NEUROTRANSMITTER ROLE-PLAY DESCRIPTION

Carlton Erickson, Ph.D.
The University of Texas
1-18-03


This role-play can be used with high-school students or audiences who have minimal knowledge of brain function. Everything not in ( ) should be spoken, and should be customized to the level of learner and knowledge of the presenter. ( ) = unspoken instructions

  1. Imagine that this building is a brain, and the room we are in is the mesolimbic system, one of the parts of the brain that causes us to feel emotions. Imagine that each of you is a nerve cell in this portion of the brain.

  2. (Give out colored sheets of paper randomly to everyone in the room.) In your hand is a colored piece of paper. Let’s crumple it up into a ball, which will now be known as a neurotransmitter. A neurotransmitter is a chemical that helps nerve cells communicate among each other. Nerve cells “talk” to one another through chemistry.

  3. Each colored ball represents a different neurotransmitter in the brain. There are five major neurotransmitters involved in chemical dependency (“addiction”) to drugs such as heroin, cocaine, alcohol, and so on:
    (colors are arbitrary)
    red = dopamine
    green = serotonin
    blue = endorphins
    yellow = GABA (gamma aminobutyric acid)
    orange = glutamate

  4. What we’re going to demonstrate in just a moment is how nerve cells talk to each other. But let’s give this some action! Let’s give some sounds to these neurotransmitters:
    1. dopamine is involved with pleasure in the brain, so if you were to listen to dopamine’s
      action in the brain it would sound something like: “ahhhhhh”
    2. serotonin is known to affect craving for food and drugs. It would sound something like:
      “gimmee, gimmee, gimmee”
    3. endorphins are involved in the rush people feel when they exercise: “wow!”
    4. GABA is a chemical affected by drugs like Valium, that make you sleepy: “sszzzzzzz”
      (snoring sound)
    5. glutamate is a major stimulatory neurotransmitter in the brain involved with excitement”
      “yippee!”

  5. OK, dopamine, when I count to three, make the sound of your neurotransmitter. (Do the same for each neurotransmitter. It is probably best to have each neurotransmitter group identify themselves and make the sound as you describe it for that neurotransmitter in 4. above)

  6. Now, to show the excitement of the brain, when I count to three, pass your neurotransmitter to another nerve cell in the mesolimbic system, and make the sound of your neurotransmitter at the same time. Just be sure you don’t hurt the other cell by passing it too hard! 1-2-3- Go! (People throw the balls around the room.)

  7. Now please pick up a neurotransmitter. It doesn’t have to be the same color you started with. If anyone can’t find one, raise your hand and someone with two or more will give you one.

  8. Now the brain really doesn’t act in such a disorganized manner. It operates more in what we call “functional tracts”. The medial forebrain bundle or MFB (can have them point to it with one finger in the middle of the forehead, and another above their right or left ear) is a functional tract that regulates our feeling of “pleasure”. Let’s create a MFB in the front of the room.

  9. Will about 10 of you who have a red ball “dopamine” please come up and form a straight line in the front? Don’t be shy, this won’t hurt! OK, line up, with the bundle beginning in the center of the brain (usually right side of the stage when facing the audience), and the end of the bundle (cortex) in the front part of the brain (left side of the stage when facing the audience).

  10. The front part of the brain is the cortex where some vocalization occurs. So the person at the end of the bundle will be expected to “vocalize” what the bundle is feeling. (Have them practice by saying “ahhhhh”.) So let’s practice on this nice day, with just a feel-good pleasure activity. Each nerve cell should pass its neurotransmitter to the next person, in an orderly fashion - only one at a time!, until it reaches the cortex (person says “ahhhhhh”).

  11. But wait! We’re missing a feedback pathway. Is there anyone in the audience who is in good physical shape and would like to run? (Volunteer comes up and takes a place next to the cortex nerve cell.) The feedback system runner takes the neurotransmitter from the cortex, back to the center of the brain’s portion of the MFB. (Person does this, and is instructed to return back to the cortex.)

  12. Now let’s see what happens if this medial forebrain bundle gets a “just won $10,000” stimulus. (Ask the nerve cell volunteers to pass the balls a little faster, while remaining coordinated.) (Remind the cortex to express how it feels, such as “holy cow” or “wow”.)

  13. Now to demonstrate how a drug affects this system, let’s use cocaine as an example. What will happen if a drug is given to this system, in an unlimited supply? Let’s find out. (Instruct the MFB volunteers to pass their neurotransmitters from one to the other as fast as they can. If they drop a ball, tell them “DON’T pick it up”) OK, let’s go, all the cocaine in the world. Let’s go! Let’s go! (Remind the cortex to shout how it feels – “whoopee” “aaahhhhhhhh”)

  14. (Finally, most of the nerve cells have dropped their neurotransmitters on the floor.) How many nerve cells have any neurotransmitter left? (Only a few or none) This is what happens when someone takes too much cocaine for too long a time. It’s called the cocaine crash! The crash - lots of sleep, people wake up depressed, they crave cocaine, but they have anhedonia: the inability to experience pleasure. The crash is caused by a relative depletion of dopamine, and perhaps another neurotransmitter, serotonin in the MFB. No wonder people feel so bad when they use too much cocaine!

  15. Some people ask whether this is a permanent change or whether nerve cells are killed by cocaine. There is presently no scientific evidence that either of these occur. However, sometimes cocaine-dependent people report that they don’t experience pleasure for months or even years after a major cocaine crash – they just don’t feel “normal”. This suggests that some of the neurotransmitter systems that are knocked out by cocaine take a long time to recover.

  16. (The group is then dismissed - “Thanks a bundle, folks!”). This role-play exercise illustrates a 1985 hypothesis called the dopamine depletion hypothesis of cocaine withdrawal. Most scientists still believe this is a valid hypothesis.

  17. (If you want to demonstrate an alcohol hangover, alcohol is associated with effects on all of the five neurotransmitters listed above. Alcohol is a “dirty” drug, and affects most systems of the brain. So you can ask for volunteers with any color of neurotransmitter. Then you replace “hangover” for “crash”, and the point - while a little less scientific - is still a good representation of what happens with too much drinking. You should also explain that there are other aspects of a hangover that occur outside of the brain – upset stomach, headache, “blah” feeling - perhaps caused by electrolyte depletion or dehydration.)

 

For further information, please write or call:

University of Texas
Addiction Science Research and Education Center
The College of Pharmacy
1 University Station A1915, PHR 5.224
Austin TX 78712-0125
512.471.5198
fax 512.471.5198
Carlton Erickson, Director

31 August 2004