Neurosurgeon creates Geordi's VISOR

[Netko]

Or similar to the way kids that never learn to speak later in life can't learn it beyond a very basic level. There was a case of child abuse where the parent(s) locked up their daughter in the basement and never let her out nor did they communicate with her. When she was finaly rescued in her early teenage years, development specialists tried to teach her to speak and understand language in general, but they had very limited succsess since the parts of the brain usualy responsible for it had been retasked.

Unfortunatly, I haven't been able to find the story on google. I belive it is a fairly well known case in the US so maybe someone can remember the details a little better? There were issues with her handling in foster care and disagreements about how to take care of her. Later on, there was also a TV movie made I belive.

[TheBlackCat]

I love Oliver Sacks...

Ah, so this is the same principle, for example, because of which if you remove some of a rats whiskers very early on, during its sensitive period (shortly after birth), the "barrels" in the brain that correspond to the removed whiskers will simply not develop?

Exactly. So for instance, if you simply cover the eyes during the critical developmental period then uncover them afterwards, the person will be able to see just fine (at the pre-cortical level) but their ability to process and interpret what they see will be extremely limited. They are recieving visual infromation, but cannot actually understand what they are seeing. This was seen in congenital cataracs that were removed late in life, but not when they are removed in early infancy. There was an early treatment for "lazy eye", where they covered one eye during early infancy. When they removed it, they found that uncovered eye had come to pretty much dominate both sides of the visual cortex. They were effectively blind in the eye that was covered and they completely lacked binocural depth perception, despite the fact that the retina was operating normally. Such changes are not reversible.

[His Divine Shadow]

So if someone was born blind, or went blind early, you'd having to perform sight-restoring surgery on them pretty quickly so you wouldn't miss that developmental window. Even people who lost their vision in, say, their early 20's and then regained it 20 or 30 years later (usually due to various medical advances) have a very hard time readjusting to using vision however much they want and are happy to have their vision again. The brain has to relearn things like perspective and how to make three dimensional sense out of the images relayed by the eyes.

This is where stemcell therapy would come in handy I think.

Also what of transplanting eyeballs if those are whats "broken"? I mean the biggest problem is the nerves right? We've got a material that hinders the formation of scarring now and allows nerves to regrow(another thread). It restored sight to lab mice after their visual nerves where severed.

[Broomstick]

So if someone was born blind, or went blind early, you'd having to perform sight-restoring surgery on them pretty quickly so you wouldn't miss that developmental window. Even people who lost their vision in, say, their early 20's and then regained it 20 or 30 years later (usually due to various medical advances) have a very hard time readjusting to using vision however much they want and are happy to have their vision again. The brain has to relearn things like perspective and how to make three dimensional sense out of the images relayed by the eyes.

This is where stemcell therapy would come in handy I think.

And how would stemcells solve that problem?

It's not simply a matter of adding in new cells - it also involves integrating them into the existing neural networks.

[TheBlackCat]

Also what of transplanting eyeballs if those are whats "broken"? I mean the biggest problem is the nerves right? We've got a material that hinders the formation of scarring now and allows nerves to regrow(another thread). It restored sight to lab mice after their visual nerves where severed.

It's also a matter of nerves finding the right location. In the rate experiments there was already a path leading to the correct spot that the neurons could follow. In people who have been blind since birth no such pathway exists.

[His Divine Shadow]

And how would stemcells solve that problem?

It's not simply a matter of adding in new cells - it also involves integrating them into the existing neural networks.

Yes I know but as I understood it won't they do that on their own then when the patient is learning to see again? I was under the impression that stemcell therapy in this way would mean the stemcells would create fresh neurons that would then integrate and speed up the learning process, or enable it at all to begin with incase it's too late for the brain to naturally re-learn it.

[TheBlackCat]

Yes I know but as I understood it won't they do that on their own then when the patient is learning to see again? I was under the impression that stemcell therapy in this way would mean the stemcells would create fresh neurons that would then integrate and speed up the learning process, or enable it at all to begin with incase it's too late for the brain to naturally re-learn it.

It's not just a matter of sticking neurons in the brain and expecting them to do the right thing. Development of the cortex is a very specific and directed process. The neurons follow chemical and cellular clues, including chemical gradients and guide cells that do not exist in adults as well as monitoring organizational patterns that have already changed in adults.

It is not just a matter of throwing cells in there and expecting them to do the right thing, cortical neurons cells do very specific things at very specific places at very specific times and in a very specific order following very specific cues. There are many different types of neurons in the cortex, each with very specific roles and connections and many localized in very specific places. Once they are in the correct place they undergo still more specialization. Even with all of this specificity, about half the neurons that form in the mammalian nervous system or useless and kill themselves during development.