Students will be able to determine what stage of sleep someone is in by analyzing their EEG.

Transcription

1 Outline 2Lesson Unit1.2 OVERVIEW Rationale: This lesson is intended to engage students with the concept of the neural circuit. The lesson and unit as a whole use sleep, a behavior everyone is familiar with, to further explore neural circuits and how they control behaviors. In this lesson students are introduced to the sleep stages and how they are visualized and studied using EEGs. The lesson sets the students up to begin to learn about sleep in the context of neuronal control, a logical progression from the previous unit that focused on simple pathways. Objectives: Students will be able to describe sleep and what happens to the activity of our brain, muscles, and eyes as we progress through the different sleep stages. Students will be able to determine what stage of sleep someone is in by analyzing their EEG. Activities: Students begin the lesson by taking a sleep quiz. The purpose of the sleep quiz is to uncover misconceptions about the role of sleep. The sleep quiz is used as a springboard to take students interactively through basic information about sleep. Additionally, this lesson introduces the EEG because researchers use this tool to analyze sleep as well as the activity of neural circuits. With a partner, students complete a worksheet to analyze an EEG. The class concludes with a short discussion of how much sleep is enough. Homework: In order to prepare for tomorrow s lesson which analyzes the students sleep journals, students are asked to calculate their average hours slept, caffeine consumed, and sleepiness scale score using their sleep journals. If students haven t completed sleep journals, you can give them sample data from a mock sleep journal. Additionally, students are asked to read a short article about the effects of sleep deprivation. The Lesson Plan Lesson : What is sleep? 1. Do Now (5 min): Sleep quiz: What do you know about sleep? The students work with a partner to determine whether four statements are true or false. 2. Socratic (15 minutes): The sleep quiz is used to drive a Socratic discussion about what we know about sleep, how it is measured and sleep characteristics. 3. Activity (10 minutes): Analysis of an EEG 4. Wrap-up (10 minutes): How much is enough sleep? 5. Homework: Using their sleep journals, students are asked to calculate their average hours slept, caffeine consumed and sleepiness scale score. Students are asked to read a short article about the effects of sleep deprivation. 5. Homework: 1. Printed materials Activity worksheet Homework worksheet Sample sleep journal 129

2 1. DO NOW 2. Introduction to Unit 4: Before beginning this lesson briefly introduce the students to Unit 4. Tell the students that now that we know how neurons communicate with each other, we will explore how they work together to control behaviors. This unit explores how neurons work together in groups called circuits to control behaviors. One behavior we will explore is sleep. Slide 1 1. You will die if you don t get enough sleep. Ask the students is the first statement You will die if you don t get enough sleep. True or False? True (by extrapolation). Rats who are deprived of sleep die within a couple of weeks. This is because their homeostatic mechanisms (that control physiological processes) are linked to the sleep-wake cycle. The human record for going without sleep is 12 days. Animate the slide to show the students that when they are deprived other basic needs (air, water, and food) as well as sleep, the result is death. Do now: What do you know about sleep? Have the students work with a partner to determine if the four statements are true or false. Slide 4 Slide 3 After giving the students 5 minutes to complete this task, review the answers using the next set of slides. 130

3 2. You sleep so your body can repair itself from the day s activities. Slide 5 Ask the students is the third statement You can t perform properly if you don t get enough sleep. True or False? True. Being sleep deprived impairs performance to the same extent as being drunk. When you re asleep your brain is less active than when you re awake. Slide 7 Ask the students is the second statement You sleep so your body can repair itself from the day s activities True or False?False. Most people think that sleep is a time to recharge their batteries however there s no evidence that more repair occurs during sleep than during rest or relaxed wakefulness. You can t perform properly if you don t get enough sleep. Slide 6 Ask the students is the fourth statement When you sleep your brain is less active than when you re awake. True or False? False. We will revisit the concept of sleep deprivation in the next lesson, through the analysis of the students sleep journals, so you might want to stress this idea of sleep deprivation having an equally powerful effect on performance now. Your brain is incredibly active during sleep. Brain activity during sleep is the focus of the remainder of this lesson. 131

4 2. You can measure the brain s activity during sleep with an EEG Ask the students has anyone had an EEG before? If so, have that student describe what was done to record the EEG. Slide 8 Ask the students if they can figure out the coding system. The coding system is for the lobe that the electrode is recording from: F Frontal lobe involved in planning P Parietal lobe involved in sensory processing T Temporal lobe involved in auditory processing O Occipital lobe involved in visual processing C Motor in this case involved in motor control Tell the students that even numbers are placed on the left hand side and odd numbers are place on the right hand side. The EEG measures activity between electrodes Use this slide to show the students what the data from an EEG looks like. If not, describe for the class how an EEG is A cap is placed on the head that has electrodes in it spaced out at regular intervals. The EEG records the voltage flowing through the brain between each pair of electrodes. Because each pair of electrodes samples the activity of different populations of neurons in different brain regions, each of the individual EEG traces will be unique. Slide 9 Draw the students attention to the coding of the different electrodes placed on the scalp. At the front of the head the electrodes are coded with the letter F and at the back of the brain the electrodes are coded with the letter O. Draw the students attention to the coding system for each electrode on the trace. Tell the students that the electrodes measure the electrical activity between the two coded electrodes, which is why each trace is reported as Fp1-F7 or P3 O1. 132

