the mind is complicated, there are a number of theories.
one theory is that it is comprised of a great many 'agents'...multitasking...hive mind...what we preceive as 'self' is the result.

another theory is that the mind is a standing wave of all the electromagnetic nerve impulses...of which there are trillions.. Shut off the 'machine' and the wave function collapses...never to return..(what happens to the program when you turn OFF the computer? Is a reeboot the same?)
and there are many more hypothesis and theories..
perhaps not even mutually exclusive.