Minds of their own

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: In one of William Gibson’s early mind-bending stories, the protagonist suddenly needs to fly a jump jet. In the cockpit, he finds his employer has thoughtfully stashed a biochip containing all the necessary piloting skills for him to plug into his own nervous system. While your correspondent applauded the idea at the time, he nevertheless dismissed it as pure science-fiction. Today, he’s not so sure.

The progress being made in neuroengineering—devising machines that mimic the way the brain and other bodily organs function—has been literally eye-opening. In the decade since Kevin Warwick, professor of cybernetics at Reading University in Britain, had a silicon chip implanted in his arm so he could learn how to build better prostheses for the disabled, we now have cochlear implants that allow the deaf to hear, and a host of other spare mechanical parts to replace defective organs.

A bionic eye, to help people suffering from macular degeneration, is in the works, and artificial synapses are being tested as possible replacements for damaged optic nerves. An implantable electronic hippocampus—the world’s first brain prosthesis—is being developed for people who lose the ability to store long-term memories following a stroke, epilepsy or Alzheimer’s disease.

Meanwhile, a team at the University of Sheffield in Britain has built a ‘brainbot’ controlled by a mathematical model of the brain’s basal ganglia—the part that helps us decide what to do next. Depending on how much simulated dopamine (the neurotransmitter in the brain that controls movement, behaviour, mood and learning) is dialled into the mathematical model, the brainbot responds differently.

Too much, and the machine has trouble suppressing unwanted actions, or tries to do two incompatible things at once—like patients with Huntington’s disease, Tourette’s syndrome or schizophrenia. Too little digital dopamine, and the machine has difficulty deciding how to move—like patients with Parkinson’s disease.

Warwick’s team at Reading has now gone a stage further. Instead of using a computer model of part of the brain as a controller, the group’s new ‘animat’ (part animal, part material) relies solely on nerve cells from an actual brain.