The article is pretty light on the details, so I'll try to add to it. In my prior career as a cognitive neuroscientist, I analyzed an fMRI data set on blindsight patient GY, and read up on the blindsight literature at the time.
The neurons in the retina don't go straight to the occipital (primary visual) cortex; they all synapse onto the thalamus first. From there, the vast majority of exiting neurons go on to occipital cortex, but a few percent go off to other regions, such as the superior colliculus, amygdala, MT and FEF.
It's been shown in diffusion studies that people with damage in thalamus or prior to it, don't show blindsight effects, while people with post-thalamic or occipital damage can.
Now, the really interesting part is that, these non-occipital signals are enough to help people perform tasks at above-chance levels, but not enough for them actually be aware. Nobody knows for sure why. Conscious awareness is one of the biggest unsolved mysteries of neuroscience. Top candidates are information integration theory, higher-order thought theories, and signal-detection-based theories.
The neurons in the retina don't go straight to the occipital (primary visual) cortex; they all synapse onto the thalamus first. From there, the vast majority of exiting neurons go on to occipital cortex, but a few percent go off to other regions, such as the superior colliculus, amygdala, MT and FEF.
I wonder if there's a similar explanation for some people (like myself) who sometimes have difficulty reading facial expressions by instinct, and have to rely on conscious interpretation and training to determine others' emotional state.
Now, the really interesting part is that, these non-occipital signals are enough to help people perform tasks at above-chance levels, but not enough for them actually be aware. Nobody knows for sure why.
Without the non-occipital signals, are the visual cortex signals alone enough to perform tasks?
Blindsight seems to be a powerful demonstration of how a brain can perform high order actions - e.g. respond to social stimuli such as facial expressions - without consciousness. It's a reminder that many things we think inseparable from self awareness and consciousness are no such thing. Perhaps you could consider a person with blindisight to have been "downgraded" to the condition of a mammal without consciousness.
I read Jeff Hawkins book On Intelligence recently. Would these observations fit with the idea of visual data being passed up the hierarchy of the cortex far enough to be recognising objects as obstructions, but not far enough to be conscious of them?
After hearing about those parasitic brain bugs that you can catch from cats I started to wonder if conscious awareness could be merely the collective experience of some kind of bug we caught that has just hitched along for the ride and that hasn't actually really got much of a control over anything really, but just believes that it is the creature it is inhabiting, because it is a bit stupid. Perhaps you could cure someone of it and not even be able to tell the difference. These are the kind of thoughts that keep me awake at night ;)
Here's my story: Three (or was it four?) day non-stop coding stint to get a robot ready for a conference. No sleep at all. Almost non-stop coding and the usual coffee+sugar+pizza binge. Got on a plane to go to the conference and continued coding in flight. Got to the hotel, checked in and decided to get some sleep. I woke up about three or four hours later. I started to hear a nearly perfect 1KHz tone as my field of view slowly (30 sec?) faded to full bright white. By this time I was sitting on the bathroom floor: I could only hear this tone and all I saw was a bright white light. Somehow I kept my cool and could, also somehow, navigate the room. Over the following few minutes the tone started to go away and my field of view returned to normal. Freaked the crap out of me. No permanent damage that I could identify. Now I keep my overnighters to just one night, only if there's absolutely not choice at all.
Sounds like hypotension, a drop in blood pressure, like when you get up "too fast" sometimes from a relaxed state. Maybe hypoglycemia otherwise, or as well, especially if you hadn't eaten in a while.
That hasn't happened to me recently but it used to happen to me when I was a teenager, I'd wake up and be unable to see for a few minutes (although no hearing problems). It happened every few months. For me it was never related to too much / too little sleep.
I was afraid your story was one of a stroke. we should have a good thread on sleep deprivation. (e.g. someone should submit a story.)
visual hallucations are pretty standard after a certain period of time that isn't even so long. (i.e. I would get them around, say, the 28 hour mark from when I last woke up and started staying up by pulling an all-nighter. So if I get up at 7 every day but then simply not go to sleep one night but try to start the next day - by 11 AM it's hard not to hallucinate. In case you get up later the following is equivalent: If you get up at 11 every morning after calling it a night at 3 am or so, then if one night you don't sleep at all then working past 11 am and on by 3 PM you will be very out of it and may easily hallucinate.)
