Thanks in significant part to the groundbreaking work of many Foundation-supported scientists over the last two decades, we know that brand new nerve cells are born each day throughout life in parts of the adult brain, including in humans. This has opened a door to a host of potentially revolutionary treatment concepts to enhance the brain’s previously unexpected ability to renew and repair itself after injury or trauma, or to retain or restore memory capacity as people reach their senior years.
In a paper published November 10th in Nature Neuroscience, three current and former NARSAD Grant recipients are part of a team of neuroscientists helping to further decode the adult brain’s process of renewal. Led by Hongjun Song, Ph.D., and Guo-li Ming, M.D., Ph.D., of Johns Hopkins University School of Medicine, both recipients of NARSAD Independent Investigator Grants, and including Kimberly Christian, Ph.D., a 2012 NARSAD Young Investigator Grantee, the question the researchers addressed involved discerning how tissue in the hippocampus, a part of the brain where neurogenesis occurs in adults, “communicates” to neural cell “progenitors” to start production of new cells, and how many to make.
A progenitor (or precursor) cell is a biological cell that differentiates into a specific type of cell as/when needed by the body to repair or maintain system functions. In the case of neural cell progenitors, their role is to replenish neurons. Most progenitor cells lie dormant though, until they are directed or activated to differentiate and mature into the specific cell type. It is this process of activation of neural cell progenitors that the researchers sought to better understand in the current study.
Working in adult mice, whose brains resemble human brains, the research team discovered an important role played by a subtype of nerve signal-inhibiting neuron, called PV neurons (for parvalbumin). They found that PV neurons communicate to local circuits to promote survival of newborn progeny and advance the development of newborn neurons and guide their development. The PV cells are key in determining―and translating―what is needed by the hippocampus at a given moment.
This new insight into the process of neurogenesis will be of importance to those who are trying to harness the brain’s plasticity to spur memory enhancement, with potential application in degenerative illnesses like Alzheimer’s in which memory is degraded; but also in behavioral disorders, since, as the team notes, “evidence suggests that a proper rate of addition and elimination of new neurons optimizes behavioral outcomes” in animal models of various behavioral disorders.
Read an abstract of this paper.