Ecclesiastes 12:7: “Then the dust will return to the earth as it was, and the spirit will return to God who gave it.”
The spirit or breath of life leaves the body. 
The body and all its organs and systems cease to function.
The body returns to dust.
The brain no longer processes information that comes into it through the five senses and thus the writing of the biographical record ends.
This is how the Bible describes the condition of man in death: Psalm 146:3-4: “Put not your trust in princes, nor in the son of man, in whom there is no help. His breath goeth forth, he returneth to his earth; in that very day his thoughts perish.”
Stephen Bohr