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Blind man shocks researchers with what he sees. (seedmagazine.com)
429 points by felipellrocha on July 31, 2012 | hide | past | web | favorite | 144 comments



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.


Well, that would be a bit like the opposite of blindsight, being forced to do something consciously that most of us do unconsciously.

I'm not sure which regions subserve facial expression recognition (probably amygdala, FFA and others), but it could be a deficit in those regions. Alternatively, if you think you have Asperger's/ASD, they tend to have general deficits in emotion-reading and theory-of-mind-type tasks.



It might involve similar regions, such as the Fusiform Face Area (FFA), but people with prosopagnosia don't necessarily have difficulty with identifying facial emotions; what they have difficulty with is in distinguishing and remembering faces from each other. It's a bit like the way most of us couldn't tell one sheep from another in a flock.

Prosopagnosics tend to rely on things like voice, gait, haircuts, facial hair, and name badges.


You may want to read Oliver Sacks' "The Man Who Mistook His Wife for a Hat" and "The Minds' Eye".


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?


Oh, certainly. If the signal is reaching your occipital/visual cortex, then you have the experience of seeing. There would be other deficits (weakened orienting responses, cross-modal congruency effects, diminished RT to dangerous/frightening stimuli), but nothing quite as major as no longer "seeing".


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 think it's a bit more complicated, since mammals without consciousness (ouh, vague concepts ftw) still show immediate reaction to visual stimuli, where as patient TN and others can react and act upon to visual stimuli, although the traditional "chain of command" is broken.


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?


People into higher-order and SDT-based theories of consciousness have argued similar things.

One problem with the hierarchy model, though, is that the brain does not use layers as cleanly separated as in software. So, it's quite possible that after exiting the thalamaus and entering area MT or the amygdala, the signal goes on to "higher" regions such as the prefrontal cortex. So even though it's reaching the region, it's still insufficient. It could be because it's not stimulating enough neurons, but it's also possible that there's some qualitative difference as well.

For example, sheer numbers of neurons don't guarantee awareness. The cerebellum has half the total number of neurons in the brain, but they're arranged in a very repetitive manner and seem to have nothing to do with awareness. If you had your cerebellum removed (say, for cancer), you would have difficulty with fine motor control, but not much else. It wouldn't alter your awareness, even though you've just lost half your brain's neurons. If you believe the information integration theorists, what matters is heterogeneity and interconnectivity, rather than mere numbers.


The term "recognising" is a bit misleading here. Blindsight is in fact a very nice case where traditional cognitive science and AI paradigms suggesting a hierarchy of processing (bottom up of primal stimuli until they end up as meaningful concepts, top down of thoughts until they turn into actions (roughly)) doesn't quite fit.


Yes perhaps categorising would be better?


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 ;)


That's funny, I had the almost same sci-fi scenario thoughts during one night. The thought of the nature of our minds being defined by a disease that we caught at some point in time and now completely identify with it, that that disease made us forget our true nature. It's pretty great as a sci-fi scenario, but I now believe it has a deep truth to it.

I later discovered the writings of Eckhart Tolle. According to him, we are diseased in the sense that we identify with our mind/ego, instead of realizing what it actually is: a tool. Part of the problem is we often don't know what exists underneath. We are 100% convinced we are our mind. But obviously we're not - if we were, we wouldn't be able to observe it. Once we realize we're not our mind, we're free of its control. Until we do, we're in a way, severely ill. We're actually not disfunctional in our true nature - but we're unenlightened.

At least that's what Eckhart Tolle says. I personally find it disarmingly logical - and reasonably easily provable within my perception, not to mention deeply liberating/changing. Finding out you can stop your thoughts and not only still be aware, but become the most aware you can be, that's quite a doozy of a realization.


> It's pretty great as a sci-fi scenario

I've actually read a short SciFi novel with that very premise, but I can't for the life of me remember the name of it. Something about the other sentient lifeforms in the galaxy not requiring sleep and being able to breathe cyanide, but humans were unique in that we needed to sleep, and that was because we were all infected by some sort of mind parasite that now saw its chance to expand to other lifeforms.


You're probably thinking of "Hostess", by Isaac Asimov: http://en.wikipedia.org/wiki/Hostess_%28short_story%29


Yes, that was it! Thanks!


>> we're not our mind

Okay, what does this mean?


"Mind" is a very poorly defined term, unfortunately.

To determine what you are or aren't, consider this for an exercise: You are a view point, yes? What you can observe is not part of your identity because you can observe it, and therefore it must be external to "you". This is obvious when it comes to things like your body parts; you could cut off your hand, but that wouldn't cut off a part of your "you-ness".

The interesting bit comes when you start to examine your mind itself. Normally, we think of our thoughts as part of our identity. But with a little practice, you can watch thoughts arise, at which point they seem more "separate" and less "you". I always liken them to those biplanes at the beach with a banner fluttering behind them.

So, if you can observe thoughts and not identify with them, then they're not "you". What makes up "you", then? The more you observe, the fewer candidates for "you" there are, no? ;)


Perhaps that is a definition of sentiency: being able to observe that which is "you."


Well, this would explain the internet's fondness for cat photos...


See, there's evidence and everything!


These are the kind of thoughts that keep me awake at night ;)

Then you probably don't want to read Thomas Ligotti's "The conspiracy against the human race". It's a philosophical and neuroscientific treatise on existentialism written by a lovecraftian horror writer...

http://www.amazon.com/The-Conspiracy-Against-Human-Race/dp/0...


