Can we fully digitize the brain and run it real time ?

Petr Hruškaphruska@gmail.comFinal ProjectUnderstanding the Brain: The Neurobiology of Everyday Life

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One day, several months ago an article in Czech magazine took my attention.

In that article the author cited some interesting words of Raymond Kurzweil, an American author, scientist, inventor, futurist, and director of engineering at Google.

Mr.Kurzweil said in that article he is looking to the future (~2045), where computers will have enough capacity and power to fully simulate the human brain so we will be able to upload ourselves into the cybernetic body.

Mr. Kurzweil's claim about uploading minds by 2045

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And questions started attacks in my mind:

Is Mr.Kurzweil serious or does hejust provoke to attract attention ?

Could really silicon chips and electrical circuitsfully simulate all the brain functions ?

Is all what we are the matter of CNS, can we live without our body as digital beings ?

I'm software engineer and I have some idea how computers work, but I did not know really much about the brain. I decided I need to study to find out more. So I enrolled for Computational Neuroscience and Understanding the Brain: The Neurobiology of Everyday Life courses to get some background to asses Mr.Kurzweil prediction.

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So the question is, in future, can we fully simulate the human brain functions ? Andcould such simulation also bring the self-awareness and intelligence of living organism ?

My project is to briefly compare the human brain and computer performance to havebetter idea for the the former question. For the latter one, my current feeling is unlesswe try, we're not going to know really ...

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Basic Description and Characteristics

The human brain is complex neuronal network supported by glial cells and powered by oxygenated blood. It's a very parallel system with multiple core centers communicating each other simultaneously.

Stimuli are sensed and transformed to electrical signals , which are transmitted by neuronal pathways to the brain. Brain is storing and interpreting inputs from outside and inside the body and process it up to decision how and if to react.

Computers are complex systems of electrical circuits organized to

integrated processor unit(s), other silicon chips and memories,

powered by electricity.

Computers are very fast, still mainly sequential systems. Inputs from

peripheral devices are transformed to binary code and translated

through several layers to limited amount of instructions which can be

processed in CPUs. Outputs are predictable reaction based on

programming and logic burned in the chips.

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Compatibility

So we have biological and artificial systems for information processing . Are these two systems compatible enough that we can thing about full simulation of the brain ?

While there are major differences in used materials, brain anatomy and computer system architecture, one essential and very key aspect is common. Information is processed as a binary code, where 1 is represented as higher electrical potential than 0. Both systems transform stimuli or input information into binary code ~ electrical impulses to be processed and reactions are transformed back to whatever output systems you have available, muscle contractions or robotic arm movements. The fact that both systems can be and are compatible has been proven by many ways, from mind-controlled prosthetic limbs to such experiments where you read neuronal motorfunction signals from one person and send the information over the computer network to another body, where the resulting movement is performed.

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Speed and Overall Performance

Brain neurons response time is measured in milliseconds or tens of milliseconds. You will be disqualified from 100m sprint race if your start reaction time is <100ms. You can't simply react more quickly. Computers on other side operate on GHz frequencies ~ a few billion cycles per second, so are about million times faster.

The speed is certainly not only performance criterion. Thanks to massive parallelism in neuronal networks, human brain is still overperforming computers. As computer speed has quite reached materials limits, we can see big focus on parallel computing nowadays. New processors are multicore and multithread units, but despite this fact machines are still quite sequential systems.

But there is one important fact. While our brains will be pretty much the same in following few decades, computers are doubling their performance approximately every 18 months. So we can expect that computers will match the brain performance one day and overmatch it right after.

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Capacity

Another essential feature is ability to store and re-use information. We have many types of memories stored mainly in neocortex and other parts of the brain. Rough estimation of brain talks about 100 billion neurons passing signals to each other via as many as 1,000 trillion synaptic connections.

Let's say 1% of neurons with a few trillion connections are participating in memory functions and we would like to store such amount to computer memory, assessing each neuron not only as a number of it's synaptic connections, but also including its strange, type and other conditions determining if action potential can go through, we may end up somewhere between hundreds of terabytes or tens of petabytes.

The above estimation does not care about how our memory works, how stores and reads the information. That's the other story of “software” area, here we can limit to sort of hard drive of long-term memory and say that computers already have such capacity, although it would not be a notebook, but rather a middle size storage server.

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Software

It's nice to have powerful hardware, but it does nothing without a software. How we learn, how we store our experiences, how we make decisions ? We know quite little about higher mental brain functions and we're still in phase of “being impressed”, inspecting a black box which internals are too complex to understand.

Computational neuroscience is trying to encode and decode information processing in our neuronal system and has already achieved some amazing results. We can estimate which particular neurons will fire on given stimuli, using statistical observations on single neurons and probability theory, but there is certainly still a lot of work to do to understand at least some of more advanced brain functions.

What we already have is brain computer interface (BCI), able to read and send back neuronal signals. This is a huge opportunity for neurobiology and medicine that we can at least bridge lost neuronal pathways and recover from some serious damages of our CNS. And also we have the interface that brain and computers can communicate each other and transfer the information.

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Final Words

So where we are in order to make full simulation of the human brain ? We know the anatomy into very much details, having fascinating visualization methods like Clarity, FMRI or ultra-microscopic data. We know how neurons and their synaptic connections work. We should be able to build a computer with required speed and capacity. We can also program data structures to represents neurons and their connections. We have the interface to send neuronal activity data into the computer.

It would be tremendous effort to gather all the data from the brain, prepare the computer system to which we can upload it. We can use computational neuroscience and probability theory, which has some magic to replace all the biological environment which keeps neurons alive, functional and determining if action potential pass to other cell.

And actually there are researchers trying to do so and they are quite close. Next generation of supercomputers is coming in a few years and will have enough power for real time simulation. Just guessing if the first stimuli will be “Hello” and the reaction will be “Hello World”, but expecting once tuned it will be more than that.

Not now, still some work to do ...

Petr Hruškaphruska@gmail.comFinal ProjectUnderstanding the Brain: The Neurobiology of Everyday Life