From Neurons to Habits |
Happy New Year!
Let us begin the new year with a renewed commitment to protecting our brain health.
We often hear that the mind and body are connected—and this is absolutely true. Brain health is body health.
Thanks to remarkable advances in science and medicine, humans now live longer than at any other time in history. We have learned to control infections, reduce deaths from heart disease, and cure or manage many cancers. We can replace worn joints, transfuse blood, implant new lenses in the eyes, and sometimes even transplant kidneys or livers.
But there is one organ that cannot be replaced: the brain.
Brain cells—called neurons—have a unique and sobering property. For the most part, they do not regenerate. We are born with billions of neurons, and once they die, they are gone. Every day, we have slightly fewer neurons than the day before. This is very different from blood cells, bone cells, or liver cells, which continuously regenerate. Simply put: The longer we live, the fewer brain cells we have. That is a biological fact.
This does not mean we should despair.
Neurons have an extraordinary ability to adapt by forming new connections—a property known as plasticity. This is the foundation of learning and compensation, and much of my writing has focused on this hopeful aspect of the brain. Today, however, I want to focus on a more “neuroscience-heavy” question:
What causes brain cells to degenerate and die—and how can we slow that process?
If we can minimize neuronal loss, that is clearly a good thing. And understanding how neurons die is the first step toward protecting them.
Many conditions can damage brain cells—this is essentially the entire field of neurology, my discipline. But as we age, two broad processes dominate:
Let’s briefly discuss the first, because the remainder of this post will focus on the second.
All cells—including neurons—require a steady blood supply to survive. Blood delivers oxygen, glucose,........