That's a legitimate approach:

https://en.wikipedia.org/wiki/Epiphenomenalism


You may like the short science fiction story Learning To Be Me, by Greg Egan. The idea is that people put a microchip in their brain (the "jewel") that learns to mimic the brain's signals, so when the brain fails the microchip can take over.

The interesting question is: "am I the jewel?"


When I first read animorphs I thought the same thing. That maybe I was actually a yeerk controlling a human host and I didn't know it...


Isn't it kinda like .. in a way Krang from the Teenage Mutant Ninja Turtles?

He had this exo-body that he was able to hop in freely. The body was just a dumb machine that needed him to control. It was merely a tool, jet it had a head, harms, legs and can shoot missiles.

Well, we can't do that just yet. But in away, our bodies are just tools to that brain/consciousness uses to do things. If we loose a limb, we just build another one. Sure, we haven't mastered replaced limb awareness (touch, feel), but we're getting close. Like a machine, we need fuel (food), maintenance (doctors appointment, exercise), periods of rest and recovery (sleep).

I'm trying to figure out how sex, anger, and jealousy comes in, but we are essentially tools. And I guess the brain is really a complex OS that runs our bodies. Some brains/OS are, of course, have a better way of processing tasks/programming/apps than others.


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 a migraine: look under "Aura" : http://www.mayoclinic.com/health/migraine-headache/DS00120/D...


I've gotten this. You can get (painless) ocular migraines.


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.


Yep, same thing happened to me when I was 16 (hypotension from standing for too long). Everything faded to white, but I could still somehow navigate the space well enough to go sit down.

Or, at least, that's now I remember it now (or remember thinking about it then). It's been a long time.


I had this happen to me in similar age a few times, only with things fading to gray instead. Once blacked out totally and was later surprised to find myself having managed not to drop in place but seat myself beside the bed.


I'm sorry, but what? You're telling me you're an engineer, and your very first reaction to this was not to immediately call an ambulance?


Well, there's the part about not being able to see and hear.

I was exhausted and most-definitely not thinking straight. I pretty much collapsed into bed and probably slept ten hours. I woke up feeling just fine and just in time to present my paper.

I was younger and definitely stupider. No, I didn't go to the doctor. Dumb. Lived to tell about.


Some engineers can have a (dangerous) tendency to want to either fix themselves or diagnose themselves.


Some engineers may have been raised in an environment of distrust of doctors, or of scorn upon those who call the doctor for anything less than a confirmed broken bone or heart attack.

Edit: for such people, it would be useful if schools taught what sorts of issues are doctor worthy, and which should be ignored or dealt with by over-the-counter remedies.


I live in an environment where I find it appalling that I need to pay $150 to wait an hour to see the doctor who studies me for thirty seconds and gives me a high-price prescription for a double dose of what I can get over the counter. It's not so much "trust" as it is "should it seriously cost this much?"

I personally had a strange episode a few years ago where I just ... felt really awful. But I was lucid the entire time. Wife checked my blood sugar (not a diabetic, but she having been diagnosed with gestational diabetes years ago we have the equipment around) and it was scarily low. Kept hydrated, got some smal bits of food in me, felt better, slept the night with no problems. Called the doctor the next day, they had no interest in seeing me immediately - so they gave me an appointment a few days later. Did some blood work and ... he had no idea what was up. It's never happened again. If I'd gone to the hospital, I'd probably gotten a glucose drip and sent home with a $1,000 bill.

So I tend to keep my cool, self-diagnose, watch my kids closely when they're complaining of problems, get medical help when it's necessary. At $150 a visit, I can fix my own sniffles - I'll call the doc when it's doesn't clear up after a few weeks.


> I live in an environment where I find it appalling that I need to pay $150 to wait an hour to see the doctor who studies me for thirty seconds and gives me a high-price prescription for a double dose of what I can get over the counter. It's not so much "trust" as it is "should it seriously cost this much?"

This is a rather specious argument.

If one of the many freelancers on this board were called in to consult on a seemingly intricate technical issue, and they end up just changing a few characters in the source (change a '=' to '==' or correct a typo, for instance) which fixes the problem, would the client be justified in thinking "He changed only 2-3 bytes in the source! Should it seriously cost this much?" on being charged the full engagement rate?

It is a classic case of "knowing where to tap". [1]

[1] http://p4b.blogspot.co.uk/2012/04/knowing-where-to-tap.html


In my comment, I "know where to tap" and I know what to buy for much less money to get the job done. If I can figure it out, why do I need to hire someone else to do it? "Because," says the medical community, "you should always let your doctor treat you so that he has a complete picture of your health."

You call me in on a technical issue that I see you could have handled on your own with a modicum of intelligence and research, I'm certainly going to charge you for it.


Yes, there is that factor, too. It's especially an issue when you're striving to be ramen profitable in a bootstrapped company. $150 buys a lot of ramen.


I've had similar experiences, one of them even involved low blood sugar like you.

I didn't have to test though, had a parent with periods of low blood sugar so I just ate some food and observed myself suddenly feeling drastically better.

I don't think we're that far past doctors just being quacks throwing spaghetti at the proverbial wall. They don't seem to be able to, in any given single case, observe/detect/test for much unless there's an associated infection or physical injury.


