The technique called fMRI creates images from activities in the brain based on the flow of blood in different parts of the brain. The researchers then take measurements of the brain based on these activities.

Gallant states, "Our results suggest that it may soon be possible to reconstruct a picture of a person's visual experience from measurements of brain activity alone. Imagine a general brain-reading device that could reconstruct a picture of a person's visual experience at any moment in time." [The Guardian: “Scary or sensational? A machine that can look into the mind”]

The conclusions of the Gallant study (“Identifying natural images from human brain activity”) are written up in the March 5, 2008 issue of journal Nature. The authors include Kendrick N. Kay, Thomas Naselaris, R.J. Prenger, and Jack L. Gallant. [Story in Nature about the study: “Mind-reading with a brain scan”]

The team’s experiment involved scanning the brains, specifically the visual cortex, of two of its members—co-authors Thomas Naselaris and Kendrick Kay—using fMRI and a computer decoder.

The subjects looked at a set of 1,750 photographs over a period of five hours involving such things as food, people, and buildings.

The fMRI device scans the brain’s activity during this time. In this attempt, the researchers are teaching the decoder device to reconstruct how the brain identifies certain activities, shapes, and things.

How did they get their results from the experiment performed on their co-authors' brains? Please read on.