Culturing brain material and plugging it into robots, or "animats" as they are known. Rise of the rat-brained robots. This is no ordinary robot control system - a plain old microchip connected to a circuit board. Instead, the controller nestles inside a small pot containing a pink broth of nutrients and antibiotics. Inside that pot, some 300,000 rat neurons have made - and continue to make - connections with each other. To create the "brain", the neural cortex from a rat fetus is surgically removed and disassociating enzymes applied to it to disconnect the neurons from each other. The researchers then deposit a slim layer of these isolated neurons into a nutrient-rich medium on a bank of electrodes, where they start reconnecting. They do this by growing projections that reach out to touch the neighbouring neurons. "It's just fascinating that they do this," says Steve Potter of the Georgia Institute of Technology in Atlanta, who pioneered the field of neurally controlled animats. "Clearly brain cells have evo
