The Trouble with Brain Scans
Happy Holidays. In this special issue we are reprinting our top stories of the past year. This article first appeared online in our “Mind” issue in March, 2021.
One autumn afternoon in the bowels of UC Berkeley’s Li Ka Shing Center, I was looking at my brain. I had just spent 10 minutes inside the 3 Tesla MRI scanner, the technical name for a very expensive, very high maintenance, very magnetic brain camera. Lying on my back inside the narrow tube, I had swallowed my claustrophobia and let myself be enveloped in darkness and a cacophony of foghorn-like bleats.
At the time I was a research intern at UC Berkeley’s Neuroeconomics Lab. That was the first time I saw my own brain from an MRI scan. It was a grayscale, 3-D reconstruction floating on the black background of a computer screen. As an undergraduate who studied neuroscience, I was enraptured. There is nothing quite like a young scientist’s first encounter with an imaging technology that renders the hitherto invisible visible—magnetic resonance imaging took my breath away. I felt that I was looking not just inside my body, but into the biological recesses of my mind.
It was a strange self-image, if indeed it was one. My hair did not show up, leaving just the skull and outline of the face with a cross section of the tissues inside. Dragging my mouse, I cruised through the horizontal slices of my brain—there were the branching, root-like patterns of the cerebellum, the gaping black holes of the ventricles, and the undulating ridges of my cortex looking like snakes wiggling in the sand.
Full of excitement after my encounter with MRI, I consumed scientific papers and studied their figures, which were usually grayscale brains with bright orange and blue blobs on them indicating regions of increased activation. The following year I joined a lab at Harvard, where I started working on an experiment that used functional MRI, or fMRI, to study the brain regions involved in social decision-making. fMRI allows us to record what the brain is up to while people perform mental tasks. I committed to a senior thesis and set my future sights on a Ph.D. in cognitive science.
We seek something deeper in these pictures of blood flow in the brain.
Little did I anticipate what a scientific morass I had entered. Functional magnetic resonance imaging has transformed medicine. It allows non-invasive mapping of a patient’s brain regions to enable more accurate, precise neurosurgery, as well as validating pharmacological effects of potential drugs on human brains. But fMRI’s use in cognitive and psychological science is notoriously controversial. This is partly because the technology doesn’t directly measure neural activity but rather a proxy for it—oxygenated blood flow. It also requires a tremendous amount
