Brain grafts are a very difficult idea in actual brain tissue today.
One of the key reasons, however, will begin to become a non-factor: tissue rejection. We can now grow neurons that have the same genetic code as yours or mine in the lab (I actually did this.) A method is to turn induced pluripotent stem cells (iPSCs) which may have been created from your own skin, into nerve cells.
I grew a small plate of such cells. I did not try to distinguish which among them were neurons, and which were glia. I am sure how far along we are toward growing a complete neural column, or a section of brain.
Assuming the neurons were grown, however, installation would still be very difficult. I am not willing to say impossible, but we have some challenges.
The balance and configuration of the glia would be difficult to control. Blood flow through both large vessels and capillaries would have to be restored to the added section.
Another issue importantly, perhaps, is that neurons in the brain have long axons. The “white matter” of the brain contains portions of these axons that string from brain region to brain region. It is a tangled net. Replacement neurons might have to be literally “woven in” to this net. Advantageously, the axons that are already there are sometimes bundled, but they are stuck together. It is not like stripping a large wire and seeing many filaments pop out.
Physically “weaving” new neurons into the brain is a lot more challenging than weaving them into a WBE or a piece of neuromorphic tissue.
At any given point in the early history of neuromorphic engineering, there will be a greater or lesser understanding of the relationship between structure and function. However, using WBEs and neuromorphic tissue in experiments to try to elicit function from structure will be very inexpensive. Tens of thousands or billions of experiments could be run with a single set of macros.
For this reason, I forecast, with considerable but not complete certainty, that the existence of either WBEs or functional neuromorphic tissue would quickly lead to a much greater understanding of the relationship between structure and function.
Can we be absolutely certain that this understanding would very quickly permit designs of purpose-built brain configurations that improve along the dimensions of particular performance metrics? We should try to build the case for and against that hypothesis. My instinct is to believe that these experiments would facilitate mind design, but people could present other evidence.
Brain grafts are a very difficult idea in actual brain tissue today.
One of the key reasons, however, will begin to become a non-factor: tissue rejection. We can now grow neurons that have the same genetic code as yours or mine in the lab (I actually did this.) A method is to turn induced pluripotent stem cells (iPSCs) which may have been created from your own skin, into nerve cells.
I grew a small plate of such cells. I did not try to distinguish which among them were neurons, and which were glia. I am sure how far along we are toward growing a complete neural column, or a section of brain.
Assuming the neurons were grown, however, installation would still be very difficult. I am not willing to say impossible, but we have some challenges.
The balance and configuration of the glia would be difficult to control. Blood flow through both large vessels and capillaries would have to be restored to the added section.
Another issue importantly, perhaps, is that neurons in the brain have long axons. The “white matter” of the brain contains portions of these axons that string from brain region to brain region. It is a tangled net. Replacement neurons might have to be literally “woven in” to this net. Advantageously, the axons that are already there are sometimes bundled, but they are stuck together. It is not like stripping a large wire and seeing many filaments pop out.
Physically “weaving” new neurons into the brain is a lot more challenging than weaving them into a WBE or a piece of neuromorphic tissue.
At any given point in the early history of neuromorphic engineering, there will be a greater or lesser understanding of the relationship between structure and function. However, using WBEs and neuromorphic tissue in experiments to try to elicit function from structure will be very inexpensive. Tens of thousands or billions of experiments could be run with a single set of macros.
For this reason, I forecast, with considerable but not complete certainty, that the existence of either WBEs or functional neuromorphic tissue would quickly lead to a much greater understanding of the relationship between structure and function.
Can we be absolutely certain that this understanding would very quickly permit designs of purpose-built brain configurations that improve along the dimensions of particular performance metrics? We should try to build the case for and against that hypothesis. My instinct is to believe that these experiments would facilitate mind design, but people could present other evidence.