So while the right and the left hemispheres are equal in size, they are not equal in function.
This is referred to as hemispheric lateralization.
So for example, the right hemisphere of the brain is going to receive somatic sensory signals
from and control muscle movements on the left side of the body.
It is also responsible for musical and artistic awareness
which is why a lot of times, people who are very artistic
or good at poetry or painting are called right-brained.
It also is responsible for recognition of faces as well as the emotional content of facial expressions.
It's responsible for generating emotional content of language
and finally, for identifying and discriminating among odors.
On the left side of the brain, we're gonna receive somatic sensory signals
from and control muscle movements on the right side of the body.
The left hemisphere is also responsible for reasoning as well as numerical and scientific skills.
A lot of times, people who are really good at math, engineering,
and any type of science and logic are referred to as left-brained.
Also in the left hemisphere, this is going to be responsible for our ability
to understand sign language as well as spoken and written language.
So now let's talk a little bit about how we measure brain activity.
We can look at brain waves by way of an instrument known as an electroencephalogram or EEG
and the brain waves can give us ideas about the electrical activity
that is occurring in the cerebral cortex.
In a normal awake adult, you have alpha waves which are about 8 to 13 hertz
and these waves are going to disappear when that adult is sleeping.
When you are undergoing some type of mental exercise like taking a test
or trying to figure out a complex problem, the brain will exhibit beta waves.
These waves are a little larger than the alpha waves at about 14 to 30 hertz.
The next type of wave is the theta wave.
These are going to appear in emotional stress and these are smaller than our alpha waves at about 4 to 7 hertz.
And then finally, we have our delta waves.
Delta waves are only present while we are asleep.
They are small with about 1 to 5 hertz.
If delta waves are present in an awake adult, this indicates some type of brain damage.