Until a few years ago, it was assumed that humans were born with the maximum number of neurons that we were ever going to have. There was no chance of self-replenishment as we got older, or if we suffered some sort of neurological disease or trauma. But our understanding of the brain is changing all that and there’s good news.
While we thought that the human brain was more or less static, studies in mice and rats had shown that they make new neurons throughout life. Many of these neurons are made in a region of the brain called the hippocampus, which plays an essential role in learning and forming new memories.
Remarkably, these newborn neurons are able to form connections (synapses) with pre-existing cells. The strength and effectiveness of these new, immature synapses is especially dependent on the level of electrical activity within the newly-made neuronal networks.
This means that the new circuits are highly adaptable, changing in response to life’s experiences. These changes are believed to be especially important when laying down new memories in adult brains.
Until now, these insights into adult learning and memory were restricted to studies in rodents, but a landmark paper published earlier this month in the journal Cell...
