traditional chinese medicine talks about the brain as the sea of marrow. if the kidney essence is abundant, the sea of marrow will be full. if the brain is nourished, it will be full of energy, quick thinking, smart ears and eyes, and strong memory. on the contrary, if the kidney essence is insufficient and the marrow sea is not replenished, it is manifested as brain incomplete development and mental depression; in adults, it is usually manifested as memory loss, mental depression, slow thinking, dizziness, tinnitus, and insomnia. in severe cases, it can develop into neurasthenia.