As primitive as modern medicine still really is, I think it is important to remember that it is not like engineers with no medical training are actually going to do any better. Yes, you figured out that you had low blood sugar. Doctors would have as well. If that weren't the case, we'd sack all the doctors and hire engineers to fill the hospitals instead.

Put it this way: your average highschool geek can program a little. If they put their back into it, it is not unheard of for them to engineer solutions to whatever it is that they are trying to achieve (they are after all rather bright.) On particularly rare occasions, the untrained highschooler can teach himself enough to rival seasoned software developers in a very narrow segment of the field, but will quickly be out of his depth again if the situation changes.

I would say the gap between highschool geek and seasoned software developer is somewhat comparable to the gap between engineer and medical doctor (if anything, the comparison gives doctors too little credit.) The difference really is that you are playing with your own health, not some relatively speaking inconsequential software.

(This all said, the cost problem is of course very real.)


Why does everyone always reduce everything I say on here to a simplistic strawman?

I didn't say untrained engineer > doctor

I said, untrained engineer > most sundry health problems, doctor > untrained engineer for everything else.

Stop wasting peoples' time with strawmen and be more charitable to their intellect.


>I don't think we're that far past doctors just being quacks throwing spaghetti at the proverbial wall. They don't seem to be able to, in any given single case, observe/detect/test for much unless there's an associated infection or physical injury.

>be more charitable to their intellect.

Uh.. ok.


I said test for, that doesn't mean their internal pattern matchers aren't good enough for figuring out most things.


If you don't trust doctors, why would you trust schools? Admittedly in each case you'd hopefully see their claims as input worth considering.


I don't mean "trust" in the sense of "willingness to incorporate input into one's rational model of the world," but rather in the sense of "deep-seated instinctive aversion that is difficult to change." One can consciously consider the word of a doctor as highly valuable input, while simultaneously having a visceral distrust of the abstract concept of doctors that is beyond their immediate control.

It does not follow that this instinctively learned distrust must necessarily extend to schools, though perhaps if a particular person's distrust of doctors originates in a general distaste for authority, it is possible.


I do expect it to come down to distrust of authority, but maybe that's too optimistic.


>Some engineers may have been raised in an environment of distrust of doctors, or of scorn upon those who call the doctor for anything less than a confirmed broken bone or heart attack.

Are you me?


Are you me?

It's doubtful ;). One of my parents was a coach when I was young, always complaining about hypochondriac players who were "faking" their injuries just to avoid playing. This same parent still refuses to get treatment for an easily treatable ailment after years of low-level pain and annoyance.

As a result, I have an instinct to avoid doctors, and don't really know what requires a doctor and what doesn't. Despite my conscious awareness of this, I still have difficulty overriding the instinct.


I have an over-literate under-educated mother who has a home-spun German cure for everything and a grumpy mechanical engineer for a father...

...and I'm a programmer.

My parents never took me to the hospital/doctor for anything. This caused problems a couple times, but I was fortunate enough to be an otherwise healthy individual.

Pretty strong internal distrust of doctors still, partly because most doctors I've encountered don't seem to understand how to map statistics onto their mental pattern-matchers.

I go to a doctor if it might lead to something permanent, otherwise I wait it out.


This is an exact description of what happens right before you pass out(faint). If you are unsure of the cause I would see a doctor.

In the final stage the field of vision gradually fades to black from the edges in.


That has happened to me before, exactly the same tone although I had the sensation of running in a desert before awaking on the floor.

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.


I've had a syncope like that before when I was younger.

I had the flu at the time, and one morning I immediately got out of bed and went to the bathroom. On the way back to my room, I started to feel dizzy and noticed my eyesight fading. First it seemed to go black and white, then to tunnel-vision, as if I could only see what was directly in front of me. My hearing faded as well - I was on the verge of collapsing (unbeknownst to me) and I could hear my family shouting out as if I was listening to them through a poor AM radio signal and speaker. My father grabbed me before I collapsed and hit my head on the corner of a desk.

After going to the doctor, we determined the causes:

* Standing up too quickly (jumping straight out of bed)

* Low blood pressure

* Possible dehydration

* Going to the bathroom

The trick to prevent passing out when you start feeling dizzy is to get blood flowing back into your head. The easiest way to do that is lie on your back and lift your feet high in the air. And of course, keep hydrated and avoid standing too quickly.


I've done a lot of over-nighters and more (3.5 hours in a week in the Army) and never, ever experienced something like that.

I'm not a doctor, but you were either dreaming or having a stroke in my mind.


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.


My instinct would have been to head straight to a doctor.


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.


There doesn't seem to be a sharp line between sleep and wakefulness. I once fell asleep while driving and was awakened by something I saw. It's an odd sensation to be woken up by something you see instead of by something you hear or feel. I had fallen asleep with my eyes open but was staying upright in the driver's seat, maintaining my speed and staying on the road. It was an extremely frightening experience, because I was very keenly aware of not being conscious a few seconds earlier, and having no sense of how much time had passed. I couldn't even remember what I saw, because duh, I was unconscious when I saw it. It freaked me out so much that even fifteen years later I think about it every time I get the slightest bit sleepy behind the wheel.

A few times in extreme states of sleep-deprivation, I've been lying down or slouched on the couch and realized, after being startled into getting up suddenly, that my memory of what I had been thinking about was fading away just like a dream. My eyes were open the whole time, and unlike when I was driving, I was conscious of seeing and having a consciously driven train of thought. Yet in some way I was asleep, so my mind let my memories slip away as if they were dreams.


