[LINK] Claustrum Stimulation Temporarily Turns Off Consciousness in an otherwise Awake Patient

post by shminux · 2014-07-04T20:00:48.176Z · score: 37 (37 votes) · LW · GW · Legacy · 43 comments

This paper, or more often the New Scientist's exposition of it is being discussed online and is rather topical here. In a nutshell, stimulating one small but central area of the brain reversibly rendered one epilepsia patient unconscious without disrupting wakefulness. Impressively, this phenomenon has apparently been hypothesized before, just never tested (because it's hard and usually unethical). A quote from the New Scientist article (emphasis mine):

One electrode was positioned next to the claustrum, an area that had never been stimulated before.

When the team zapped the area with high frequency electrical impulses, the woman lost consciousness. She stopped reading and stared blankly into space, she didn't respond to auditory or visual commands and her breathing slowed. As soon as the stimulation stopped, she immediately regained consciousness with no memory of the event. The same thing happened every time the area was stimulated during two days of experiments (Epilepsy and Behavior, doi.org/tgn).

To confirm that they were affecting the woman's consciousness rather than just her ability to speak or move, the team asked her to repeat the word "house" or snap her fingers before the stimulation began. If the stimulation was disrupting a brain region responsible for movement or language she would have stopped moving or talking almost immediately. Instead, she gradually spoke more quietly or moved less and less until she drifted into unconsciousness. Since there was no sign of epileptic brain activity during or after the stimulation, the team is sure that it wasn't a side effect of a seizure.

If confirmed, this hints at several interesting points. For example, a complex enough brain is not sufficient for consciousness, a sort-of command and control structure is required, as well, even if relatively small. A low-consciousness state of late-stage dementia sufferers might be due to the damage specifically to the claustrum area, not just the overall brain deterioration. The researchers speculates that stimulating the area in vegetative-state patients might help "push them out of this state". From an AI research perspective, understanding the difference between wakefulness and consciousness might be interesting, too.

 

43 comments

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comment by Sophronius · 2014-07-05T16:01:17.103Z · score: 15 (17 votes) · LW(p) · GW(p)

Personally I have never understood why people keep acting and talking as if consciousness were binary. I mean, no other human trait works that way. People don't pretend that you either have intelligence or you don't, or that you are either nice or you are mean. Heck, the article even literally states that the woman started out normal and gradually lost consciousness, which seems to very clearly imply that her consciousness level was gradually decreasing from whatever her normal level was to 0. Yet people keep asking things like "do animals have consciousness?" and I keep wondering if I'm missing something or if the answer is just really obviously "yes to varying degrees depending on the animal but almost always less than humans do."

comment by shminux · 2014-07-05T23:38:39.574Z · score: 3 (3 votes) · LW(p) · GW(p)

Personally I have never understood why people keep acting and talking as if consciousness were binary.

I agree and I don't think that's what anyone claims it here. What is interesting is that one small area of her brain can be reversibly affected in a way that completely removes both consciousness and memory formation while keeping the person awake otherwise, which is very much different from sedation or general anaesthesia.

Yet people keep asking things like "do animals have consciousness?" and I keep wondering if I'm missing something or if the answer is just really obviously "yes to varying degrees depending on the animal but almost always less than humans do."

I don't think serious neuroscientists ask questions like that, and yes, the obvious answer better be correct.

comment by MugaSofer · 2014-07-07T18:44:10.849Z · score: 3 (3 votes) · LW(p) · GW(p)

I agree and I don't think that's what anyone claims it here.

I've definitely seen it used on and around here.

The example that springs to mind is the argument that infanticide is acceptable "before they become conscious" (which in practice seems to mean "before they can talk" for some reason) - which I believe was invented by Eliezer as a steelman of "it's OK to eat babies" and then escaped into the wild - and I believe I've seen it in discussions of vegetarianism and even Friendly AI ("well, there are two options. Either X is conscious, in which case...")

comment by DanielLC · 2014-07-05T16:31:25.383Z · score: 2 (2 votes) · LW(p) · GW(p)

For what it's worth, you're not the only one who doesn't think consciousness is binary.

Here's a thread on it on felicifa.org.

comment by chaosmage · 2014-07-07T10:29:57.611Z · score: 1 (1 votes) · LW(p) · GW(p)

From a medical perspective, the question of whether rather than to what degree a patient is conscious has serious ethical/practical importance. Basically, to treat a conscious patient you need his/her consent, for an unconscious one you don't, because you're excused for not getting it. So that variable, in a binary sense, is something every medical researcher is very aware of.

