These are very unique times for brain research. The aperitif for the course will thus highlight the present “brain-excitements” worldwide. You will then become intimately acquainted with the operational principles of neuronal “life-ware” (synapses, neurons and the networks that they form) and consequently, on how neurons behave as computational microchips and how they plastically and constantly change - a process that underlies learning and memory. Recent heroic attempts to realistically simulate large cortical networks in the computer will be highlighted (e.g., “the Blue Brain Project”) and processes related to perception, cognition and emotions in the brain will be discussed. For dessert we will deliberate on the future of brain research, including the questions of “brain and art”, consciousness and free will. For more information see the course promo below and read “About the course.”
Brainbow
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En provenance du cours de Hebrew University of Jerusalem
Synapses, Neurons and Brains
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À partir de la leçon
Brain Excitements for the 21st Century
Welcome to synapses, neurons and brains!
Rencontrer les enseignants
Idan SegevProfessor
Computational Neuroscience
So I want to go now to the next breakthrough, or to the next excitement
in brain research, and this is what I called, or what is called the braibow
technology. As you know, the brain as you look at it,
we call it the grey matter. It's grey matter.
So when you look at it unstained, when you open the brain, of any element, the
tissue is the quality of grey, or black, or white.
So you call it the white matter, the grey matter, but it's very, very difficult to
see So you can think about the jungle of trees, not staying there as you saw
before, and you see kind of a meshy thing, a brain, a gray matter.
But now there is this new jump. A few years ago, a group from Harvard
develop a molecular technique, a genetical technique, that where they can
really intervene with the genes In this case of a mouse.
Particular genes and they can locally insert pieces of DNA, pieces of DNA into
the gnome of this animal. There are many techniques to do it this
is the wizards, these are the miracles of molecular biology.
They are able to really go into a, a, a genome, and really manipulate it engineer
it, in order to add in this case, a piece of a DNA, and when this piece of DNA is
expressed during the expression of DNA, if the DNA is in a correct location some
cells, some cell types in the brain, becomes colorful.
So we can speak about the brainbow because suddenly the brain is glowing
with colors, fluorescent colors. And so we see beautiful brains today,
brain of mouse, or other animals we can do it today, of course we don't do it to
humans because you don't intervene With the embryo of humans, but you can do it
to animals. Inside you'll get this fantastically
buetiful brainbow images. A colorful brain.
For example this is a piece of a brain, not the cortex, but a peice that's called
the hypocamphus. Inside you'll see the hypocamphus.
A particular regions in the hypocamphus, the ca1 region Glowing with colors.
Each cell has, different cells have different colors, what, some, some are
green, some are gray purple, some are red, and some are yellow.
And suddenly the brain is not anymore gray matter.
It's a bainbow brain. And this brainbow brain enables you to do
something fantastic. Because for the first time at the level
of light microscope without cutting and cutting and cutting and then
electromicroscope but at a light microscope level we can just open the
brain, look at it, and suddenly you see this.
And if you zoom in more and more you can start to see really the fibers.
And you can see, at least at the the first approximation, that the green cell,
so to speak, is touching the red. Is going towards the red cell, so you get
some kind of a gross anatomy. And we show you later that you cannot
really say that there is a synapse, that there is a connection, yes or no, between
this cell or another cell. Because the light microscope resolution
is not good enough to speak about synapses, which are smaller, too small to
see in the light microscope. But still, you can get kind of a general
first order map, which is very, very, very, very important for modern anatomy.
We are talking now about modern anatomy unlike [INAUDIBLE] , which were the
origin of anatomy. This is more than anatomy.
It's a colorful anatomy at the light microscope level.
And it's a connectomics anatomy at the EM level that I just showed you before.
So this is a new technology, very useful for many, many purposes.
And we'll talk about what purposes are being used about it.
But you can just stop for a second and enjoy The beauty of this technique.
So this is part of the cortex, this was hippocampus, this is hippocampus, cortex,
other regions in the brain, motor nerve ending, that activate muscles.
So you can see the beauty of it, and there are now a lot of exhibitions, art
exhibitions based on the brainbow technology.
So this is another contribution, not only to science, but also to the arts.
So what can we do with the brainbow that we could not do before?
So here are some prospects, or some examples, for what you can do with this
new technology. So, for example, we are all interested
for many, many years about the structure and basis for learning.
So now, I'm talking to you, I hope you'll learn new things.
Now, you didn't hear about the brainbow before, now you know something about the
brainbow. What happens in your brain when you
learn? What is changing in your brain when you
learn? So, that means that you want to look at
the brain in real time, online, when it is learning now, when the mouse in the
maze is finding his way from here to the cheese and the second time he does it
better. And the third time he does it better,
what is changing in his in the brain when he learns?
We can use this technology to look at the brain In real time, during learning.
And suddenly you can see changes, anatomical changes, related to learning.
That's a breakthrough. In a black jungle or in a grey jungle, it
would be very difficult. In a colorful jungle, it will be much
easier to say that the green thing is moving or making contact or going there.
So, this is very useful as a technique to study online learning in the brain.
Another use of this brainbow technology is that you want to really start to tag
using this different dyes, different cell types.
You want to ask a very basic question, how many cell types anatomically do I
have in the brain? Is it 100?
Is it 1,000? Is every cell different than another
cell? How many types?
So I can use these genetic tools. To stain population of cells, different
cell types, and say okay there are so many red cells, this one type, so many
blue cells, another type. So I'm using this Brainbow tagging
technology to categorize same type in terms of anatomy.
Very useful. So we know today how many cell types we
have in the retina. It's not one cell type, but it not
million cell types. There are subtypes, subclasses.
These are another use of the brainbow. A third use of the brainbow, that's very
important for us, neurobiologist, is to tag long range connections.
Because we know that some cells, sends this long, long process, axons sometimes
from one region to another region in the brain.
It's extremely difficult to detect this long path, very difficult, especially
when it's a dark jungle. But when it's a red cell, you can really
follow the red process, very long distances.
And for the first time we now know better.
Where does the cell send this information?
Long range, not only locally. So this is also kind of a new advanced
due to a new technology. So you can see how technology enables us
to ask old questions but in a new way. So this was the second frotier, let's go
to the thrid frontier, brain machine interface.
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