If we consider 'kamma' as intention and habits, how are these transferred from a brain to next life when the brain breaks-up and cease to function?

According to the Pali Canon, how are intentions and habits passed on from one existence to another without any material support? What do the texts tell us about rebirth and the transference of these material phenomena into inmaterial phenomena, and the back to material ones? More specifically, how is kamma transmitted from one life to the next. If we consider 'kamma' as intention and habits, how are these transfered from a brain which, as you observed, is destroyed and dissolved after the breakup of the body? Aren't intention and habits a function emerging form the conjuncted activity of brain cells? Thanks in beforehand.