> I had fallen asleep with my eyes open but was staying upright in the driver's seat, maintaining my speed and staying on the road. It was an extremely frightening experience, because I was very keenly aware of not being conscious a few seconds earlier, and having no sense of how much time had passed.

I don't know your specific story, but this is not to be confused with the hypnotic state that one usually enters when doing something routinely (e.g daily commute) and the brain simply drops the irrelevant information before it reaches you consciousness. Then something unusual happens that crosses the relevancy engine (a pattern, a sound, anything) and the brain plugs itself back into conscious mode just in case the situation might ever so slightly require highly cognitive decision-making functions. In those cases consciousness can drift away and think about what you'll be having for dinner or some project you're working on. When consciousness snaps back into the driver role you'll have no idea of how much time has elapsed or even which road you took.


Ducks and dolphins routinely sleep one hemisphere at a time. It doesn't seem improbable that humans might also from time to time.


So, this is maybe a silly question, but methodologically, how did researchers establish that? Did they actually somehow attach and keep EEG contacts on an animal that moves around and lives submerged in salt water? 'Cuz that sounds awesome.



we need to have a thread about this.


For all I know this was a mini-stroke of sorts. I wish I had gone to the doctor but I was younger and much stupider than I am today. After I regained my senses (meaning sensory abilities) I slept and woke up on time to present my paper. Years later my though is always the same: What a dumb-shit! Things you do when you are young and stupid.


This will surely differ from person to person.

My experience with all nighters is decent productivity through most of the night, extreme tiredness and the low productivity phase around 20-24 hours in (5-9 am, typically), then what I thought of as the circadian rhythm would kick in and "wake me up" again and I would be fine and almost normal productivity through the day, typically until a second tiredness crash after 30-32 hours (3 to 5 pm).

The nap-sleep around 5 to 9 am would restore some productivity during next day and ease off the second crash, but it never got me back to 100%.

When I was 19 or 20 I once stayed up 66 hours straight to see if I could (not the greatest of ideas, I know) and while I won't claim I was perfectly fine I did not hallucinate. I actually drove for an hour and a half about 60 hours in and managed alright (spectacularly bad idea I'm ashamed of nowadays, please don't do this).



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).


i do get (painless) migraines from time to time

What is a painless migraine?


One kind is called "visual migraine" or "ocular migraine". A simulation can be seen here http://www.knownjohnson.com/?p=73/ . I tried to explain this 15 years ago to a doctor, without success - and then one day I read about it in a website, and apparently, I'm not crazy and also not alone in the world with this phenomenon.

See also: Restless Leg Syndrome.


I'm guessing he is talking about this: http://www.mayoclinic.com/health/ocular-migraine/AN01681/

I get them from time to time; the only down side is the inability to read until the flashing zig-zag hallucination moves out of my field of view. Generally much preferred to a migraine headache.


Some people think the definition of migraine is "very painful headache". This is wrong. Migraine is a class of very specific neurological events, usually involving one side of the head (hence the name migraine, which comes from the Greek hemikrania). There are many potential symptoms, one of which is pain.


Case study! I've been getting mostly-painless migraines for maybe eight years now.

An area of my visual field stops reporting data. It doesn't look like anything, I just get no data. This is a relatively rare form of "aura"; most people who get aura report some kind of positive phenomenon. It starts as a few-degrees-wide field near my focal region; later in the cycle it gets bigger as it moved farther from the focus. I can only locate the region by moving my focal point and watching for bright objects to disappear. I discovered it when trying to figure out why reading was suddenly very difficult.

My blind-spot episodes last about 30 minutes. When I first started having them, there was no pain at all. Since then, they've started to be followed by mild headaches, and sometimes by a cognitive stupor. If you read up on migraines, that's consistent enough that I almost wonder if I've tricked myself into adding these symptoms psychosomatically.

More generally, I've met lots of people who have migraines who think they don't, because their headaches don't debilitate them. When they also report aura, I tell them to go look up "migraine".



when your sight goes, basically :o) (maybe that's not the correct term - i once tried to find out if there was anything when wrong with me, and when i explained the symptoms that is what i was told it was).

[beagle3's link is a very accurate description of what happens; it makes it really hard to use a computer, otherwise it's not a big deal, since it doesn't hurt]


A migraine that someone else has.


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.


"What is it?"

At its simplest it is quieting the mind. A long time ago I took a transcendental meditation course (TM) (I know, I know, it dates me, there was a girl involved) they are (were?) the folks who claimed you could defy gravity if you were good enough. There was a lot of eastern mysticism but as the scientific type I was more interested in what, if any, physiological effects were to be had. Being an undergrad in a pre-med school has some perks and one of them was being able to practice meditation wearing an EEG cap.

As far as I can tell, the primary benefit of meditation is shutting down all the noise in your head. Your brain thinks a lot, about a lot of things, often all at the same time. You might be like me where you get solutions to problems that 'bubble up' from somewhere in your brain that you didn't know was working on the problem.

Anyway, if you meditate (and there aren't any big secrets here you are simply training yourself to stop thinking without going to sleep) you clear out your brain. Like doing a power cycle reboot on a computer. Flush everything all resources available for thinking. Then when new things come up you can respond more quickly because you've got cycles to spare.

