[MURG] Cortex activity

[digfarenough]

now, keep in mind that I said I consider myself one, not that I necessarily am one :)
but I'm currently working on a project, and it isn't the first research project I've done.. so I consider that the active part, and I'm a grad student in a neuroscience ph.d. program, so that's the neuroscience part
 
if you want a "real" neuroscientist, there's always randal koene who occasionally posts.. he even has a ph.d. which in theory means he's quite knowledgeable :)
and as he's said, there are other lurkers who are also neuroscientists and likely know much more than I
 
anyhow.. I'll just throw out a few comments on parts of the discussion..
 
first, the brain as hardware, mind as software thing.. there's a finer distinction between hardware and software, even in a computer, than you might think.. for instance, the software exists as physical data: magnetic spots on harddisks and transistor states in ram.. even varied colors and brightness of phosphors on the monitor.. I suppose it seems as if software magically exists apart from the hardware but simply runs on it, instead of software just being a state of the hardware.. in this way the mind does seem like software running on the brain, but only on this more sophisticated level I think
 
but as joseph said, you can't take the analogy too far because while computers have a simple way to read out data, the brain doesn't--the computer has direct access to every bit of memory, something our brains don't have.. we would have to use an external probe to access each neuron, but unlike a computer in which execution can be paused so the data doesn't change while it's being read, the brain goes on in time, so the entire state would have to be read nearly simultaneously to get all the data
 
as for your idea of a cortical interface between the brain and computer (which someone else had mentioned last week as well), the problem is that at *best*, the brain would use the computer as an addition to its neural network and would become inexorably tied to your identity... I suppose if the number of neurons in the computer were much much larger than those in the brain (like orders of magnitude larger), and if you set up one of these huge networks for each function area of the cortex, eventually, if the brain was plastic enough, you'd be able to get enough function into the network that removing the brain wouldn't much effect the new cortex
 
but that's based on some not necessarily true assumptions.. and my problem with that would be that I don't feel I'm completely defined by my cortex, sure that's where executive function and sensory memories and such are stored, but, for instance, I'm a musician and I have all those nice motor programs stored in my basal ganglia that I'd lose.. and what about my problem telling left from right and west from east? that might be my hippocampus and that wouldn't get transferred either (but that might be good).. not to mention emotional problems.. wait.. it seems like all my bad stuff is stored away from the cortex.. :)
 
I'm not saying you shouldn't do this, but I'm saying you should consider the full consequences before you do... if you wanted to be a voluntary autist (a la greg egan's distress), I'd say go for it, as long as you know what autism is like.. note that I'm not saying cortical transfer is related to autism, that's just an example
 
you also talked some about visual cortex and visual mental imagery.. I'm definitely not a vision person, so I can't say much.. but there's an abstract on pubmed from kosslyn and thompson that says that there's sometimes activation in early visual cortex (areas 17 and 18) during imagery, but that seems to be about it.. personally I'm not sure I'd expect primary visual cortex to activate during visual imagery, because it seems to be that such imagery isn't a picture so much as a conglomeration of visual characteristics (which makes it easy to picture green grass, then just switch the color to red), so I would expect more associative cortical activity.. but that's just a guess
 
however, when you hear that there's an image formed on the primary visual cortex (area v1 I'm guessing), it isn't like a digital photograph.. I've only seeing imaging data of it once, on a poster showing evidence for multiple spotlights of attention in the visual field, but it was more like very rough shapes from the visual field.. by the time the visual information reaches the visual cortex, it has already been processed by retinal ganglia as it leaves the eye, things like edge enhancement and even crude motion detection and is broken into multiple spatio-temporal channels

Thomas Weber <aad1trailmaker at yahoo.ca> wrote:
Hi MURG, Hi digfarenough,
Good to know we have a neuroscientist around. As you
have been watching our conversation you have observed
that Joe and I spoke of mind uploading from two
different angles. Which parts of our conversation you
agreed with and which you did not?

Kind Regards,
Thomas Weber




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