Scientists create `most realistic artificial human brain yet`
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Last Updated: Sunday, December 02, 2012, 18:14
  
London: Scientists claim to have developed the "closest model" to a functioning human brain ever created and it is advanced enough to pass a basic IQ test.

The simulated brain - which runs on a supercomputer, has a digital eye which it uses for visual input and a robotic arm that it uses to draw its response, the 'Daily Mail' reported.

Neuroscientists and software engineers at the University of Waterloo in Canada claim it is world's most complex, large-scale model simulation of the human brain so far created, according to www.Extremetech.Com.

The brain, called Spaun (Semantic Pointer Architecture Unified Network), consists of 2.5 million simulated neurons, allowing it to perform eight different tasks.

These tasks range from copy drawing to counting, to question answering and fluid reasoning.

During the tests the scientists flashed up numbers and letters, which Spaun reads into memory, and then another letter or symbol acts as the command, telling Spaun what to do with its memory.

The output of the task is then inscribed by the robotic arm, the team reported in the journal Science.

Spaun's brain consists of 2.5 million neurons that are broken down into a bunch of simulated cranial subsystems, including the prefrontal cortex, basal ganglia, and thalamus, which are wired together with simulated neurons that very accurately mimic the wiring of a real human brain.

The basic idea is that these subsystems behave very similarly to a real brain: Visual input is processed by the thalamus, the data is stored in the neurons, and then the basal ganglia fires off a task to a part of the cortex that's designed to handle that task.

All of this computation is performed in a physiologically accurate way, with simulated voltage spikes and neurotransmitters.

Even the limitations of the human brain are simulated, with Spaun struggling to store more than a few numbers in its short-term memory.

The end result is a brain that is mechanistically simple, but which is surprisingly flexible.

The next step, said the research team, led by Chris Eliasmith, is to imbue Spaun with adaptive plasticity - the ability to rewire its neurons and learn new tasks simply by doing, rather than being pre-programmed.

"It lets us understand how the brain, the biological substrate, and behaviour relate. That's important for all sorts of health applications," Eliasmith said in an interview with PopSci.

In testing he has 'killed' synthetic neurons and watched performance degrade, which could provide an interesting insight into natural ageing and degenerative disorders, the report said.

PTI


First Published: Sunday, December 02, 2012, 18:13


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