When President Obama recently complained, that although "we can identify galaxies light years away, study particles smaller than an atom ... we still haven't unlocked the mystery of the three pounds of matter that sits between our ears" - he called on scientists to unravel the trillions of neural connections inside our brains that make our minds work.

Some researchers are already doing that - trying to understand the brain by starting to build one. At Reading University, at the newly constructed Brain Embodiment Laboratory, researchers plan to connect cultures of living human neurons to robots - to give meaning to their neural activity. At Georgia Tech, Atlanta, neuroengineer Steve Potter, agrees that cultured neurons not connected to the outside world suffer sensory deprivation. His neural arrays descend into spasms of epileptic activity when left alone. When plugged in, they can control machines across the planet.

"I believe these cultures are half-way to having a mind," says Potter. "Wired up to listen to their own outputs, they could be self aware."

Other researchers are building brains from inanimate materials - using tendrils of silver, silicon and sulphur that spring into life like activity when wired up to electricity. At Stanford University, plans are afoot to meld them with living neurons - perhaps to enhance our thought processes.

These devices can learn, remember and process information - but do they think? Can these scientists really build a brain? And what would it tell us about ours if they could?