一般认为，人体阴、阳的关系是左、右关系。“识神”、“元神”是中医学的一对重要概念。（1）识神是脑最高级部分的功能，元神是脑较低级部分的功能。淤识神是脑（以额叶、大脑皮层为代表的）最高级部分的功能，元神是脑较低级部分的功能。于由于识神是脑最高级部分的功能，元神是脑较低级部分的功能。所以，在发生上，识神主要相关于后天，元神主要相关于先天。（2）识神为阳，元神为阴。淤动为阳、静为阴；日为阳，夜为阴：识神显现多见于应激，多在白天；元神显现多见于睡眠、入静，多在夜晚。于热为阳，寒为阴：元神显现（睡眠、入静）时，能量代谢多降低。（3）所以，从识神、元神看，人体阴、阳的关系实应是上、下关系。

With that general outlook, the relationship between Yin and Yang is "left" and "right" relationship. "Conscious spirit" and "primordial spirit" are a couple of important concepts in traditional Chinese medicine (TCM). Firstly, "Conscious spirit" is the function of the highest part of brain while "primordial spirit" is the function of the lower-level part of the brain. The function of highest part of brain is represented by the frontal lobe and cerebral cortex. In conclusion, from the development and evolution point of view, "conscious spirit" is corresponded with postnatal aspects while "primordial spirit" is corresponded with prenatal aspects. Secondly, "conscious spirit" is Yang while "primordial spirit" is Yin. Motion is Yang while stillness is Yin. Daytime is Yang while nighttime is Yin. "Conscious spirit" is mainly appeared in reaction and daytime. "Primordial spirit" is mainly appeared in the rest and nighttime. Hot is Yang while cold is Yin. "Primordial spirit" is mainly appeared in the sleep and rest when the energy metabolism degrades. Therefore, from the viewpoint of "conscious spirit" and "primordial spirit", the relationship between Yin and Yang is "up" and "down" relationship.

中国中医科学院中央级公益性科研院所基本科研业务费专项资金团队建设项目（YZ原1113）：中医“根”概念的“层次”实质及其中国传统文化根源探讨，负责人：陈小野。