Inside Information Part 1

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Objective

SWBAT determine the pathway information takes in reflex and voluntary motor responses.

Big Idea

Students test their powers of deduction as they attempt to determine how the brain and the body communicate.

Warm-up

10 minutes
This lesson was adapted from the NIH module The Brain: Our Sense of
Self. (BSCS. (2005). The Brain: Our Sense of Self. NIH publication No. 05-5171.
Copyright © 2005 by BSCS. All rights reserved.)

The purpose of this lesson is to show students how the brain receives and processes information.  This is part 1 of a 2 part lesson. I use Inside Information Part 1 PowerPoint to guide this lesson.  This also contains some notes/suggestions in the comments section below each slide.

Begin the lesson by displaying two Two Types of Animal Cells, on the overhead projector. Ask students to make observations about the two cells.

Focus discussion on similarities and differences between the two cells. Students may say that the top cell is smooth and round, while the bottom cell is long and thin. They may comment that although both cells have a cell body and a nucleus, there appear to be some “extra” parts sticking out of the bottom cell.  The following prompts may be used to jump start student observations:

  • What is the same?
  • What is different?
  • Where is the nucleus?  
  • How would you describe each cell?
  • What might explain the difference in shape? (Best guess at this point, accept any reasonable answer.)

Explain to the class that the top cell is the most common type of animal cell, such as a skin cell. The bottom cell is a special cell that passes information through the body. It is a nerve cell, or neuron.

Activity

30 minutes

This modeling activity allows students to better envision how information travels between neurons and relates to SEP 2, specifically having students develop and/or use a model to predict and/or describe phenomena and develop a model to describe unobservable mechanisms. 

This video provides a very quick overview of the key points of the activity.  The video, along with the notes in the Inside Information Part 1 PowerPoint, provide quite a few suggestions for this modeling activity.  This video is also good for giving the gist of the activity to students who were absent for the actual activity.

Explain briefly that a neuron is made up of three parts: the dendrites, the cell body, and the axon.

Ask students to stand and form a line around the classroom. Explain that they will model information flow through a neural pathway.

A neural pathway is a path of information flow through the body. Each student represents one neuron along the pathway.

Ask students to hold out their arms, forming a fist with their right hand and leaving their left hand open.

Students should stand close to one another but leave a space between adjacent hands. Explain that as neurons, the open left hand of each student represents their axon end, and their right fist represents their dendrite end.

Tell students that they will be passing information through their model pathway by using their open hand to tap the fist of the person next to them.

Start the flow of information through the pathway by tapping the fist of the rightmost student of the line with your left hand. Each student should pass the information along by using their axon (left hand) to tap the dendrite (right fist) of the student next to them. Allow the information to be passed through the entire line of students.

At this point I ask a few students to explain what is happening in their own words and how this activity connects to how the brain transmits information.  

Now ask a student in the middle of the line to face the opposite direction from the rest of the line, leaving the same hands open and fisted. Once again, start the flow of information by tapping the fist of the rightmost student in the line. What happens to the signal?

To make the point of directional information flow, you may want to reinforce the idea that the open hand can only send information and the fist can only receive information. The signal should stop at the student facing the opposite direction from the rest of the line.

I compare this to magnets: fist-fist and palm-palm connections are like similarly charged magnets.  For information to travel the connection must be fist-palm.  I also compare the open palm sending information to Iron Man shooting "energy" out of his palm.  Making these connections for students gives them a way to connect this new information to some of their prior knowledge.

Ask students what this experiment suggests about information flow through neurons.

Information flows through neurons in one direction only.

This video demonstrates another model of how neurons communicate (start at 2:14 to show just the modeling activity).  The Rope Neuron Modeling Activity has the directions on how to make the rope neuron model if you prefer the hands-on experience.  

During the video (or immediately following the live activity) have students work in lab groups to answer the following question: What evidence from the video supports the idea that information flows through neurons (nerve cells) in only 1 direction?  I prefer students to use the following sentence stem to shape their answer: "I think....because...." as it forces students to explain their thinking in greater detail.

Finally, I have students compare/contrast the different models and discuss the strengths and limitations of each (SEP 2). I begin this by having students work in lab groups to discuss the similarities and differences of each model (students should write this information in their science journals).  

After students have had a few minutes to discuss, I regroup as a whole class to create a Venn diagram on the whiteboard.  This is an efficient method for sharing information between groups.  Once the Venn contains all of the important class information, I allow the students a few minutes to copy it into their journals.  I also have students state which model they prefer and why.  I do this to encourage students to think more deeply about each model in an effort to help them remember the information gained from the modeling activity.

Wrap-up

5 minutes

To allow for the assessment of student understanding, for homework I have students create an illustration that depicts how information travels through neurons.  

Students are encouraged to create their own model which can be literal (showing actual neurons) or metaphoric (depicting other objects acting in the manner of neurons), but must accurately depict the flow of information.  It is important that students develop this on their own using a format that makes sense to them as it allows them to better remember the information because it is more personal and meaningful.

Student Examples