It was the Spirit of God who enlightened Adam's mind and filled his heart. He was a Spirit-filled man from the crown of his head to the soles of his feet. However, when Adam sinned in the garden of Eden, the Spirit of God withdrew Himself from the person of Adam. Since the Spirit is the Author and sustainer of spiritual life, His withdrawal left Adam in a state of death and condemnation. Spiritual death occurs when one is separated from the Spirit of God.
Physical death occurs when one is separated from the body.
Eternal death is the eternal separation of the whole person, body and soul, from the love and grace of God. Regeneration happens when the Spirit of God takes up residence in the soul. The Spirit brings life and immortality to the dead sinner. But as it is written, Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love him. Just exactly how the Spirit regenerates the soul remains a great mystery.