Unit 3 Biopsychology PDF

Communication within the brain ============================== - Neuron: - Cell in nervous system that receives, integrates, and transmits information Parts of the neuron =================== - Dendrites: - Receives messages from other neurons - Soma: - Cell body...

Communication within the brain ============================== - Neuron: - Cell in nervous system that receives, integrates, and transmits information Parts of the neuron =================== - Dendrites: - Receives messages from other neurons - Soma: - Cell body - Cell nucleus - life support of neuron - Axon: - long thin fiber that transmits signals - Myelin sheath - insulating material that coats axons and speeds transmission of info - Terminal buttons: small knobs that secrete neurotransmitters to transmit the neuron's message - Synapse: - Tiny gap between neurons where info is transmitted  How does a neuron transmit info? ================================ - Action potential (brief electrical charge) travels down axon to terminal buttons - When action potential reaches terminal buttons, they release neurotransmitters into synapse - Neurotransmitters: - chemical messengers released from terminal buttons that travel synapse to receptors on dendrites of other neurons - When enough neurotransmitters bind to receptors sites on the next neuron's dendrites, it causes the neuron to fire - This is an "all or nothing" phenomenon Neurotransmitters ================= - Several types, each with specific functions - Receptors on dendrites are specialized: only certain neurotransmitters can bind to them - Reuptake: the process of reabsorbing unused neurotransmitters - Agonists: - Chemical that mimics action of neurotransmitters causing similar effects. - Can also stop reuptake - Antagonists - Chemical that opposes the action of neurotransmitters - Blocks the receptor sites Other cells in the brain? ========================= - Glia cells: - Cells in the nervous system that support, nourish and protect neurons - Supply nourishment - Get rid of waste (dead neurons and extra sodium ions) - Provide insulation The Nervous System ================== - Electro-chemical communication systems - Two major branches: - Central Nervous System (CNS): - Brain and spinal cord - Peripheral Nervous System (PNS): - All nerves that are outside of brain and spinal cord - Somatic Nervous System: - Nerves that connect to voluntary skeletal muscles and sensory receptors - Controls all voluntary movement of the body - Afferent nerve fibers - Carry info to CNS from the body - Efferent nerve fibers - Carry info to body from CNS - Autonomic Nervous System - Made up of nerves that connect to the heart, blood vessels, organs, glands. - Sympathetic Nervous System - Mobilizes body's recourses for emergencies - Parasympathetic Nervous System - Calming system that tries to conserve body's resources when there isn't an immediate  Stages of Sleep: REM ==================== - REM sleep characterized by: - Rapid eye movements (REM): Every 30 sec, eyes move rapidly under closed lids - Active Brain Waves, similar to Beta waves - High level of physiological arousal - Body is "paralyzed" - Paradoxical sleep: body still, peaceful while highly aroused - Frequent dreaming - Majority of dreaming occurs in REM Stages of Sleep =============== - Every night, go through stages multiple times - 1 -- 2 -- 3 -- 2 - But instead of re-entering stage one, we enter REM - Cycle repeats throughout sleep period - 1 -- 2 -- 3 -- 2 -- REM -- 2 -- 3 -- 2 REM - Each time through takes around 90 minutes - As time goes on less time in deep sleep, more time in REM as night passes Dreaming ======== - Everyone (with healthy non-medicated brains) dreams - REM: more dreams, dreams ore likely to be bizarre, emotional, vivid memorable. - NREM: fewer dreams, dreams mundane/boring - Usually includes familiar people and places - Affected by our daily experiences and culture - Majority have negative content - Might be because they are more memorable Dreams: What Do They Mean? ========================== - Freud and Psychoanalytic Theory: dreams represent unconscious desires/ conflicts. - Manifests content - Actual content of dream - Latent content - Hidden meaning of dream - No evidence to support this view subjective - Activation-Synthesis Theory - Dreams are a byproduct of neural activity - During REM sleep, random activation of brain triggers sensory system - Brain makes sense of random firing by synthesizing it with memories - Threat simulation theory - Dreams allow us to rehearse survival strategies - Social simulation theory - Dreams allow us to rehearse strategies dealing with social/behavioral situations Sleep Problems and Disorders ============================ - Sleep Paralysis: Waking up, feeling paralyzed - Usually occurs when waking or falling asleep - Cause: Brain becomes aware before deep muscle relaxation of REM stops - Hypnogogic Sleep Paralysis: - In addition to paralysis, experience hallucinations - Stress, sleep deprivation, alcohol increase likelihood Psychoactive Drugs: Hallucinogens ================================= - Distort perceptions and evoke sensory images in the absence of sensory stimulation - "Classic hallucinogens" (LSD, DMT, Psilocybin) affect serotonin system - Have dramatic