I'm very skeptical whether there is any amount of productivity to be had what-so-ever as for me, personally, it would easily take me 2 minutes to do 30 seconds of (any kind of) work at the end of that time, even moving a box from one place to another or whatever. So I'm very skeptical how a 3-4 hour nap at 22 hour mark could possibly not make up for lost time after waking up.
going on 3 hours of sleep each night for several days (e.g. 2-3) is possible and easy.
like I said, it would make an interesting thread and someone should submit a story on this subject (sleep deprivation and whether it's even worth working after a certain time mark).
as for your story, it sounds like a simple dream/waking dream. it's really hard to tell dream and non-dream apart under conditions of sleep deprivation.
i've experienced something (vaguely) similar. i once had a nasty accident on a bike. initially, i was ok. a car had stopped and the driver asked me how i was, and i answered that i was in pain, but otherwise fine. then, as the passer-by started talking to someone else, i had to call out to him "excuse me - but i can't see". because i couldn't see. so he put me in his car (he was actually an extremely nice chap - i found out later he also took my ruined bike back to where i was staying; i never found him to say thank-you) and drove me to hospital. on the way there i started to realise that i could see shapes - although i couldn't actually "see" anything, i could make out moving cars (imagine white cars against a white background, but somehow you can see them moving). and then my sight started to return, first at the centre of my vision, and then spreading out. i related all this to him as we drove, and what with the blood dripping from various places, i suspect he thought i was delirious. anyway, eventually everything returned to normal and i was checked by a gorgeous doctor (i was 18 or so at the time...) and sent home to rest, but went to work because i was working away from home and no-one i knew would be at the house i was staying at. at work they were impressed by the various bandages and sat me in a corner til end-of-day. never experienced anything similar since, although i do get (painless) migraines from time to time (like, once a year or so - i can't see properly, but it's not interesting).
You experience these same sort of phenomena in meditation: things that we normally think of as requiring consciousness reveal themselves as being controlled autonomically, and you also gain conscious control over autonomic functions. It's pretty cool, and it starts happening within the first few days, it's not something that takes years to experience or whatever.
Since you brought up meditation, a question I never quite find the right moment to ask:
What is it? I mean, that question sounds so simplistic as to be inane, but bear with me: I have had absolutely no interaction with anyone who meditates, beyond observing them at a distance with casual skepticism.
Alternative questions to "What is it?" would be "What is its purpose?" and "What is it like?" Having gone to my university's weekly meditation sessions twice and simply fallen asleep, I used to assume it was just that: people sleeping while sitting upright. The idea of a third state the system of sleeping/awake seems utterly alien to me.
EDIT: Having just done the obvious and skimmed over the Wikipedia article for Meditation, it's far more broad than my question here. Obviously "to meditate on something" is to ponder/think about it, sometimes while moving or working. I'm asking in regard to a the more specific, often motionless, act that Alex3917 seems to be describing.
Honestly that doesn't sound very fun to me. I'd much rather "space out" and not be consciously aware of my blinking/heartbeating/breathing/etc at a higher frequency than I naturally do.
This is rather an accurate way to put it. Even more unsettlingly, the conscious "self" can be seen as a manager of sorts that has a delusion of being the entity that pulls the strings, even though its "subordinates" usually keep the wheels turning quite adeptly all by themselves. The manager usually just receives executive reports after the underlings have done the actual decisions.
If you want to get your mind blown about the "other" one, read "The emergence of consciousness in the breakdown of the bicameral mind" by Julian Jaynes. It argues, e.g. that schizophrenia is a disease in which communication with that other self becomes an internal (voiced) dialogue that sounds.
An interesting collection of essays and short stories that investigate concepts related to your observation is http://www.amazon.com/The-Minds-Fantasies-Reflections-Self/d..., which I'm almost finished with. It has a lot of thought-provoking arguments. Edited by Douglas Hofstadter and Daniel Dennet.
