Tag Archives: Centre for Theoretical Neuroscience

University of Waterloo researchers use 2.5M (virtual) neurons to simulate a brain

I hinted about some related work at the University of Waterloo earlier this week in my Nov. 26, 2012 posting (Existential risk) about a proposed centre at the University of Cambridge which would be tasked with examining possible risks associated with ‘ultra intelligent machines’.  Today (Science (magazine) published an article about SPAUN (Semantic Pointer Architecture Unified Network) [behind a paywall])and its ability to solve simple arithmetic and perform other tasks as well.

Ed Yong writing for Nature magazine (Simulated brain scores top test marks, Nov. 29, 2012) offers this description,

Spaun sees a series of digits: 1 2 3; 5 6 7; 3 4 ?. Its neurons fire, and it calculates the next logical number in the sequence. It scrawls out a 5, in legible if messy writing.

This is an unremarkable feat for a human, but Spaun is actually a simulated brain. It contains2.5 millionvirtual neurons — many fewer than the 86 billion in the average human head, but enough to recognize lists of numbers, do simple arithmetic and solve reasoning problems.

Here’s a video demonstration, from the University of Waterloo’s Nengo Neural Simulator home page,

The University of Waterloo’s Nov. 29, 2012 news release offers more technical detail,

… The model captures biological details of each neuron, including which neurotransmitters are used, how voltages are generated in the cell, and how they communicate. Spaun uses this network of neurons to process visual images in order to control an arm that draws Spaun’s answers to perceptual, cognitive and motor tasks. …

“This is the first model that begins to get at how our brains can perform a wide variety of tasks in a flexible manner—how the brain coordinates the flow of information between different areas to exhibit complex behaviour,” said Professor Chris Eliasmith, Director of the Centre for Theoretical Neuroscience at Waterloo. He is Canada Research Chair in Theoretical Neuroscience, and professor in Waterloo’s Department of Philosophy and Department of Systems Design Engineering.

Unlike other large brain models, Spaun can perform several tasks. Researchers can show patterns of digits and letters the model’s eye, which it then processes, causing it to write its responses to any of eight tasks.  And, just like the human brain, it can shift from task to task, recognizing an object one moment and memorizing a list of numbers the next. [emphasis mine] Because of its biological underpinnings, Spaun can also be used to understand how changes to the brain affect changes to behaviour.

“In related work, we have shown how the loss of neurons with aging leads to decreased performance on cognitive tests,” said Eliasmith. “More generally, we can test our hypotheses about how the brain works, resulting in a better understanding of the effects of drugs or damage to the brain.”

In addition, the model provides new insights into the sorts of algorithms that might be useful for improving machine intelligence. [emphasis mine] For instance, it suggests new methods for controlling the flow of information through a large system attempting to solve challenging cognitive tasks.

Laura Sanders’ Nov. 29, 2012 article for ScienceNews suggests that there is some controversy as to whether or not SPAUN does resemble a human brain,

… Henry Markram, who leads a different project to reconstruct the human brain called the Blue Brain, questions whether Spaun really captures human brain behavior. Because Spaun’s design ignores some important neural properties, it’s unlikely to reveal anything about the brain’s mechanics, says Markram, of the Swiss Federal Institute of Technology in Lausanne. “It is not a brain model.”

Personally, I have a little difficulty seeing lines of code as ever being able to truly simulate brain activity. I think the notion of moving to something simpler (using fewer neurons as the Eliasmith team does) is a move in the right direction but I’m still more interested in devices such as the memristor and the electrochemical atomic switch and their potential.

Blue Brain Project

Memristor and artificial synapses in my April 19, 2012 posting

Atomic or electrochemical atomic switches and neuromorphic engineering briefly mentioned (scroll 1/2 way down) in my Oct. 17, 2011 posting.

