Consciousness, Sleep, and Wakefulness

Consciousness, Sleep, and Wakefulness

• Consciousness is the state of being awake and aware of one's surroundings.
• Sleep is a recurring condition of body and mind characterized by closed eyes, relaxed muscles, altered brain activity, and suspended consciousness of surroundings.
• Wakefulness is the state of not sleeping or being unable to sleep, also known as sleeplessness.

Biological Rhythms and the Biological Clock

• Biological rhythm is often interchangeably used with circadian rhythm.
• The body's internal clock regulates bodily functions like sleep, wakefulness, body temperature, and hormone secretion,
• The circadian rhythm is a natural, roughly 24-hour oscillation that can refer to any process originating within an organism.
• The biological clock is an innate mechanism controlling physiological activities on a daily, seasonal, or yearly cycle, strengthened by habit.
• Homeostasis is the tendency toward a stable equilibrium between interdependent elements, maintained by physiological processes.

Suprachiasmatic Nucleus and Melatonin

• The suprachiasmatic nucleus (SCN) is a brain region within the hypothalamus that uses signals from the eyes to maintain the biological clock or circadian rhythm.
• The pineal gland, located beneath the corpus callosum, is part of the endocrine system and secretes the hormone melatonin.

Sleep Regulation and Circadian Rhythm Problems

• Transitions between wakefulness and sleep are controlled by the brain but are influenced by external factors like light and caffeine.
• Problems with circadian rhythms are conditions that disrupt the body's natural sleep-wake cycle, affecting sleep quality.
• Jet lag is extreme tiredness and physical effects felt after a long flight across time zones.
• Insomnia is a common sleep disorder characterized by difficulty falling or staying asleep, or waking up too early, leading to fatigue and mood disturbances.
• Rotating shifts are work schedules that change from one shift to another on a rotating basis.
• Sleep debt refers to the negative consequences of sleep deprivation, including depression, cognitive difficulties, emotional reactivity, and slowed reaction times.

Evolutionary Psychology

• Regulation of sleep is processed by the homeostatic physiology of the circadian rhythm, the sleep/wake cycle.
• Evolutionary psychology studies behavior, thought, and feeling through the lens of evolutionary biology.
• Evolutionary psychologists assume human behaviors reflect physical and psychological predispositions that helped human ancestors survive and reproduce.

Stages of Sleep

• Rapid eye movement (REM) sleep, the fourth stage of sleep, features relaxed muscles, quick eye movement, irregular breathing, elevated heart rate, and increased brain activity.
• Non-REM (NREM) sleep is a state of sleep occurring regularly with intervening REM periods, characterized by delta wave brain activity, little dreaming, and reduced autonomic physiological activity.
• Stage 1 sleep is a transitional phase between wakefulness and sleep, marked by slowed respiration and heartbeat, decreased muscle tension, and reduced body temperature.
• Stage 2 sleep involves deep relaxation with theta waves interrupted by sleep spindles.
• Stages 3 and 4 sleep, also known as deep sleep or slow-wave sleep, feature low-frequency, high-amplitude delta waves, and slowed heart rate and respiration. It is difficult to awaken someone from this stage of sleep.

REM Sleep and Dreaming

• Dreams occur for longer than a few seconds, with later REM periods lasting for up to half an hour.
• Paradoxical sleep is another name for rapid eye movement (REM) sleep.
• Dreams occur more frequently in REM sleep and are emotional, illogical, and prone to plot shifts.
• Non-REM dreams are shorter, more thought-like, repetitive, and deal with everyday topics.
• Dream reports from NREM sleep (starting with stage 2) resemble REM dream reports as the night goes on.

Theories of Dreaming

• Freud's Dream Protection Theory suggests dreams provide access to the unconscious, representing disguised, unacceptable wishes.
• Manifest content is the literal, surface-level elements of a dream.
• Latent content refers to the hidden, symbolic meaning beneath the manifest content of dreams.
• Jung believed dreams tap into the collective unconscious, a store of information everyone is born with.
• The activation-synthesis theory suggests that dreams are caused by the physiological processes of the brain.
• Cartwright's neurocognitive theory proposes dreams are reflections of waking life and a product of cognitive capacities.

Sleep Disorders

• Brief bouts of insomnia result from stress, relationship problems, medications, illness, variable shifts, jet lag, caffeine, or napping.
• Insomnia can become recurrent if individuals become frustrated and anxious when they cannot fall asleep quickly.
• Sleepwalking, or somnambulism, involves getting up and walking around while asleep and is more common the younger you are
• Sexsomnia is a sleep disorder characterized by engaging in sexual activities during sleep, potentially related to other sleep disorders and external factors.
• Night terrors are feelings of great fear experienced upon suddenly waking in the night.
• Sleep apnea is a disorder marked by pauses in breathing or shallow breaths during sleep.
• Obstructive sleep apnea is the most common sleep-related breathing disorder, characterized by repeated stops and starts in breathing during sleep
• Central sleep apnea occurs when the brain doesn't send proper signals to the muscles that control breathing.
• Sleep apnea may be caused by a lack of oxygen and the buildup of carbon dioxide which can lead to night sweats, weight gain, fatigue, hearing loss, an irregular heartbeat, dementia or cognitive impairments and an increased risk for death
• Sudden infant death syndrome (SIDS) is the unexplained death of a seemingly healthy baby less than a year old, often during sleep.
• Narcolepsy is a condition causing excessive daytime sleepiness and sudden sleep onset, sometimes accompanied by muscle weakness.
• Cataplexy, which occurs in healthy people during REM sleep, causes people with narcolepsy to remain alert, even though they cannot move.

