From the article "Dr. Robin Carhart-Harris is the first scientist in over 40 years to test LSD on humans - and you're next."
"When people take psychedelics recreationally, in a social context," he says, "they might get preoccupied by the perceptual changes and the novelty, and they'll laugh their way through with a certain amount of confusion and anxiety. But in an experimental context, particularly in the therapeutic context, people lie on a couch with their eyes closed and have a very introspective experience. It's richer; psychologically, it's more interesting.
Presumably he is doing fMRI scans similar to what he did with psilocybin.