Devibhagavatapurana 7.36.8

7.36.8

arā iva rathanābhau saṃhatā yatra nāḍyaḥ |
sa eṣo'ntaścarate bahudhā jāyamānaḥ ||

In Him the life-webs (nâdis) are fastened, as the spokes to the nave of a chariot; He is this (Âtman) that pervades the heart, and by his own free will manifests Himself in diverse ways (as Visva, Taijasa, etc., in waking, sleeping, etc., states); and also as One as Prâjña in the dreamless state. Meditate on the Âtman as Om (full of all auspicious qualities and who is the chief aim of the Vedas), in order to acquire the knowledge of the Paramâtman, Who is beyond the Prakriti and the S'ri Tattva. Your welfare consists in such knowledge.
Note. -- This shows that Brahman is the Antaryâmin Purusa. He resides in the heart where all the 72,000 Nâdis meet, as the spokes meet in the navel of the wheel. He moves within the organs, not for His own pleasure, but to give life and energy to them all. The Om with all its attributes must be constantly meditated upon. He manifests Himself in manifold ways in the waking and dreaming stews as Vis'va and Taijasa; while He manifests as One in the state of Susupti or Dreamless sleep as Prâjñâ. He is beyond darkness; He has no mortal body. Meditate on such Visnu in the heart in order to get the Supreme Brahman, with the help of the Mantra Om. The result of such meditation is that there is the welfare of yours--all evils will cease, and you will get the bliss of the manifestation of the Divinity--your Real Self within your Heart.