Exploring Sensations in the Visual Cortex for the Blind

[Andrew Wright]

Hi,

Are the any documented examples of descriptions of a subject's sensations during stimulation of the visual cortex, when given by people born blind?

This is something I am curious about after hearing a creative musical piece sung by a disabled child.

I am assuming that many people born blind can respond to measured stimulation of the visual cortex caused using drugs or meditation.

Thanks

 

[Andrew Wright]

I have been reading about electrode implants into the visual cortex but this seems far more invasive and perhaps undesirable.

 

[Andrew Wright]

One answer I got online is that someone described seeing the same thing that I am able to see with my elbow. In many ways this is quite thought provoking.

 

[jim mcnamara]

Answer: I cannot find anything reputable on the subject
Below I give a reason why this may be the case, opinion only.

Thread with some partial answers:
https://www.physicsforums.com/threads/born-blind-how-might-i-dream-differently-then-you.581042/

Note: complete non-perception of light affects melanin diurnal production cycles in the pituitary, there are many kinds of bad things that may cause blindness. Let's assume zero light perception through the eyes. From birth.

The central point is this: our brains are very plastic, we acquire all kinds skills through exposure. Environment, if you like. There is a catch.

Let's use an analogy, sort of.
A classic plasticity example is "hearing" and understanding language sounds. Phonemes are the basic sounds of human languages that separate words uniquely. See link below.

Small children excel at learning new languages because their newly minted brain is set up to hear any of the 100+ phonemes. Each human language uses a subset of these phonemes.

As children age, the unused pathways of phoneme perception decline. This is why immigrants who grew up speaking a language with different sounds from, say, English, have trouble rendering and maybe clearly hearing or pronouncing some words in English. Native English speakers hear the newbie as having an accent. Because the newbies are mostly past the perception point due to brain ageing. So this point is perceiving and vocalizing previously un-encountered phonemes no longer works well.

Now, let's bring in twin languages (autonomous languages or Cryptophasia ) - wholly made up languages that twins create ad hoc. Unless you are part of the twin package, the language is unintelligible.

This shows plasticity pretty clearly, IMO.

[opinion]
What does that tell us? There is a strong possibility that someone born blind is probably doing something with spatial representations. Because some are able to learn to navigate objects in the rooms they live in.
So, if you apply the bit above on language creation in twins it is possible that the physical representations of the world normal to us may shift to other parts of the brain in humans born blind. Or not exist at all.

FWIW:
Color blindness could also be construed as being born blind to certain properties of the world.

Bottom line: If we cannot understand twin languages, then I do not believe we can ever make perfect sense of the blind person's world. The "unsighted" world is likely to be unique in ways the sighted world does not perceive. Like twin languages. Because their optical "hardware" is wired in new ways.
[/opinion]
Twin languages: https://en.wikipedia.org/wiki/Cryptophasia
Phonemes: https://en.wikipedia.org/wiki/Phoneme

 

[atyy]

Due to the cochlear implant, there are many more examples of people being born deaf who then receive auditory stimulation (capable of reaching the cortex) via the implant.

 

[Laroxe]

There is a similar issue in people born profoundly deaf, who develop schizophrenia. Around half will report hearing voices.
Its suggested that this reflects the way in which people make sense of specific experiences, the fact is, is that the actual characteristics of sensory input bear little relationship to the way people construct and make sense of them. So what we see, doesn't really reflect how our visual systems collect data about our environment.