My totally non-scientific theory is that normally, when you start thinking about something new, your brain has to pick something to stop thinking about so that it can free up the cycles. If you are trying to keep a lot things in your head, that is hard because you are already trying not to stop thinking about the things you need to remember. Whereas when you just come out of meditation you aren't thinking about anything so you can quickly pick up a new train of thought.

Note that this is different than sleep because when you sleep you dream, and dreaming is a way of thinking. If you're successfully meditating, you are awake, aware of your surroundings, but keeping your finger on the 'halt' button so that you don't start up new thoughts. Then you lift your finger and off you go.


Thanks for the detailed response. It sums up some of what I had heard/suspected, and the theory about regaining spare cycles is appealing.

>there aren't any big secrets here you are simply training yourself to stop thinking without going to sleep

This is definitely the first hurdle I encounter. The handful of times I have attempted this, I end up thinking about not thinking (isn't that silly?), or a song comes into my head, or I hear a noise in the distance, and attempts to clear out those thoughts lead to, well, more thinking!

I struggle with even imagining what it's like to not think about something. Something new or something old. Anything at all. I will note that I also have trouble sleeping for the same reason, and when someone describes "the feeling just as you fall asleep", for me that's a synonym for stress and frustration. I can never really remember how I eventually fall asleep.


> This is definitely the first hurdle I encounter. The handful of times I have attempted this, I end up thinking about not thinking (isn't that silly?), or a song comes into my head, or I hear a noise in the distance, and attempts to clear out those thoughts lead to, well, more thinking!

Warning! Completely subjective descriptions ahead:

In my experience the best approach to clearing your mind is not to try and actively clear your mind (i.e. thinking about not thinking) it is training yourself to let your thoughts be more transient.

When I try to meditate I try to let all my thoughts slip. Of course, just like you I will hear a noise or some thought tries to worm its way in, but when this happens I try to relax (physically, there is a wonderful link between relaxing your muscles and relaxing your brain. Instead of forcing your brain to relax, trick yourself by relaxing physically) and let the thought go.

Of course, thoughts keep floating into my mind of course, but the longer I keep the meditation up the more transient they become. At some point they even stop being thoughts because they exist to short to even have any content or feeling associated with them.

I have noticed that with practice the time and difficulty of achieving this transient state go down, making it easier to just start. Early on I would need to be in a quiet spot alone, nowadays I can get the process fairly far even with people in the same room talking (if not to loud).

Anyhoo, I hope that description maybe helps you!

TL;DR - You don't stop thinking or actively try to shut down your brain, you passively let your thoughts become more transient.


"This is definitely the first hurdle I encounter. The handful of times I have attempted this, I end up thinking about not thinking (isn't that silly?), or a song comes into my head, or I hear a noise in the distance, and attempts to clear out those thoughts lead to, well, more thinking!"

Yup, that is exact right. The guy who taught me that it was about 'being the stillness' (I know, I know, but this was they 70's). Lets say you are looking at pond, smooth as glass and a pebble falls, ripples spread out. You can't stop the ripples, you can just note them and wait for them to pass. So you note the thoughts as they pop unbidden into your brain, and then wait for them to pass. If you were in a horror movie and the killer was walking in your house, you'd be scared to death trying to be invisible. That is 'being the stillness'. Actively not thinking.

"I struggle with even imagining what it's like to not think about something. Something new or something old. Anything at all. I will note that I also have trouble sleeping for the same reason, ..."

There were lots of people who fell asleep in our class. I did too a couple of times. One of the party tricks you can do while meditating is what some folks call 'lucid dreaming' which is you are balanced on the knife edge between consciousness and unconsciousness, you can learn to let your unconsciousness start up without leaving consciousness completely behind. Me, I end up going to sleep if I try that.

But having a lot of stuff happening at work, at home, and in the world, sometimes I meditate to go to sleep. But its a two step process, meditate, then once there allow yourself into the unconscious state rather than holding on to the conscious state.

There was an engineer at Google who had dug up a lot of interesting references on meditating. Some folks have decided it is a form of self hypnosis since the mental state most closely resembles that of being hypnotized.


An often used approach is to think of and feel your entire body. You start with the pinky toe on one foot. You just focus everything on the toe and try to "feel it". When you believe you can eel it you move on to the next toe, eventually to the foot, the lower leg and so fourth. In this way you move through your entire body in detail just concentrating on what you can feel. It usually works for me when my mind is overflowing with thoughts and I can't sleep.


Try this: Sit in a relaxing posture. As you inhale, think "1". Exhale and think "2". Inhale and think "3" and so on up to "10". Then start over. In the beginning you will often end up counting 11, 12, 13, 14 and then realize you counted to far. Just start over with inhaling and counting "1" and so on. In my experience, after 30-45 minutes, the mind and body will come to rest in a profound manner. For details check out "Mediation for dummies", this is where I leared the technique. Best of luck.


I can tell you how I experienced it.

I did Astanga yoga (also refered to as power yoga) for many years. Such a class would consist of some 10 - 20 students and 1 - 2 instructors. In this form of yoga at no time do you close you eyes (expect for the final relaxation time).

Contrary to what you might think this particular form of yoga is very very psychically hard. Although you move slowly you are never still in a relaxed position. You move a lot of small muscles and carry your own weight for 1.5 - 2 hours.

The concentration needed takes all your focus until you know the series of movement of the back of your hand. For me this took about a year. After this I would occasionally slip into a kind of mindlessness. I would "come back" and be conscience about this mindlessness at some point near the end of the session. It very much felt like 1.5 hours had passed in an instance. I would not be able to recall any detail or anything the instructors have said and I would feel immensely relaxed and full of energy. It was a great sensation.

