THE TEEN BRAIN Curriculum for High School Teachers

Transcription

1 THE TEEN BRAIN THE TEEN BRAIN Curriculum for High School Teachers Module 5 Neurons & Neurotransmission How do cells in the brain communicate? What are the major chemicals in the brain that affect behavior? Center for Neuroscience & Society, University of Pennsylvania The Franklin Institute

2 Acknowledgments The Franklin Institute Julia Skolnik, M.S.Ed. Jayatri Das, Ph.D. Center for Neuroscience & Society Laurel E. Ecke, Ph.D. Martha J. Farah, Ph.D. Teachers Maria Fitzgerald David Jones Helen B. Murray Karen S. O Hara Robert H. Rineer Khaing Win Evaluation Goodman Research Group, Inc. The Franklin Institute, in collaboration with the University of Pennsylvania, This project was supported by funding from the National Institutes of Health Blueprint for Neuroscience Research under grant #R25DA Its content is solely the responsibility of the authors and does not necessarily represent the official views of NIH.

3 THE TEEN BRAIN In Module 5, students more deeply examine the neuroanatomy of a neuron and the chemical process of neurotransmission. Through acting out the sequence as a group, they experience this process in a hands-on and interactive way. This module invites students to explore the questions: How do cells in the brain communicate? What are the major chemicals in the brain that affect behavior? While exploring this idea, students will: Understand the anatomy of a neuron. Understand that there are electrical and chemical components of a synapse. Know the major neurotransmitters in the brain that affect behavior (glutamate, dopamine, serotonin, norepinephrine). Demonstrate the process of neurotransmission through acting it out with classmates. The PowerPoint slides that accompany this module are meant to help guide the lesson, transitioning between activities and providing relevant information when necessary. Frequently engage students in discussion by asking questions, eliciting their prior knowledge, experience, and ideas. Examples of probing and reflective questions are embedded throughout the curriculum guide, to scaffold meaningful and relevant experiences for students. Time Frame: 2 hours Activities: Review of neuron Simulation of neurotransmission Neurotransmission Game Neurotransmitter Challenge Preparation: Make copies of Neurotransmitter Challenge worksheets. Load PowerPoint slides onto computer/tablet. Assemble signs representing different components of neurotransmission for the Neurotransmission Game (printed signs, hole punch, ribbon/yarn to go around neck). Assemble other materials needed for the game (e.g. ping pong balls, markers, etc.). Materials Needed: Exploration 1: Simulation of Neurotransmission Computer/tablet with PowerPoint slides Students neuron activity handouts from last class

4 Exploration 2: Neurotransmission Game Printed signs for students to wear: Enough copies of PowerPoint sign printouts for groups of 5 students Yarn or ribbon Hole punch 5 ping pong balls or tennis balls 2 batons or paper towel roll Markers Whiteboard or paper Exploration 3: Neurotransmitter Challenge Copies of Neurotransmitter Challenge activity sheets Pens/pencils Journal Reflection Journal books for each student Review (10 mins) Driving Questions: What did we learn about memory in the brain? How do cells in the brain communicate? 1. Review learning & memory: a. What did we learn about different types and phases of memory? b. What did we learn from HM? 2. Review the structure and function of a neuron, using the Neuron Activity sheet as a guide. a. Dendrites located near cell body, connect with other neurons b. Cell body contains nucleus and DNA (command center of neuron) c. Axon long extension from cell body through which electrical signal is carried, sends information to other neurons d. Myelin sheath fatty coating on the axon that insulates the signal to be sent quickly; the more frequently the neuron is fired, the thicker and stronger the myelin sheath is which makes the signal travel faster. e. Axon terminal the end of the axon which connects to the dendrites of other neurons f. Synapse a small gap between two neurons where a signal is transferred. 3. Discuss how a signal travels through a neuron to the next neuron. a. In the synapse (the gap between the neurons), chemicals are released from the first neuron to the second, which carries the signal to the next neuron. Simulation of Neurotransmission (10 minutes) Driving Question: How does a signal transfer from one neuron to the next? 1. Introduce neurotransmission a chemical release from one neuron to another that transfers the signal from one neuron to the next. a. Packages of chemicals are contained in vesicles. b. When the electrical signal/action potential reaches the axon terminal, the vesicle releases the chemicals called neurotransmitters, which are received by receptors on the next neuron. 2. Show the neurotransmission simulation. Explain that neurotransmitters are chemicals released from vesicles and receptors are meant to receive specific chemicals. Dopamine is an example of a chemical, which when released results in feeling good/happy.

