Adventures in blobology: 20 years of fMRI brain scanning

Neuroimaging is commonplace, but do you know what you’re getting into? Katrina Lawrence/AFP

This month, fMRI brain imaging celebrates its 20th anniversary. And so it should. It has come to dominate cognitive neuroscience.

Massive amounts of precious funding are poured into it and thousands of studies are published every year.

Critics say it’s not worth it – brain imaging will not explain the mind. But this criticism is premature: brain imaging is maturing and holds explanatory promise.

Fun and games

Lying in the MR scanner, you are playing rock, paper, scissors on a computer screen. Half the time, you’re told your opponent is a computer program, the rest of the time that it’s another person.

Though the sequence of play is, in fact, exactly the same, the game feels different when you believe you are playing against a person.

This a functional magnetic resonance imaging (fMRI) experiment. As you play, a massive magnetic field pulsates through your body and picks up minute changes in the blood flow of your brain.

The pattern of changes differs when you believe you play a person as opposed to when you believe your opponent is a computer.

Subtract the patterns from each other, do some more statistics, and the result is a neat coloured blob on a picture of the brain.

Since the only real difference between the playing conditions is your mental state, the difference in brain activity must be specific to that type of mental state.

So the blob signifies the part of the brain that explains why we interact differently with people and computers.

Meaningful blobs

The technique for this research – functional magnetic resonance imaging – was published 20 years ago this month in Science. It caused a dramatic shift in neuroscience.

Thousands of papers have subsequently been published, all with images of blobs on brains.

All sorts of mental phenomena are now routinely scanned, from viewing simple shapes to emotional states, such as disgust, religious belief, love and beyond, to psychosis, depression and psychopathy.

We love the blobs and have become accustomed to them. No matter what the quality of the message, if it’s accompanied by images of brain blobs and explained with some neurobabble, we are ready to believe it.

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