Scientists recently discovered that a sophisticated type of brain scanner showed activity when cognitive tests were performed on a dead salmon. In other words, they bought a whole salmon at a market, stuck it in the machine, showed it some pictures and asked it some questions, and found activity in the scanner data. Ultimately, the paper is trying to highlight the fact that using these sorts of devices isn't as simply as a point-and-shoot camera, and if proper care isn't taken, well, your results will show a dead salmon thinking about a beach picture you're showing it.