Head direction cells efference copy") preparing the network for an impending head turn. HD cells continue to fire in an organized manner during sleep, as if animals were awake. However, instead of always pointing toward the same direction—the animals are asleep and thus immobile—the neuronal "compass needle" moves constantly. In particular, during rapid eye movement sleep, a brain state rich in dreaming activity in humans and whose electrical activity is virtually indistinguishable from the waking brain, this directional signal moves as if the animal is awake: that is, HD neurons are sequentially activated, and the individual neurons representing a common direction during wake
Imagined speech intent of providing a foundation for synthetic telepathy. According to DARPA, the project “will allow user-to-user communication on the battlefield without the use of vocalized speech through neural signals analysis. The brain generates word-specific signals prior to sending electrical impulses to the vocal cords. These imagined speech signals would be analyzed and translated into distinct words allowing covert person-to-person communication.” DARPA's program outline has three major goals: The process for analyzing subjects' "silent speech" is composed of recording subjects’ brain waves, and then using a computer to process the data and determine the content of the subjects' "covert speech". Subject