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andyandy
29th April 2007, 09:21 AM
US researchers have simulated half a virtual mouse brain on a supercomputer.
The scientists ran a "cortical simulator" that was as big and as complex as half of a mouse brain on the BlueGene L supercomputer.

In other smaller simulations the researchers say they have seen characteristics of thought patterns observed in real mouse brains.

Now the team is tuning the simulation to make it run faster and to make it more like a real mouse brain.

snip

Half a real mouse brain is thought to have about eight million neurons each one of which can have up to 8,000 synapses, or connections, with other nerve fibres.

Modelling such a system, the trio wrote, puts "tremendous constraints on computation, communication and memory capacity of any computing platform".

The team, from the IBM Almaden Research Lab and the University of Nevada, ran the simulation on a BlueGene L supercomputer that had 4,096 processors, each one of which used 256MB of memory.

Using this machine the researchers created half a virtual mouse brain that had 8,000 neurons that had up to 6,300 synapses.

The vast complexity of the simulation meant that it was only run for ten seconds at a speed ten times slower than real life - the equivalent of one second in a real mouse brain.

On other smaller simulations the researchers said they had seen "biologically consistent dynamical properties" emerge as nerve impulses flowed through the virtual cortex.

In these other tests the team saw the groups of neurons form spontaneously into groups. They also saw nerves in the simulated synapses firing in a ways similar to the staggered, co-ordinated patterns seen in nature.

The researchers say that although the simulation shared some similarities with a mouse's mental make-up in terms of nerves and connections it lacked the structures seen in real mice brains.

Imposing such structures and getting the simulation to do useful work might be a much more difficult task than simply setting up the plumbing.

For future tests the team aims to speed up the simulation, make it more neurobiologically faithful, add structures seen in real mouse brains and make the responses of neurons and synapses more detailed. http://news.bbc.co.uk/1/hi/technology/6600965.stm

very early stages...but pretty impressive...

DanishDynamite
29th April 2007, 09:39 AM
I don't quite see what is impressive about it. Yes, they managed to gather enough computational power to create a "simulation" with 8,000 nodes, each of which had up 6,300 connections to other nodes, but I fail to see where this simulation had any other results or any other similarity to a mouse brain (or half a mouse brain).

andyandy
29th April 2007, 10:06 AM
I don't quite see what is impressive about it. Yes, they managed to gather enough computational power to create a "simulation" with 8,000 nodes, each of which had up 6,300 connections to other nodes, but I fail to see where this simulation had any other results or any other similarity to a mouse brain (or half a mouse brain).

it's impressive [to me] because it's a snapshot into how the constraints of computer modelling are further being pushed back....

On other smaller simulations the researchers said they had seen "biologically consistent dynamical properties" emerge as nerve impulses flowed through the virtual cortex.

In these other tests the team saw the groups of neurons form spontaneously into groups. They also saw nerves in the simulated synapses firing in a ways similar to the staggered, co-ordinated patterns seen in nature.

...and this part in particular of the researchers' work is rather impressive....

Earthborn
29th April 2007, 10:10 AM
I would be impressed if they hooked that thing up to a robot with high bandwidth sensors and it showed some degree of intelligent behaviour in the real world. Lots of real animals that don't have nearly half a mouse's brain still manage to perform very complex tasks and have a very good capability for learning. And getting pattern recognition that is 'ten times slower than that of a mouse' would be a huge techonological advance.

DanishDynamite
29th April 2007, 10:21 AM
it's impressive [to me] because it's a snapshot into how the constraints of computer modelling are further being pushed back....
The constraints are constantly being pushed back as computers get more powerful. My point is just that the simulation didn't simulate any part of a mouse's brain.
...and this part in particular of the researchers' work is rather impressive....
Maybe. But from the description it just seems to say "Wow, neural nets have some things in common with a real brain!". This is old news.

DanishDynamite
29th April 2007, 10:23 AM
I would be impressed if they hooked that thing up to a robot with high bandwidth sensors and it showed some degree of intelligent behaviour in the real world. Lots of real animals that don't have nearly half a mouse's brain still manage to perform very complex tasks and have a very good capability for learning. And getting pattern recognition that is 'ten times slower than that of a mouse' would be a huge techonological advance.
I would be impressed if the simulation of an ant could be achieved.

Paul C. Anagnostopoulos
29th April 2007, 10:41 AM
If half a mouse brain has 8 million neurons and they simulated 8,000 neurons, then they did not simulate half a mouse brain's worth of neurons. Plus the simulation does not have brain structures. So how is it a simulation of half a mouse brain?

~~ Paul

Thabiguy
29th April 2007, 01:50 PM
I wouldn't mind that the simulation didn't have enough neurons. After all, it's a simulation, not a reconstruction. Fluids are also simulated with much less than accurate number of particles and nobody minds, as long as the result provides a useful approximation.

The question is, what particular parameters of the simulation were based on a mouse brain? In other words, what made this a simulation of a mouse brain, and not, say, a hummingbird brain?

Paul C. Anagnostopoulos
29th April 2007, 05:33 PM
I have no problem if they don't simulate all the neurons, either. But then don't call it a simulation of "half a mouse brain." Can I simulate giving you half of what I owe you if I only give you 1/1000 of half the money? :D

~~ Paul

rockoon
29th April 2007, 08:15 PM
8000 vs 8000000

This is a non-issue as its not a 1:1 problem.

A real neuron is likely to have inputs that have no bearing on its output. An artificial neuron can have such inputs removed from the input list, replaced by inputs that DO have an effect on its output.

Thus an artificial neuron is capable of "0% input waste" whereas a real one is highly likely to be wasting some, if not many of its inputs.

(for those who understand the typical "sum and threshhold" or "sum and sigmoid" style artificial neuron, imagine some of the input weights being very small while others very large .. many if not all of the small weight inputs will have no effect on the output)