brain melding

Sounds interesting. Didn't some conjoined twins share some brain matter? How would you assess the connection given that it seems unlikely that the brains wouldn't belong to two different people at the same time?

EEG, CAT, PET, MRI, MEG...or just ask them

I mean.... how would you attach two brains and still have the owners lucid?

Since we do not have the technology to connect a brain to a body we would have to rely on both bodies as separate power sources. If it worked, it would probably take several months for them to grow together. I imagine it would require cutting the skulls of two animals open and getting their brains in contact. The tricky part is they would probably require some damaging to coax them into growing together, but not enough to cause serious hemorrhaging. Then they would have to be kept immoble in a catatonic state while they grew together. Sounds pretty gruesome I know...but perhaps someday it could lead to medical procedures for transfering and storing memories between people..

one person but he(or she) has two bodies.

It could be tested by providing information to one twin and then asking the other twin to access that information. It would depend on which parts of the brain were shared as to which kinds of information was shared. Split brain experiments are really amazing, and kind of related to how you would test this.

http://en.wikipedia.org/wiki/Split-brain

Conjoined twins were recently born in British Columbia -- they are joined at their heads and there are concerns about how linked their brains are if they are to be separated in the future. Medical staff have already noticed that if one girl is crying and the other is given a pacifier they are BOTH comforted.

I have heard that the Hensel twins are able to read each others minds. But it would only seem natural that conjoined twins share the same memories. It's not like on can go to Chicago and the other can't!

Yes but intimate understanding is so different from reading thoughts...I wonder if this is really true, can they literally hear the thoughts of one another? I would think that, if this were the case, then they could not think independently...but that every decision would be a sort of collaboration of voices.

You assume seperate voices Stuh?

Perhaps they only really have the one? I'm sure they claim to be different and have different likes / dislikes...but you would do that, wouldn't you...to try to see yourself/selves as normal. I wonder how you could test to prove seperate personalities? If the feeling of ice in the left hand of one could be remembered by the other, can they really be seperate? Perhaps they are no more seperate than the different personas we use in different situations like home v work?

Cool topic.

The Hensel twins are quite remarkable. Check out http://www.geocities.com/heldenkline/Hensel.html

That's great NickFun, but I'd like to see some serious scientific research on these girls. I take it they do not share a brain, as such, but they do have intertwined nervous systems, so perhaps direct thought transfer is possible. What is really going on in there? I'd love to know.

There is no chance of direct thought transfer if their brains are not connected. Thoughts cannot be sent as nerve signals.

However...it is certainly not impossible for the brains to communicate by sending and recieving nervous signals in much the same way that two separate computers could exchange information over an ethernet cable.

Given the brain's amazing ability to adapt, it would not surprise me (although it would interest me) if their brains had developed a communication language through nerve signals, so it's possible that they do have a telepathic link in this fashion.

the brain is composed entirely of nerve cells, isn't it?

Point well taken. I suppose it was a bit premature of me to make that claim given that we do not have a good scientific understanding of thoughts. I tend to think that it is the behind the scenes calculations that are processed via neurons, while the actual thoughts or consciousness layer is occuring in some localized region at a sub-atomic level.

Connecting two brains would not allow them access to each other's memories. Brains are not digital computers. They use neural networks, not data streams. In order for me to "experience" your memory of an apple, each of the outputs from the neural networks in your brain that generate the sensation of "red", "round," "fruit," "grows on trees," "sweet/tart," etc. would have to be connected to the corresponding areas of my brain. It would not happen automatically since our brains never needed to develop such a capacity. You must actually experience something, either directly from the senses or by imagining them (such as reading someone else's description of an apple), in order to form new neural connections.

Perhaps you were thinking about connecting the right half of one person's brain to the left half of another's? Note that the corpus callosum has 200-250 million contralateral axon projections, and I doubt if you could get few, if any, of them connected correctly.

I do not think that the Hensel twins can actually read each other's mind, since they have separate heads and brains. But I have been married long enough that I often have a pretty good idea what my husband is thinking despite my lack of telepathic ability.

Terry,

Yes, a brain is mostly just a neural network (to our present knowledge), which is precisely why I think that it would be possible.

The reason is because so many of the neural connections in our brain are not hard-wired at birth. The neural connections in our brain literally self organize in order to deal with the environment around us.

For instance, if a fetus is raised in a black void, it will develop extremely primitive visual processing capabilities, and will be essentially blind if exposed to a lit environment later in life. To a lesser degree, kittens that are raised in an environment lacking horizontal lines but only containing vertical lines will develop receptive fields that are only capable of recognizing vertical lines.

In another experiment, a tactile matrix was attached to a mature patient's chest which responded roughly to a digital camera. After some time, the patient's skin nerves in the chest re-wired themselves into the visual cortex and the patient described being able to see with the device.

Although we have a rough mapping of what areas of the brain are responsible for processing what, if an area is not used it's function can be adaptively modified to perform some other function or expand upon the processing power of another area.

You're right, nothing at all like a digital computer....fundamentally similar to a modern ANN, but unimaginably more efficient and capable.

Because of examples like these, and countless more, we know that the brain's neural network is capable of rewiring itself to make the most out of the nerve signals coming in. For this reason, if two brains were kept in close enough contact then the nerve signals of one brain could trigger the synapses of the adjoining brain, and eventually the other brain would learn to interpet these signals in a meaningful way. No doubt the converse would happen, and they would most be able to set up some communication layers at a subconscious level whereby they take advantage of the sensory input from the other bain and perhaps even collaborate in subconscious computations.

Yes the brain can rewire itself to a limited extent, but putting two brains next to each other and expecting them to grow together would not be sufficient (even if the rejection and infection problem was overcome). The cerebral cortex has 6 layers through which neurons grow to form a hierarchal structure for information processing. Cutting and splicing brains would disrupt the structure, and I don't think you could overcome that. I don't see the point, anyway. If you want to share information/memories, there are much easier ways to do so.

1. Curiosity

2. It is often curious exploration of new areas that leads to major advancements and technologies we never even thought of wanting before, but that suddenly become possible.

3. Conventional methods of passing information (eg, communication) are of course not replaceable...but there would be obvious benefits to being able to "download" and "save" information across generations.

Yes the rejection problem would be an issue that probably would consider a lot of work to get around in serious experimentation.

As to if it is possible to do this without disrupting the structure...you are being too premature, because it hasn't really been tried yet, has it?