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PSYCH NOTES FOR TEST 2

Consciousness and Sleep (Chapter 4) 

Stages of Sleep 

  1. Stage 1 (NREM): Light sleep, transition between wakefulness and sleep, characterized by  theta waves. 

  1. Stage 2 (NREM): Deeper relaxation, sleep spindles (rapid bursts of high-frequency brain activity), and K-complexes. (Theta, K complex, Spindles) 

  1. Stage 3 (NREM): Deep sleep, presence of delta waves, difficult to awaken (Less than 50%). 

  1. Stage 4 (NREM): Deepest sleep, characterized by delta waves (more than 50%), essential for physical restoration. 

  1. REM Sleep: Rapid eye movement, high brain activity similar to wakefulness, muscle paralysis, and dreaming. Beta Waves 

  1. Awake- Beta Waves 

  1. Drowsy- Alpha Waves 

Sleep Disorders 

  • Insomnia: Difficulty falling or staying asleep. 

  • Parasomnias: Sleep disorders including night terrors, sleepwalking, and REM sleep behavior disorder. 

  • Sleep Apnea: Breathing interruptions during sleep. 

  • Narcolepsy: Uncontrollable sleep episodes, often with cataplexy (loss of muscle tone). 

  • Restless Leg Syndrome: Uncomfortable leg sensations leading to an urge to move them. 

Circadian Rhythm 

  • A biological rhythm lasting approximately 24 hours. 

  • Regulated by the suprachiasmatic nucleus (SCN) in the hypothalamus. 

  • Influenced by light exposure, melatonin secretion, and lifestyle factors. 

Brain Regions Associated with Sleep and Dreaming 

  • Hypothalamus: Regulates circadian rhythms and homeostasis. 

  • Pineal Gland: Produces melatonin, aiding in sleep regulation. 

  • Thalamus: Relays sensory signals, reducing sensory input during sleep. 

  • Pons: Plays a role in REM sleep by inhibiting muscle movement. 

Theories of Dreaming 

  • Freud’s Theory: Dreams reflect unconscious desires (manifest vs. latent content). 

  • Jung’s Theory: Dreams access the collective unconscious and universal archetypes. 

  • Cartwright’s Theory: Dreams are a reflection of personal life experiences. 

  • Hobson’s Activation-Synthesis Model: Dreams result from random neural activity that the brain attempts to synthesize into a coherent story. 

Effects of Drugs on the Brain 

Stimulants 

  • Cocaine, amphetamines, MDMA (ecstasy), nicotine, caffeine. 

  •  Increase overall level of neural activity 

  • Agonists of the dopamine neurotransmitter system 

 

Opioids 

  • Heroin, morphine, methadone, codeine 

  • Decrease pain 

  • Naturally, the body makes small quantities of opioids compounds that bind to opioid receptors reducing pain and producing euphoria. 

  • Extremely high potential for abuse 

 

Hallucinogens 

  • Marijuana, psylocibin (shrooms), mescaline (peyote), LSD. 

  • Result in profound alterations in sensory and perceptual experiences. 

  • Impact different neurotransmitters 

 

Hypnosis 

  • Hypnosis: State of extreme self-focus and attention in which minimal attention is given to external stimuli. 

  • Dissociation view: Dissociated state of consciousnesses 

  • Social-Cognitive theory of hypnosis: People perform a social role. 

 

 

Meditation 

  • Clearing the mind in order to achieve a state of relaxed awareness and focus.  

 

Sensation and Perception (Chapter 5) 

Parts of the Eye 

  • Retina: Contains photoreceptors (rods for low light, cones for color vision). 

  • Optic Nerve: Transmits visual information to the brain. 

  • Blood Vessels: The eyes contain a network of blood vessels that supply them with oxygen and nutrients. These vessels are located in various parts of the eye:   

  • Optic Nerve: The connection that lets your eyes send signals to your brain describing what they detect. Your brain takes those signals, processes them and uses them to construct the picture you see. 

  • Blind Spot: Made up of light-sensitive cells which send messages to your brain about what you see. Everyone has a spot in their retina where the optic nerve connects. In this area there are no light-sensitive cells so this part of your retina can't see.  

  • Sclera: Supporting wall for your eyeball. It maintains your eye's shape and protects it from injuries. Muscles attached to the sclera help you move your eyeball. 

  • Choroid Coat: A part of the uvea, the middle layer of your eyeball's outer wall. It's a key supplier of blood to some of your eyes' most critical structures. The choroid (pronounced “KOR-oid”) also plays a role in how light acts inside your eye, making it a crucial part of how you see the world around you. 

  • Retina: Whole back part of the eye. Contains photoreceptors and processes light for us. Fovea has the highest concentration of receptors. 

  • Iris: The front of the eye that contains the pupil in the center. The iris helps control the size of the pupil to let more or less light into the eye. 

  • Cornea: The outer clear, round structure that covers the iris and the pupil. The cornea directs light rays into the eye and helps focus them on the light-sensitive retina at the back of the eye, providing sharp, clear vision. The lens is located behind the iris and is normally clear. 

  • Pupil: Let’s light into your eye as the muscles of your iris change its shape. The lens in your eye focuses light that passes through your pupil. Light then goes to the back of your eye and hits your retina. Your retina turns light into electrical signals. 

