Understanding Consciousness, Sleep, and Sensation: A Comprehensive Guide
-What is consciousness? Our awareness of our environment and ourselves. -What is dual processing? Which track (conscious or unconscious) processes information in parallel? Which track processes information serially? Dual processing is the principle that information is often simultaneously processed on separate conscious & unconscious tracks. It is the unconscious track that processes information in parallel. Serial conscious processing processes information serially. – What is selective attention? Inattentional blindness? Change blindness? Selective attention is the focusing of conscious awareness on a particular stimulus. Inattentional blindness is failing to see visible objects when our attention is directed elsewhere. Change blindness is failing to notice changes in the environment. -What are circadian rhythms? What is sleep? How do we study sleep? Circadian rhythms are the biological clock, regular bodily rhythms (e.g., temperature) that occur on a 24-hour cycle. We study sleep by measuring brain-wave activity, eye movements, and muscle tension by electrodes that pick up weak electrical signals from the brain, eye, and facial muscles. -(NREM-1, NREM-2, NREM-3, REM: what brain waves are present in each stage? What is a hypnagogic sensation and in what stage does it occur? What stage is deep sleep? In what stage do we usually dream? Why is REM sleep called paradoxical sleep? Stage 1 NREM sleep: mixture of alpha & theta brain waves. Stage 2 NREM: sleep spindles, K complexes, theta brain waves, & beginnings of delta waves. Stage 3 NREM: mixture of theta & delta brain waves. Stage 4 NREM: delta brain waves. REM: fast active brain waves accompanied by rapid eye movement. Hypnagogic sensations occur in stage 1 when you feel like you are weightless. Stages 3 & 4 are deep sleep. REM is paradoxical sleep because the muscles are relaxed but other body systems are active. -How long does a sleep cycle last? How many do people have per night? A sleep cycle lasts 90 minutes and repeats 4-6 times over the course of a night. The amount of time you spend in each stage of sleep changes as the night progresses. -How does light affect sleep? What hormone induces sleep? What are some of the theories of why we sleep? Light in the morning tweaks the circadian clock by activating light-sensitive retinal proteins. These proteins control the circadian clock by triggering signals to the brain’s suprachiasmatic nucleus, which is part of a grain-of-rice-sized, 20,000-cell cluster in the hypothalamus. The SCN does its job by causing the brain’s pineal gland to decrease its production of melatonin in the morning or increase it in the evening. Melatonin is the hormone that induces sleep. Theories are: 1) sleep protects. 2) Sleep helps us recuperate. 3) Sleep is for making memories. 4) Sleep also feeds creative thinking. 5) Sleep may play a role in growth. What is sleep deprivation? What are the consequences of sleep deprivation? Be familiar with the Coren study. Sleep deprivation is the slowed performance and impairment of concentration that can be caused by sleep deprivation. Consequences of sleep deprivation: Irritability, Cognitive impairment, memory lapses or loss, impaired judgment, severe yawning, hallucinations, symptoms similar to ADHD, impaired immune system, Risk of diabetes type 2, Increased heart rate variability, risk of heart disease, decreased reaction time and accuracy, tremors, aches, other growth suppression, risk of obesity, decreased temperature. On the Monday after the springtime change when people lose one hour of sleep, accidents increased as compared with the Monday before. In the fall, traffic accidents normally increase because of greater snow, ice, and darkness, but they diminished after the time change. -What are dreams? What do we tend to dream about? (see Dement and Wolpert 1958 study). Can we learn while sleeping? Dreams are a sequence of images, emotions, & thoughts passing through a sleeping person’s mind. Dreams are notable for their hallucinatory imagery, discontinuities, and incongruities, and for the dreamer’s delusional acceptance of the content and later difficulties remembering it. Common themes are failing in an attempt to do something, being attacked, pursued, or rejected. Dement & Wolpert experiment: researchers sprayed water on sleeping people’s faces, and the people were more likely to dream about waterfalls, leaky roofs. No, we do not remember recorded sleep. Sleep DISORDERS: WHAT IS INSOMNIA? Sleep apnea? Narcolepsy? Night terrors? Sleepwalking? Insomnia is a persistent inability to fall asleep or stay asleep. Sleep apnea is repeated awakening after breathing stops; time in bed is not restorative sleep. Narcolepsy is sleep attacks, even a collapse into REM/paralyzed sleep. Night terrors refer to sudden scared-looking behavior, with rapid heartbeat and breathing. Sleepwalking happens in NREM 3 sleep. Run genes. -What are psychoactive drugs? What is tolerance? Withdrawal? Physical dependence? Psychological dependence? Addiction? Psychoactive