New type of brain state

[Lukas1986]

The findings arose as part of a larger research project into Huntington's disease, a condition that stops the brain working properly. The team want to understand why human patients respond differently to various drugs if they carry the gene for this disease. Sheep were used because they are recognised as a suitable pre-clinical model of disorders of the human nervous system, including Huntington's disease.

Six of the sheep were given a single higher dose of ketamine, 24mg/kg. This is at the high end of the anaesthetic range. Initially, the same response was seen as with a lower dose. But within two minutes of administering the drug, the brain activity of five of these six sheep stopped completely, one of them for several minutes -- a phenomenon that has never been seen before.

"This wasn't just reduced brain activity. After the high dose of ketamine the brains of these sheep completely stopped. We've never seen that before," said Morton. Although the anaesthetised sheep looked as though they were asleep, their brains had switched off. "A few minutes later their brains were functioning normally again -- it was as though they had just been switched off and on."

The researchers think that this pause in brain activity may correspond to what ketamine abusers describe as the 'K-hole' -- a state of oblivion likened to a near-death experience, which is followed by a feeling of great serenity. The study is published today in the journal Scientific Reports.

Taken from: https://www.sciencedaily.com/releases/2020/06/200611094127.htm

It seems Ketamine can produce a flat EEG when the subject is alive. Also here:

Most strikingly, when the animals were given high doses at one stage of the experiment, electroencephalography (EEG) readings of their cortical activity appeared to show brain activity turning off completely, in an instant.

Taken from: https://www.sciencealert.com/ketami...eals-brain-phenomenon-we-ve-never-seen-before

 

[theprestige]

electroencephalography (EEG) readings of their cortical activity appeared to show brain activity turning off completely, in an instant.

Interesting.

Reading science reports written for a lay audience is always a little frustrating, though. Extremist and absolutist language is a bit of a warning sign for me.

I wonder how an actual neuroscientist would describe the EEG data in factual, scientific terms. I wonder what the actual EEG data is.

 

[Lukas1986]

In the science alert article are pictures of the EEG and it shows for a while that it is flat which is quite interesting in the perspective that it was always claimed mostly in the NDE circles that a flat EEG equals dead. This challenges these claims because the brain was not dead at a long shot only drugged.

 

[casebro]

The researchers think that this pause in brain activity may correspond to what ketamine abusers describe as the 'K-hole' -- a state of oblivion likened to a near-death experience, which is followed by a feeling of great serenity.

Reminds me of hypnosis, or getting knocked out. Which might be the same thing- you might be blacking out (hypnosis?) before the baseball hits you so hard it breaks the batting helmet. Or before the motorcycle crash. Then when you come to, after the dust has cleared, you feel very comfortable, rested.

 

[casebro]

What is the two-word anesthetic cocktail? F/V words? It's like a light switch. Just BOINK, you are out. Then POP you are back.

 

[William Parcher]

What is the two-word anesthetic cocktail?

Police-Baton.

 

[Elaedith]

Interesting.

Reading science reports written for a lay audience is always a little frustrating, though. Extremist and absolutist language is a bit of a warning sign for me.

I wonder how an actual neuroscientist would describe the EEG data in factual, scientific terms. I wonder what the actual EEG data is.

There is open access to the original article.

 

[gerdbonk]

"A few minutes later their brains were functioning normally again -- it was as though they had just been switched off and on."

 

[William Parcher]

Ketamine is a drug, and like any drug user the human brain has to take a little break.

 

[casebro]

Police-Baton.

Politics everywhere.

Fentanyl & Versed.

 

[dann]

Are there any indications that the sheep feel more serene?

 

[Squeegee Beckenheim]

I think the main takeaway is that it's wrong to say that brain activity stopped totally. It would be right to say that it dropped below the detection threshold for the EEG. That's a very different statement.

It's also worth noting that if you look at the actual paper, then the one instance for which data exists shows that the heart slowed, but did not stop. If there were truly no brain activity you'd expect there to be no heartbeat, absent outside stimulation.

 

[William Parcher]

If there were truly no brain activity you'd expect there to be no heartbeat, absent outside stimulation.

I thought that the heart continues to beat after a decapitation. I thought this is the story behind chopping a chicken's head off and letting the heart pump out the blood.

That's not low brain activity. That's no brain at all.

 

[Cheetah]

I think the main takeaway is that it's wrong to say that brain activity stopped totally. It would be right to say that it dropped below the detection threshold for the EEG. That's a very different statement.

It's also worth noting that if you look at the actual paper, then the one instance for which data exists shows that the heart slowed, but did not stop. If there were truly no brain activity you'd expect there to be no heartbeat, absent outside stimulation.

A heart doesn’t need a brain or even a body to beat, it has it’s own internal pacemaker.

 

[Lukas1986]

I think the main takeaway is that it's wrong to say that brain activity stopped totally. It would be right to say that it dropped below the detection threshold for the EEG. That's a very different statement.

It's also worth noting that if you look at the actual paper, then the one instance for which data exists shows that the heart slowed, but did not stop. If there were truly no brain activity you'd expect there to be no heartbeat, absent outside stimulation.

Even if that is the case for that paper it still destroys the argument that a flat EEG equals death and therefore NDE are a proof of a afterlife.

I would also like to know if there are more papers that show that EEG cannot detect deeper brain activity. So far I have found only one or two papers besides this one dealing with this problem. If there is more I would be thrilled to read them if someone knows.

 

[Elaedith]

Even if that is the case for that paper it still destroys the argument that a flat EEG equals death and therefore NDE are a proof of a afterlife.

I would also like to know if there are more papers that show that EEG cannot detect deeper brain activity. So far I have found only one or two papers besides this one dealing with this problem. If there is more I would be thrilled to read them if someone knows.

EEG specifically measures cortical rather than deeper brain activity, although it can detect sub-cortical activity. Absence of cortical activity usually indicates irreversible coma, however, there can still be sub-cortical activity occurring in the presence of a flat EEG.

 

[Lukas1986]

EEG specifically measures cortical rather than deeper brain activity, although it can detect sub-cortical activity. Absence of cortical activity usually indicates irreversible coma, however, there can still be sub-cortical activity occurring in the presence of a flat EEG.

Thanks for the article but I already read that before. I mentioned that I found two more articles that EEG cannot detect deeper brain activity or that it is flawed. The second one is this:

https://www.newsbreak.com/news/0NfH...very-that-eeg-doesnt-always-track-being-awake

If there is more about this it would be great but I could only find the one you posted and the second one I am posting. Thanks anyhow for the links.