Neuronas
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Underneath the new-fangled cortex, the brain stem, the limbic system, and the basil ganglia
date back to the mastadons, the dinosaurs and the first anphibians
In humans, the olds parts of the brain
oversee emotion and help build memories
They control heart rate and breathing
They also form intimate connections with the new brain
The cortex, though less than a ΒΌ inch thick,
The cortex is the brain's crowing glory
Among its roles, the cortex is our reality check
It filters and orders the outside world for us
and allows to see, touch, hear, and speak
The cortex is also the human thinking cap
All our plans, thoughts and ideas
originate in this layer
The cortex is packed with nerve cells
About 2/3 of all our neurons operate here
A piece of cortex tissue, no larger than a pinhead
can house 30,000 of these cells
Each neuron has a job: to communicate with other neurons
the brain works by forming networks among these cells
The long, spiny branches of the networks
create a neuron forest of astounding intricacy
Neurons use these communication lines
to talk to each other with electric and chemical signals
Here under microscope are two neurons linking up
Though it may look like they fused together
neurons don't actually touch each other
A closer look reveals that a tiny gap called
called the synapse, separates their branches
this is where one message passes from one neuron to the next
The message comes from here: small sacs that store chemical molecules
When stimulated, these sacs release their molecules
which cross the cell membrane into the synaptic gap
An electric zap allows this to happen
Meantime the receiving neuron has special welcome sites
for the incoming molecules
These receptor sites bind with the molecules
When they do, special gates open up
The gates let in a flood of charged particles:
sodium and potassium ions
which start up a new electrical signal in the receiving neuron
This simple chain of events: an electrical zap
followed by chemical changes, followed by another zap
is the basis of all brain activity
It's how neurons speak to eachother
Here then is the key to the brain's complexity
There are 100 billion neurons in the brain
each neuron, like a bit player in a grand production
processes its information, then hooks up
with as much as 50 thousand other neurons
to send and to receive messages
100 billion neurons x 50 thousand connections
It's this complexity that allows us to think imaginitively
On their own, neurons aren't very bright
But put 100 billion of them together in a small space
and let them all start talking to each other
and you start to get brainstorms
The trillions of neuron networks, like an improvisational orchestra,
create new ideas and connect different thoughts
in a whimsical and sometimes inspired fashion
It's this impromptu ability to create new things in our brains
that allows us to progress
That quite simply takes us from here
to here