The power of the concentration in the heart-centre is to open that centre and by the power of aspiration, love, bhakti, surrender, remove the veil which covers and conceals the soul and bring forward the soul or psychic being to govern the mind, life and body and turn and open them all fully to the Divine, removing all that is opposed to that turning and opening.   

The power of concentration above the head is to bring peace, silence, liberation from the body sense, the identification with mind and life and open the way for the lower (mental, vital, physical) consciousness to rise up to meet the higher consciousness above and for the powers of the higher (spiritual nature) consciousness to descend into mind, life and body.

The power and concentration in the eyebrows is to open the centre there, liberate the inner mind, and vision and the inner or yogic consciousness and its experiences and powers.