away. The rats could be instructed to turn left or right, climb trees and ladders, navigate piles of rubble, and jump from different heights. They could even be commanded into brightly lit areas, which rats usually avoid. It has been suggested that the rats could be used to carry cameras to people trapped in disaster zones. In 2013, researchers reported the development of a radio-telemetry system to remotely control free-roaming rats with a range of 200 m. The backpack worn by the rat includes the mainboard and an FM transmitter-receiver, which can generate biphasic microcurrent pulses. All components in the system are commercially available and are fabricated from surface mount devices to reduce the size (25 x 15 x 2 mm) and weight (10 g with battery). Ethics and welfare concerns Concerns have been raised about the ethics of such studies. Even one of the pioneers in this area of study, Sanjiv Talwar, said "There's going to have to be a wide debate to see whether this is acceptable or not" and "There are some ethical issues here which I can't deny." Elsewhere he was quoted as saying "The idea sounds a little creepy." Some oppose the idea of placing living creatures under direct human command. "It's appalling, and yet another example of how the human species instrumentalises other species," says Gill Langley of the Dr Hadwen Trust based in Hertfordshire (UK), which funds alternatives to animal-based research. Gary Francione, an expert in animal welfare law at Rutgers University School of Law, says "The animal is no longer functioning as an animal," as the rat is operating under someone's control. And the issue goes beyond whether or not the stimulations are compelling or rewarding the rat to act. "There's got to be a level of discomfort in implanting these electrodes," he says, which may be difficult to justify. Talwar stated that the animal's "native intelligence" can stop it from performing some directives but with enough stimulation, this hesitation can sometimes be overcome, but occasionally cannot. Non-invasive method Researchers at Harvard University have created a brain-to-brain interface (BBI) between a human and a Sprague-Dawley rat. Simply by thinking the appropriate thought, the BBI allows the human to control the rat's tail. The human wears an EEG-based brain-to-computer interface (BCI), while the anesthetised rat is equipped with a focused ultrasound (FUS) computer-to-brain interface (CBI). FUS is a technology that allows the researchers