Building a Functional Model of the Human Brain

[lnx990]

yeah, that should. I am not completely sure wot he meant by it thinks at that speed. If your referring to pure thought you cannot realisticaly put a measurment of speed on it. However, measuring the chemical signaling of the brain, it is much slower. um, I am going to brush up on my neuroBiology ang get back to youall on the exact processes required to make this happen.

 

[evernow]

speed of light

From my master (research) notebook: "Scientists have found ways to break the speed limit. In one experiment, published in the May 22 issue of Physical Review Letters, scientists at the Italian National Research Council of Florence shone light beams at a curved mirror. The mirror then shot the beams back at the instrument that measured the ray's speed. The beam coming from the center of the mirror was measured at 5% to 7% faster than light speed. The authors said this effect only works over short distances, such as the one meter used the the Italian researchers."

 

[Guybrush Threepwood]

I seriously doubt it... could you provide a link?

 

[evernow]

http://science.howstuffworks.com/news-item6.html

 

[lnx990]

neuron mechanics

The diagram (attachment) is self-explanatory.

Nevertheless, essentially the nerve impulse is a sudden rush of sodium ions. The rush then triggers the next few proteins to let in more ions. This process continues in a relay fashion until the pulse reaches the presynaptic membrane. As soon as the pulse passes an indicated area of proteins, they will immediately stop allowing sodium into the pathway. Then active transport kicks in via the sodium potassium pump and resets the nerve. This entire process occurs at about 100m/sec. (much slower than the speed of light).
For those of you that are curious about claims that nerves are electric well, here is the explanation. The axon has positive ions on the outside and negative ions on the inside. This creates an electric potential. So then, why doesn’t the pulse travel at the speed of electricity? Well, the protein gates that keep the ions out have different ways of being activated, chemically, and electrically. The main pulse is mostly controlled by electrically activated proteins. However, they have a high "Tolerance.” That is, while they can "feel" the pulse coming via the weakened electric current, they do not activate until the pulse is near to them. Ultimately, the signal sent across the synaptic cleft is chemical. Thus, it would seem to be inefficient to keep changing the signal medium. However, there are some organisms that do have nerve that rely solely on electricity.
This electric method is fast but it does not integrate information well. Electric transmission across synapsises is very fast and can proceed in either direction. However, they are less common in vertebrates and other organisms that have complex nervous systems. First, electrical continuity between neurons does not allow temporal summation of synaptic inputs (one way that signals are integrated). Second, an effective electrical synapsis requires a larger area of contact between the cells. This makes it impossible to have thousands of connections coming from one cell (witch is common in vertebrates). Third, electrical synapses cannot be inhibitory (not allowing for complex brain chemistry); and fourth, there is little plasity (modifiability) of connections (much harder to learn). Essentially, all there good for if speed, but not so good for complexity.

The statistic I got for brain speed came from a friend of mine, ill try to contact him about his source whenever he is back from the holidays.

The question "do computer think faster than us?"
Well, yes and no. They are capable of transferring information faster than we are, and are faster at processing in a linear fashion. However, they are much slower when it comes to nonlinear systems and processing also known as thought. Simply computers "think" what we program them to. So yes, computers process linear equations faster than we process, but could never understand their environment (at least with current tech).

As far as either building or emulating a brain, I think we should start small. We should try to create something called a ganglion. A Ganglion is simply a small cluster of nerve cells that carry out a specific task. These tasks could be something simple like detecting danger then relaying the signal, of cause the creature to disengage itself from prey. This simple basis of neuro-networking would not allow the subsequent computers to gain emotions or anything and would be reacting on instinct. Thus it wouldn’t decide one day that it no longer likes the scientists and lock them out side the space craft... “HAL. Let me in”...

Another interesting thing to put to the test would be what the DNA says about creating a brain. I mean, it eventually has to do it some way or the other.

 

[evernow]

Fascinating! I would call the "wiring" in the brain associative wiring, which makes sense. Also, thinking about nanite mapping, each individual brain would need to be mapped as we are like snowflakes. But an overall, general map could be acquired, but I wouldn't want it used on my surgery for fear I'd come out someone else. Hey, let's say in 30 years or so we advance molectronics enough to build a brain-interfacable computer. I've giving this a lot of thought, but what do YOU guys think? Would using this bioware restructure the brain? How might it change us? How would it alter society? 'xcuse the pun, but pretty heady stuff.