I agree that it is not ideal as a measure of how well someone is able to integrate information into his/her subjective worldmap (or however you want to define consciousness), but it is very available.

comment by ThisSpaceAvailable · 2014-07-08T21:02:37.309Z · score: 1 (1 votes) · LW(p) · GW(p)

Basically, to treat a conscious patient you need his/her consent, for an unconscious one you don't, because you're excused for not getting it.

That's really stretching the word "basically". If a patient is unconscious and there's an urgent issue that will cause serious injury if not addressed and it can't wait until the patient regains consciousness and you did not have an opportunity to get consent while the patient was conscious, then you have an argument for not getting consent, but you can't go around treating unconscious patients willy-nilly.

comment by chaosmage · 2014-07-09T08:28:34.539Z · score: 1 (1 votes) · LW(p) · GW(p)

You are correct. I omitted these points because they didn't seem relevant to my point.

comment by kokotajlod · 2014-07-06T13:58:21.998Z · score: 0 (0 votes) · LW(p) · GW(p)

There are at least two distinct senses in which consciousness can be binary. The first sense is the kind you are probably thinking about: the range between e.g. insects, dogs, and humans, or maybe between early and late-stage Alzheimers.

The second sense is the kind that your interlocutors are (I surmise) thinking about. Imagine this: A being that is functionally exactly like you, and that is experiencing exactly what you are experiencing, except that it is experiencing everything "only half as much." It still behaves the same way as you, and it still thinks the same way as you; it's just that it's thoughts only count half.

If this sounds ridiculous to you, well, then you agree with your interlocutors. :) Personally, I think that there IS such a thing as partial consciousness in the sense described above, and I can link you to literature if you like.

EDIT: The place to start is Nick Bostrom's "Quantity of Experience: Brain Duplication and Degrees of Consciousness," available for free online.

EDIT: But the people who ask "Do animals have consciousness" are probably talking about the first kind, in which case I share your frustration. The second kind is more what people talk about when they ask e.g. "Could a machine have consciousness?"

comment by Sophronius · 2014-07-06T14:52:35.177Z · score: 3 (3 votes) · LW(p) · GW(p)

I don't think the first sense and the second are mutually exclusive.

A dog has half as much processing power as a human = a dog can think the same thoughts but only at half the speed.
A dog has half as much consciousness as a human = a dog is only half as aware as a human of what's going on.

And yes, I definitely think that this is how it works. For example, when I get up in the morning I am much less aware of what's going on than when I am fully awake. Sometimes I pause and go "wait what am I doing right now?" And of course there's those funny times when you end up going to your old school by accident because you're not aware of what you're doing until it's too late...

The only part I disagree with is "A being that is functionally exactly like you, and that is experiencing exactly what you are experiencing". A being that is only half as conscious is going to have a different brain, so will act differently. You definitely notice when someone is only at 50% consciousness.

Finally, I submit that consciousness works just like will power: It is a limited resource which you can allocate to certain tasks/thoughts, and by training it you can get more of it. A good rationalist needs a large pool of consciousness.

comment by [deleted] · 2014-07-12T13:48:51.908Z · score: 0 (0 votes) · LW(p) · GW(p)

Imagine this: A being that is functionally exactly like you, and that is experiencing exactly what you are experiencing, except that it is experiencing everything "only half as much."

IOW halfway between a person and a p-zombie?

comment by Kaj_Sotala · 2014-07-05T12:17:45.790Z · score: 4 (4 votes) · LW(p) · GW(p)

For example, a complex enough brain is not sufficient for consciousness, a sort-of command and control structure is required

Possibly the global workspace. (For more detailed descriptions, see e.g. Baars 2002, 2004, Deheane 2011.)

comment by CellBioGuy · 2014-07-04T20:10:31.865Z · score: 4 (4 votes) · LW(p) · GW(p)

This reminds me of 'absence seizures', something that's been reported for a long time:

http://www.epilepsy.com/learn/types-seizures/absence-seizures

http://en.wikipedia.org/wiki/Absence_seizure

http://www.webmd.com/epilepsy/guide/understanding-absence-seizure-basics

Simple absence seizures: During a simple absence seizure, a person usually just stares into space for less than 10 seconds. Because they happen so quickly, it’s very easy not to notice simple absence seizures — or to confuse them with daydreaming or not paying attention.