I suspect this has something to do with how you breath during yoga. It kind of resembles the way you breath when you are deep at sleep. It takes a long time to learn and I have a feeling that the breathing is actually the most important part of yoga.

Besides swimming this is by far the best workout I have ever done. Being a programmer it does wonders for a body which spends most of the time sitting down in an office chair. If you get the chance I recommend that you try it out. You will be very surprised how hard it is - and how rewarding it is.


>The concentration needed takes all your focus until you know the series of movement of the back of your hand. For me this took about a year. After this I would occasionally slip into a kind of mindlessness.

That strikes a chord with me, actually. Just after responding to ChuckMcM's comment, I realized that there is one way I can achieve a state of non-thought: Whenever I'm physically struck by something, clearly not injured (and thus not worried), but still in pain enough to be distracted. Somewhere in those moments I'm too busy with the sensation to think, and my brain finally shuts up.


Meditation can be many things, it's really up to the person what they do while they meditate.

The best explanation I have is ignoring your thoughts. You aren't sleeping, your mind is blank. Meditation feels like (to me at least) the feeling right before you fall asleep.

Imagine you're playing with bubbles, these bubbles are your thoughts. Generally, your mind tries to capture the bubbles, exploding them and seeing what was inside. When you meditate, the bubbles just kind of whizz by without looking inside.

It's a good way to explore what we are as humans, and it's sobering in it's power to tap into things we otherwise wouldn't experience.


How do you learn how to play baseball, for example? You have to train repeatedly in order to build up each individual skill such as batting, throwing, running, etc. What you're doing is using repetition to create associations that you can then use semi-consciously. For example, you put yourself into the "batting" mode and you cue up a bunch of sub-conscious reflexes that let you hit a pitched ball.

Meditation works very similarly except the goal is to train the mind. Much like our bodies our minds are not under our complete conscious control. We can't, normally, just turn off or on feeling sad, or being angry, or relaxed, etc. That lack of control has consequences. For example, when a person is in a heated argument the fight or flight reflex will dump adrenaline into their system and create a variety of other reactions that results in diminished rationality, aggressiveness, etc. That phenomenon is the root cause of a ton of negative behaviors in people and a reason why verbal arguments turn into verbal, and then perhaps even physical, fights instead of conversations.

Generally the most important transition is to a state of relaxation, since it's easier to consciously go from that state to most other mental states intentionally and it's typically harder to go to a state of relaxation from many other mental states (anger, sadness, anxiety, frustration, etc.) However, meditation isn't limited to just relaxation.


I worry that my fellow commenters may be glossing over the really important aspects of meditation. Here's my understanding:

There are many different types of and approaches to meditation, but the essence of all of them is mindfulness. The concept is of being "present"-- not living in the past, or the future, but experiencing what is happening right here, right now.

This is a subtly but importantly different idea from that of ignoring or quieting your thinking. You are your thoughts; you can't ignore them. (Don't think of an elephant.) However, your thoughts are not all that is happening to you, and most of the time your thoughts serve only to distract you from what is actually going on.

So, for example, one of the most basic forms of meditation is simply to be aware of your breathing. You are breathing one hundred percent of the time, but you are almost never aware of the fact that you are. So take one moment, right now, close your eyes, and breathe. Feel how your chest expands and contracts. Feel how the air flows through your nostrils.

Thoughts will occur, and it's important that you don't push them away, or try to ignore them, because you can't-- even very experienced meditators cannot. Instead, recognize that thought is occurring, be aware of it, but don't dwell on it. Let the thought exist, notice that it is happening, and let it drift away as you return your attention to your breathing.

You will find your mind drifting to more and more intrusive thoughts: The things you're stressed about, worried about, upset about. This is not wrong; it is what is happening to you right now. Be aware of it, let it pass into you just like the air through your nostrils, and let it pass out as you return to breathing.

If you really attempt this, you will notice at least a brief moment where you feel suddenly, absolutely aware of who you are, where you are, what it is that you are experiencing right now in a way that you may never have felt before. If you've never meditated before, it is very likely that you'll be terribly upset by this awareness of all of the unpleasant thoughts and feelings that you've been ignoring, trying to push under the surface and bury inside yourself. Remember that it is okay to cry. Let the emotions happen, just the way they are. You can't make them go away. But they don't control you; once you've felt them, it's okay to return your attention to your breathing.

I hope I don't make this sound easy-- it's incredibly difficult. But over time, with practice, you'll find this state of presence and awareness easier and easier to achieve, and that it's no longer necessary to close your eyes or be still to feel this. You'll be able to experience exactly what it feels like to walk down the street, or to eat a meal, in a way you never have before. You'll find yourself no longer being ruled by the emotions you've tried to suppress for so long. You will be angered, or saddened, or terrified, and you will be able to let those feelings happen inside of you, really experience them, and continue with what you are doing.

That is meditation.

(My references: My mother is a clinical psychiatrist who is trained in mindfulness-based cognitive therapy, which is, believe it or not, a clinically validated treatment for many serious mental illnesses, but especially depression and anxiety. I've used these techniques myself to overcome major recurring depression.)


In retrospect this is probably a much better explanation than my comment, which focuses on what you experience while being present. But yeah, the goal in most types of meditation is to be present, rather than experiencing the different 'states' that come up. In fact, you are basically supposed to ignore them. The reason my comment was focusing on them I guess is because that's how I got onto the topic, in relation to sightedness being separate from consciousness.


