This is Brian the Brain. He's going to help me show you what the brain's made
of The Cerebrum is the uppermost portion of the brain. It's also the largest
part of the brain, covering about 2 3rd of the whole brain mass. And it's
divided into two main hemispheres. Now, the outer layer of the Cerebrum is
called the Cerebral Cortex. Interestingly, it's only about 1 10th or 1 5th of
an inch thick. However, even though it's really small, this is where much of
our human thoughts, planning, perception, and consciousness take place. The
Frontal Lobe, in the front of the brain, of course, makes up about 1 3rd of the
area of the Cerebral Cortex. It's best known for its role in attention, working
memory, impulse control, being creative, and also abstract reasoning and
thinking. It's what really makes us human. Because it's the youngest part of
our brain, this is why children and teenagers can act more impulsively than
adults. Their frontal lobes aren't fully developed. It isn't around until 20
years old or so, before the frontal lobe is fully developed. One important area
of the frontal lobe is the primary motor cortex. This is in this area of the
frontal lobe. It's pretty cool how this was discovered. A German psychologist
in the 1860s notice that when he was caring for injured soldiers, he would
touch the surface of this area of the brain. And he found that a soldiers body
would actually twitch on the opposite side. So, say he touched the right side.
The left side of the soldier's body would twitch. From this and other research,
we now know that different parts of the cortex are responsible for different
functions. All of the parts of our body that we can move have a dedicated
region of the motor cortex that is activated when we move our body parts. For
example, we have a region for our fingers, one for our wrists, one for our
lips, one for our legs and more. You get the picture.
