Réntǐ dànǎo zhōng yuē yǒu 860 yì gè shénjīngxìbāo.
The human brain has approximately 86 billion nerve cells.
Shénjīngxìbāo sǔnshāng hòu hěn nán zàishēng.
Nerve cells are difficult to regenerate after damage.
Kēxuéjiā zhèngzài yánjiū rúhé bǎohù shénjīngxìbāo.
Scientists are studying how to protect nerve cells.
