0:00
Today I'm going to talk
about neuroglial cells
and about a specific
subtype of neuroglial cells
which are called
astroglia or astrocytes.
Now, by means of
self-introduction,
my name is Alexei Verkhratsky
and I am a professor
of Neurophysiology at the
University of Manchester.
All my life, I was studying
glial cells in
health and disease,
trying to understand
how the cells
are working together with
others in the brain,
and what happens to them in
conditions of pathology.
0:33
I'm going to talk
about the brain.
Of course, the human
brain is something
really outstanding
and is probably
the most complicated
system which
has ever been known to
the natural sciences,
because if you think about
it, the evolution of it
which lasted, probably, for
about half a billion years,
about 200 billion cells,
100 billion neurons
and another 100 billion
supportive cells,
which we call
neuroglia, and which is
going to be the topic of
my today presentation.
On top of that, there
are endothelial cells,
pericytes, smooth muscle
cells of blood vessels,
all in the 1.5 litres
volume of the skull.
All of these cells
are connected with,
we don't know precisely,
but certainly many 10s,
if not 100s of trillions
of connections.
All this operates at a cost
of 300-400 calories per day,
which gives you about
12 watts an hour.
As a computing machine,
the brain has an operational
memory in the range
of more than 2.5 petabytes
and operates at a
petaFLOP range.
Now, just for comparison,
one of the world's fastest
supercomputers, in Guangzhou,
has a maximum processing
speed of 33 petaFLOPS,
a memory of 1.3 petabytes
and does it all at
the support of 17.6
megawatts of power.
Now, on top of this,
this particular computer
occupies a huge space,
its surface area is 720 m^2.
In a sense, our brain is very
much stronger and more powerful
than any supercomputer
in the world.
It will probably remain so
for a long time to come.
Now, of course, the
brain is really complex,
and here I do very much
love this quotation
from Desiderius
Erasmus, who said that,
"All things in life
are so multifaceted,
contradictory and obscure
that we can never be
sure about the truth."
That very much
applies to the brain,
because our knowledge
is in a constant flux.
What we know today
probably contradicts
with what we knew yesterday,
and it will be
contradicted again
by what we will know tomorrow.
