Donald Hebb, a Canadian neuropsychologist found a simple way to articulate a process that’s still a mystery: he said that “neurons that fire together wire together.” That linkage could take place as you learn a new movement, or form a mental association between an experience and a scent or flavor.

According to Fast Company, some of the tech companies that are trying to simulate this action include Facebook, which uses neural networks to identify your friends in photos, and Google, whose Deep Dream technology layers artificial neurons (think CPUs) that work together to interpret or “see” images presented to the network. Deep Dream is designed to transcend the limitations of the linear connections among transistors in a computer processor and function more like human neurons. Google engineers have been able to train Deep Dream to make more refined inferences from images, to the point where the technology can identify images of specific objects and even create pictures of them.