A visual way of exploring the current or general topics of interest to a person. Can be any shape, although generally manifests as a brain. Useful for sharing commonalities in subject areas and core interests.
Brain maps began appearing on a Research Club subtopic Research Club Posterous account. The sub-account was called Draw Your Brain - Who needs an MRI when you've got a pen and a napkin?
Since then, many images have been posted, each a unique representation of how each person thinks.