For many decades, the prevailing belief was that the number of cells in the adult human brain was static, incapable of producing new neurons after adulthood.
However, research has established that this is not true, at least in an important part of the brain called the hippocampus. Studies since the 1960s have established that several mammals can regenerate neurons in this region throughout their lives. There had since then been considerable research into the same phenomenon in human brains, with inconclusive outcomes. Finally, plausible evidence that adult human brains can also regenerate and renew hippocampal cells was collated in a detailed 2021 Spanish review, “Evidences for Adult Hippocampal Neurogenesis in Humans”.
