In November 1991, a team of researchers at Massachusetts General Hospital described a radical new method for visualizing activity within the human brain. By using giant, superconducting magnets, the scientists were able to peer inside the skull, constructing precise maps of the mind at work. The black box had been flung wide open.
The brain-scan image—a silhouette of the skull, highlighted with bright splotches of primary color—has even become a staple of popular culture, a symbol of how scientific advances are changing the way we think about ourselves. The expensive machine is like a high-tech window into the soul.
Many of these limitations are rooted in the fact that the scanners are forced to measure brain activity indirectly: Neurons speak in squirts of neurotransmitters and bursts of electricity, but fMRI machines can track only changes in blood flow.
In theory, this discrepancy shouldn’t be a big obstacle, as numerous studies have found that blood flow is a useful approximation for what’s actually happening in the brain.
The problems begin, however, when researchers attempt to take complex psychological phenomena, such as the experience of love, and reduce them to particular blobs of cortex. They do this by leaning heavily on complex statistical algorithms that allow them to sort the “noise” from the “signal.”
While it is exciting to directly peek into human mind through fMRI, the tech now is still at its infancy.