A study of brains aged between 43 and 87 suggests our brain cells remain alive-and-generating throughout our lives. The tentative finding could mean that age-worn brains could be more resilient to damage than we originally believed.
Although the renewal and repair of tissues and organs throughout our body, even during old age, is relatively common place, it is thought that neurogenesis (i.e. the growth of new neurons) is a much rarer occurrence. María Llorens-Martín at the Severo Ochoa Molecular Biology Centre in Spain and her colleagues, took to studying hippocampal brain tissue from 13 deceased adults, in a quest to find signs of neurogenesis.
It has been well documented that the hippocampus – an area associated with memory, emotion and spatial navigation, regularly sprouts new neurons, bringing with them specific proteins as they mature.
To identify new cells, one must identify signs of these proteins, which Llorens-Martín and her team did, via sending out antibodies that would attach themselves to such proteins – highlighting their existence. The antibodies, it was found, latched onto thousands of neurons across the variety of samples.
When the team inspected the neurons formulating these proteins, they found these brain cells has an assortment of shapes and sizes. Llorens-Martín postulates that this indicates these neurons are in the process of developing, and therefore suggests they were born later in life. “Even people in their 90s have to store new memories every day, so I’m not surprised we found this,” Llorens-Martín told New Scientist.
These examined brain cells, however, could have conceivably remained dormant, or slowly maturing, within the hippocampus for a prolonged period of time and, therefore, would not prove neurogenesis. Likewise, these cells could have been producing these certain signifying proteins to differentiate the cell later on during its life cycle. To absolutely prove these cells are a result of neurogenesis, we would need a tool that could tell us a cells date-of-birth.
It is likely that some neurogenesis occurs in the ageing brain, yet it is not likely enough to prevent the foulest aspects associated with age and, at worse, the sprouting of new neurons could be functionless – due to a preceding fault of old age rendering these baby faced brain cells useless I. e. there could be some other brain mechanism initially needed to turn them on.
Journal reference: Nature, DOI: 10.1038/s41591-019-0375-9