But devices will be irrelevant in the future suggested by the “Through the Wormhole” episode. “What if hackers learned to read, or tamper with, our most precious and private store of data, the contents of our minds?” Mr. Freeman, the show’s host, says in his ominous introduction. “Hacking into our thoughts requires decoding the logic of our neurons,” he adds. “Science is getting close to achieving that goal.”

The episode checks in on Marc Salem, whose popular stage shows feature what seem like mind-reading tricks, and on an effort to create a communication device for people with amyotrophic lateral sclerosis (Lou Gehrig’s disease) that would read the electrical pulses of their brains.

“By seeing the activation of particular brain structures, we can tell, ‘Ah, this person is trying to move his hands,’ ” explains Philip Low, a neuroscientist.

It is both frightening and exhilarating that science is getting close to decoding the logic of our neurons.