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Psychology

<OpenstaxParagraph>
	As we begin to fall asleep, we enter NREM sleep, and brain wave patterns decrease in frequency and increase in amplitude. The first stage of NREM sleep is known as stage 1 sleep. <OpenstaxTerm>Stage 1 sleep</OpenstaxTerm> is a transitional phase that occurs between wakefulness and sleep, the period during which we drift off to sleep. During this time, there is a slowdown in both the rates of respiration and heartbeat. In addition, stage 1 sleep involves a marked decrease in both overall muscle tension and core body temperature.
</OpenstaxParagraph>
<OpenstaxParagraph>
	In terms of brain wave activity, stage 1 sleep is associated with both alpha and theta waves. The early portion of stage 1 sleep produces <OpenstaxTerm>alpha waves</OpenstaxTerm>. These patterns of electrical activity (waves) resemble that of someone who is very relaxed, yet awake, but they have less variability (are more synchronized) and are relatively lower in frequency (8–12 Hz) and higher in amplitude than beta waves (<a href="#Figure_04_03_Stages">Figure 4.8</a>). As an individual continues through stage 1 sleep, there is an increase in theta wave activity. <OpenstaxTerm>Theta waves</OpenstaxTerm> are even lower frequency (4–7 Hz), and higher in amplitude, than the alpha wave patterns. It is relatively easy to wake someone from stage 1 sleep; in fact, people often report that they have not been asleep if they are awoken during stage 1 sleep.
</OpenstaxParagraph>
<OpenstaxFigure id="Figure_04_03_Stages" src="https://openstax.org/apps/archive/20240226.174525/resources/a037714121c50634c24e59379f0def7806eb6ccd" alt="A graph has a y-axis labeled “EEG” and an x-axis labeled “time (seconds.) Plotted along the y-axis and moving upward are the stages of sleep. First is REM, followed by Stage 3 NREM Delta, Stage 2 NREM Theta (sleep spindles; K-complexes), Stage 1 NREM Alpha, and Awake. Charted on the x axis is Time in seconds from 2–20 in 2 second intervals. Each sleep stage has associated wavelengths of varying amplitude and frequency. Relative to the others, “awake” has a very close wavelength and a medium amplitude. Stage 1 is characterized by a generally uniform wavelength and a relatively low amplitude which doubles and quickly reverts to normal every 2 seconds. Stage 2 is comprised of a similar wavelength as stage 1. It introduces the K-complex from seconds 10 through 12 which is a short burst of doubled or tripled amplitude and decreased wavelength. Stage 3 has a more uniform wave with gradually increasing amplitude. Finally, REM sleep looks much like stage 2 without the K-complex." mediaType="image/jpg" width="650" height="485" />
<OpenstaxFigureText width="650">
	Figure 4.8 Brainwave activity changes dramatically across the different stages of sleep.
</OpenstaxFigureText>
<OpenstaxParagraph>
	As we move into <OpenstaxTerm>stage 2 sleep</OpenstaxTerm>, the body goes into a state of deep relaxation. Theta waves still dominate the activity of the brain, but they are interrupted by brief bursts of activity known as sleep spindles (<a href="#Figure_04_03_Stage2">Figure 4.9</a>). A <OpenstaxTerm>sleep spindle</OpenstaxTerm> is a rapid burst of higher frequency brain waves that may be important for learning and memory (Fogel &amp; Smith, 2011; Poe, Walsh, &amp; Bjorness, 2010). In addition, the appearance of K-complexes is often associated with stage 2 sleep. A <OpenstaxTerm>K-complex</OpenstaxTerm> is a very high amplitude pattern of brain activity that may in some cases occur in response to environmental stimuli. Thus, K-complexes might serve as a bridge to higher levels of arousal in response to what is going on in our environments (Halász, 1993; Steriade &amp; Amzica, 1998).
</OpenstaxParagraph>
<OpenstaxFigure id="Figure_04_03_Stage2" src="https://openstax.org/apps/archive/20240226.174525/resources/be62c72cc7c508782dbd58c526c48af8749ab353" alt="A graph has an x-axis labeled “time” and a y-axis labeled “voltage. A line illustrates brainwaves, with two areas labeled “sleep spindle” and “k-complex”. The area labeled “sleep spindle” has decreased wavelength and moderately increased amplitude, while the area labeled “k-complex” has significantly high amplitude and longer wavelength." mediaType="image/jpg" width="487" height="252" />
<OpenstaxFigureText width="487">
	Figure 4.9 Stage 2 sleep is characterized by the appearance of both sleep spindles and K-complexes.
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<OpenstaxParagraph>
	<OpenstaxTerm>NREM stage 3 sleep</OpenstaxTerm> is often referred to as deep sleep or slow-wave sleep because this stage is characterized by low frequency (less than 3 Hz), high amplitude <OpenstaxTerm>delta waves</OpenstaxTerm> (<a href="#Figure_04_03_Deltawaves">Figure 4.10</a>). These delta waves have the lowest frequency and highest amplitude of our sleeping brain wave patterns. During this time, an individual’s heart rate and respiration slow dramatically, and it is much more difficult to awaken someone from sleep during stage 3 than during earlier stages. Interestingly, individuals who have increased levels of alpha brain wave activity (more often associated with wakefulness and transition into stage 1 sleep) during stage 3 often report that they do not feel refreshed upon waking, regardless of how long they slept (Stone, Taylor, McCrae, Kalsekar, &amp; Lichstein, 2008).
</OpenstaxParagraph>
<OpenstaxFigure id="Figure_04_03_Deltawaves" src="https://openstax.org/apps/archive/20240226.174525/resources/205a3775986ea2feb81f10357c8f5ec711fbab1e" alt="Polysonograph a shows the pattern of delta waves, which are low frequency and high amplitude. Delta waves are found mostly in stage 3 of sleep. Chart b shows brainwaves at various stages of sleep, with stage 3 highlighted." mediaType="image/jpg" width="975" height="363" />
<OpenstaxFigureText width="975">
	Figure 4.10 (a) Delta waves, which are low frequency and high amplitude, characterize (b) slow-wave stage 3 and REM sleep.
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4.3.1 NREM Stages of Sleep