Psychoactive Drugs

• Psychoactive drugs contain chemicals similar to those in the brain act by altering chemical processes in neurons.
• Drugs can be used to treat physical and mental illnesses or for recreational purposes.
• Diagnosis is the identification of the nature of an illness or problem by examining the symptoms.
• Physical dependence is a physiological adaptation where the body becomes accustomed to a substance.
• Psychological dependence involves persistent craving for a substance or behavior, driven by emotional and mental needs.
• Tolerance is the ability or willingness to tolerate something that one does not necessarily agree with
• Withdrawal is the act of taking back or away something that has been granted or possessed
• Depressants reduce functional or nervous activity.
• Stimulants raise levels of physiological or nervous activity in the body.
• Cocaine is an addictive drug derived from coca, used as an illegal stimulant and sometimes as a local anesthetic.
• Methamphetamines are potent central nervous system stimulants mainly used as recreational or performance-enhancing drugs.
• Euphoric High is a feeling of great happiness and excitement
• Opioids are a class of natural, semi-synthetic, and synthetic drugs, used for medical purposes to treat pain, and illegal drugs such as heroin.
• Opiates are relating to, resembling, or containing opium.
• Hallucinogens cause hallucinations.

Hypnosis and Sensation

• Hypnosis uses techniques providing suggestions for alterations in perception, sensation, thoughts, feelings, memories, and behaviors.
• Meditation involves focusing on a single target to increase awareness of the moment.
• An induction Method includes suggestions for relaxation, calmness, and wellbeing, along with instructions to imagine pleasant experiences
• Sensation is the detection of physical energy by sense organs, which send information to the brain.
• Transduction is the nervous system changing stimuli into electrical signals the brain can use.
• Absolute threshold is the lowest level of a stimulus detectable 50% of the time.
• Subliminal messages are presented below the threshold for conscious awareness.
• The Just noticeable difference, also called this difference threshold, is the amount of difference in stimuli required to detect a difference between them and depends on the stimulus intensity.
• Weber's Law states that the stronger the stimulus, the greater the change necessary for detection of a difference.
• Perception is sensory information being organized, interpreted, and consciously experienced.

Bottom-Up vs Top-Down Processing

• Bottom-up processing starts with sensory input and reacts to stimuli as they are presented.
• Top-down processing is conceptually driven, influenced by beliefs and expectancies.
• Sensory adaptation occurs when we stop perceiving stimuli that remain relatively constant.
• Inattentional blindness is a failure to detect something plainly visible while attending to something else.
• Signal detection theory is the ability to identify something in a distracting background.

Wavelength & Culture

• Individuals from Western cultures were more prone to experience certain types of visual illusions than individuals from non-Western cultures, and vice versa.
• Amplitude is the height of a wave.
• Wavelength is the length of a wave from one peak to the next.
• Frequency is the number of waves that pass a given point in a given time period.
• Hertz is cycles per second.
• Longer wavelengths = lower frequencies
• Shorter wavelengths= higher frequencies
• Visible spectrum is the part of a larger electromagnetic spectrum that we can see.
• The electromagnetic spectrum is all electromagnetic radiation that occurs in our environment.
• Light wavelength is associated with perception of color.
• The experience of red is associated with longer wavelengths, greens are intermediate, and blues and violets are shorter in wavelength.
• The amplitude of light waves is associated with our experience of brightness or intensity of color, with larger amplitudes appearing brighter.

Frequency and Amplitude of Sounds

• Pitch is the frequency of a sound wave.
• High frequency sound waves equals high pitched sounds
• Low-frequency sound waves equals Low pitched sounds
• Decibels is the height of sound wave which relates to our experience of loudness.
• Timbre is the quality or complexity of a sound wave, determined by the frequency, amplitude, and timing of sound waves.

Structures of the Eye

• The cornea is a transparent covering over the eye that focuses light waves.
• The pupil is a small opening in the eye that lets in light and changes size with light levels and emotional arousal.
• The iris is the colored part of the eye.
• The lens is a curved, transparent structure that provides additional focus and can change shape to focus light.
• The fovea is a small indentation in the back of the eye where the lens focuses images.
• The retina is the light-sensitive lining of the eye.

Cones, Rods, and Optic Nerves

• Cones enable color vision, acute details, and spatial resolution and require more light, concentrated in the fovea.
• Rods are long and narrow, enable basic shapes and forms, and function at low-light levels, and are located throughout the remainder of the retina.
• Dark adaptation is time for rods to adjust to greater sensitivity.
• The optic nerve is formed by axons from retinal ganglion cells, which exit through the back of the eye and carries visuals from the retina to the brain