Yes, of course, everything about us, from the simplest sensation to the most elaborately constructed sense of self, requires a brain in some kind of working order. Remove your brain and bang goes your IQ. It does not follow that our brains are pretty well the whole story of us, nor that the best way to understand ourselves is to stare at “the neural substrate of which we are composed”.
This is because we are not stand-alone brains. We are part of community of minds, a human world, that is remote in many respects from what can be observed in brains. Even if that community ultimately originated from brains, this was the work of trillions of brains over hundreds of thousands of years: individual, present-day brains are merely the entrance ticket to the drama of social life, not the drama itself. Trying to understand the community of minds in which we participate by imaging neural tissue is like trying to hear the whispering of woods by applying a stethoscope to an acorn.