Yeah, I tried to avoid saying that you were wrong, because you're not-- in practice, meditation does result in a quieter state of mind, and does enable altered forms of consciousness. It's just that's not the core, and for someone who's never meditated before a lot of the advice about what meditation feels like (clear your mind, ignore conscious thought, etc.) is likely to be quite counterproductive. The first and (in my opinion) most important step is to just be.


This is an excellent description of mindfulness/vipassana/shikantaza-style meditation, which Jon Kabat-Zinn based MBCT/MBSR on. If I could, I would only like to add that mindfulness is not the only style of meditation.

In a concentration practice (such as samatha in theravadan buddhism, not sure about zen/tibetan), you eventually cultivate one-pointedness to the point that you become aware of nothing else but the object of concentration, whether it's the breath, a flame, or an imaginary colored disc.

Concentration practices feel very different, produce different effects, and have different uses. They can frequently be way more pleasurable than mindfulness practices, help improve concentration (naturally), but are generally assumed not to be able to lead to enlightenment.


Definitely a very good point. I'm obviously quite biased toward mindfulness, since it's such an easy thing to get started with, since it has experimentally validated therapeutic value quite apart from any New Age-y "Eastern" philosophy, since it's been so valuable to me personally, and since I strongly believe it's something every human being should be practiced in, but I'll readily grant it's not the only thing the word "meditation" is used to describe. (And given my experiences with mindfulness, I'm quite willing to believe other conceptions of meditation may have value as well.)


If you're more interested in the science side, you might like James Austin's Zen and the Brain. It's a bit old, but pretty interesting. For more modern analysis of meditation, the Mind and Life Institute has funded a lot of research, but much of it requires access through a university library, sadly. (Google Scholar might help.)

Also, if you're open to the idea that there might be more, but like me, not interested in anything mystical, I highly recommend checking out Stephen Batchelor's Buddhism Without Beliefs.


Thanks for the recommendations! I do tend to avoid media about meditation as a matter of course since it's so hard to escape the mysticism. I'll definitely check those out.


There's a Feynman story about him trying to experience the moment of falling asleep.

I tried the same thing, and had some interesting experiences. Around bed-time, lie down in a relatively quiet, not too bright place. For me, a hardwood floor with thin carpet works well. Close your eyes, and try to breathe slowly. Whenever you have a startling thought or start to feel impatient (why isn't this working?) just remember that all you need to do is to breathe slowly.

Over time my mind gets quieter and quieter. I may focus on the greenish patterns inside my eyelids (similar to photo-luminescent plankton). These patterns may swirl and move like a fluid-simulation.

If I'm lucky, at some point I'll realize that I'm asleep. I've never experienced the transition -- just the realization that, yup, I'm asleep. In winter this is accompanied by an overall feeling of warmth. There's also a feeling of disconnection from hearing and motor. It's not that I can't hear, but if there were crickets or bird noises outside, I realize it's gone suspiciously quiet. It's not that I can't move, but it feels like I'd have to surface first before moving.

Often the reaction to the realization "I'm asleep" is to startle and to wake up, but you can train yourself not to.


"What is it?"

There are many types of meditation which frankly don't have all that much in common. In buddhist meditation, which is probably the most common type in the US, there are two main types:

- Concentration meditation (shamatha): This involves training the mind to concentrate, often by focusing on a mantra, an object (like a candle), or some imaginary object (like a mandala). There are different mental states that you can reach as you get better, called jhanas.

- The second type of meditation is insight meditation, also called vipassana. In this type of meditation you focus on the sensations of the body. It basically involves starting at your head and noting every physical sensation (warm, cold, clothing touching your skin, etc.) and working all the way down to your toes, and then going up. As you progess you begin to notice more sensations that the buddhist mental map describes as being part of the 'subtle body'. These involve things like vibrations, electric shocks, etc. You also begin to feel waves of energy traveling up and down your body. To get to this point takes 3 or 4 days, assuming you are at a retreat where you are doing it 10 hours a day. The next step is where you can feel 'inside' of yourself, like all of your organs, and then being able to feel inside your organs until they dissolve into what feels like rising bubbles. This takes a bit longer, but you can often begin to feel these 'bubbles' after a week or so. Note that you don't have to believe in any of this, it just happens whether you want it to or not. There are many more mental states and experiences you will have if you continue. There is a description here of the rest of the states:

http://kennethfolkdharma.wetpaint.com/page/Collection+of+tip...

They culminate in something called stream entry, which is the first of four stages of enlightenment according to the buddhist model.

There is also a book called Mastering The Core Teachings Of The Buddha which also has a description of all the things you go through between being a beginner and reaching enlightenment. The best way to learn though is probably to do a meditation retreat, there are free vipassana retreats offered by dhamma.org that are pretty good. (There is a suggested donation of about $300 to pay for your food and housing for the 10 days, but it's optional.) There are many reviews of this online. There are also many other retreats, but most of them cost money. One example of a popular one is the insight meditation society, http://www.dharma.org/.

There are many books also. The best one for learning vipassana is probably Mindfulness In Plain English, which you can download for free as a PDF: http://www.urbandharma.org/udharma4/mpe.html

While this is good to read, you really don't want to try it without a teacher, as you are likely to hurt yourself or do it wrong (and not make progress) unless you have an actual teacher.

