Researchers have been able to make neurons 'glow in the dark' to help measure brain activity.
In other primate species, the brain areas that comprise the default mode network involve two systems that are not strongly connected to each other. The regions, one responsible for cognitive tasks and the other for the suppression of external events, appear to be only recently linked by evolution. This linkage may have facilitated the capacity for abstract thought that lead to the rapid evolution of human cognitive abilities.