‘One foot in sea, and one on shore, to one thing constant never.’ –Shakespeare
Back in 2009, researchers at the University of California, Santa Barbara performed a curious experiment. In many ways, it was routine — they placed a subject in the brain scanner, displayed some images, and monitored how the subject’s brain responded. The measured brain activity showed up on the scans as red hot spots, like many other neuroimaging studies.
Except that this time, the subject was an Atlantic salmon, and it was dead.
Dead fish do not normally exhibit any kind of brain activity, of course. The study was a tongue-in-cheek reminder of the problems with brain scanning studies. Those colorful images of the human brain found in virtually all news media may have captivated the imagination of the public, but they have also been subject of controversy among scientists over the past decade or so. In fact, neuro-imagers are now debating how reliable brain scanning studies actually are, and are still mostly in the dark about exactly what it means when they see some part of the brain “light up.”