Philosophical question: what makes you think that entity is human? I think I would have left out 'human', because I am not aware of similar cases where people speak coherently without being conscious of doing it.
My ability to solve difficult problems in coding and in Computer Science is much like the blindsight described in the article. I look at a problem for awhile then go away and do something in the shower. I might be relaxing or in the shower, and the answer will pop into my head, as if from nowhere.
The older I get the more I think we should think of our talents as "superpowers." They are somewhat like bolt-ons. We shouldn't let them define us. We should have some depth of character beyond that.
"Similar abilities have been observed in monkeys, but TN’s is the first study of these abilities in humans."
Maybe it's not exactly the same thing, but quite a while ago (10-15 years) I read in a book about the brain of a patient who had similar damage in one half of the brain. Both his eyes worked, but he couldn't see on one side, and when a piece of paper was held up into his "blind spot", reading "plese stand up", he stood up, making up a rationalization for it (like "my leg felt sleepy", "I thought I heard something", etc.) I'm not even sure if that was just about one patient, maybe it was several. But at any rate, I knew this ages ago, by randomly picking it up from a book from the library -- so how is this a surprise?
I get that this is the first dedicated study of that stuff, but it surely it isn't complete news?
That's fascinating. It makes sense, in an odd way. His eyes are still functioning, but the brain can't process the incoming data, so things get remapped to areas of the brain responsible for other types of functions.
I have a bit of the opposite problem. I have a mild form of Charles Bonnet syndrome. The visual hallucinations I experience aren't extremely frequent or complex. I may have one every few days to every few weeks, and they usually only last for a couple of seconds. Mostly I just see abstract shapes (usually the same shape - kind of a glowing horseshoe). Once or twice, I have seen chairs.
His eyes are still functioning, but the brain can't process the incoming data, so things get remapped to areas of the brain responsible for other types of functions.
Actually, as KingMob explains in [1], the mappings are already there in healthy persons as well. This is the "lizard brain" - the original neural pathways transmitting visual information to various subconscious modules that evolved hundreds of millions of years before the relatively new invention of the mammalian cerebral cortex. As evolution rarely throws out anything that works, the archaic modules are still there, functioning, and in this patient's case, only the more recent higher-level capacities were destroyed.
The novel Blindsight by Peter Watts is partially about what blindsight and other similar phenomena can tell us about conciousness. If you like the article, and speculative fiction in general, you'll probably like that novel (although the ending is horribly bleak).
Well, here is a partial explanation. The eyes developed as a sense organ attached to the midbrain and only later were wired to the forebrain. The midbrain retains complex circuits that we use in our reflexive behaviour. We use these circuits more than we would suspect eg while walking along corridors or while turning away from an object thrown towards the face. A stroke in the forebrain would leave these neural pathways intact. Hence the sight without concious vision.
Of course in reality these things are much more complex...
I'm reading through "Consciousness: a very short introduction" and one of the points that the author makes is that these kind of proccesses(object detection) are distributed throughout the brain, and that we have specilized "circuits" for most if not all common tasks we perform on a daily basis. This seems counter intuitive to me, and I presume most people, because it feels that these kind of proccesses are conscious and under my control, when apparently they are not.
HN readers might enjoy the science fiction novel Blindsignt by Peter Watts [1]. Alien contact in deep space with some interesting speculation on neuroscience and consciousness. I enjoyed it a lot.
This subject was presented in a book I read recently, along with many interesting aspect of how our mind works. The book is definitely worth reading, it was "Thinking, Fast and Slow" by Daniel Kahneman.
I wonder if it can explain the fact that I don't fall or bump into obstacles when I walk and read at the same time...
I think this man's signal to noise ratio for playing high stakes poker could be a sizable advantage. It would be very interesting to see him play.
Making good reads is mainly an input problem. There's so much to pay attention to that it interferes with noticing the important things. Tuning into emotions and mannerisms while also tuning out of visual noise could give this man exceptional situational awareness that's also free of his conscious mind's biases.
