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a condition in which a person cannot thnik about anything.
The mental patient has a brain jam. We would rather take him to a mental asylum.
by uttam maharjan July 09, 2012
A complex melody or a chord sequence that sounds brilliant put in a musicians head, but sounds bizzare when actually played in front fellow bandmates.
"Yeah, get ready for this next riff, its got like 2 measures of 5/4 then 1 of 13/16 then 2 measures of 7/8 at the end"

"Oh god you were brainjamming at work again weren't you, Steve"
by ohgodwhat May 31, 2009