drugs are chemical substances that alter perceptions and moods. Tolerance is when the drug user needs to take larger doses to get the desired effect. This is referred to as withdrawal, which is the discomfort and distress that follow discontinuing an addictive drug or behavior. Physical dependence is a physiologic adaptation of the body to the presence of a drug associated with withdrawal (e.g., nicotine). Psychological dependence is a pattern of compulsive drug use characterized by a continued craving for the drug and the need to use it for effects (e.g., nicotine). Addiction is defined as a behavioral syndrome characterized by the repeated compulsive seeking. -What are depressants? Review the numerous effects alcohol can have, including these issues: What stage of sleep does alcohol suppress? Depressants: drugs (such as alcohol, barbiturates, and opiates) that reduce neural activity and slow body functions. Effects of alcohol can slow body functions, reduce neural activity. 1) expectancy effect 2) Reduce self-awareness and self-control 3) Memory Disruption 4) Slowed neural processing. Alcohol suppresses REM sleep and nerve cell death. What are barbiturates? What are opiates? Barbiturates: drugs that depress central nervous system activity, reducing anxiety but impairing memory and judgment. Opiates: opium and its derivatives, such as morphine and heroin; depress neural activity, temporarily lessening pain and anxiety. What are stimulants? What are amphetamines? What are the physiological effects of nicotine? How does cocaine have an effect? What is methamphetamine? What neurotransmitter does methamphetamine increase? Stimulants: drugs (such as caffeine, nicotine, and the more powerful amphetamines, cocaine, Ecstasy, and methamphetamine) that excite neural activity and speed up body functions. Amphetamines: drugs that stimulate neural activity, causing speeded-up body functions and associated energy and mood changes. Physiological effects of nicotine: reaches the brain within 7 seconds. Within minutes, the amount in the blood soars. Arouses the brain, increases heart rate, relaxes muscles & triggers the release of neurotransmitters that reduce stress, reduces circulation, suppresses appetite for carbohydrates. Cocaine Effect: euphoria to crash. Methamphetamine: a powerfully addictive drug that stimulates the central nervous system, with speeded-up body functions and associated energy and mood changes; over time, appears to reduce baseline dopamine levels. Increases dopamine, serotonin, and norepinephrine. -What is ecstasy? What neurotransmitters does ecstasy impact? What are its long-term risks? Ecstasy is a synthetic stimulant and mild hallucinogen. It produces euphoria and social intimacy, but with short-term health risks and longer-term harm to serotonin-producing neurons and to mood and cognition. It blocks the reuptake of serotonin. Ecstasy impacts serotonin. Risks are a weaker immune system, memory impairment, slowness of thought, sleep disruption, and disrupts serotonin production. What are hallucinogens? What is LSD? Hallucinogens: psychedelic (“mind-manifesting”) drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input. LSD: a powerful hallucinogenic drug; also known as acid (lysergic acid diethylamide). What is THC? What are some of the effects of marijuana use? THC: the major active ingredient in marijuana; triggers a variety of effects, including mild hallucinations. Effects are amplified sensitivity to colors, sounds, tastes, and smells; euphoria, perception, intensifies feelings, stays longer than alcohol. Alcohol-depressant-initial high followed by relaxation-depression memory loss organ damage Heroin-Depressant-rushes of euphoria-depressed physiology, pain withdrawal Caffeine-stimulant-increased alertness & wakefulness-anxiety, restlessness, insomnia Nicotine-stimulant-arousal & relaxation, sense of wellbeing-heart disease cancer Cocaine- stimulant-rush of euphoria, confidence-cardiovascular stress, suspiciousness, depressive Methamphetamine-stimulant-alertness, energy-irritability, insomnia hypertension, seizures Ecstasy- Stimulant, hallucinogen- emotional elevation-dehydration, overheating, depressed mood, LSD- hallucinogen- visual trip- risk of panic Marijuana-mild hallucinogen- enhance sensation, pain relief, relaxation-impaired learning & memory, lung damage -What is the difference between sensation and perception? What is bottom-up processing? Top-down processing? Sensation is the process by which the sense organs gather information about the environment. Perception is the process by which the brain selects, organizes, and interprets sensation. Bottom-up processing is analysis that begins with the sensory receptors and works up to the brain’s integration of sensory information. Top-down processing is using prior experience, knowledge, and expectations to influence perception. -What is transduction? Sensory neurons project to the somatosensory cortex in the parietal lobe. -What is an absolute threshold? The minimum stimulation needed to detect a particular stimulus 50 