Directions for teachers:

Before students answer the first question, have them read “Scientists have mapped an insect brain in greater detail than ever before” from Science News online and watch the video “See all of the nerve cells in a larval fruit fly’s brain” linked in the article. A version of the article, “The fruit fly brain in exquisite detail,” appears in the April 22, 2023 issue of Science News.

Next, ask students to read the Science News Explores article “Explainer: What is a neuron?” and answer the first section’s remaining questions. Use the second section’s last question to lead a class discussion about techniques for studying the brain. Reading “Scientists Say: Neurotransmitters” from Science News Explores will help students with question 5 in the first section.

Thinking about nerve parts

1. After watching the video “See all of the nerve cells in a larval fruit fly’s brain,” discuss what you noticed with a partner. What did you observe? What was interesting or surprising?

Student answers will vary. Some possible answers could include that the nerve cells look like balloons with strings. The colors seem to indicate that there are many different types of nerve cells that appear to have no regular distribution around the brain. The overall shape of the brain with its two distinct sides is surprising.

2. Read “Explainer: What is a neuron?” and re-watch the video. Use the information from the article to explain what you see in the video. Use correct vocabulary.

The fruit fly brain is made up of many different types of neurons that appear to be randomly distributed among two spherical structures, one on the left side of the brain and one on the right. The round objects represent cell bodies, which means the strings probably represent axons and dendrites. From the video, it is hard to tell where the connections (synapses) are between the various parts of the nerves.

3. What questions do you still have about what you’re seeing in the video?

Why are the tails attached to the cell bodies so long in the larval fruit fly’s brain? Where are the synapses? How many cross-sections of the brain did it take to create this image? What do each of the colors represent? What’s in the fluid in synapses?

4. What is neuroscience? Explain why neurons are the foundation of neuroscientists’ work.

Neuroscience is the study of the nervous system, including its development and structures. Neurons are nerve cells found in the brain, spinal cord and other parts of the body. The job of neurons is to relay information and give directions to the rest of the body. To understand the nervous system, neuroscientists work to understand neurons and how they function.

5. Based on what you have read, consider how neurons help you sense, respond and learn. Describe a behavior and give a simple explanation of what neurons do.

If I smell toast burning, I hurry to the toaster and pull the toast out. The next time I make toast, I will lower the toasting setting. Neurons in my nose helped me sense the smoke and told my brain I had to do something. My brain signaled nerves in my arms and legs to move those body parts, and my brain learned what to do to prevent my toast from smoking in the future.

Neurons sense all kinds of information around us and send signals to the brain. The body uses chemicals called neurotransmitters to signal nerves that they must act. The neurotransmitters go across a space called a synapse. Dendrites, which are part of a nerve cell, pick up the signal and send it to a cell body, another part of a nerve cell. The cell body sends the message to the axon, and the message then goes to the end of the axon, which is the axon terminal.

Studying brains

1. How could studying a larval fruit fly’s brain lead to better understanding of the human brain?

Larval fruit flies share a wide range of behaviors with humans. Fruit flies take in sensory information and learn. Findings from fruit fly studies might help scientists identify patterns in brain function and behaviors that are shared by many species, including humans. Methods of investigating larval fruit fly brains also might be useful in studying human brains.

2. What tools did scientists featured in the Science News article use to study the fruit fly’s brain?

To create a 3-D model of the larval fruit fly brain, the scientists used an electron microscope to take cross-sectional images of the fly’s brain and then used a computer to combine the images.

3. Search the Science News or Science News Explores archives for articles about brain studies. Pick one article and explain what tools or methods scientists used in their brain research. An example of a tool is a PET scan; an example of a method might be a behavioral evaluation. More tools are listed in Explainer: How to read brain activity from Science News Explores.

Students’ selected articles will vary. In “Brain scans suggest the pandemic prematurely aged teens’ brains” from Science News online, the scientists used MRI scans to study teen brains. In “Cell phones on the brain” from Science News Explores, the researchers used PET scans for their imaging work.

4. Is the method described in the article used to study human brains, animal brains or both? Research your chosen method and describe what you can learn about the brain using this method. Cite your sources.

Student answers will vary. For example, one method of brain imaging uses a PET scan, which can be used on both human and animal brains. With this method, you can measure activity in different parts of the brain. This can tell you which parts of the brain and its tissues are functioning normally and where there might be a problem. “Cell phones on the brain” from Science News Explores highlights a study that used PET scans.

5. Share the method you researched with your class. As a class, discuss the different methods of studying the brain and the advantages and disadvantages of each. In what situation would researchers choose to use one method over another?

Student answers will vary.