Here's an example of "User Wish" mind map including "Why", "Who" and "When" branches.



Gathering requirements or "User Stories" is always a challenging activity in Agile or in any other approaches. The primary factors that make this activity effective are communication and facilitation skills of the interviewer. In this session, I propose using mind mapping that focuses on those primary factors to explore “User Wish” -- a vague shape of user requirements before it is written into a form of User Stories.

Here's a whitepaper of the concepts.
http://astah.change-vision.com/en/zen/index.html