Well, you're into writing, so let me put it this way:
When you write and brainstorm, you're using your right brain.
When you edit and revise, you're using your left brain.
Does that make sense?
The only further point I could make is that the left brain is about precision processing and analysis, while the right is about holistic processing and synthesis. It's classically defined as the difference between an accountant, mathmatician, or secretary (left), and an author, artist, or entertainer on the other (right). The difference between open-ended and present behavior, as opposed to goal-oriented and future behavior.
In MBTI terms, you could define it as in one sense being P (right) vs J (left), but also being N (right) vs S (left). So essentially, NPs exemplify the right-brained approach, and SJs exemplify the left-brained approach, especially ENTPs and ISTJs, IMO. Actually, you might also choose to describe it as the difference between perceiving and judging functions.
The left brain's function is to evaluate and organize, the right brain's is to create and change.
Ne types are all massively right brained from memory (as Athenian said). My left is a little backup rig in the corner. (what's sense and order?)
Freude, schöner Götterfunken Tochter aus Elysium, Wir betreten feuertrunken, Himmlische, dein Heiligtum! Deine Zauber binden wieder Was die Mode streng geteilt; Alle Menschen werden Brüder, Wo dein sanfter Flügel weilt.
Like, to the person who has the brain or the person looking at it?
You always have to ask the little but important questions that no one else thinks to ask.
To the person who has it, of course. The person looking at it could be standing anywhere relative to the brain. If they're standing behind the person, it's on the same side for both of them. If they're off the the side, one side is in front of them, and if they're in front, the person's left is on the observer's right.
But the point is, the same side of your brain will always be on YOUR left and right, but not always on the same sides for an observer. Thus, it has to be your own left and right for the sake of consistency.
At least, I hope everyone thought so. If none of the researchers remembered that, all the data might be imaginary or flawed because they didn't keep accurate track of, or even agree on which side of the brain was which.