Some people also call the higher function of the astral body the mental body.
A person focused on spirituality and enlightenment will have their prana energy centred on the crown chakra at the top of the head.
When I see the aura, I am looking at the outer part of the astral body.
The Hindus call the astral body the Linga-Sharira, a Sanskrit word meaning “design body.” The Ancient Egyptians called it the Ka, the Greeks called it the pneuma, and the Jewish Kabbalistic doctrines call the astral bodies the five souls.
Centred along the spine, the chakra points correspond with the base of the spine, just below the navel, just below the rib cage, the centre of the chest, the top of the throat, the centre of the forehead, and the very top of the head.
As a person spiritually awakens, his life force becomes centred on the upper chakras.