Complex absence seizures: During a complex absence seizure, a person will make some kind of movement in addition to staring into space. Movements may include blinking, chewing, or hand gestures. A complex absence seizure can last up to 20 seconds.

comment by shminux · 2014-07-04T20:59:57.589Z · score: 2 (2 votes) · LW(p) · GW(p)

Right, it seems similar. However, the memory of absence seizures is partially retained, so consciousness is not necessarily completely off:

while verbal responses were very often interrupted during seizures, some patients recalled questions or commands given during a seizure, and responded appropriately after the seizure ended

See also this review:

electrical stimulation of the claustrum, in a conscious patient with intractable complex partial epilepsy undergoing a preoperative investigation, produces a clinical state of immobility and complete lack of interaction with the environment, but retainment of some automatic movements, quite similar to cases of partial complex seizures.

comment by XiXiDu · 2014-07-05T08:25:06.321Z · score: 2 (2 votes) · LW(p) · GW(p)

...memory of absence seizures is partially retained, so consciousness is not necessarily completely off..

Might be a stupid question, but why do we assume that unconsciousness must be accompanied by memory loss? Do all animals have consciousness ? If not, are they unable to retain memory?

comment by gwern · 2014-07-05T15:51:10.015Z · score: 4 (4 votes) · LW(p) · GW(p)

'unconsciousness' isn't really a good word to take literally as a negation of 'being conscious'. Taken literally, an animal is 'unconscious' when it's asleep, you've hit it on the head really hard, shot it with a tranq, and it's awake and hunting...

That said, there's still a bit of question about the relationship between memory and consciousness in humans. See the suggestive mentions of trauma & PTSD-like symptoms in http://lesswrong.com/lw/8wi/inverse_pzombies_the_other_direction_in_the_hard/

comment by [deleted] · 2015-08-24T11:34:17.062Z · score: 1 (1 votes) · LW(p) · GW(p)

Every one of my PTSD symtoms appears to be in remission except scanning, which may just be due to a paranoid personality. PTSD symptoms emrergen when I swell on them in therapy though...so Im not going to do that. Not cause of avoidance coping just caus I don't need to bother with that. It's the past.

comment by tut · 2014-07-05T10:14:00.475Z · score: 3 (3 votes) · LW(p) · GW(p)

why do we assume that unconsciousness must be accompanied by memory loss?

If you weren't conscious at a time, then you didn't experience whatever happened at that time, and so you didn't have any opportunity to form a memory of it in the first place.

Do all animals have consciousness?

It would surprise me to find out that at least some mammals and birds were not conscious.

are they unable to retain memory?

We don't know if animals who can't talk have memories in the relevant sense. When people talk about animals retaining memories what they are talking about is conditioned responses. But conditioned responses can survive retrograde amnesia, and people with anterograde amnesia can form new conditioned responses.

comment by David_Gerard · 2014-07-05T12:31:42.669Z · score: 2 (2 votes) · LW(p) · GW(p)

If you weren't conscious at a time, then you didn't experience whatever happened at that time, and so you didn't have any opportunity to form a memory of it in the first place.

You sure about that?

comment by NancyLebovitz · 2014-07-05T13:29:36.850Z · score: 1 (1 votes) · LW(p) · GW(p)

Turtle appears to be conscious

comment by pinyaka · 2014-07-06T00:55:28.224Z · score: 1 (1 votes) · LW(p) · GW(p)

I don't think it's a stupid question. From my perspective, I have remembered things that I didn't notice consciously at the time such as the location of my wife's car keys. I don't remember their presence grabbing my attention, but later I am able to recall the last place I saw them. Not being a neurologist, I don't see a reason why shutting down the awareness part of the brain would also shut down the sensory processing and commitment of said processing to memory.

comment by Strilanc · 2014-07-05T18:26:59.563Z · score: 2 (2 votes) · LW(p) · GW(p)

Is it expected that electrically disabling key parts of the brain will replace anesthetic drugs?

comment by shminux · 2014-07-05T23:33:22.545Z · score: 2 (2 votes) · LW(p) · GW(p)

