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Medical News : Bionic Eye

  1. Feb 17, 2007 #1
    http://www.newscientisttech.com/article/dn11200?DCMP=Matt_Sparkes&nsref=bionic-eye

    Title : Better 'bionic eye' offers new hope of restored vision

    A tiny electronic pad is placed onto the retina of one eye, so that the electrodes are in direct contact with the ganglion cells. Each of the devices' 16 electrodes can stimulate 20 to 30 cells.

    The user wears a pair of glasses that contain a miniature camera and that wirelessly transmits video to a cellphone-sized computer in the wearer's pocket. This computer processes the image information and wirelessly transmits it to a tiny electronic receiver implanted in the wearer's head.

    The received in the implanted chip, the digital information is transformed into electrical impulses sent into the ganglion cells. From there, the brain takes over as the information travels down the optic nerve to the visual cortex at the back of the brain. The whole process occurs extremely rapidly, so that patients see in real-time. This is important any noticeable lag could stimulate the "vestibular-ocular reflex", making people feel dizzy and sick.

    For the technique to work, the patient must still have some functioning ganglion cells - nerve cells that transmit visual information from the retinal cells to the optic nerve - as well as a fully-functioning optic nerve.

    -- AI
     
  2. jcsd
  3. Mar 4, 2007 #2

    Q_Goest

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    Hi Tenali, this is really fascinating. I located the research paper that discusses the experiment here: http://www.homepages.ucl.ac.uk/~smgxmdc/humayun.pdf
    Seems we're getting closer and closer to the brain in a vat scenario! lol

    What's most intresting to me is that this and other research really emphasizes the location in the brain that's responsible for the phenomenon of visual experience*, the visual cortex, and that stimulation of those nerve inputs gives rise specifically to this phenomenon. To give rise to this phenomenon, it's as simple as stimulating those nerves.

    It's interesting also that these nerves and that portion of the brain don't give rise to any other phenomenon, such as auditory experience, the sensation of taste, or any other phenomena. That may sound like an obvious observation that doesn't warrent stating, but what I find interesting is that even someone blind from birth has this location in their brain which is responsible only for the phenomenon of visual orientation (ie: how various shapes in a visual scene inter-relate) and visual experience.

    There's an interesting article here regarding a brain scan on a person blind from birth.
    Ref: http://www.boston.com/news/globe/ideas/articles/2006/01/15/old_brain_new_tricks/?page=1

    The article also mentions some tests done on subjects that could see perfectly well. The subjects were blindfolded and after a few days, these subjects seemed to exhibit the same phenomena as the blind subject - the portion of the brain responsible for visual experience was again being used...
    Ref, page 3: http://www.boston.com/news/globe/ideas/articles/2006/01/15/old_brain_new_tricks/?page=3

    So although it may seem obvious that stimulation of a given nerve will result in the proper subjective experince occuring, just as predicted by the brain in vat thought experiment, this kind of research really helps to bolster that conclusion, and show there are specific areas in the brain responsible for specific types of subjective experience. Furthermore, these areas of the brain seem to also be responsible for representing in the mind, how the world 'looks' or how locations of things in the world are oriented.

    That said, I also noticed a neat article on a technology which might be seen as a competitor of visual implant technology you mentioned. It seems possible that information from other senses (auditory) could be used to feed information into the visual cortex. There's a web site that explains it here:
    http://www.seeingwithsound.com/retinal.htm

    Basically, there are no implants. Instead, the visual field collected by the cameras is converted to noise which is supposed to give the wearer information about spatial locations.
    Ref: http://www.seeingwithsound.com/retinal.htm

    I'll have to read a bit more to see what they're claiming exactly, but it seems as if it's saying the wearer of these special glasses will be able to percieve (visual orientation), not unlike how the surgical implant subject might percieve (visual experience). I guess what I'm saying is that it seems the visual cortex might be responsible for two phenomena we might entitle "visual orientation" and "visual experience". To actually produce visual experience, I wonder if the information doesn't necessarily have to come in from the visual nerves, whereas visual orientation does not produce the phenomenon of experience and instead only gives orientation of things in the visual field. Both phenomena use the visual cortex as the substrate, but they are different in how the phenomena is percieved by the mind.

    Does that make sense, or does it thoroughly confuse the topic? :confused:

    *Note: here, I'm using the term "experience" in the sense of a conscious phenomenon such as is used by Chalmers.
     
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