or the mind is a mere collection of memories, experiences stored in the brain?
Of course the mind is not independent of the brain. Otherwise, nobody would do recreational drugs, psychiatric drugs would be useless, and our whole theory of light and color perception, sound perception, and every other sensory perception would be useless and make no predictions. All of these things tell us how signal in the environment are transduced into electrical signals and processed in the brain. And while we don't know exactly how it becomes a mental experience (The Hard Problem), we know that there are many direct relationships between activity in the brain and perceptions and states in the mind.
The mind isn't just memories and experiences stored in the brain though, it's also active processing of current stimuli, which includes spontaneous activity that may randomly draw on memories and experiences, but not in a sensible or meaningful way. That is to say, there are biological processes that aren't really necessary to brain/mind, but to metabolism or long-term evolutionary benefit, yet they still influence brain/mind and we sometimes ascribe meaning to them without merit.