Śatapatha Brāhmaṇa ("of a hundred paths") 10.3.3.6

10.3.3.6

sa hovāca prāṇo vāva so'gniryadā vai puruṣaḥ svapiti prāṇaṃ tarhi vāgapyeti prāṇaṃ cakṣuḥ prāṇam manaḥ prāṇaṃ śrotraṃ yadā prabudhyate prāṇādevādhi punarjāyanta ityadhyātmam

He said,--Verily, that Agni is the breath; for when man sleeps, speech passes into the breath, and so do the eye, the mind, and the ear; and when he awakes, they again issue from the breath. Thus much as to the body.