Neuroscientist Miguel Nicolelis (Duke University) studies brain-machine interfaces. In this study, Nicolelis and colleagues connected two rats together electronically, allowing signals to pass from one to the other.
Scientists have wired the brains of two rats together and shown that signals from one rat’s brain can help the second rat solve a problem it would otherwise have no clue how to solve.
The rats were in different cages with no way to communicate other than through the electrodes implanted in their brains. The transfer of information from brain to brain even worked with two rats separated by thousands of kilometers, one in a lab in North Carolina and another in a lab in Brazil. - from Rodent Mind Meld: Scientists Wire Two Rats’ Brains Together (Wired, Greg Miller).
This is interesting by itself. However, last week I read a novel by Ramez Naam called Nexus:
In the near future, the experimental nano-drug Nexus can link human together, mind to mind. There are some who want to improve it. There are some who want to eradicate it. And there are others who just want to exploit it.
When a young scientist is caught improving Nexus, he’s thrust over his head into a world of danger and international espionage – for there is far more at stake than anyone realizes.It was a fast-paced and gripping novel in the growing "post-human" genre. Good science-fiction is often just on the horizon of current technology. If you're interested in thinking about the consequences of linking humans (not just rats) mind-to-mind, this book provides both a grim and inspiring tale.