Neurotransmitter Lab

Purpose: For this lab the goal is to view both the chemical and electrical signals that our brain sends to our muscles that causes them to move. We also are learning more about the difference between antagonist and agonist muscles and why both types of muscles are very essential to our bodies.



Background: According to the lab handout, our body contains over six hundred skeletal muscles that receive signals from our brain in order to function. Every time we want to move any muscles in our body our brain send signals or messages down through our spinal cord and then to our muscle fibers. Once the muscle fibers receive the signals and messages, they are then able to move and contract. The lab also explains the difference between an antagonist and agonist muscle. An antagonist muscle is when the opposing muscles is relaxed, whereas an agonist muscle is when the muscle that is contracting makes movements.

IMG_1522 IMG_1521


  1. Place two electrode patches on your biceps and then two patches on your triceps and one patch on your hand
  2. Connect one black clip and one red clip on your patches on your triceps and biceps. Make sure that the red clip goes on the top patch and the black goes on the lower patch.
  3. Connect the two white clips together and then connect them to the patch on your hand.
  4. Make sure you have downloaded the app for either your phone or computer, which allows you to see the contractions of you muscles through graphs.
  5. Then connect the stereo speaker to the SpikerBox
  6. Connect the blue cord for the computer or the green cord for your phone to the device and SpikerBox
  7. Adjust the  thumbwheels to hear the contraction of your muscles
  8. Next make these movements while connected to the wires to perform the experiment:
    • Waving
    • Flex your arm
    • Extend your arm back and forth
    • push-ups

Data: During this lab, unfortunately we were unable to conduct the experiment due to technical difficulties.  Although the experiment did not work I learned from the lab hangout that waving your hand is almost the same movement as flexing your arm or even as extending your arm back and forth. When your arm is extended, your biceps act as the antagonist muscle and your triceps act as the agonist muscle. Flexing is different from waving and etc because in this case, your tricep acts as the antagonist muscle and your bicep acts as your agonist muscle.


Since we could not collect any real data while simply waving, flexing and extending our arm during the experiment, we tried doing a pushup. During the pushups we noticed some activity on our phones as seen in the picture below. While you are pushing up your bicep acts as the antagonist muscle and your triceps are acting as agonist muscles. Where as when you push down during a push up it is the opposite, your bicep acts as the agonist muscle and your tricep acts as the antagonist muscle.


You can see this data shown using an EMG. On the EMG you will see spikes in the graph when its an agonist muscle moving. However, on an EMG if you do not notice any spikes in the graph it is most likely an antagonist muscle that is moving. Some examples of antagonist muscles in our body are the back and chest, the abdomen and lower back, and the shin and calf muscles.

Since we could not see visible contraction of the muscles through our data we were still able to see the signals being sent from our brain to our muscles while performing different movements. Above, in the first graph it shows no brain signals being sent because there was no arm activity. However in the second graph you will notice some smaller spikes that shows some brain signals because there was arm activity.

One thought on “Neurotransmitter Lab

  1. Hey Krystal,
    I really like how you laid out your post. The specific sections you created really made your post easy to follow along. I like how you described the lab in a really easy to follow manner. I also really enjoyed how you put pictures all throughout your post, so there wasn’t just a bunch of words everywhere.


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