In a lab at Harvard Medical School, a man is using his mind to wag a rat’s tail. To send his command, he merely glances at a strobe light flickering on a computer screen, and a set of electrodes stuck to his scalp detects the activity triggered in his brain. A computer processes and relays the electrodes’ signal to an ultrasound machine poised over the rat’s head. The machine delivers a train of low-energy ultrasound pulses into the rat’s brain, stimulating its motor cortex – the area that governs its movements. The pulses are aimed purposely at a rice-grain-sized area that controls the rat’s tail. It starts to wag.

This link-up is the brainchild of Seung-Schik Yoo, and it works