1. Begin the lesson with the statement, “People often compare the brain to a computer.” Then ask, “What do you think they mean? How is a brain like a computer?”

Students will provide a variety of responses. Some may indicate that the brain, like a computer, processes large amounts of information. Affirm this response by saying, “Yes, both computers and brains take information in and interpret it.” Then ask, “What do they do with the information?” Students may say that the brain uses information to “run” the body the way a computer uses information to run programs. You can elaborate on this response by saying, “Yes, both computers and brains respond to information—they send information out.” Summarize the discussion by emphasizing three points about how the brain functions: 1) it receives information (“information in”); 2) it interprets the information; and 3) it responds to the information (“information out”).

2. Ask students to provide some examples of the types of information that come in to the brain and the information that goes out from the brain.

Students will likely identify sensory information such as seeing, hearing, tasting, touching, and smelling as “information in.” Point out that their brains also receive information from within their bodies, such as information about heart and breathing rates. Remind students of the Memory Station in Lesson 1, and note that information stored within their brains also contributes to “information in” for responding to a particular situation. If students are puzzled by the idea of “information out” from the brain, ask, “How do you respond to information that comes into your brain, such as when someone calls your name from behind?” When students respond that they turn around, point out that their brains direct that movement. “Information out” refers to actions that we choose, such as moving/not moving, speaking/not speaking, or paying attention/not paying attention. Information out also refers to actions in the body that the brain controls automatically, such as heartbeat and breathing.

3. Ask, “Where do different types of information come into the brain? From where in the brain is information sent out?”

Students probably will not know how to answer. These questions are meant to encourage students to think about the structures and functions within the brain. Move on quickly to the next step.

4. Explain that to determine where information comes into the brain, scientists use special techniques to “see” inside the brain. One of these techniques is the PET scan.

Tip from the field test: Using the transparency of Master 2.1, Basics about PET Scans, will assist you in guiding students through an explanation of PET scans.

Content Standard A:
Technology used to gather data enhances accuracy and allows scientists to analyze and quantify results of investigations.

5. Show a transparency of Master 2.2, Sample PET Scans. Ask students what they observe about brains that are receiving and responding to different types of information. Do the PET scans look the same? What does this suggest about the brain?

Explain to students that each PET scan on Master 2.2 shows brain activity for a single type of information, as indicated by the label below the image. Remind students that the bright regions of the scan show the active regions of the brain. Students should notice that the active regions of the brain differ with the type of information going into or out of the brain. Students should conclude that the brain has specialized regions that receive and respond to different types of information.

Assessment:
Listening to students’ responses allows you to assess their understanding of specialized regions in the brain. An understanding of functional specialization within the brain is an important prerequisite for Activity 2.

1. Organize students into pairs.
2. Project a transparency of Master 2.3, Scenario Diagram. Ask students to watch and listen as you describe the following scenario.

“You are riding your bike on a country road. A bike path curves sharply off the road to your right, crossing a swift stream with a rickety wooden bridge. A bit further up the road, a second bike path slopes gently to the right, but the path is riddled with rocks and potholes. To the left, a thunderstorm appears to be moving in your direction. Suddenly, you hear a loud truck horn directly behind you.”

Tip from the field test: Students were less distracted and listened more carefully if colored pencils were handed out after teachers described the scenario (in Step 4) rather than before.

Content Standard C:
Specialized cells perform specialized functions in multicellular organisms.

3. Instruct the pairs to work with their partners to

• make a list of the information their brains would receive in this scenario (information in);
• decide what their response to the scenario would be (information out); and
• identify the type of information (such as visual or auditory) for each item on their list and for their response.

4. Provide each group with a copy of Master 2.2, Sample PET Scans, Master 2.4, Brain Outline, and a set of six colored pencils.
5. Tell students to use the colored pencils to color in the brain regions on Master 2.4, Brain Outline, that would be active in the scenario, based on the type of information they identified in Step 3.

Allow groups 15 minutes to complete Steps 2 to 5. Students should use different colored pencils to indicate the different regions of the brain that are active. Student diagrams should include a key indicating the color corresponding to information from each source. Let students know that they will be presenting their findings to the class.

Teacher note: In this activity, students use different colors to indicate different regions of the brain (such as red for the visual cortex and blue for the motor cortex). This is effective for demonstrating the lesson concept that different regions of the brain are active for different types of information in and information out. Although color PET scans may look similar to students’ diagrams, the colors in a PET scan represent the intensity of activity in regions of the brain, not regions that receive information from different sources, as in students’ diagrams. Although this point is not important for students’ understanding of the major concept in the lesson, some of your students may be familiar with PET scans. If students ask whether they are producing PET scans with their diagrams, you should explain that they are not and clarify the difference.

6. Ask one of the pairs to provide a one-minute presentation of their results to the class. Advise students to take notes because they will need to discuss the scenarios in a homework assignment.

The presentation should include the information presented in the scenario, the brain regions that receive that information (color-coded by source), their group’s response to the scenario, and the brain regions that are active in carrying out their response. Encourage students to use their diagrams to identify the various brain regions involved.

7. Ask a pair who had a different response to the scenario to present their results to the class.

The second pair should follow the same guidelines for their presentation as the first pair.

8. Repeat Step 6 for a third pair.
9. Ask students to compare the brain regions they colored in with the regions colored in by the pairs that presented their results. Ask, “Did you all color the same regions? Why (or why not)?”

Students should find that all pairs colored in the same brain regions. The scenario included multiple types of information, so multiple brain regions had to be active. Because all pairs were working with the same scenario, they had the same types of information coming in from outside the body. Thus, regardless of the colors used, all diagrams should indicate activity in the same brain regions.

10. Point out that different pairs suggested different responses to the scenario. Ask, “How can you explain that although everyone had the same ‘information in,’ the responses (‘information out’) varied?”

Students will likely say things such as, “We knew we could ride around the potholes and rocks, so we took the second path” or “We just speeded up to get ahead of the truck and get home before the storm broke.” Point out that these thoughts—information about their abilities to navigate or to go faster—represent a type of “information in” that was based on past experiences and that varied from pair to pair, even though each pair’s brain diagram indicates that the same brain regions were active. This information originated within the brain, rather than from an external source.

Assessment:
This assignment allows you to assess students’ understanding of the role of past experience in defining sense of self. As an informal assessment, you can have several students read their paragraph and listen to the class discussion. As a formal assessment, you can collect the students’ written work.

11. As a homework assignment, ask students to write a 5-to-10-sentence paragraph describing

• similarities in all pairs’ lists of information in and out and in the active regions depicted in their diagrams;
• differences in the pairs’ responses to the scenario; and
• how responses can be different for different individuals even though the information coming in from outside the body and the brain regions that process this information are the same.

Students should indicate that all pairs described visual, auditory, and tactile “information in” and motor “information out,” as well as activity in the same regions of the brain. They should describe several different responses to the scenario. Students should indicate that the brain also uses information from memory (past experiences) to determine a response. Differences in past experiences help account for differences in responses. The way sensory information is related to past experiences contributes to the sense of self.