The third type of meditation you hear a lot about is transcendent meditation. This is basically a form of concentration meditation, although its adherents claim it is different based on brain scans. It costs a lot of money to learn, and many consider it to be a cult. I don't know a lot about it personally.

Many other religions have some form of meditation, such as catholicism. Tibetan buddhism also has its own form of meditation, as does hinduism. (Some types of yoga are basically an active form of meditation.)

If you're looking to learn one type then vipassana is probably the place to start. Advantages are:

- Free instruction, and a large community that can help you.

- A large encyclopedia of the different mental states you will encounter, so you know what you're experiencing and whether or not they are 'part of the path' or just a distraction.

- A well defined path to follow to get from a complete beginner to very advanced.

- What r/meditation is most familiar with, which is a great place to ask questions and such.

Tibetan buddism also has a very well defined path, but it's really only taught to people within the tradition, so I can't comment much on it. It's also generally hard to learn unless you happen to live in Ithaca, NY or Boulder, CO, as there aren't many tibetan llamaseries around.

Lastly, I should mention there is also zen meditation, which is fairly popular in the US. Zen is a lot of judaism, in that it combines certain practices with what are basically brain teasers as a way of trying to coax you toward enlightenment faster. There are all sorts of parables, commentaries, commentaries on the commentaries, etc. I don't know a ton about this, but there are all sorts of blogs and places you can learn. Anyway I'm not an expert by any means, but hopefully that helps a bit.


I have been doing short sessions of vipassana and can confirm you will begin to feel energy.

It is intense and feels like it is going to explode.


> llamaseries

Is this a hilarious typo for "monasteries" or is this an actual thing?


You may want to read Stephen Batchelor's secular book "Buddhism Without Beliefs".

In there, meditation is a structured way to develop awareness (mindfulness) of your subconscious thought processes and beliefs (which determine your day-to-day activities and your overall path in life, but which few people consciously monitor).

If you are a particularly introspective person, or have worked with CBT (cognitive behavioural therapy), the concepts will seem quite familiar albeit presented from a different angle.


> things that we normally think of as requiring consciousness reveal themselves as being controlled autonomically

Like what?


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.


Benzodiazepine is effective at doing that.

Causes an almost meditative state where you don't worry about body function (which is why its effective at treating anxiety).


My experience is that you start out being aware of your breathing etc, in order to get into the "spaced out" state.

I'm not lying there the whole time thinking about my breathing. I start by thinking about my breathing, so I can use that focus to exclude/ignore the usual rush of other thoughts. After some time, I'm not consciously thinking at all.


There's probably a form of meditation that is just spacing out.


This is so bizarre. It's as though our conscious selves share an existence with an independently operating human animal. The one that flinches.


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.


Jaynes' ideas occasionally surface in science fiction. Two examples are Snow Crash by Neal Stephenson and Aristoi by Walter Jon Williams. The last one is an underappreciated gem IMHO.


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.


Would it be more accurate to say that the former is built on top of the latter? As opposed to an equal share, that is.


Very interesting but the news is over 3 years old. http://www.eurekalert.org/pub_releases/2008-12/cp-bmw121508....


The concept is actually 30 to 40 years old.


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.

EDIT: And we should use them "only for good."


Elizabeth Gilbert made that same point in a TED talk.

http://www.ted.com/talks/elizabeth_gilbert_on_genius.html


"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.

Here's a great TED talk on it: http://www.ted.com/talks/oliver_sacks_what_hallucination_rev...


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.

[1] http://news.ycombinator.com/item?id=4319700


That's awesome, fascinating stuff - thank you!


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).


I am surprised Peter Watts' story wasn't mentioned yet. The story gets its name from this condition.

http://www.rifters.com/real/Blindsight.htm


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.

[1] (Contains plot spoilers) http://en.wikipedia.org/wiki/Blindsight_(science_fiction_nov...


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.


If you want more information about this Through The Wormhole Season 2 Episode 5 "Is there a sixth sense" explored this and presented some theories on how it occurs. https://en.wikipedia.org/wiki/Through_the_Wormhole#Season_2

The show is excellent and presents a lot of science topics in and interesting and understandable way. Highly suggested viewing.


The video of him walking down the obstacle course (!!) is pretty amazing and can be found at the bottom of this page http://www.sciencedirect.com/science/article/pii/S0960982208...


Interestingly, this report comes from 2008 and is presented by SEED as something totally new.

The original findings were published in Current Biology (2008; 24: R1128-R1129).

That said, it is quite fascinating, non the less.


<Off Topic

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.


If sight is independent of visual awareness does that mean we should be searching for a new test for drivers?


This would suck but it sounds a lot better than being straight-up blind.


"So there I was .. installing some blinds ..


he's almost a zombie


[deleted]


I don't know why I'm even responding to this - but Daredevil "sees" by sound.


>I don't know why I'm even responding to this

Judging by the comment thread below; so you could ferret out the rest of the accounts controlled by reddit trolls.

EDIT: Since the junk in the comment thread appears to be getting cleaned up, I would like to note that at the time of writing it was worse.


I also hear by sound, am I Daredevil?


this comment thread reminds me of reddit


To be fair, the submission (which is from 2009) is also very reddit-shallow. (Six whole paragraphs, wow!)


Without reading the article, let me take a guess: Attackships on fire off the shoulder of orion, c-beams glittering in the dark near Tannhäuser Gate?




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