John Page

How would I know part of my brain is missing?

Godless Wonder

Depends which part. You may or may not be able to tell.

My uncle had brain cancer. One of the first symptoms was that he couldn't seem to figure out how to tie a simple knot he'd tied a million times before. It ended up killing him.

But, read a book called "The man who mistook his wife for a hat."

excreationist

By getting a MRI done.
They look like this:



http://www.sciencedaily.com/releases...0528074455.htm
This talks about using MRI to detect Alzheimer's before the symptoms appear. The MRI would be used to analyse the sizes and shapes of parts of the brain.

BTW, I think MRI's can be done in any orientation - so not just a vertical cross-section down the middle - they can be horizontal, at any position down the head (or body?). I think they can be used to create a 3D map of the brain so you'd get an accurate idea of whether parts of the brain are missing.

Will I Am

Just a "reported fact". An officer who was shot through the head in the Falklands 'war' lost 40% of his brain. But, eventually, he seemed 'normal'. To me (he was interviewd on TV). 40%.

There are many other reports similarly supporting the idea of the brain's resilience.

excreationist

Will I Am:
He might have lost a lot of memories/skills after the loss of 40% of his brain. But he would be able to relearn things and store new memories and skills in the remaining 60% of his brain.

Will I Am

Yes.

Which all rather questions Science's current ideas of The Brain.

That memories are stored in a particular places (disputed).

That parts of the brain are dedicated for certain purposes. (disputed).

I'm pretty sure that what we think we know about the brain, we don't.

Magic Primate

The latest think on the brain seems to be that the same information is stored multiply (even 'holistically' to use a rather scientifically unfashionable and perhaps over-used word) across many neural pathways. This doesn't mean the entire brain is used for one memory, but it does mean that it cannot be tied down to a single location.

excreationist

Neural net researchers have even demonstrated roughly how this works. Cognitive science calls this idea "connectionism". With neural networks, the network is "trained" to recognize patterns, and that information is smeared across the network.

Each of the 4 internal neurons here are getting input from all of the input neurons... so if one of those 4 was destroyed, the neural network would still retain most of its information.

excreationist

Most or all neuroscientists would be very aware about the things you describe - e.g. they'd probably know that some people have half of their brain surgically removed to deal with a certain type of epilepsy, etc.

That man might have had a hemisphere of his brain removed like these kids...
http://abcnews.go.com/sections/GMA/G...itis_girl.html
http://www.telegraph.co.uk/news/main...3/wbrain23.xml

the remaining hemisphere would have similar components to the first one (see pic of basic brain parts)
About our two brains....
Note that (according to Encarta, not all right-handed people's hemispheres are specialized like that, and "in left-handed people, the pattern of brain organization is more variable."

Like this diagram...
Well those who deal with brains would be aware that during injury the brain can functionally reorganize itself - so that the functions of the missing or damaged areas done by other areas of the brain.

I don't think we're completely wrong about everything. Just some of the stuff. And even if the theories are wrong, the experimental data (with split brain patients, etc) would be accurate - unless the researcher is lying or hallucinating or something.