 

[lnx990]

I was alerted to a good source from another thread about the processing power of the brain. Thanks go out to Lyuokdea for posting it. http://www.aeiveos.com/~bradbury/Authors/Computing/McEachern-RH/HaMIAEV.html Scroll down to the bit about "A ONE HUNDRED MILLION GIGAFLOP PROCESSOR"

 

[evernow]

Thanks for the link. Highly interesting that the writer sets a timetable of only 30 years. I think he's being optimistic, but that's just my opinion. 100 million gigaflops is a measure of quantity, not speed. I still need a confirmation on the brain's signaling speed. Even if we find a documented speed, it's my theory that the actual speed will exceed the findings due to the associative nature of neuronal interaction. Another rung in my ladder of research.

 

[lnx990]

the statement that it will take 30 years is a little optimistic, but not impossible. the only thing would be if anyone would do it. I mean, we have the technology to do somany things, yet that dosent mean we have. The technology to create a human equivalent brain will be there but there is a certain problem. The human brain rewires itself to learn stuff. Thus the robotic brain would proly end up running some sort of emulation program.

as for the 100million gigaflops being a measure of quantity vs. speed.. well it is a measure of speed. Its the unit of measure used to judge supercomputers, largly because they have so many processors. An example of this would be the comparison between Intel and AMD chips. An Intel P4 running @ 1.6 GHz will process information at about the same rate of a 1.4 GHz AMD chip. Thus, the measurment of flops is much more accurate.

as for the source of the brains signaling speed, i got the info from my AP Biology book [Life, the science of biology 5th edition. William K. Purves. Copyright 1998 by Sinauer Associates, Inc. pg. 910, 915-6] just incase you wanted to look it up yourself.

Furthermore, could you more thoroughly explane your position about the speed of the brain.

 

[pallidin]

The human brain, like anything "finite", can be modeled. If current technologies and resourses can achieve this is, well, another matter.

 

[evernow]

As to mapping the brain... Image mapping of the brain was a key component in developing speech recognition software, according to Microsoft. So it's already been done. My interest is in what we do next. I overheard on CNN that with nanotechnology we could build a cell phone small enough for an ant to use. OMG Now, which egghead thought that might be a viable goal for such technology? I'd rather see communication devices nanoscaled and implanted for direct use in the brain. By programed firing of neurons the brain could experience a total virtual world without external devices. The liberty I'm taking in my current SF fiction work incorporates this and goes a bit beyond to explore social issues.

As to previous questions about the computational speed of the brain... My research suggests that the brain actually works at the quantum level, where speed can't be measured because everything is in an infinite-motion state. We can, of course, measure stimulus and response, and we can measure the all-over activity of the brain at any given time. However both of these sums will not give us the speed of thought, for thought preceeds both.

 

[Squeeze]

Originally posted by evernow
As to previous questions about the computational speed of the brain... My research suggests that the brain actually works at the quantum level, where speed can't be measured because everything is in an infinite-motion state. We can, of course, measure stimulus and response, and we can measure the all-over activity of the brain at any given time. However both of these sums will not give us the speed of thought, for thought preceeds both.

Neural science suggest that the brain does not work at the quantum level. Neural connections communicate through firings. The higher the frequency of firing the more excited the neuron, the limit to the frequency of a neuron is about 25 HZ, so it's extremely slow by modern processors standards. The fact that there are billion of neurons in the brain allows for it to perform enormous amounts of processing. Neurons migrate together to form circuits that learn stimuli. The chemical conditions of each connection determine its conductivity and therefore its contribution to a task. So the means by which neurons react to their environment pretty much disqualifies a quantum process for consciousness.

 

[Averagesupernova]

I watched something on Nova on PBS that suggested that the human brain had more possible pemutations than there are atoms in the universe. Now is that impressive or what?

I think if we are a long way from recreating a human brain. We need to stop and realize why the human brain is the way it is and how the human being developes from a learning standpoint. I suspect that the human brain is the way it is partially due to the social nature of humans. We have a need to interact. It is hard wired in our genetics. The brain through evolution has wired itself to what it is today to continue to fulfill the basic need. Now if we could create simulations or machines to have that basic need to learn and interact, and accelerate their evolution, could we gain some answers? Maybe we would end up with something TOTALLY different than the brain, but with just as much if not more mental power than we have ourselves. Who knows...

 

[evernow]

The Brain

To Squeeze:
It sounds like the old chicken and egg quandry.
Does thinking inniate pattern firing, or does pattern firing produce
thougt? If the former, from where does thought originate? If it's the latter, who begins the thought process?
It's to the latter that I posited a quantum state in which lies
the unconscious strucutes of the brain.
Evernow