percent of the time. -What is signal detection theory? A theory predicting how and when we detect the presence of a faint stimulus “signa”) amid background stimulation “nois”). Assumes there is no single absolute threshold and detection depends partly on a person’s experience, expectations, motivation, and level of fatigue. -What does it mean that something is subliminal? Can we detect subliminal stimuli unconsciously? What is a prime? Does subliminal persuasion have a powerful enduring effect on behavior? Below one’s absolute threshold, for conscious awareness, stimuli cannot be detected 50 percent of the time. Yes, subliminal stimuli can be detected unconsciously. Priming shows that we can process some information from stimuli below our absolute threshold for conscious awareness. But the effect is too fleeting to enable people to exploit us with subliminal messages. Yes, subliminal persuasion can have a powerful enduring effect on behavior. -What is a difference threshold/JND? What is Weber’s law? The minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference. Weber’s law is the principle that, to be perceived as different, two stimuli must differ by a constant minimum proportion/percentage (rather than a constant amount). -What is sensory adaptation? What is a perceptual set? How do expectations, context, and emotions change our perception? Sensory adaptation is diminished sensitivity as a consequence of constant stimulation. Perceptual set is a mental predisposition to perceive one thing and not another. Perceptual set is a mental predisposition that functions as a lens through which we perceive the world. Our learned concepts (schemas) prime us to organize and interpret ambiguous stimuli in certain ways. Our physical and emotional context, as well as our motivation, can create expectations and color our interpretation of events and behaviors. -What is the stimulus we “see”? What determines hue? What determines brightness? Be familiar with these parts of the eye and their functions: pupil, iris, lens, retina – and the path that light waves take through the eye. We see pulses of electromagnetic energy. The distance from one wave peak to the next determines its hue. Intensity, the amount of energy in light waves (determined by a wave’s amplitude, or height), influences brightness. Functions are: 1) pupil: the adjustable opening in the center of the eye through which light enters. 2) iris: a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening. 3) lens: the transparent structure behind the pupil that changes shape to help focus images on the retina. 4) retina: the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information. -What is accommodation? Accommodation is a process by which the eye’s lens changes shape to focus near or far objects on the retina. -What are the differences between rods and cones? What is the fovea? Rods: retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don’t respond. Cones: retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations. Fovea: the central focal point in the retina, around which the eye’s cones cluster. Why do we have a blind spot? The point at which the optic nerves leave the eye, creating a”blin” spot because no receptor cells are located there. -What are feature detectors? What is parallel processing? Feature detectors are nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement. Parallel processing: the processing of many aspects of a problem simultaneously; the brain’s natural mode of information processing for many functions. *Studies of patients with brain damage suggest that the brain delegates the work of processing color, motion, form, and depth to different areas. After taking a scene apart, the brain integrates these subdimensions into the perceived image. -What is a gestalt? What do gestalt psychologists emphasize we perceive? Gestalt: an organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes. Gestalt psychologists emphasize that we perceive whole objects or figures rather than isolated bits & pieces of sensory information. -What is figure-ground? Be familiar with the laws of grouping- proximity, continuity, and closure. The organization of the visual field into objects (the figures) that stand out from their surroundings (the ground). Figure-ground: the organization of the visual field into objects (the figures) that stand out from their surroundings (the ground). Grouping is the perpetual tendency to organize stimuli into coherent groups. Proximity: we group nearby figures together. We see not six separate lines, but three sets of two lines. Continuity: we perceive smooth, continuous patterns rather than discontinuous ones. This pattern could be a series of alternating semicircles, but we perceive it as two continuous lines – one wavy, one straight. Closure: we fill in gaps to create a complete, whole object. Thus, we assume that the circles on the left are complete but partially blocked by the (illusory) triangle. Add nothing more than little line segments to close off the circles, and your brain stops constructing a triangle.
