The Brain Makes Its Own GhostsThe Brain Makes Its Own Ghosts

The Brain Makes Its Own Ghosts

When I was little, whenever I climbed a flight of stairs in the dark, the climbing quickly turned to running. About halfway up the steps, every time, I was overcome with an unshakeable certainty that there was a monster behind me, chasing me. I won’t say I never get that feeling anymore, but I force myself to walk up the stairs slowly and calmly when it happens now, swallowing my fear. That’s called being an adult.

The sense of someone near you when no one is actually there is called “feeling of presence” or FOP, apparently, according to a new study in Current Biology that identified the regions of the brain associated with this sensation and, wildly, recreated it in a lab setting.

“Although it is described by neurological and psychiatric patients and healthy individuals in different situations, it is not yet understood how the phenomenon is triggered by the brain,” the study reads.

First the researchers, who mostly hailed from Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland, studied the brains of 12 patients with neurological disorders (mainly epilepsy) who had experienced FOP, and found lesions in three regions of their brains: the insular cortex, frontoparietal cortex, and temporoparietal cortex. These areas deal with self-awareness, movement, and spatial positioning, suggesting that when sensorimotor signals get confused, people can feel presences that aren’t there.

Further supporting this argument was the next experiment, in which the researchers had a robot give confusing sensorimotor signals to healthy people with no neurological disorders, and were able to create FOP on command. Participants controlled the robot by moving a stick in front of them, which caused a metal arm behind them to touch them on the back in the same pattern, as seen in the video below.