Madhvaon Brahma Sūtra 4.2.19

As long as the body lasts, the connection of the rays also does exist- Accordingly the Madhyandinayana Sruti says: “ Connected indeed are these rays and the veins; they are not separated so long as this body lasts ; for by these (rays) he perceives (the way through the veins), aud with these (by their light) he passes upwards aud by these he proceeds (to make his way out).”