Beware of your thoughts when you're around a functional magnetic resonance imaging (ie an fMRI). Because with it, scientists can easily know what you're thinking!
In a new study, led by neuroscientist Frank Tong of Vanderbilt University, volunteers were shown two different patterns and were then asked to picture one or the other.
Using fMRI brain scans, the researchers predicted with 80 percent accuracy which of the two patterns each person was actively holding in memory 11 seconds later.
fMRI images reveal which groups of neurons are active by measuring blood flow.
Tong explained that some of the visual cortex's neurons are associated more with vertical visual patterns, while others with horizontal or angled patterns.
The difference made the team to predict which pattern volunteers had in mind, even after the images were removed from the screen.
"Here we find that the visual parts of the brain, those involved in seeing, are also involved in actively remembering something," National Geographic News quoted Tong as saying.
He added: "That's not been shown before. What might be happening is that you're maintaining a representation of what you just saw by very faint levels of activity in the visual cortex."
Henry Rusinek, a radiologist at New York University School of Medicine, said that the analysis of an area of the primary visual cortex called V1 suggested that the region performs complex functions, like focusing one's attention, independently of other brain regions.
The primary visual cortex receives the visual signal from the eyes and then sends these signals to a host of higher visual areas.
Rusinek called the study "pretty convincing evidence that [the] V1 network-only a couple of neurons distant from the eye-has a short-term memory."
The study was published online in the journal Nature.