[+] [-] KingMob|13 years ago|reply
The neurons in the retina don't go straight to the occipital (primary visual) cortex; they all synapse onto the thalamus first. From there, the vast majority of exiting neurons go on to occipital cortex, but a few percent go off to other regions, such as the superior colliculus, amygdala, MT and FEF.
It's been shown in diffusion studies that people with damage in thalamus or prior to it, don't show blindsight effects, while people with post-thalamic or occipital damage can.
Now, the really interesting part is that, these non-occipital signals are enough to help people perform tasks at above-chance levels, but not enough for them actually be aware. Nobody knows for sure why. Conscious awareness is one of the biggest unsolved mysteries of neuroscience. Top candidates are information integration theory, higher-order thought theories, and signal-detection-based theories.
[+] [-] nitrogen|13 years ago|reply
I wonder if there's a similar explanation for some people (like myself) who sometimes have difficulty reading facial expressions by instinct, and have to rely on conscious interpretation and training to determine others' emotional state.
[+] [-] adamio|13 years ago|reply
Without the non-occipital signals, are the visual cortex signals alone enough to perform tasks?
[+] [-] finisterre|13 years ago|reply
[+] [-] boothead|13 years ago|reply
[+] [-] ktizo|13 years ago|reply
[+] [-] robomartin|13 years ago|reply
[+] [-] postfuturist|13 years ago|reply
[+] [-] WiseWeasel|13 years ago|reply
[+] [-] blhack|13 years ago|reply
[+] [-] moheeb|13 years ago|reply
In the final stage the field of vision gradually fades to black from the edges in.
[+] [-] weekendlogic|13 years ago|reply
From your mention of the bathroom floor, I can only assume you were urinating while standing, which is a very common trigger for http://en.wikipedia.org/wiki/Vasovagal_response. For more specific definition see: http://en.wikipedia.org/wiki/Micturition_syncope
Not a big deal really, but as always might want to get it checked out to rule out more serious conditions.
[+] [-] run4yourlives|13 years ago|reply
I'm not a doctor, but you were either dreaming or having a stroke in my mind.
[+] [-] citricsquid|13 years ago|reply
[+] [-] pavel_lishin|13 years ago|reply
[+] [-] its_so_on|13 years ago|reply
visual hallucations are pretty standard after a certain period of time that isn't even so long. (i.e. I would get them around, say, the 28 hour mark from when I last woke up and started staying up by pulling an all-nighter. So if I get up at 7 every day but then simply not go to sleep one night but try to start the next day - by 11 AM it's hard not to hallucinate. In case you get up later the following is equivalent: If you get up at 11 every morning after calling it a night at 3 am or so, then if one night you don't sleep at all then working past 11 am and on by 3 PM you will be very out of it and may easily hallucinate.)
I'm very skeptical whether there is any amount of productivity to be had what-so-ever as for me, personally, it would easily take me 2 minutes to do 30 seconds of (any kind of) work at the end of that time, even moving a box from one place to another or whatever. So I'm very skeptical how a 3-4 hour nap at 22 hour mark could possibly not make up for lost time after waking up.
going on 3 hours of sleep each night for several days (e.g. 2-3) is possible and easy.
like I said, it would make an interesting thread and someone should submit a story on this subject (sleep deprivation and whether it's even worth working after a certain time mark).
as for your story, it sounds like a simple dream/waking dream. it's really hard to tell dream and non-dream apart under conditions of sleep deprivation.
[+] [-] andrewcooke|13 years ago|reply
[+] [-] naner|13 years ago|reply
What is a painless migraine?
[+] [-] Alex3917|13 years ago|reply
[+] [-] chao-|13 years ago|reply
What is it? I mean, that question sounds so simplistic as to be inane, but bear with me: I have had absolutely no interaction with anyone who meditates, beyond observing them at a distance with casual skepticism.
Alternative questions to "What is it?" would be "What is its purpose?" and "What is it like?" Having gone to my university's weekly meditation sessions twice and simply fallen asleep, I used to assume it was just that: people sleeping while sitting upright. The idea of a third state the system of sleeping/awake seems utterly alien to me.