There are speculations, certainly. But so far this is one experiment on one epileptic patient with a piece of hippocampus removed in an attempt to control her seizures. This is a long way away from reliably and reversibly switching off consciousness and memory formation on demand.

comment by Strilanc · 2014-07-06T03:30:49.330Z · score: 0 (0 votes) · LW(p) · GW(p)

That sounds like what I expected. Have any links?

comment by ChristianKl · 2014-07-05T09:04:24.044Z · score: 2 (4 votes) · LW(p) · GW(p)

I don't think the state of "awake" but not "conscious" is new. It's a trance state which is quite frequently used in hypnosis. I don't think there's anything surprising about the fact that you can induce such a trance state where the person isn't conscious by stimulating specific parts of the brain.

comment by falenas108 · 2014-07-05T14:42:25.005Z · score: 4 (4 votes) · LW(p) · GW(p)

Is that actually the same thing? I was under hypnosis once, and it wasn't that I wasn't thinking at all, just less. I would expect not conscious to mean I had no awareness of what is going on.

comment by ChristianKl · 2014-07-05T15:41:52.107Z · score: 3 (3 votes) · LW(p) · GW(p)

It depends on the depth of the trance. If you are in a light trance than you will still remember thinking a bit. When it comes to deep trance stages, it's possible to induce a trance in someone and do something for 10 minute and then wake the person up without the person having an awareness that ten minutes have passed.

comment by pinyaka · 2014-07-06T00:59:12.666Z · score: 0 (0 votes) · LW(p) · GW(p)

I don't think this is the same. There is no memory of the event with the electrical stimulation and my (very limited) impression of hypnosis is that there's nothing about the process in itself that stops you from being able to remember.

comment by ChristianKl · 2014-07-06T12:43:06.966Z · score: 4 (4 votes) · LW(p) · GW(p)

"The same" would assumt that hypnosis is always done in the same state. That's not true. I have plenty of experiences where I myself don't remember certain parts of a hypnosis session but no suggestions where given not to remember that part.

There are plenty hypnotherapist who think that you don't need a state a state where everything is forgotten to give successful suggestions. The client not remembering everything can produce problems with getting the client feel that hypnosis is working for them.

comment by Jurily · 2014-07-20T12:35:54.689Z · score: 1 (1 votes) · LW(p) · GW(p)

The hypnotic induction is just a Ritual designed to convince the client that they can be "hypnotized" in a way that matches their preconceptions. After the first session, it's much more efficient to use an instant reinduction trigger or suggestions like "I can hypnotize you in hundreds of ways impossible to resist" or "all my suggestion will work easily, automatically, whether or not you think you're hypnotized, in exactly the way that benefits you most".

As for amnesia, stage techniques are awesome. It's really hard to doubt you've been hypnotized when you count your 11 fingers, can't get up from the chair or watch your arm grow to twice the size.

comment by ChristianKl · 2014-07-20T15:17:32.378Z · score: 2 (2 votes) · LW(p) · GW(p)

The hypnotic induction is just a Ritual designed to convince the client that they can be "hypnotized" in a way that matches their preconceptions.

'With that definition you define hypnosis in a way where hypnosis has nothing to do with trance. It's certainly possible to give another person suggestions that do work without having the person in a somnambulistic state. That no useful definition if you want to talk about how certain trance states come with amnesia.

I had multiple times the experience of creating a trance state in someone that causes amnesia without giving suggestions for amnesia and without the person thinking they were supposed to have amnesia.

As for amnesia, stage techniques are awesome. It's really hard to doubt you've been hypnotized when you count your 11 fingers, can't get up from the chair or watch your arm grow to twice the size.

Yes, you can do those things. It's commonly called convincers. On the other hand feats like counting 11 fingers are not phenomena that will succeed for every subject the first time.

comment by MugaSofer · 2014-07-07T18:47:37.634Z · score: 0 (0 votes) · LW(p) · GW(p)

I have heard it said that anyone in a "deep trance", required for some hypnosis things, will not remember it.

