study uses "empirical measures of conscious level" called PCI (perturbational complexity index), while the studies mentioned by Bernardo essentially took in consideration blood flow. They are two very distinct and different things, I fear.

More here: http://stm.sciencemag.org/content/5/198/198ra105

Cheers
? - you are pointing to a a 2013 study. The OP has linked to a just published 2017 study in Nature that uses a MEG scan to measure what goes on in the brain. Pretty sure the study Bernado points to used fMRi - but even though these two scans of brain activity isn't directly comparable I think the 'brain activity is dampended' thesis is debunked by this new study.
 

Brian_the_bard

Lost Pilgrim
Member
#6
"Yet, a very recent and as-of-yet unpublished study has shown that at least one particular psychedelic, psilocybin (the active component of magic mushrooms), actually does the opposite: It dampens the activity of key brain regions."

Disables the usual filters perhaps, allowing the brain to produce a more intense reality. It certainly doesn't feel like your brain is dampened when you are under the influence.
 
#7
The study found increased global neural signal diversity which suggests that the psychedelic experience is above the awake and sleep state of consciousness.

It's a pity that only 75 micrograms of LSD were used and the subjects were with their eyes open, since the most intense experiences occur when you're relaxed and with your eyes shut. Using accomplished meditators as subjects along with a higher dose of LSD or psilocybin would have produced much more interesting results.

The study's description is loaded with complicated technical jargon. If there is someone on this forum with the scientific training necessary to interpret the results of this study, your help would be appreciated.
 
#8
It certainly doesn't feel like your brain is dampened when you are under the influence.
What does a brain feel like? Or how do we know, based on our subjective experience, what to attribute to the brain, and what to attribute to something which is 'not brain'?

Maybe the more revealing insights come from NDE accounts where the most intense experiences correspond to a lack of brain activity.
 

Brian_the_bard

Lost Pilgrim
Member
#9
What does a brain feel like? Or how do we know, based on our subjective experience, what to attribute to the brain, and what to attribute to something which is 'not brain'?

Maybe the more revealing insights come from NDE accounts where the most intense experiences correspond to a lack of brain activity.
Maybe it is better to say "I didn't feel in any way "dampened" in fact I felt like all my senses were heightened and I was full of good feelings and an intensified sense of meaning when I was under the influence" The brain may not be responsible for this of course.
 
#10
? - you are pointing to a a 2013 study. The OP has linked to a just published 2017 study in Nature that uses a MEG scan to measure what goes on in the brain.
It's an article defining PCI, the index used in the 2017 posted by the OP.
Pretty sure the study Bernado points to used fMRi - but even though these two scans of brain activity isn't directly comparable I think the 'brain activity is dampended' thesis is debunked by this new study.
Can you clarify how do PCI and blood flow compare?

Thanks
 
#12
It's an article defining PCI, the index used in the 2017 posted by the OP.

Can you clarify how do PCI and blood flow compare?

Thanks
I don't think they are using PCI as you are reffering to.

One disadvantage of the PCI approach is that it requires brain stimulation, which limits its applicability and generalisability. A complementary approach is therefore to measure signal diversity of spontaneous neural activity recorded under various manipulations of conscious level. Following early studies of anaesthetics14,15,16 and natural sleep states17,18, we recently found reliable reductions in neural signal diversity with diminished conscious level across a range of measures and experimental manipulations, focusing on spontaneous electrophysiological recordings.
What they measure is increased entropy in the neural signal measured with the MEG scan. It does in no way support the thesis about 'dampen' the brain. When it comes to blood flow they explicitly write:

Functional MRI-based measures of entropy have previously been found to be greater in the psychedelic state than in normal waking consciousness8,24,25,26and this effect has been related, both theoretically8,24 and empirically8,26, to the phenomenal qualities of the psychedelic state.
 
#14
Interesting - this study directly contradicts a cornerstone of Bernado Kastrup's recent arguments.

http://www.bernardokastrup.com/2011/11/consciousness-and-memory.html


I wonder if the study he is referring to was ever published.
He's never been very clear about what he means by 'dampened activity'. I feel sure I've written about this before... somewhere on here. IIRC trying to say that reduced energy supply/usage/consumption etc means that there must be less 'activity' (less complexity etc) is just wrong. For instance Borjigin measured far more activity (associated with conscious), in rats during cardiac arrest, at the same time as power dropped overall.