5 3. Show the dopamine neurotransmission simulation, highlighting step by step the sequence of what happens: a. Action potential travels down axon to the axon terminal where the vesicles are. b. Vesicles release neurotransmitter (e.g. dopamine). c. Dopamine is released into the synapse and binds to a receptor on the next neuron. d. This releases a messenger, which carries the signal forward in the next cell. e. The neurotransmitter (dopamine) is released back into the synapse. f. The transporter on the first neuron takes the neurotransmitter back into that cell, and re-enters the vesicle. g. As more and more neurotransmitters are released, more action potential/signal builds in the second neuron and when it has enough energy it releases the signal down the next axon to fire to the next neuron. 4. Ask students to reflect: Does this seem to make sense? Where might this be confusing? Neurotransmission Game (35 mins) Driving Question: How can we model the process of neurotransmission between neurons? 1. Divide the group of students into teams of 5. Each team should have a person representing the following role. Describe to students, using the simulation as demonstration. a. Action Potential run down the axon and tag the vesicle. b. Dopamine Vesicle when tagged, toss the neurotransmitter (tennis ball) across the synapse to the receptor. c. Dopamine Receptor catch the neurotransmitter (tennis ball) and hand the baton (signal) to the messenger. After you get the baton back from the messenger, throw the neurotransmitter (ball) over the synapse to the transporter. If balls drop, the receptor can t pick them up it must stay in the membrane and get collected by the vesicle. d. Messenger catch the baton and run toward the board/paper to make a mark. This mark represents a signal that is contributing to a signal large enough to make the next neuron fire. Then give the baton back to the receptor. e. Transporter catch the neurotransmitter from the receptor. Throw the neurotransmitter to the vesicle, to return it to its starting place. Any balls that fall down must be collected by the transporter and go back into the vesicle. f. Once the neurotransmitter re-enters the vesicle, the Action Potential can go down the axon again and REPEAT the sequence. The sequence should run until the messenger marks 10 marks on the board or paper, which is a large enough accumulation of signal for the next neuron to fire and the synapse is complete. 2. Bring one group up to demonstrate for all students. Move chairs to create the neuron boundaries for pre-synaptic and post-synaptic neurons, similar to the diagram included in the PowerPoint presentation. Run through the game once to show the role of each person. 3. Break the groups up. Have students set up their chairs to represent neuron boundaries. Count down to let all groups start at the same time. 4. After one group has finished first, allow other groups to finish, or bring game to a close. Debrief with students the process of modeling neurotransmission, and the significant role each component plays. Ask students to reflect: What was it like for you to play the role you played? Short Break (10 mins)

6 Neurotransmitter Challenge (45 hour) Driving Question: What are the major chemicals in the brain that affect behavior? 1. Describe 6 major neurotransmitters in our bodies glutamate (excitory), GABA (inhibitory), serotonin (affects mood), dopamine (reward system), acetylcholine (memory & attention), and norepinephrine (alertness). 2. Encourage students to think about: What happens when these chemicals/neurotransmitters are out of balance? Allow students to discuss predictions for each neurotransmitter, and share the results. 3. Introduce the Neurotransmitter Challenge. Explain that groups will do the following: a. Pick one neurotransmitter from the previous list, and research how it normally operates in the brain. b. Research what happens if it s out of balance. c. Complete the Neurotransmitter Challenge activity sheet. d. If there s time, act out a modified version of the Neurotransmission Game to simulate how their neurotransmitter works normally and abnormally, presenting to and educating the rest of the class. 4. Show example of glutamate during epilepsy. a. Explanation: Glutamate excites neurons and make them more likely to fire action potentials. Epileptic seizures are an electrical storm in the brain caused by an impaired balance of excitation (glutamate) and inhibition (GABA). b. One cause of seizures may be over activation of glutamate neurons. This causes the release of high levels of glutamate into the synapse. This glutamate binds to glutamate receptors and causes positive ions to cross through the channels into the post-synaptic neurons. This influx of positive ions makes these neurons more excitable and more likely to fire action potentials as well, causing over-activation across the brain and resulting in that electrical storm. 5. Allow students to break into groups of three and do the challenge. If time allows, encourage each group to act out a simulation of how their neurotransmitter functions in the brain, and what an imbalance of that neurotransmitter might lead cause. Journal Reflection (10 mins) Driving Question: What are you thinking about after today s session? 1. Encourage students to think about what they did and learned today. Ask them to consider and write about: a. What does that make you think? b. Where do you feel confused? c. What are you still curious to learn more about?