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This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute.

For decades, scientists have used an imaging technique called functional¹ magnetic resonance² imaging, or fMRI, to chronicle the brain in action. But a study in the January 22nd issue of Nature suggests that fMRI might show more than what the brain is doing—it might reveal what the brain’s about to do.

FMRI studies assume that blood flow in the brain correlates with neuronal activity. Active brain cells need nutrients³, which are brought to the cells by freshly oxygenated blood. But in the new study, scientists found that fMRI also detects increased blood flow in brain regions that aren’t active—but that may be in the near future.

The researchers trained monkeys to perform a specific visual task. And they found that, even when the animals were sitting in the dark waiting for the test to begin, fMRI nevertheless revealed an increased blood flow to the monkeys’ visual cortex.

The study suggests that fMRI data may be a lot more interesting than we thought. Scientists may be looking at their imaging data in a way that’s too simplistic. And fMRI may not be measuring exactly what we thought it did. What will they think of next? Maybe fMRI can tell.

Thanks for the minute for Scientific American's 60-Second Science. I'm Karen Hopkin.