Great topic. The answer is both . . . and it really must originate in your born-again spirit. Jesus said that God is a Spirit, and those who worship Him must worship Him in spirit and in truth. So worshipping God in spirit is a requirement.
Now, and as I said it is a great topic, Paul addresses this to the Corinthians. He says that he will pray in the spirit, but he will pray with the understanding also. He says that he will sing in the spirit, and he will sing with the understanding also. The heart (or the inner man) must worship God, but that doesn't mean we don't worship God with our minds . . . indeed, we must; becasue we are commanded to play skillfully and well, to do whatever our hands find to do with all our might, and to stir up the gift that is within us. So the answer is, worship comes from the spirit, but must involve the heart and the mind. Be Blessed . . . BBoy