effect on senses: - Sensations intensified, hallucinations, time distortion - Synesthesia: - Blending/crossing of sensory perceptions - Ex: tasting green from eating lettuce - Also effect mood/thoughts: - Often highly emotional - Can cause mystical/dream like state - Can have "bad trip" - Possible Medical Uses: - Treatment of alcohol, nicotine, and cocaine dependence (addiction) - In terminally ill: treatment of anxiety, depression, fear of death - Treatment of "treatment resistant" depression - Very low chance of dependency (addiction), no withdrawal effects, but tolerance (and cross-tolerance) develops quickly - Cross tolerance means if u take a different version of the drug, you will still have a tolerance MDMA ==== - Hard to classify, has properties of both stimulants (happy) and hallucinogens - Serotonin agonist (increases serotonin "feel good hormone"), also increases dopamine (but less than other stimulants) - Energizing, creates feelings of euphoria, aphrodisiac properties (associated with riskier sexual practices) - An "empathogen": - Enhances social intimacy, empathy, trust, feelings of safety - Possible Medical Uses: - Treatment of PTSD - Concerns/Risks: - Dehydration (or overhydration due to fears of dehydration) - Long term heavy users: - Increased risk of depression - Anxiety - Sleep disorders - Memory and cognitive deficits due to damage of serotonin systems - Effects may not be permanent - Impossible to know how strong/pure it is - Tolerance can build quickly, mild withdrawal symptoms possible, but rates of dependency are low Marijuana ========= - Most widely used illegal drug in US - Hard to classify with properties of stimulants, depressants, and hallucinogens - Works on brain's natural endocannabinoid system - Affects many areas of the brain to produce a variety of effects - Relaxation - Euphoria - Time distortion - Appetite increases - Enhancement of sensation and feelings - Memory impairment - Medical Uses: - Paim relief - Appetite stimulation - Control of nausea - Reduction of tremors and seizures - Correcting Common Misconceptions: - Marijuana DOES NOT cause "amotivational syndrome" - Marijuana is NOT a "gateway drug" (drug that is an excuse to use harder drugs) - Marijuana CAN have harmful effects: - Lung damage from smoke - High doses can cause paranoia, panic, fast heart rate nausea, vomiting - Reaction times slowed, judgement/thinking impaired so NO DRIVING! - Memory problems - People CAN become addicted (dependent) on marijuana - Heavy users may experience mild withdrawal symptoms - Psychological dependency can occur - Using it to escape from things/ it becomes the focus of your life - Estimate 5% develop dependency Sensation and Perception ======================== - Sensation: - Simulation of sense organs - Perception: - Process of organizing and interpreting sensory information - Absolute threshold: - Lowest intensity at which participant notices stimuli half the time Sensation ========= - Difference threshold (aka the just noticeable difference): - Smallest difference between two stimuli that is needed for a person to notice half of the time - Weber's Law: - differences between bigger/more intense stimuli need to be larger to be noticed - Selective attention: - Art of focusing on a specific stimulus while ignoring others - Inattentional Blindness: - Failure to notice unexpected events when working on a tasks - Sensory Adaptation: - Change in the responsiveness of the sensory system based on the average level of surrounding sensation - Bottom-up processing: - Using individual sensory pieces to build and perceive whole sensory events - Top-down processing: - Using context, expectations, etc. to perceive whole sensory event Visual System ============= - Vision is the dominant sense for most humans - The McGurk Effect - What you see changes what you hear  - Pupil: - Black hole in your eye that light goes into. - Changes size to control the amount of light that goes in. - Iris - Colored part of eye - Helps control the size of the pupil to let more or less light into the eye - Cornea - Cover the outside of the eye - Lens - Transparent structure behind pupil that changes shape to focus light on back eye - Accommodation: - When lens adjusts to focus image - Image is inverted when it hits back of the eye brain then processes and flips it right side up - Nearsightedness (myopia) - Faraway objects are blurry - Eye is too long - Farsightedness (hyperopia) - Nearby objects are blurry - Eye is too short or lens does not thicken enough - Presbyopia - "Old vision" - Nearby objects are blurry - Lens becomes less elastic with age - Glasses changes focus of image - Retina - Inner surface of eye - Made up photoreceptors - Light sensitive neurons - Types of photoreceptors: - Cones: - Short, stubby cells located in the center of the retina - Fovea: center of retina, which contains only cones - Vision in bright light and color vision, fine detail - Rods: - Elongated cells more concentrated on sides of retina - More sensitive to light, night vision, vision in low light, peripheral vision - Not sensitive to color - Optic Nerve: - Axons of all neurons in retina gather together and leave eye through optic disc - Blind spot: - Hole in retina where light cannot be processed 6 basic taste receptors