Decoded - How the Brain Hears Words

By placing electrodes on the brains of research subjects and then having them listen to conversations, scientists were able to analyze the sound frequencies registered and figure out which words they were hearing.

"We were focused on how the brain processes the sounds of speech," researcher Brian Pasley of the Helen Wills Neuroscience Institute at the University of California Berkeley told AFP.

"Most of the information in speech is between one to 8,000 hertz. Essentially the brain analyzes those different sound frequencies in somewhat separate locations."

By tracking how and where the brain registered sounds in the temporal lobe -- the center of the auditory system -- scientists were able to map out the words and then recreate them as heard by the brain.

"When a particular brain site is being activated, we know that roughly corresponds to some sound frequency that the patient is actually listening to," Pasley said.

"So we could map that out to an extent that would allow us to use that brain activity to resynthesize the sound from the frequencies we were guessing."