If we want to look more concretely at the matter of the fall we will say that, as St John of Damaskos teaches, the fall in reality is darkness of the image, loss of the divine life and putting on coats of skin. The darkness of the image is nothing else but the darkening of the nous. The nous was darkened and could not have communion and unity with God….according to the anthropology of the Fathers, man’s soul is rational and noetic. This means that man has two centers of functioning. One is the reasoning mind, which is connected with his nervous system, and the other his nous, which is connected with his heart.
Adam’s fall, then, is the darkening of his nous, the loss of its noetic function, confusion of the nous with the functions of reason and its enslavement to the passions and to the environment. Instead of moving according to nature and above nature, instead of moving towards God and being mindful of God, man’s nous is turned towards the created things and the passions.
That is why in the Church we speak of repentance, which is not simply a change in the head, as some theologians say, but a change of the nous. The nous must break away from the created and the passions and turn towards God.
~Metropolitan Hierotheos
Prayerful Life 