The brain cannot store memories.

The brain is material form (rūpa) and cannot store memories, because memories are mental sense-objects (dharma-viṣaya), formless and without marks, having no intersection with the brain. Moreover, the brain is subject to arising and ceasing; if it stored memories, then after the brain perishes nothing would remain, and in future lives there would be no way to continue all the dharmas of past lives—even with superknowledge, one would not be able to recall events of past lives. All dharmas are recorded and stored by the tathāgatagarbha, and when needed, the tathāgatagarbha provides them forth. Dharmas come from the tathāgatagarbha, and after operating, they return into the tathāgatagarbha; when needed again, the tathāgatagarbha can manifest them once more.