Where are the contents of memory stored?

The content of memories—all dharmas become seeds stored in the tathāgatagarbha, not in the brain. Seeds are formless and without marks, whereas the brain is material form; material form has shape and appearance and can be destroyed. 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 also disappear; then one could not recall them afterward.

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