Stephen Macknik’s work on prosthetic vision

This is pretty wild.  In her latest Brain Science podcast, Ginger Campbell interviews Stephen Macknik on his work to develop a visual replacement implant for blind people.  For a quick overview, check out this short video.

One question Campbell asks, that I was wondering myself: how does the light reach the neurons in the LGN nucleus of the thalamus deep in the center of the brain?  Macknik points out that the gene therapy causes the protein receptor genes to develop in the whole neuron, including the axon terminals that reach into the visual cortex, so the implant doesn’t need to project to the thalamus, just to the end of their axons in the visual cortex.

For more details, check out the podcast itself (it’s about 69 minutes).  It gets a bit technical, but it’s a fascinating interview, and a powerful demonstration about how neuroscientific knowledge can be used.

9 thoughts on “Stephen Macknik’s work on prosthetic vision

    1. Not in this case. It’s just a creative way to restore vision for a blind person, by essentially creating a new retina in the visual cortex. But it’s still using the existing neural circuitry of the brain. If someone is blind due to cortical lesions, this wouldn’t be able to help.


      1. Incidentally despite sone earlier comment I made elsewhere on your website, I remain deeply fascinated by consciousness. But I refuse to bow to the extreme physicalism of the likes of Dennet.


          1. I can, must readily concede that consciousness relies on the physical for its substrate. The brain. From there I do not believe anybody has as yet found any “cause” for the subjective experiences we all bear witness to. Dennet and his particular branch of absolute physical claim that self and qualia are an illusion. Or near as dammit. I prefer to seek other explanations. A mirage is not an illusion ~ it is a trick if the light. There is a reality behind what the mirage portrays but in a different physical location from where it appears to be. I do not find it satisfactory to consider either self or subjective experience as being non existent.


          2. Thanks. Yeah, I agree with Dennett on many things, but disagree on others, one of which is the use of the “illusion” label. I have sympathy with the argument that if phenomenal experience is an illusion, then the illusion is the experience.

            I think illusionism is really aimed at everything that people try to sneak in on top of the pre-theoretical concept of experience, but use of the i-word then requires so much follow up explanation that it comes across as vacillation. (There’s been a Twitter conversation in the last few days on illusionism reminding me of this point.)

            My own way of threading this needle is to accept that consciousness exists subjectively, but that introspection isn’t a reliable mechanism for getting insights into what’s happening objectively. Our introspective intuitions eventually need to be accounted for, but not validated.


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