It's starting to move around in so-called Waddington landscape space, or epigenomic space, and it's becoming a different type of cell. A nerve cell in an old person maybe partly a skin cell. I mean, think about that.
Similarly, people have trouble discriminating color patches that are small. Every nerve cell in the fovea sends one fiber.
So when the terminal of one cell wants to talk to a dendrite of another nerve cell , there's a space. And so for one nerve cell to talk to the other nerve cell , the first nerve cell must release a little chemical neurotransmitter. You've probably heard some of these, dopamines, acetylcholine, GABA, glutamate, serotonin.
And that's how signals are sent in your brain. Electrical signals within a nerve cell and chemical signals between nerve cells. So if you don't remember anything else that we have to say today, if you just remember that, I'd be very, very happy.
There are about 20,000 genes, about 15,000 are turned on, but a different set gets turned on in large part to make a nerve cell compared to a liver cell and a skin cell. That's gene expression. And what controls that gene expression is what's called not not the genome,
That is pristine when we're young, but as we get older we lose that epigenetic information. The ability to tell a cell to be a nerve cell versus a liver cell versus a skin cell, it starts to get erased. So it when we look at a mouse or or an old tissue, if I took maybe not your skin, but but my skin,
And then it generates a little bit of electricity. When that electricity gets to the end of the nerve cell , it causes those chemicals to come out. Those chemicals cross that small little space.
How does this work? What we've been able to show is that -- this is a nerve cell , this is one of the cells that we think actually are strengthening connections. As we're studying this and trying to understand it, it's really providing a lot of different ways of how we're framing what is depression.
Even in the brain in Alzheimer's disease, there's local inflammation occurring in the brain. Another mechanism in the brain is that intermittent fasting increases the production of a nerve cell growth factor. That's a protein that, as its name implies, promotes the growth and also stress resistance of nerve cells.
and what happens is cells lose their identity. That's really important. A nerve cell in an older person is no longer fully a nerve cell . It's starting to move around in so-called Waddington landscape space, or epigenomic space, and it's becoming a different type of cell.
There's a gap, a physical gap between two nerve cells. So when the terminal of one cell wants to talk to a dendrite of another nerve cell , there's a space. And so for one nerve cell to talk to the other nerve cell , the first nerve cell must release a little chemical
neurotransmitter. You've probably heard some of these, dopamines, acetylcholine, GABA, glutamate, serotonin. Those are all types of chemicals that are stored in the terminal of a nerve cell . So each neuron is like a little battery.
Those chemicals cross that small little space. They're picked up by receptors on the dendrite of the next nerve cell , which can then increase or decrease the likelihood of an electrical signal in that next nerve cell . And that's how signals are sent in your brain.
So if you don't remember anything else that we have to say today, if you just remember that, I'd be very, very happy. OK, electrical inside of a nerve cell , and chemical between nerve cells. So let's talk a little bit about what our brain does for us.
These four Yamanaka factors are called O, S, K, and M for short. Now Yamanaka won his Nobel Prize because it's a great discovery to be able to take a skin cell and turn it into a nerve cell . It could give rise to new treatments, new organs that we can put back in our bodies.