Can we, as adults, grow new nerve cells?
There's still some confusion about that question,
as this is a fairly new field of research.
For example, I was talking to one of my colleagues, Robert --
who is an oncologist --
and he was telling me,
"Sandrine, this is puzzling,
some of my patients that have been told they are cured of their cancer,
still develop symptoms of depression."
And I responded to him,
"Well, from my point of view that makes sense.
The drug you give to your patients that stops the cancer cells multiplying,
also stops the newborn neurons being generated in their brain."
And then Robert looked at me like I was crazy and said,
"But Sandrine, these are adult patients, adults do not grow new nerve cells."
And much to his surprise, I said, "Well actually, we do."
And this is a phenomenon that we call Neurogenesis.
[Neurogenesis]
Now, Robert is not a neuroscientist, so when he went to medical school,
so when he went to medical school he was not taught what we know now --
that the adult brain can generate new nerve cells.
So, Robert, you know, being a good doctor that he is,
wanted to come to my lab to understand the topic a little bit better.
And I took him for a tour
of one the of most exciting parts of the brain,
when it comes to Neurogenesis --
and this is the Hippocampus.
So this is this gray structure in the center of the brain.
And what we've known for what seems like already for very long,
is that this is important for learning, memory, mood and emotion.
However, what we have learned more recently,
is that this is one of the unique structures of the adult brain
where new neurons can be generated.
And if we slide through the Hippocampus
and zoom in,
what you actually see here in blue
is a newborn neuron in an adult mouse brain.
So when it comes to the human brain,
my colleague Dr. Jonas Frisén from the Karolinska Institute,
has estimated that we produce
700 new neurons per day in the Hippocampus.
So you might think this is not much according the to billions of neurons we have,
according to the billions of neurons we have,
but by the time we will turn 50