There are some basics that all of us learn while in school. Modern science is turning many a learning of the type on its head. For instance, we all learnt that brain cells do not grow beyond a certain age. If Maura Boldrini and group are to be believed, according to a study that they published in Cell Stem Cell, apparently they do. Not just up to the age of 13 when they are supposed to have stopped but up to death.
The brains studied were of donors whose age ranged from 14 to 79. The part studied was the dentate gyrus (part of the hippocampus thought to contribute to the formation of new episodic memories) of the hippocampus, the region where neurons are born as shown by previous studies in mice and humans. In this area, both neurogenesis (growth of neurons) and angiogenesis (growth of blood vessels) was observed. So, whether a person was 14 or 79, neurons are progenitor cells abounded, somewhere in thousands.
This study raises multiple hopes and questions. If neurogenesis indeed does happen, can this really be tapped into to treat neurodegenerative diseases? Considering the fact that the neurogenesis happens in the areas of memory formation and emotional responses, does this indicate the evolving behaviour of humans across their lifespans to be a factor of this growth? If neurogenesis happens, what are the factors that affect it? Can our understanding of brain development still have facets that we do not understand yet? The biggest question this study raises is: How did other research groups miss this for so long?
In fact, another group that recently published their findings in Nature has questioned the findings. They have raised questions about the methodologies that Boldrini used and also the interpretation of the findings. To bring things into perspective, the Nature study published in the previous month, studied the brains of 59 donors and reconfirmed the original belief that the brains do not grow beyond the age of 13. Boldrini, however, has questioned the Nature study’s methodologies, in turn.
The only way this debate can be settled may be in the form of independent studies that can prove either of the findings. This study raises many pertinent questions. If brain growth throughout the lifespan of other species has been observed and well documented, it needs to be established why humans are an exception. Irrespective of whether Boldrini’s study or the Nature study is proven right, important questions about the methodologies used for preservation and studying of the brain sections have been raised, with both groups holding ground regarding their methodologies.
It is well-known that the brain is one of the least understood organs of the human body so far and results like this brings into sharp focus the need for greater collaboration among neuroscientists. Novel technologies and newer findings will slowly but surely spring up more surprises. For now, this debate continues. [Related reports and articles]