EDIT: Having just done the obvious and skimmed over the Wikipedia article for Meditation, it's far more broad than my question here. Obviously "to meditate on something" is to ponder/think about it, sometimes while moving or working. I'm asking in regard to a the more specific, often motionless, act that Alex3917 seems to be describing.
[+] [-] pavel_lishin|13 years ago|reply
Like what?
[+] [-] daenz|13 years ago|reply
[+] [-] wwwtyro|13 years ago|reply
[+] [-] Sharlin|13 years ago|reply
[+] [-] beagle3|13 years ago|reply
[+] [-] bcbrown|13 years ago|reply
[+] [-] Someone|13 years ago|reply
[+] [-] chao-|13 years ago|reply
[+] [-] sp332|13 years ago|reply
[+] [-] ars|13 years ago|reply
[+] [-] stcredzero|13 years ago|reply
The older I get the more I think we should think of our talents as "superpowers." They are somewhat like bolt-ons. We shouldn't let them define us. We should have some depth of character beyond that.
EDIT: And we should use them "only for good."
[+] [-] nyellin|13 years ago|reply
http://www.ted.com/talks/elizabeth_gilbert_on_genius.html
[+] [-] frankseidank|13 years ago|reply
Maybe it's not exactly the same thing, but quite a while ago (10-15 years) I read in a book about the brain of a patient who had similar damage in one half of the brain. Both his eyes worked, but he couldn't see on one side, and when a piece of paper was held up into his "blind spot", reading "plese stand up", he stood up, making up a rationalization for it (like "my leg felt sleepy", "I thought I heard something", etc.) I'm not even sure if that was just about one patient, maybe it was several. But at any rate, I knew this ages ago, by randomly picking it up from a book from the library -- so how is this a surprise?
I get that this is the first dedicated study of that stuff, but it surely it isn't complete news?
[+] [-] kellishaver|13 years ago|reply
I have a bit of the opposite problem. I have a mild form of Charles Bonnet syndrome. The visual hallucinations I experience aren't extremely frequent or complex. I may have one every few days to every few weeks, and they usually only last for a couple of seconds. Mostly I just see abstract shapes (usually the same shape - kind of a glowing horseshoe). Once or twice, I have seen chairs.
Here's a great TED talk on it: http://www.ted.com/talks/oliver_sacks_what_hallucination_rev...
[+] [-] Sharlin|13 years ago|reply
Actually, as KingMob explains in [1], the mappings are already there in healthy persons as well. This is the "lizard brain" - the original neural pathways transmitting visual information to various subconscious modules that evolved hundreds of millions of years before the relatively new invention of the mammalian cerebral cortex. As evolution rarely throws out anything that works, the archaic modules are still there, functioning, and in this patient's case, only the more recent higher-level capacities were destroyed.
[1] http://news.ycombinator.com/item?id=4319700
[+] [-] zenon|13 years ago|reply
[+] [-] outworlder|13 years ago|reply
http://www.rifters.com/real/Blindsight.htm
[+] [-] VJayK|13 years ago|reply
Of course in reality these things are much more complex...
[+] [-] lifty|13 years ago|reply
[+] [-] andyjohnson0|13 years ago|reply
[1] (Contains plot spoilers) http://en.wikipedia.org/wiki/Blindsight_(science_fiction_nov...
[+] [-] jfno67|13 years ago|reply
I wonder if it can explain the fact that I don't fall or bump into obstacles when I walk and read at the same time...
[+] [-] awolf|13 years ago|reply
Making good reads is mainly an input problem. There's so much to pay attention to that it interferes with noticing the important things. Tuning into emotions and mannerisms while also tuning out of visual noise could give this man exceptional situational awareness that's also free of his conscious mind's biases.
[+] [-] boyter|13 years ago|reply
The show is excellent and presents a lot of science topics in and interesting and understandable way. Highly suggested viewing.
[+] [-] chasingtheflow|13 years ago|reply
[+] [-] sdoering|13 years ago|reply
The original findings were published in Current Biology (2008; 24: R1128-R1129).
That said, it is quite fascinating, non the less.
[+] [-] ThomPete|13 years ago|reply
Anyone here used to be a subscriber to seed magazine the printed version?
I paid way back and never received a single issue from them.