-What is depth perception? What is the visual cliff and how is it used to test depth perception? Will crawling infants cross the cliff? Depth perception is the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance – allows us to estimate an object’s distance from us. The visual cliff is a laboratory device for testing depth perception in infants and young animals. Devised this miniature cliff with a glass-covered drop-off to determine whether crawling infants and newborn animals can perceive depth. Even when coaxed, infants are reluctant to venture onto the glass over the cliff. No. -What are monocular cues for depth perception? What are relative size, interposition, relative height, relative motion, linear perspective, and light and shadow? Monocular cues for depth perception are depth cues, such as interposition or linear perspective, available to either eye alone. Relative size: if we assume two objects are similar in size, most people perceive the one that casts the smaller retinal image as farther away. Relative height: the fact that objects that are closer to you are lower in your visual field, while faraway objects are higher. Interposition: the fact that when one object partly blocks another, you can infer that the blocking object is closer than the blocked object. Relative motion. As we move, objects that are actually stable may appear to move. If while riding on a bus you fix your gaze on some point, say a house, the objects beyond the fixation point will appear to move with you. Objects in front of the point will appear to move backward. The farther an object is from the fixation point, the faster it will seem to move. Linear perspective: parallel lines appear to meet in the distance. The sharper the angle of convergence, the greater the perceived distance. Light and shadow: shading producing a sense of depth consistent with our assumption that light comes from above. If you invert this illustration, the hollow will become a hill. The angle of convergence, the greater the perceived distance. Light and shadow: shading producing a sense of depth consistent with our assumption that light comes from above. If you invert this illustration, the hollow will become a hill. -What is the stimulus? What determines loudness? What determines pitch? Stimulus is something that causes a reaction, especially interest, excitement, or energy. The amplitude of sound waves determines their loudness. The length, or frequency, determines the pitch we experience. Long waves have low frequency and low pitch. Short waves have high frequency and high pitch. – PARTS of the ear and their functions including the middle ear, inner ear, cochlea, and basilar membrane. Middle ear: the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window. Inner ear: the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs. Cochlea: a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses. Basilar membrane: bends hair cells lining its surface. -How are sound waves converted to a neural impulse? Outer ear funnels sound waves to the eardrum. The bones of the middle ear (hammer, anvil, and stirrup) amplify and relay the eardrum’s vibrations through the oval window into the fluid-filled cochlea. (b) As shown in this detail of the middle and inner ear, the resulting pressure changes in the cochlear fluid cause the basilar membrane to ripple, bending the hair cells on its surface. Hair cell movements trigger impulses at the base of the nerve cells, whose fibers converge to form the auditory nerve. That nerve sends neural messages to the thalamus and on to the auditory cortex. What are the two types of hearing loss? How is each treated? Sensorineural hearing loss: the most common form of hearing loss, also called nerve deafness; caused by damage to the cochlea’s receptor cells or to the auditory nerves. Conduction hearing loss: less common form of hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea. -How do we perceive loudness? How do we locate sounds? From the number of activated hair cells. Sound waves strike one ear sooner and more intensely than the other. The brain analyzes the minute differences in the sounds received by the two ears and computes the sound’s source. -What are the two theories of how we perceive pitch? What theory and how they might both explain perception of pitch. Place theory proposes that our brain interprets a particular pitch by decoding the place where a sound wave stimulates the cochlea’s basilar membrane. Place theory explains how we hear high-pitched sounds, but it cannot explain how we hear low-pitched sounds. Frequency theory (temporal) proposes that the brain deciphers the frequency of the pulses traveling to the brain. It explains how we hear low-pitched sounds, but not how we hear high-pitched sounds. Some combination of the two helps explain how we hear sounds in the middle range. Volley theory: neural cells can alternate firing. High pitches: place. Low pitches: frequency. -What are the four skin senses? 4 senses are – Pressure, warmth, cold, and pain – that combine to produce other sensations, such as”hot” There is no simple relationship between what we feel at a given spot and the type of specialized nerve ending found there. What is gate-control theory and how does it explain how we experience pain? What fibers open the gate? Close the gate? How do biological, psychological factors, and social-cultural factors affect how we experience pain? Gate-control theory is the theory that the spinal cord contains a neurological”gat” that blocks pain signals or allows them to pass on to the brain. The”gat” is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain. -Taste – how do we taste? What are the five basic tastes? Taste, a chemical sense, influences it. 5 sensations: – sweet, sour, salty, bitter, and umami. -What is sensory interaction? Sensory interaction is the principle that one sense may influence another, as when the smell of food influences its taste. -Smell – how do we smell? How do we experience 10,000 different odors with only 350 different types of receptors? Why is smell linked to emotion and memory? There are no basic sensations for smell… it is a chemical sense. Some 5 million factory receptor cells, with their approx 350 different receptor proteins, recognize individual odor molecules. The receptor cells send messages to the brain’s olfactory bulb, then to the temporal lobe and to parts of the limbic system. Odors can spontaneously evoke memories and feelings, due in part to the close connections between brain areas that process smell and memory. -What is kinesthesis? The vestibular sense? Kinesthesis is the sense that gives us information about the location of our body parts with respect to each other and allows us to perform movements. Vestibular sense gives us information about body position, movement, and acceleration – factors critical for maintaining our sense of balance. The sensory organs for the vestibular sense are located in the inner ear: vestibular sacs and semicircular canals, both of which contain fluid that moves when the head rotates. The movement causes the hair cells inside the sacs and canals to bend, which is transduced into electrochemical impulses in the nerve.
mpulses in the nerve.