Thoughts are free, who can guess them?” are the lyrics of a well-known German folksong. And in actuality, in a world in which our behavior is becoming increasingly transparent thanks to social media, GPS tracking and the internet, it sometimes seems that thoughts are the only things that remain hidden from others. Only the person herself knows what she is thinking. For many, this report from the other end of the world may thus sound like a horrible nightmare: the neurologist Tom Oxley and his team at the University of Melbourne in Australia are working on a device to precisely read thoughts and record them. One goal for this device in the future might be to control computers with thoughts alone.

The focus of global research is on what is known as a brain modem—a tiny transmitter, just the size of a paperclip. It’s a modem because the transmitter serves as a translator between two end devices. In this case, the brain modem would translate the electrochemical language of the brain’s neurons into the zeros and ones of common information technology.

This transmitter can significantly advance the ability of researchers to investigate the brain: previously, collecting information on neurological activities was primarily done with helmets of electrodes, yet these are not very exact. A transmitter would guarantee more detailed information. However, until now one could only be inserted with a risky surgical procedure.

Based on existing stent technology, these new small transmitters will soon be able to be injected directly into the bloodstream. These “stentrodes”—a combination of stent and electrode—are monitored until they reach the brain of their own accord and are then commanded to expand and latch onto the sides of a blood vessel. The technology has thus far been tested on sheep. 
Yet it remains to be seen whether these brain modems will actually be able read thoughts. Although initial tests with human subjects are currently planned, the neurologist Tom Oxley is playing down expectations. Presumably we’ll still be able to think what we want to for a long time yet—with our thoughts safely hidden in the privacy of our own heads.