This is a pretty impressive advancement in mind-computer interfaces. Their technology can actually read and interpret the visual cortex, reconstructing what you are seeing. This would apply to actual visual images coming thorough the eye, or things you “see” in a dream.
“In a nutshell, the device converts electrical signals sent to the visual cortex into images that can be viewed on a computer screen. In their experiment, they showed test subjects the six letters in the word neuron and succeeded in reconstructing the word on screen by measuring their brain activity.”