Whenever you recognize someone or something–your mother, the Space Needle, an iguana–it’s because certain neurons in your brain light up with activity almost exclusively in response to that one thing. You may pretend you don’t know who Heidi Montag is, but somewhere in your gray matter, your brain cells are proving you wrong. Researchers at CalTech used this principle to create a spooky game in which subjects manipulated a computer screen with their minds.

For each of 12 electrode-implanted subjects, the researchers repeatedly flashed over 100 familiar images on a screen while monitoring the activity of their neurons. Then they chose four images that elicited a particularly big crackle of activity in one area of the subject’s brain. For one subject, this meant they identified an area of Marilyn Monroe neurons, one of Josh Brolin neurons, one of Michael Jackson neurons, and a fourth area of Venus Williams neurons.

The actual experiment required each subject to sit in front of a screen, which would flash one of their four images: say, Michael Jackson. This was the “target.” Then the screen would show Michael Jackson superimposed with one of the other four images. The subject had to look at the hybrid image and concentrate on their target. A nifty feedback contraption, hooked up to those electrodes in the subject’s head, listened to the activity of their neuron groups and responded accordingly: the more the subject activated the neurons for Michael Jackson, the stronger his image would become on the screen. If the subject got distracted by Marilyn Monroe, her image would take over.

Amazingly, all the subjects figured out how to “win” the game, getting their target image to 100%–often on the first try. While seeing both images, they were able to increase the activity of one set of neurons and simultaneously quiet down the other set. This technology doesn’t have a lot of (OK, any) immediate practical applications. But it’s intriguing to imagine the computers of the future responding to commands in your head.

As long as it requires brain surgery, I’m guessing the image game won’t catch on. But you can play a much less invasive biofeedback game at the Museum of Science and Industry.