Question: Is it the mind which is the 'I' also, the imagined 'I'?
Yes, the imagined 'I'.
Question: Babaji, then what is the brain, and has it come from the mind?
The brain is simply an organ, a biological organ that is in the body. You have to use this brain to live in this world. To deal with the things you have to imagine, thus brain helps you to imagine. Ultimately this is an inconclusive thing. Nobody has been able to obtain a conclusive answer in any way. A sadhak is taught not to bother this point because this is mind boggling and you can never make out which came first into existence, whether the brain came into existence or whether the mind came into existence and the mind brought the brain. It is impossible to tell. You will get involved, you will not go for Realization. A sadhak has to go for the Self Realization and as soon as possible get rid of this illusion, do not bother from where this illusion has come into existence. This is how always the Master teaches the student. It is just the same thing, droplet wants to know the depth of the ocean. It can never understand because it has to get dropped in the ocean to become one with it. Once it gets dropped, the droplet is lost. There is no more droplet there at all. That is the peculiarity.