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0:00
Hello.
My name is Jessica Filosa.
I'm in the Department
of Physiology
at Augusta University.
As part of this lecture series,
the subject of my talk
is Bi-directional Communication
at the Neurovascular Unit:
Implications
for Neuronal Function.
0:15
The outline for this lecture
is as follow.
First, I will briefly discuss
the anatomical organization
of the cerebral blood vessels
and corresponding innervations.
Second, I will discuss
neurovascular coupling mechanism
with an emphasis
on potassium signaling.
Third, I will introduce
a novel in vitro approach
to study neurovascular
coupling in the brain.
And lastly, I will talk about
bi-directional communication
at the neurovascular unit
and provide evidence
for vascular to glia
to neuronal coupling.
0:47
Even though
the brain constitutes
a small portion of our total
body mass, about 2%,
it consumes a significant
amount of oxygen and glucose,
about 25%.
Main reason for this
large energy consumption
is the need to restore
ion influxes
which are altered during
increases in synaptic activity.
Importantly, as the brain is
not efficient at storing energy,
a continuous supply of oxygen
and glucose is needed
for normal brain function.
This is chiefly
accomplished through
two fundamental mechanisms.
Functional hyperemia
or neurovascular coupling,
where a local increase
in neuronal activity is matched
with an increase in cerebral
blood flow supply
and cerebral autoregulation,
which basically maintains
constant profusion
in the phase of
blood pressure changes.
1:39
Before we discuss
the mechanisms of neurovascular
coupling in the brain,
I would like to remind you
of the structural arrangement
of the cerebral circulation.
The vascular tree of the brain
originates from large arteries
at the base of the brain
at the circle of Willis.
These large arteries branch
into small pial arterioles
at the surface of the brain
in the subarachnoid space.
These vessels constitute
the extracerebral circulation.
