Cell Replacement, 2

Current wisdom is that neurons are not replaced in the adult human brain with the exception of the hippocampus, the brain’s “search engine,” so to speak. The birth of new neurons has been confirmed in the hippocampus in the adult brain and may continue until the 5th decade of life. The hippocampus is also linked with the creation of new episodic memories. According to Margaret Reece, PhD, the formation of episodic memory is very complicated and may over-write older memories. Often

new episodic memories incorporate parts of old memories. For example, if you revisit your old school for a reunion, memory of the reunion will incorporate earlier events from the past when you attended classes at the school.  

https://www.medicalsciencenavigator.com/birth-of-neurons-continues-in-human-brain-into-5th-decade/