WEBVTT

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Can we, as adults, grow new nerve cells?

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There's still some confusion 
about that question,

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as this is a fairly new field of research.

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For example, I was talking
to one of my colleagues, Robert --

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who is an oncologist --

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and he was telling me,

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"Sandrine, this is puzzling,


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some of my patients that have been told
they are cured of their cancer,

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still develop symptoms of depression."

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And I responded to him,

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"Well, from my point of view 
that makes sense.

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The drug you give to your patients
that stops the cancer cells multiplying,

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also stops the newborn neurons
being generated in their brain."

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And then Robert looked at me 
like I was crazy and said,

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"But Sandrine, these are adult patients,
adults do not grow new nerve cells."

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And much to his surprise, I said,
"Well actually, we do."

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And this is a phenomenon 
that we call Neurogenesis.

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[Neurogenesis]

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Now, Robert is not a neuroscientist,
so when he went to medical school,

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so when he went to medical school
he was not taught what we know now --

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that the adult brain 
can generate new nerve cells.

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So, Robert, you know, 
being a good doctor that he is,

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wanted to come to my lab to understand
the topic a little bit better.

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And I took him for a tour

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of one the of most exciting
parts of the brain,

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when it comes to Neurogenesis --

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and this is the Hippocampus.

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So this is this gray structure
in the center of the brain.

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And what we've known for what
seems like already for very long,

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is that this is important for learning,
memory, mood and emotion.

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However, what we have learned
more recently,

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is that this is one of the unique
structures of the adult brain

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where new neurons can be generated.

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And if we slide 
through the Hippocampus

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and zoom in,

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what you actually see here in blue

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is a newborn neuron
in an adult mouse brain.

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So when it comes to the human brain,

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my colleague Dr. Jonas Frisén
from the Karolinska Institute,

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has estimated that we produce

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700 new neurons per day
in the Hippocampus.

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So you might think this is not much
according the to billions of neurons we have,

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according to the billions
of neurons we have,

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but by the time we will turn 50