Is it theoretically possible to emulate a human brain on a computer?

Question

Our brain consists of billions of neurons which basically work with all the incoming data from our senses, handle our consciousness, emotions and creativity as well as our hormone system, etc.

So I'm completely new to this topic but doesn't each neuron have a fixed function? E.g.: If a signal of strength x enters, if the last signal was x ms ago, redirect it.

From what I've learned in biology about our nerves system which includes our brain because both consist of simple neurons, it seems to me as our brain is one big, complicated computer.

Maybe so complicated that things such as intelligence and cognition become possible?

As the most complicated things about a neuron pretty much are the chemical aspects on generating an electric singal, keeping itself alive, and eventually segmenting itself, it should be pretty easy emulating some on a computer, or? You won't have to worry about keeping your virtual neuron alive, or?

• If you can emulate a single neuron on a computer, which shouldn't be too hard, could you theoretically emulate more than 1000 billions of them, recreating intelligence, cognition and maybe even creativity?

In my question I'm leaving out the following aspects:

• Speed of our current (super) computers
• Actually writing a program for emulating neurons

I don't know much about this topic, please tell me if I got anything wrong :)

(My secret goal: Make a copy of my brain and store it on some 10 million TB HDD and make someone start it up in the future)

Answer 1

Researchers far smarter than most recon so, see Blue Brain from IBM and others.

The Blue Brain Project is the first comprehensive attempt to reverse-engineer the mammalian brain, in order to understand brain function and dysfunction through detailed simulations.

Theoretically the brain can be modeled using a computer (as software and hard/wetware are compatible or mutually expressible). The question isn't a theoretical one as far as computer science goes, but a philosophical one:

Can we model the (chaotic) way in which a brain develops. Is a brains power it's hardware or the environment that shapes the development and emergent properties of that hardware as it learns

Even more mental:

If I, with 100% accuracy modeled my own brain, then started the simulation. And that brain had my memories (as it has my brain's physical form) ... is it me? If not, what do I have that it doesn't?

I think that if we are ever in a position to emulate the brain, we should have been working on logical system based on biological principles with better applications than the brain itself.

We all have a brain, and we all have access to it's amazing power already ;)

Answer 2

I don't think they are remotely close enough to understanding the human brain to even begin thinking about replicating it.

Scientists would have you think we are nearly there, but with regards to the brain we're not much further along than Dr. Frankenstein.

Answer 3

The key problem with simulating neural networks (and human brain is a neural network) is that they function continuously, while digital computers function in cycles. So in a neural network different neurons function independently in parallel while in a computer you only simulate discrete system states.

That's why adequately simulating real neural networks is very problematic at the moment and we're very far from it.

Answer 4

A word of caution. Current projects on brain simulation work on a model of a human brain. Your idea about storing your mind on a hard-disk is crazy: if you want a replica of your mind you'll need two things. First, another "blank" brain. Second, devise a method to perfectly transfer all the information contained in your brain: down to the quantum states of every atom in it.

Good luck with that :)

EDIT: The dog ate part of my text.

Answer 5

Simulating a neuron is possible and therefore theoretically simulating a brain is possible.

The two things that always stump me as an issue is input and output though.

We have a very large number of nerve endings that all provide input to the brain. Without them the brain is useless. How can we simulate something as complicated as the human brain without also simulating the entire human body!?!

Output, once the brain has "dealt" with all of the inputs that it gets, what is then the output from it? How could you say that the "copy" of your brain was actually you without again hooking it up to a real human body that could speak and tell you?

All in all, a fascinating subject!!!!

Answer 6

What is your goal? Do you want a program that can make intelligent decisions or a program that provides a realistic model of how the human brain actually works? Artificial intelligence can be approached from the perspective of psychology, where the goal is to simulate the brain and thereby get a better understanding of how humans think, or from the perspective of mathematics, optimization theory, decision theory, information theory, and computer science, in which case the goal is to create a program that is capable of making intelligent decisions in a computationally efficient manner. The latter, I would say is pretty much solved, although advances are definitely still being made. When it comes to a realistic simulation of the brain, I think we were only recently able to simulate a brain of cat semi-realistically; when it comes to humans, it would not be very computationally feasible at present.

Answer 7

A neuron-like circuit can be built with a handful of transistors. Let's say it takes about a dozen transistors on average. (See http://diwww.epfl.ch/lami/team/vschaik/eap/neurons.html for an example.)

A brain-sized circuit would require 100 billion such neurons (more or less).

That's 1.2 trillion transistors.

A quad-core Itanium has 2 billion transistors.

You'd need a server rack with 600 quad-core processors to be brain-sized. Think $15M US to purchase the servers. You'll need power management and cooling plus real-estate to support this mess.

One significant issue in simulating the brain is scale. The actual brain only dissipates a few watts. Power consumption is 3 square meals per day. A pint of gin. Maintenance is 8 hours of downtime. Real estate is a 42-foot sailboat (22 Net Tons of volume as ships are measured) and a place to drop the hook.

A server cage with 600 quad-core processors uses a lot more energy, cooling and maintenance. It would require two full-time people to keep this "brain-sized" server farm running.

It seems simpler to just teach the two people what you know and skip the hardware investment.

Answer 8

Roger Penrose presents the argument that human consciousness is non-algorithmic, and thus is not capable of being modeled by a conventional Turing machine-type of digital computer. If it's like that you can forget about building a brain with a computer...