But I know very little about hypnosis, and I may be misremembering.

comment by [deleted] · 2014-07-06T01:29:31.077Z · score: -1 (3 votes) · LW(p) · GW(p)

The "when you wake up you won't remember this" part of hypnosis is a myth.

comment by jimmy · 2014-07-07T00:09:08.187Z · score: 3 (3 votes) · LW(p) · GW(p)

It actually happens

Not everyone that is hypnotized will experience amnesia though, and for the most part, amnesia is suggested or expected, but it sure doesn't seem limited to that.

comment by RichardKennaway · 2014-07-06T22:20:42.690Z · score: 0 (0 votes) · LW(p) · GW(p)

That such suggestions actually work may well be a myth. On the other hand, the idea that this suggestion is often given is not. I have no experience with live hypnosis, but I have, of my curiosity, found various (purported to be) hypnosis induction soundtracks on the web, and "when you awake you will not remember this but the suggestions will continue to work" was a frequent theme. Perhaps this is life imitating the myth.

comment by [deleted] · 2014-07-06T13:42:50.172Z · score: 0 (0 votes) · LW(p) · GW(p)

Meeeehhhh. I would bet that if you're actually reducing someone's level of consciousness, they really won't remember being semi-conscious or unconscious. They just won't process much information at all in that deep a "trance", which stops it being very useful from a psychotherapeutic perspective.

comment by adam_strandberg · 2014-07-08T03:27:41.118Z · score: 1 (1 votes) · LW(p) · GW(p)

I wrote a blog post describing the article, talking about criticisms of Crick and Koch's theory, and describing related research involving salvia:

http://the-lagrangian.blogspot.com/2014/07/epilepsy-consciousness-and-salvia.html

Enjoy.

comment by adam_strandberg · 2014-07-07T20:44:39.681Z · score: 1 (1 votes) · LW(p) · GW(p)

The link to the original paper is broken.

comment by shminux · 2014-07-07T21:03:43.305Z · score: 2 (2 votes) · LW(p) · GW(p)

It works, but intermittently. I suspect issues at Science Direct.

Abstract, just in case:

Abstract The neural mechanisms that underlie consciousness are not fully understood. We describe a region in the human brain where electrical stimulation reproducibly disrupted consciousness. A 54-year-old woman with intractable epilepsy underwent depth electrode implantation and electrical stimulation mapping. The electrode whose stimulation disrupted consciousness was between the left claustrum and anterior-dorsal insula. Stimulation of electrodes within 5 mm did not affect consciousness. We studied the interdependencies among depth recording signals as a function of time by nonlinear regression analysis (h2 coefficient) during stimulations that altered consciousness and stimulations of the same electrode at lower current intensities that were asymptomatic. Stimulation of the claustral electrode reproducibly resulted in a complete arrest of volitional behavior, unresponsiveness, and amnesia without negative motor symptoms or mere aphasia. The disruption of consciousness did not outlast the stimulation and occurred without any epileptiform discharges. We found a significant increase in correlation for interactions affecting medial parietal and posterior frontal channels during stimulations that disrupted consciousness compared with those that did not. Our findings suggest that the left claustrum/anterior insula is an important part of a network that subserves consciousness and that disruption of consciousness is related to increased EEG signal synchrony within frontal–parietal networks.

The paper itself is paywalled, if someone feels like posting full text some place accessible, by all means.

comment by Manfred · 2014-07-06T22:19:28.919Z · score: 1 (1 votes) · LW(p) · GW(p)

Or if she was a robot, we might say that her memory-formation was impaired, and the chain that led from patterned stimuli to appropriate responses was broken, as well as the normal process of generating actions and carrying them out. However, she was able to carry out some actions that had been previously generated, making it likely that she was not generating new actions.

comment by shminux · 2014-07-06T22:56:29.834Z · score: 1 (1 votes) · LW(p) · GW(p)

Seeme like as good a definition of consciousness as any.

comment by kokotajlod · 2014-07-06T13:52:20.613Z · score: 1 (3 votes) · LW(p) · GW(p)

Is the claustrum located in the pineal gland? ;)

comment by MrMind · 2014-07-07T16:06:44.364Z · score: 0 (0 votes) · LW(p) · GW(p)

It's interesting that stimulating a part of the brain produces unconsciousness, rather than deactivating it (if this is even possible). I dont' know enough neurology to answer, but is claustrum somehow involved in the mechanism of sleep?
Because what we have here could be a partial sleep induction.

comment by LeBleu · 2014-07-07T18:01:22.090Z · score: 1 (1 votes) · LW(p) · GW(p)

The article noted it was high frequency stimulus that had the effect, and seemed to be disrupting normal function.

The article also says the patient was awake.