Bilateral Activation & Cognitive Functioning: Definition & Overview

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: The Benefits of Exercise on the Developing Brain

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:04 Brain Activation
  • 2:44 Lateral Activation
  • 4:46 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed Audio mode

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Devin Kowalczyk

Devin has taught psychology and has a master's degree in clinical forensic psychology. He is working on his PhD.

This lesson looks into what bilateral and unilateral activation is, as well as the machines that allow us to perceive the electrical activity of the brain.

Brain Activation

The brain is an amazingly powerful and fascinating watery lump of fat and specialized cells. It creates who we are, from the moment of our birth to the second of our death. And it really bothers me when people who don't know what they are talking about make statements as if they were experts. One of the most common ones that floats around is 'we only use 10% of our brain.' Everyone has probably heard this, and it is wrong. We use all of our brain, just not all the time.

The brain is made up of neurons and helper cells. We are going to focus on the neurons because they represent the most active and dynamic aspect of the brain. The helper cells do stuff too, but structure, clean up, and forming barriers just isn't exciting. When we look at neurons, we see they are capable of changing their electrical charge via specialized gates in their cell membrane. This means that when the gates are triggered, the neuron goes from slightly negatively charged to slightly positively charged.

Recent estimates are that a brain is made up of about 86 billion neurons, each connecting to 5 or 10,000 other neurons. There are a lot of electrical changes occurring every second, especially in the areas that are being used. What I mean is if I show you a brightly colored shape, then the part of your brain that processes visual information will activate. If I put a delicious donut in front of you, but you know you aren't supposed to eat it, then the part of your brain that deals with inhibition will activate. How do we know this? We have developed specialized technology for reading the electrical activity in your brain.

The electroencephalography machine, or EEG, is a recording device of brainwave activity. It works by being extremely sensitive to electrical changes and allows us to get an immediate understanding of the general area of activity. The functional magnetic resonance imaging machine, or fMRI, is an imaging device that measures the flow of blood through the brain. The idea behind this imaging device is that there will be higher blood flow to the parts of the brain that are more active. The good thing about this type of imaging is that it is extremely accurate; the problem falls in the time it takes to render an image. The MRI uses sensitive techniques that require translation, meaning that the image you see was a few seconds ago. Seconds, in brain terms, is a long time.

Lateral Activation

Now that you have a good idea of how we know what is going on in your brain, you should know that there have been a few findings that were surprising. When presented with a new and novel situation, like solving a complex mathematical problem or completing a complex maze, it was found that younger people have only half of their brain highly engaged, while the other half shows lower-level activity. This was labeled unilateral activation, which means one (uni) side (lateral) is more engaged.

When older people were observed doing the same task, both sides of their brain activated. This was labeled bilateral activation, which means two (bi) sides (lateral) are engaged.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it now

Earning College Credit

Did you know… We have over 220 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Used by over 30 million students worldwide
Create an account