ETA Dec. 19, 2012: There was an AMA (ask me anything) session on Reddit with the SPAUN team in early December, if you’re interested, you can still access the questions and answers,

We are the computational neuroscientists behind the world’s largest functional brain model

Existential risk

The idea that robots of one kind or another (e.g. nanobots eating up the world and leaving grey goo, Cylons in both versions of Battlestar Galactica trying to exterminate humans, etc.) will take over the world and find humans unnecessary  isn’t especially new in works of fiction. It’s not always mentioned directly but the underlying anxiety often has to do with intelligence and concerns over an ‘explosion of intelligence’. The question it raises,’ what if our machines/creations become more intelligent than humans?’ has been described as existential risk. According to a Nov. 25, 2012 article by Sylvia Hui for Huffington Post, a group of eminent philosophers and scientists at the University of Cambridge are proposing to found a Centre for the Study of Existential Risk,

Could computers become cleverer than humans and take over the world? Or is that just the stuff of science fiction?

Philosophers and scientists at Britain’s Cambridge University think the question deserves serious study. A proposed Center for the Study of Existential Risk will bring together experts to consider the ways in which super intelligent technology, including artificial intelligence, could “threaten our own existence,” the institution said Sunday.

“In the case of artificial intelligence, it seems a reasonable prediction that some time in this or the next century intelligence will escape from the constraints of biology,” Cambridge philosophy professor Huw Price said.

When that happens, “we’re no longer the smartest things around,” he said, and will risk being at the mercy of “machines that are not malicious, but machines whose interests don’t include us.”

Price along with Martin Rees, Emeritus Professor of Cosmology and Astrophysics, and Jaan Tallinn, Co-Founder of Skype, are the driving forces behind this proposed new centre at Cambridge University. From the Cambridge Project for Existential Risk webpage,

Many scientists are concerned that developments in human technology may soon pose new, extinction-level risks to our species as a whole. Such dangers have been suggested from progress in AI, from developments in biotechnology and artificial life, from nanotechnology, and from possible extreme effects of anthropogenic climate change. The seriousness of these risks is difficult to assess, but that in itself seems a cause for concern, given how much is at stake. …

The Cambridge Project for Existential Risk — a joint initiative between a philosopher, a scientist, and a software entrepreneur — begins with the conviction that these issues require a great deal more scientific investigation than they presently receive. Our aim is to establish within the University of Cambridge a multidisciplinary research centre dedicated to the study and mitigation of risks of this kind.

Price and Tallinn co-wrote an Aug. 6, 2012 article for the Australia-based, The Conversation website, about their concerns,

We know how to deal with suspicious packages – as carefully as possible! These days, we let robots take the risk. But what if the robots are the risk? Some commentators argue we should be treating AI (artificial intelligence) as a suspicious package, because it might eventually blow up in our faces. Should we be worried?

Asked whether there will ever be computers as smart as people, the US mathematician and sci-fi author Vernor Vinge replied: “Yes, but only briefly”.

He meant that once computers get to this level, there’s nothing to prevent them getting a lot further very rapidly. Vinge christened this sudden explosion of intelligence the “technological singularity”, and thought that it was unlikely to be good news, from a human point of view.

Was Vinge right, and if so what should we do about it? Unlike typical suspicious parcels, after all, what the future of AI holds is up to us, at least to some extent. Are there things we can do now to make sure it’s not a bomb (or a good bomb rather than a bad bomb, perhaps)?

It appears Price, Rees, and Tallinn are not the only concerned parties, from the Nov. 25, 2012 research news piece on the Cambridge University website,

With luminaries in science, policy, law, risk and computing from across the University and beyond signing up to become advisors, the project is, even in its earliest days, gathering momentum. “The basic philosophy is that we should be taking seriously the fact that we are getting to the point where our technologies have the potential to threaten our own existence – in a way that they simply haven’t up to now, in human history,” says Price. “We should be investing a little of our intellectual resources in shifting some probability from bad outcomes to good ones.”

Price acknowledges that some of these ideas can seem far-fetched, the stuff of science fiction, but insists that that’s part of the point.

According to the Huffington Post article by Lui, they expect to launch the centre next year (2013). In the meantime, for anyone who’s looking for more information about the ‘intelligence explosion’ or  ‘singularity’ as it’s also known, there’s a Wikipedia essay on the topic.  Also, you may want to stay tuned to this channel (blog) as I expect to have some news about an artificial intelligence project based at the University of Waterloo (Ontario, Canada) and headed by Chris Eliasmith at the university’s Centre for Theoretical Neuroscience, later this week.