Author Topic: Blindsight  (Read 206 times)

xSilverPhinx

  • Non Dvcor
  • Global Moderator
  • The Cure for Boredom is Curiosity. There is No Cure For Curiosity.
  • *****
  • Posts: 11567
  • Gender: Female
  • On The Warpath
Blindsight
« on: April 25, 2017, 02:11:59 PM »
Has anyone ever heard of this before? I thought it was fascinating:



Looks fake you might say, but it's highly probable that it's legit (This Nature news article contains a link to the same video). The study was published in the journal Cell Biology (abstract), which is basically the journal with the highest impact factor out there.


The man in the video has cortical blindness on both sides of his occipital lobe (part of the cortex that processes vision) though his eyes are still functioning. Because subcortical structures haven't been damaged he can see obstacles without being consciously aware of  them.  This man can also  "see" and react to fearful faces though he can't identify individuals or their gender.
I'm just a student of the game that they taught me.


Dave

  • Formerly known as Gloucester
  • Has an Invisible Dragon in Their Garage
  • *****
  • Posts: 3767
  • Gender: Male
Re: Blindsight
« Reply #1 on: April 25, 2017, 08:35:42 PM »
There was a mention of this on the BBC yeeterday, Scottish woman who seemed to have an "awareness" of objects and nearby people.

I was wondering about  "unconcious" peripheral vision or something then and it mentions something a bit like that in the article. I can't remember the form of blindness in this case but have heard of cases of what used to be called "hysterical blindness" in the past. However brain damage was mentioned here.

Bit ike the strange condition where stroke etc sufferers have a left or right sided "blindness" that patently isn't, can't remember the name for it. See also cortical blindness.
Tomorrow is precious, don't ruin it by fouling up today.

Arturo

  • Do Something Crazy!
  • Touched by His Noodly Appendage
  • *****
  • Posts: 2539
  • Gender: Male
  • Atheist, Humanist, and Champion
    • You two dig up, dig up dinosaurs?
Re: Blindsight
« Reply #2 on: April 25, 2017, 08:38:20 PM »
That's a weird point of view to have.

Holy BatVision Batman!
But, uh...well there it is.
"Nothing's a struggle, but everything is a challenge"-Anon
Hate Is Weakness

joeactor

  • That guy you know.
  • Global Moderator
  • Has an Invisible Dragon in Their Garage
  • *****
  • Posts: 3433
  • Gender: Male
  • Reading Invisible Ink Novels
    • Joe's Dump
Re: Blindsight
« Reply #3 on: April 26, 2017, 08:55:07 AM »
Could it be related to echolocation?

Here's Daniel Kisch:

Dave

  • Formerly known as Gloucester
  • Has an Invisible Dragon in Their Garage
  • *****
  • Posts: 3767
  • Gender: Male
Re: Blindsight
« Reply #4 on: April 26, 2017, 09:41:58 AM »
Could it be related to echolocation?

Here's Daniel Kisch:


In the Youtube example the man would have had to have emitted fairly high frequency sound to "see" reflections from the smaller objects in his path, higher than most older people can normally hear certainly. You need big ears widely separated as well! The accuracy and definition of echolocation is directly proportional to the frequency, that is why they use very high frequency radar to monitor bird movement and terrahertz radar to look for knives and guns etc on humans.

Clicks have, in theory, an infinite number of harmonic frequencies in the rising edges of their waveform, thus clicks work for fairly large and nearby objects,  especially ones with a hard surface. Bats use clucks, but people nirmally need some electronic processing to detect and interpret the reflections usefully. The people with the man would certainly have been able to hear such.

Unless, if course, there is a "sense" that some humans have and others cannot detect themselves or using instruments.
Tomorrow is precious, don't ruin it by fouling up today.

xSilverPhinx

  • Non Dvcor
  • Global Moderator
  • The Cure for Boredom is Curiosity. There is No Cure For Curiosity.
  • *****
  • Posts: 11567
  • Gender: Female
  • On The Warpath
Re: Blindsight
« Reply #5 on: April 26, 2017, 02:09:59 PM »
Could it be related to echolocation?

Here's Daniel Kisch:


I think the pathways are different. Kish had both his eyes removed at a young age, and for blindsight (unconscious sight) to work the eyes have to be intact, as the information still passes through unconscious processing centres but doesn't reach the cortical visual centre located at the back of the brain.



(Kish explains at the beginning of the video that he suffered from retinoblastoma and had his eyes removed).

Patient T.N. (which is the man in the video I posted above) is cortically blind but still has intact eyes which can still gather luminous information and pass it unto structures such as the superior colliculus which is a small structure just below the sensory system relay centre, the thalamus (sensory information except for olfactory converge here before going to the higher processing centres in the cortex).

 

I'm guessing that in the case of humans learning to echolocate, it has more to do with plasticity. Since Kish's visual cortex hasn't been damaged and has basically been left 'without a job', other functions have taken over that substrate. Maybe his auditory processing cortex (which is relatively close - located in the temporal lobes) has taken over some of that inactive cortex when his brain was developing as a young child, thus allowing him to process sound more efficiently than people who are not blind. 
I'm just a student of the game that they taught me.


joeactor

  • That guy you know.
  • Global Moderator
  • Has an Invisible Dragon in Their Garage
  • *****
  • Posts: 3433
  • Gender: Male
  • Reading Invisible Ink Novels
    • Joe's Dump
Re: Blindsight
« Reply #6 on: April 26, 2017, 04:09:49 PM »
Could it be related to echolocation?

Here's Daniel Kisch:


I think the pathways are different. Kish had both his eyes removed at a young age, and for blindsight (unconscious sight) to work the eyes have to be intact, as the information still passes through unconscious processing centres but doesn't reach the cortical visual centre located at the back of the brain.



(Kish explains at the beginning of the video that he suffered from retinoblastoma and had his eyes removed).

Patient T.N. (which is the man in the video I posted above) is cortically blind but still has intact eyes which can still gather luminous information and pass it unto structures such as the superior colliculus which is a small structure just below the sensory system relay centre, the thalamus (sensory information except for olfactory converge here before going to the higher processing centres in the cortex).

 

I'm guessing that in the case of humans learning to echolocate, it has more to do with plasticity. Since Kish's visual cortex hasn't been damaged and has basically been left 'without a job', other functions have taken over that substrate. Maybe his auditory processing cortex (which is relatively close - located in the temporal lobes) has taken over some of that inactive cortex when his brain was developing as a young child, thus allowing him to process sound more efficiently than people who are not blind.

Ah, that makes more sense. Amazing how adaptive humans are. Both of these guys found a way around blindness through different mechanisms.