Researchers have begun to show that it is possible to use brain recordings to reconstruct aspects of an image or movie clip someone is viewing, a sound someone is hearing or even the text someone is reading. A new study by University of Pennsylvania and Thomas Jefferson University scientists brings this work one step closer to actual mind reading by using brain recordings to infer the way people organize associations between words in their memories.
Epilepsy patients who volunteered for the study while awaiting brain surgery had tiny electrodes implanted in their brains, which allowed researchers to precisely observe electrical signals that would not have been possible to measure outside the skull. While recording these electrical signals, the researchers asked the participants to study lists of 15 randomly chosen words and, a minute later, to repeat the words back in whichever order they came to mind.
The researchers examined the brain recordings as the participants studied each word to home in on signals in the participant’ brains that reflected the meanings of the words. About a second before the participants recalled each word, these same “meaning signals” that were identified during the study phase were spontaneously reactivated in the participants’ brains.