EEG and Brain Waves

[jackdevries01]

Hi all
In terms of an EEG and the four types of brainwaves (alpha, beta, delta and theta), are they all present at the same time or do they change in relation to the state of consciousness an individual is in? For example, right now would I only have beta brainwaves? Or would I have all four types of brain waves, but to a different extent? Also how do you quantify higher or lower levels of brain waves?

Thanks

[Bri MT]

An EEGs results can be represented on a graph with potential difference (voltage) on the y-axis and time on the x-axis

By "higher or lower" you'd probably be referring to higher or lower frequency (ie delta waves are low frequency). 

You could also be referring to higher or lower levels of awareness correlated with those brainwaves.

Hope this helps

[jackdevries01]

Thanks for the response I think I am getting a better idea. I think I am getting confused by the textbook's wording. When it says, for example alcohol's brainwave pattern will be that it increases alpha brainwaves, does this mean that compared to being in a NWC, the brainwave in an alcohol induced ASC will be exactly like an alpha brainwave? Or more similar to an alpha brainwave compared to a normal beta brainwave? Thanks again!

[studyingg]

So what EEG detects, amplifies and records is the electrical activity of the brain. What this means is that it essentially measures the activity of the neurons in the brain, as you know from unit 3aos1 neurons in the nervous system communicate through electrochemical impulses, and EEG records these impulses and they can be graphically represented as waves  (as miniturtle said) with the voltage (measure of electricity)  on the y-axis and time on the x-axis. The way I interpret it is that your neural activity depends on the level of awareness you are experiencing, so during NWC you have a moderate to high level of awareness, this means you're likely processing information from the internal and external environment which means you will have more neural activity so the EEG will detect more voltage over time .This can then be represented on the graph that is associated with beta waves. In an alcohol induced ASC a person will:
have a lower level of awareness (as compared to NWC) ----therefore be processing less information from their internal and external environment (as compared to NWC)------ therefore the brain will have less neural (electrical) activity (compared to NWC) ------- therefore the EEG will detect less voltage over time (compared to NWC) ------ therefore the graph recorded will indicate alpha brain waves (not beta).

I can see why your book is confusing. But basically, because in any given state the EEG is recording the electrical activity associated with the activity of our neurons and therefore our level of awareness we only display one type of brainwave . Because we don't have "quantities" of beta, alpha, theta or delta waves, (as they are just the way scientists have named certain graphs in order to categorize them on the basis of frequency)  these waves are just graphical representations of our neural/electrical activity or the amount of voltage the EEG is recording in a given time.

[jackdevries01]

Thankyou so much! Great explanation and finally I've got my head around this. Would be great if the textbook explained it similar to how you did.

[studyingg]

Thankyou so much! Great explanation and finally I've got my head around this. Would be great if the textbook explained it similar to how you did.

All good! Glad you got it