Where is all the content of memory stored?

The content of memories—all dharmas become seeds stored in the tathāgatagarbha; they cannot be stored in the brain. Seeds are formless and without marks, whereas the brain is material form (rūpa); material form has shape and appearance and is subject to destruction. If the content of memories were all stored in the brain, then when the brain is destroyed, all of that content would vanish in future lives, and there would be no cause and effect. In this life, brain cells arise, cease, and mutate, and the content of memories would likewise disappear; then one would be unable to recall them afterward.

The eighth consciousness has no function of memorizing or retaining; the five consciousnesses have a weak function of retention; both the mind consciousness and the manas have the function of memory and retention, but only the mind consciousness can recall. When the manas grasps at past mental sense-objects (dharma-viṣaya), it is called remembering-and-holding (yizhi), not recollection. Recollection is relatively subtle; the manas cannot make subtle discriminations and cannot discern details.