Yogic dhyana originates in back brain, based on past experience.
Yogic dhyana commences with pranayama. Pranayama to samadhi is a single continuous process.
Prana kriya touches 350 nadis (channels) within.
Breath driven to touch pranic manas (mind), loosen grip of mental vasanas (tendencies).
B.K.S. Iyengar gave this sequence to promote immunity during the 2009 swine flu pandemic.