  • Aqueous Humor: The aqueous humor gives the eye its shape and nourishes the cornea and lens by supplying nutrition such as amino acids and glucose. It is also critical for ensuring that the optical physics and health of your eye are maintained. 

  • Lens: Absorbs, focuses and directs incoming light to the retina, the light-sensitive tissue in the back of your eye. It changes its shape automatically to focus on objects at different distances. It can make itself flatter or rounder to bend incoming light from different distances toward a single point. 

  • Ciliary muscle: An intrinsic muscle of the eye formed as a ring of smooth muscle in the eye's middle layer, the uvea (vascular layer). It controls accommodation for viewing objects at varying distances and regulates the flow of aqueous humor into Schlemm's canal. 

  • Vitreous Humor: A transparent, colorless, gel-like substance located in the posterior chamber of the eye. It helps maintain the round shape of the eye and can also help with vision clarity and shock absorbance. With aging, the vitreous humor undergoes vitreous degeneration, acquiring a thinner liquid consistency. 

  • Binocular vision (Two eyes): Gives us depth 

  • Strabismus: Lazy eye  

  • Occipital Lobe: Sit at the back of the head and are responsible for visual perception, including color, form and motion. Damage to the occipital lobe can include Difficulty with locating objects in environment. Difficulty with identifying colors (Color Agnosia) 

  • Fusiform Gyrus: Back of the lobe and can see human faces.  

 
 

Parts of the Ear 

  • Outer Ear (Pinna, Ear Canal): Captures and directs sound. 

  • Middle Ear (Eardrum, Ossicles): Amplifies vibrations. 

  • Inner Ear (Cochlea, Auditory Nerve): Converts sound waves into neural signals. 

  • Binaural: Referring to or involving both ears. Binaural hearing allows us to perceive the direction and distance of sounds by comparing differences in timing and intensity between the ears. 

  • Amplitude: The height of a wave, which determines the intensity or loudness of a sound in hearing and the brightness of a light in vision. In sound waves, greater amplitude results in a louder sound. 

  • Olfactory bulb: A structure located in the forebrain that processes information about odors detected by receptors in the nose. It plays a crucial role in the sense of smell (olfaction). 

  • Frequency: The number of waves that pass a given point per second, measured in hertz (Hz). In hearing, frequency determines the pitch of a sound—higher frequencies correspond to higher-pitched sounds. 

  • Transduction: The process by which sensory stimuli (such as light, sound, or chemical signals) are converted into neural signals that the brain can interpret. For example, in hearing, sound waves are transduced into electrical impulses by hair cells in the cochlea. 

 

Brain Structures Related to Sensation and Perception 

  • Occipital Lobe: Processes visual information. 

  • Temporal Lobe: Processes auditory information. 

  • Thalamus: Relays sensory signals to the cortex. 

  • Olfactory Bulb: Processes smell information. 

Visual Pathways 

  • Ventral Pathway: "What" pathway; processes object recognition. 

  • Dorsal Pathway: "Where" pathway; processes spatial location and movement. 

Other Sensory Components 

  • Fusiform Gyrus: Recognizes faces. 

  • Touch Receptors: Detect pressure, temperature, and pain. 

  • Taste Buds: Detect sweet, sour, salty, bitter, and umami flavors. 

  • Smell Receptors: Detect airborne molecules, contributing to olfaction. 

 

Touch:    

  • Mechanoreceptors: Sensory receptors that respond to mechanical pressure or distortion. They are found in the skin, muscles, and other tissues, helping detect touch, pressure, vibration, and stretch. 

  • Free Nerve Endings: Unencapsulated nerve endings found throughout the body, especially in the skin. They play a key role in detecting pain (nociception), temperature changes, and some forms of touch. 

  • CIPA (Congenital Insensitivity to Pain with Anhidrosis): A rare genetic disorder in which individuals are unable to feel pain and do not sweat (anhidrosis) due to mutations affecting nerve function. This condition can be dangerous because affected individuals may not recognize injuries or regulate body temperature properly. 

  • Congenital Insensitivity to Pain with Anhidrosis (CIPA): The full name of the disorder abbreviated as CIPA. It is caused by mutations in the NTRK1 gene, which affects the development and function of nerve cells responsible for sensing pain and temperature. 

Small Receptors:  

Touch and Pressure Receptors (Mechanoreceptors) 

  • Merkel Cells: Detect light touch and texture, found in the skin. 

  • Meissner’s Corpuscles: Detect light touch and vibrations, located in fingertips and lips. 

  • Pacinian Corpuscles: Detect deep pressure and rapid vibrations. 

  • Ruffini Endings: Detect skin stretch and sustained pressure. 

Pain and Temperature Receptors 

  • Nociceptors: Free nerve endings that detect pain from extreme pressure, heat, cold, or chemicals. 

  • Thermoreceptors: Detect temperature changes; include warm and cold receptors. 

Taste Receptors (Gustatory Receptors) 

  • Taste Buds: Contain chemoreceptors that detect sweet, sour, salty, bitter, and umami tastes. 

Smell Receptors (Olfactory Receptors) 

  • Olfactory Receptor Neurons: Located in the olfactory bulb, detect airborne chemicals and send smell signals to the brain. 

Hearing and Balance Receptors 

  • Hair Cells (Cochlear Receptors): Found in the inner ear (cochlea), detect sound vibrations and convert them into neural signals. 

  • Vestibular Receptors: Located in the inner ear (semicircular canals), detect balance and head movement.