Rat neurons can be used to control simple robots, researchers report.

By hooking up hundreds of thousands of fetal rat brain cells to a wheeled machine via an array of electrodes, the neurons’ spontaneous firing can direct its motion, University of Reading scientists announced yesterday.

The work is a fascinating bioengineering feat, but the robots have limited capacity to do much of anything. It’s not as if they hook the cells up to a the robot and it makes a beeline for any available cheese.

In fact, the researchers measure success by how often they can get the neurons to keep the robot from running into walls.

The New Scientist has thorough coverage on the rat/machine hyrids that go way beyond the Reading work. They detail how Steve Potter of Georgia Tech is learing to program these so-called "animats." (Or, as Potter calls them in an earlier Tech Review article, "hybrots." Personally, I prefer robomals.)

Potter has found, via trial and error, that applying electric pulses to some of the electrodes can elicit different behavior from the neurons, getting them to steer in a straight line, for example. They don’t understand the logic behind the brain cells’ response, so they simply try out random pulses:

But because all cultures are different, he doesn’t know which pulse sequences will work best for each of them. So he randomly generates 100

different sequences – called pattern training stimuli – for each culture and lets a computer work out which ones produce the best neural connections to make a virtual robot move in a desired direction. After the selected stimuli have been applied a few times, certain behaviours become embedded in the culture for some hours. In other words, the culture has been taught what to do. "It’s like training an animal to do something by gradual increments," Potter says.

The researchers at Reading and Georgia Tech say that the research could help neuroscientists learn about the brain, but caution against extrapolating too much from a few hundred thousand neurons smeared on some electrodes to the human brain’s 100 billion neuron complexity.

"This system is a model. Everything it does is merely similar to what goes on in a brain, it’s not really the same thing," he told New Scientist. "We can learn about the brain – but it may mislead us."

Video: New Scientist video of the Reading animat.

See Also:

Brandon’s 2006 Wired story on Potter’s early animat work

WiSci 2.0: Alexis Madrigal’s Twitter , Google Reader feed, and webpage; Wired Science on Facebook.