5 2. The EEG records activity in the form of waves. What do the brainwaves signify? Use this slide to discuss how the EEG varies given our state of consciousness. Use this slide to review amplitude and frequency. Slide 11 Slide 10 Ask the students When talking about a wave, what is frequency? What is amplitude? Frequency refers to how long (length) a wave is from trough to trough. Amplitude refers to how large (height) the wave is from peak to peak. Animate the slide to show the students that the red arrow labeled A refers to amplitude, and the blue arrow labeled B refers to frequency. First, make sure that the students are able to determine traces with high and low frequency, as well as traces of high and low amplitude. Ask the students to point out areas of high amplitude low frequency, high amplitude high frequency, low amplitude low frequency and low amplitude high frequency. This will be addressed in the activity 133

6 The activity worksheet is included in the Materials Folder for this lesson. 2. Explain to the students we don t really know how this translates into brain function i.e. none of the waves is equivalent to anything like a thought or a memory, they re just showing overall activity in those areas. Next, introduce the students to the concept that our brain waves differ given our state of consciousness. Show the students that when we are mentally alert with our eyes open, our EEGs have high frequency, low amplitude waves. Show the students that when we are drowsy or asleep, our EEGs have lower frequency with higher amplitude waves. 3. Activity Activity: Reading an EEG Give each student a copy of activity EEG worksheet and have them work with a partner to complete the worksheet. Before beginning the activity, make sure that the students understand that the EEG measures activity between two cortical areas. Emphasize that the measurement is overall activity through many thousands of neurons. 3. After giving the students 7-10 minutes to complete this task, review answers with them using the animations in this slide. Show the students that circle A represents an area of high frequency. Then ask the students, what leads/what area of the brain does this trace represent? T4-T6 Show the students that circle B represents an area of low frequency. Then ask the students, what leads/what area of the brain does this trace represent? P3-O1 Show the students that circle C represents an area of low amplitude. Then ask the students, what leads/what area of the brain does this trace represent? Fp2-F8 Slide 12 Show the students that circle D represents an area of high amplitude. Then ask the students, what leads/what area of the brain does this trace represent? T3-T5 134

7 3. Activity Show the students that circle E represents an area of high frequency and amplitude. Then ask the students, what leads/what area of the brain does this trace represent? CZ-PZ The EEG detects multiple stages of sleep Use this slide to describe how the EEG changes as we progress through a night s sleep. Slide 13 Ask the students can anyone guess what is happening during sleep stage 5 that would cause the brain to have an EEG that is similar to the awake brain? Rapid eye movement (REM) sleep which is the stage of sleep that we dream. Animate the slide to show the students that there are essentially two sleep stages Non rapid eye movement (NREM) and rapid eye movement (REM). Use the next slide to further discuss the two types of sleep. Two types of sleep Ask the students What is the difference between NREM and REM sleep? In NREM sleep the sleeper is still and the eyes aren t moving. If the sleeper is woken up in this stage they rarely describe dreams. REM sleep is a physiologically dynamic state. The overall physiology is active and the eyes move rapidly. If the sleeper is woken up at this stage they commonly report dreams (although they may forget them shortly thereafter). Slide 14 Show the students that the awake EEG is characterized by high frequency, low amplitude waves, which slowly decrease in frequency and increase in amplitude as we progress through the stages of sleep. That is, until we get to Stage 5, which again has an EEG with high frequency and low amplitude waves. Animate the slide to show the students the main characteristics of NREM and REM sleep. 135

8 4. Wrap Up How much is enough sleep? Use this slide to get students thinking about how much sleep is needed to function properly. The homework worksheet is included in the Materials Folder for this lesson. WORKSHEET: Sleep Analysis The sleep journal is included in the Materials Folder for ND Lesson 3.1, as well as the Materials Folder for this lesson. The sample sleep journals are included in the Materials Folder for this lesson. Slide 15 Ask the students how much is enough sleep? Student answers will typically vary, but show the students different animals sleep for drastically different amounts of time. Remind the students that they should be keeping track of their own sleeping habits using their sleep journal, and that their homework for tonight is to make sure to bring that with them to class tomorrow since we will be analyzing it as a class. Homework Have the students complete the homework worksheet for this lesson which includes a short article on the effects of sleep deprivation. This worksheet also instructs the students to use their sleep journals (which were assigned a week ago in ND Lesson 3.1) to calculate their average hours slept, caffeine consumed, and sleepiness scale score. If students haven t completed their own sleep journals, give them sample data from a sample sleep journal and have them complete the calculations using this sample data. As with a jigsaw, be sure to divide up the patient sleep journals so that when students work in groups tomorrow they aren t all using the same data. 136