Mind maps? Sounds a bit puzzling. How often do you happen to make a note of something and then forget or lose a piece of paper with the notes on it? Or maybe you read your notes later and do not understand them at all?
The process of writing or noting involves only the left hemisphere of the brain. Notes are usually long, visually monotonous, difficult to remember for the brain. When we read them, we often catch ourselves thinking about something else. This is all because you set your brain to a very monotonous, tedious work.