1 Introduction to Psychology

1.1 What Is Psychology?

1.1.1 Why Study Psychology?

1.2 History of Psychology

1.2.1 Wundt and Structuralism

1.2.2 Functionalism

1.2.3 Freud and Psychoanalytic Theory

1.2.4 Wertheimer, Koffka, Köhler, and Gestalt Psychology

1.2.5 Pavlov, Watson, Skinner, and Behaviorism

1.2.6 Maslow, Rogers, and Humanism

1.2.7 The Cognitive Revolution

1.2.8 Multicultural And Cross-Cultural Psychology

1.2.9 Women in Psychology

1.3 Contemporary Psychology

1.3.1 Biopsychology and Evolutionary Psychology

1.3.2 Sensation and Perception

1.3.3 Cognitive Psychology

1.3.4 Developmental Psychology

1.3.5 Personality Psychology

1.3.6 Social Psychology

1.3.7 Industrial-Organizational Psychology

1.3.8 Health Psychology

1.3.9 Sport and Exercise Psychology

1.3.10 Clinical Psychology

1.3.11 Forensic Psychology

1.4 Careers in Psychology

1.4.1 Other Careers in Academic Settings

1.4.2 Career Options Outside of Academic Settings

2 Psychological Research

2.1 Why Is Research Important?

2.1.1 Use of Research Information

2.1.2 NOTABLE RESEARCHERS

2.1.3 The Process of Scientific Research

2.2 Approaches to Research

2.2.1 Clinical or Case Studies

2.2.2 Naturalistic Observation

2.2.3 Surveys

2.2.4 Archival Research

2.2.5 Longitudinal and Cross-Sectional Research

2.3 Analyzing Findings

2.3.1 Correlational Research

2.3.2 Causality: Conducting Experiments and Using the Data

2.3.3 Reliability and Validity

2.4 Ethics

2.4.1 Research Involving Human Participants

2.4.2 Research Involving Animal Subjects

3 Biopsychology

3.1 Human Genetics

3.1.1 Genetic Variation

3.1.2 Gene-Environment Interactions

3.2 Cells of the Nervous System

3.2.1 Neuron Structure

3.2.2 Neuronal Communication

3.2.3 Neurotransmitters and Drugs

3.3 Parts of the Nervous System

3.3.1 Peripheral Nervous System

3.4 The Brain and Spinal Cord

3.4.1 The Spinal Cord

3.4.2 The Two Hemispheres

3.4.3 Forebrain Structures

3.4.4 Midbrain and Hindbrain Structures

3.4.5 Brain Imaging

3.5 The Endocrine System

3.5.1 Major Glands

4 States of Consciousness

4.1 What Is Consciousness?

4.1.1 Biological Rhythms

4.1.2 Problems With Circadian Rhythms

4.2 Sleep and Why We Sleep

4.2.1 What is Sleep?

4.2.2 Why Do We Sleep?

4.3 Stages of Sleep

4.3.2 REM Sleep

4.4 Sleep Problems and Disorders

4.4.1 Insomnia

4.4.2 Parasomnias

4.4.3 Sleep Apnea

4.4.4 Narcolepsy

4.5 Substance Use and Abuse

4.5.1 Substance Use Disorders

4.5.2 Drug Categories

4.6 Other States of Consciousness

4.6.1 Hypnosis

4.6.2 Meditation

5 Sensation and Perception

5.1 Sensation versus Perception

5.1.1 Sensation

5.1.2 Perception

5.2 Waves and Wavelengths

5.2.1 Amplitude and Wavelength

5.2.2 Light Waves

5.2.3 Sound Waves

5.3 Vision

5.3.1 Anatomy of the Visual System

5.3.2 Color and Depth Perception

5.4 Hearing

5.4.1 Anatomy of the Auditory System

5.4.2 Pitch Perception

5.4.3 Sound Localization

Question	Answer
very high amplitude pattern of brain activity associated with stage 2 sleep that may occur in response to environmental stimuli	K-complex
rapid burst of high frequency brain waves during stage 2 sleep that may be important for learning and memory	sleep spindle
first stage of sleep; transitional phase that occurs between wakefulness and sleep; the period during which a person drifts off to sleep	stage 1 sleep
second stage of sleep; the body goes into deep relaxation; characterized by the appearance of sleep spindles	stage 2 sleep