If a small, -say 1cc- human brain portion is safely, properly replaced/swapped with same exact lobe/area from another human; would it carry memories/functions/knowledge with it ?

Has it been done ? How good/accurate/reliable is the current surgical technology for something like that ?

No. It absolutely would not. Knowledge is not stored like books in a library, but is the sum total of the connections and the structure of the neural branching. What you are suggesting is much too rigid... As if knowledge is located in a specific spot in the brain, and is not connected to other parts.

 

You might look into full body transplants, though. Sounds like you might be interested in that crazy line of research where the head of one animal was swapped for the head of another (note, the entire head... not just some bloody bits of it).

 

http://en.wikipedia.org/wiki/Whole-body_transplant

Interesting post.

Further more to my research. what would happen if you replaced an entire hemisphere of the brain; with or without corpus calosum?

(if it were possible!)

There has been research on what happens when an entire hemisphere is removed (usually in the treatment of extreme seizures), but none about it being "replaced." Basically, we're still too early in this research to understand what happens when you transplant an entire brain, let alone, some smaller portion of it.

If a small, -say 1cc- human brain portion is safely, properly replaced/swapped with same exact lobe/area from another human; would it carry memories/functions/knowledge with it ?

Has it been done ? How good/accurate/reliable is the current surgical technology for something like that ?

 

Consider that each neuron has, on the average, 7,000 synaptic connections with other neurons. Even if you only needed to connect/reconnect the neurons on the outermost layer of your 1 cm cube, you are probably talking about millions of neurons and billions of connections. I don't think medical science is there yet -- not anywhere near.

 

As for carrying memories, etc., probably not. It is probable that memories are distributed widely over the cortex, more like a hologram than a computer disc. You can remove a small portion of brain without eliminating memories.

 

As for functions, depending on what you removed, you might cause a peculiar cognitive deficet or disability. Say for example that you picked an area that was responsible for face recognition. Upon removal, your patient would be unable to recognize faces. When you swapped in the donor chunk of brain, things would not improve (even if all the neurons were reconnected) because they would be out of context. The neurons in the old face recogntion site would not be "wired" exactly the same, and would respond unpredictably. Although human brains seem to follow the same general organization, the areas are only approximate, and the exact "circuit diagram" is believed to vary quite a bit.

This has got me thinking about AI and someone like Data from STTNG. His neural nets are built up to some desirable state of complexity, before he is ever turned on. When first switched on wouldn't he already have memories and knowledge just by the very nature of the architecture? Let's say his neural architecture happened to be an exact replica of the brain of some other living individual, wouldn't they necessarily share the same memories and knowledge? That's a testable hypothesis. They would have to, if our theory of mind is correct--that experience maps neural architecture. Wouldn't the converse have to be true--that neural architecture maps experience?

 

I'm not thinking clearly right now, but this seems all very fascinating to me. I need to be slapped.