This study measured spontaneous 'signal diversity' between placebo subjects vs drugged subjects. (Spontaneous, as opposed to using sensory stimulation to produce a response). They found increased spontaneous signal diversity in drugged subjects. However, they also got the usual overall decrease in power from these subjects - basically measured less volts (spectral power). They also found the most pronounced power drop in the alpha band (correlated with visual processing). Those latter parts (powerdrop) are what Bernardo is really relying on, but then he confusingly labels this as the same thing as activity.

A drop in measured power might be due to less energy being used, and/or it might mean firing is less synchronised (more diverse) so that peaks and troughs of waves cancel each other out, rather than waves synchronising and thus amplifying.

The authors mentioned something about testing to rule out the overall powerdrop as being responsible for their increased diversity measurements, but I didn't quite understand what/how they did that, or why they did it.
 
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#15
They claim to have proved LSD and psilocybin produce states of enhanced conscousness:
https://www.nature.com/articles/srep46421
They stress that their results don't necessarily mean 'hightened consiousness', perhaps a richer, more complex experience would be more accurate - relating to the signal diversity they measured.

Although it could be that they don't want to be seen as giving any encouragement to taking drugs.
 
#16
From a quick read I doubt it, but I might be wrong.
This study uses "empirical measures of conscious level" called PCI (perturbational complexity index), while the studies mentioned by Bernardo essentially took in consideration blood flow. They are two very distinct and different things, I fear.

More here: http://stm.sciencemag.org/content/5/198/198ra105

Cheers
I think you are right, they are using the same measurement techniques as PCI... but spontaneously. i.e. without the deliberate perturbation caused by the application of a very powerful magnetic field
 
#17
I don't think they are using PCI as you are reffering to.

What they measure is increased entropy in the neural signal measured with the MEG scan. It does in no way support the thesis about 'dampen' the brain. When it comes to blood flow they explicitly write:
Signal diversity and PCI are two "empirical measures of conscious levels". They provide a tool to quantify the "amount of consciousness" or "range of conscious content".
In other words it is a more sophisticated measure that attempts to establish the amount of conscious experience not the amount of blood flow.

Even without taking Bernardo's hypothesis and simply taking in consideration the previous studies he cited I don't see why they would be at odds or contradicting one another.
They are looking at very different things.

What this study does is correlating the measures of signal diversity with the subjective experience reported in a questionnaire by the subjects ... and they find (lo and behold) that they do correlate.

p.s. = Tononi will like this:

"Correlations of perturbational and spontaneous signal diversity with conscious states support integrated information and complexity theories of consciousness that emphasise diversity of phenomenology as a key property of consciousness that must be reflected in its neural correlates"
 
#18
Signal diversity and PCI are two "empirical measures of conscious levels". They provide a tool to quantify the "amount of consciousness" or "range of conscious content".
In other words it is a more sophisticated measure that attempts to establish the amount of conscious experience not the amount of blood flow.

Even without taking Bernardo's hypothesis and simply taking in consideration the previous studies he cited I don't see why they would be at odds or contradicting one another.
They are looking at very different things.

What this study does is correlating the measures of signal diversity with the subjective experience reported in a questionnaire by the subjects ... and they find (lo and behold) that they do correlate.

p.s. = Tononi will like this:

"Correlations of perturbational and spontaneous signal diversity with conscious states support integrated information and complexity theories of consciousness that emphasise diversity of phenomenology as a key property of consciousness that must be reflected in its neural correlates"
I think Max_B summarizes the discussion better than I can do above so I will leave it at that. I do of course get your point that the fMRI scan and the signal diversity is two different measurements of neural activity. Overall I think the weakest point in all these studies is that you can probably make arbitrary different measurements in the brain and make it correlate with something. Nobody knows how the brain really works and this makes it more difficult make good objective measurements than with many of the other organs in the body.
 
#20
I think Max_B summarizes the discussion better than I can do above so I will leave it at that. I do of course get your point that the fMRI scan and the signal diversity is two different measurements of neural activity. Overall I think the weakest point in all these studies is that you can probably make arbitrary different measurements in the brain and make it correlate with something. Nobody knows how the brain really works and this makes it more difficult make good objective measurements than with many of the other organs in the body.
I agree. It's a very complicated subject.
 
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