From The Guardian:
'My bra! My bra! I have to take off my bra!" yells Fiona Shaw, running past me into a changing room. She sounds like Richard III after the battle of Bosworth Field: "A horse! A horse! My kingdom for a horse!" What a top thesp Shaw is: even when she's in a panic about her underwear she sounds Shakespearean, such is her actorly grasp of prosody.
And this is no small matter. Shaw has come to the basement of London University's psychology department to be analysed by cognitive neuroscientists. Today's experiment will find out what – if anything – goes on in actors' brains when they perform a role. "I'm sure there's some sort of muscle," says Shaw. "I'm sure I'm using the wrong word – some sort of muscle in an actor's brain which is extended."
But why does Shaw have to take off her bra? Because it's underwired. Metal plays havoc with the huge magnet used in the machine that is going to scan her brain. There have been accidents involving highly magnetised flying oxygen canisters – not here but in scanning rooms in other parts of the world.
People who aren't actors usually have one question they ask more than any other: how do we memorize all those words? My response has stayed fairly the same for a few years now: we don't memorize the words, but rather the thoughts. Knowing the actual words becomes an inevitable byproduct of understanding the progression of a character's thoughts, needs, and impulses. This video offers an exciting and fascinating scientific view into the actor process. It's absolutely marvelous.
Now, I'll get back to memorizing lines.