First lets give the words mind and brain working definitions for the way I use them here. Brain is the name of the actual organ that controls and regulates the physical mechanics of the entire human body, including serving as the conduit that ideas are transmitted by, but it it's self is not the executive that initiates the actual chain of reactions that sets the biochemical processes of the body into motion. It is like a computer, programmed to preform certain functions, yet unable to do anything without some one there to turn it on and tell it what to do.
Mind however, refers to the "ghost in the machine" or in other words the creative intelligence that starts everything in motion by an act of will. Will in this sense can be taken to mean a force projected from a being creating the propulsion of change, or of movement within themselves and their environment. Therefore, operating under the understanding that an idea is the product of a creative act of an intelligent being having an inspiration or forming a new hypothesis, it is clear that the mind is the source of our ideas, and the brain is just a vehicle designed to enable us to act out our ideas in the material world.