BIOLOGICAL PSYCHOLOGY Everything psychological is ultimately physiological Biological
BIOLOGICAL PSYCHOLOGY Everything psychological is ultimately physiological.
Biological Psychology Includes: • Neurotransmission • Nervous System • Endocrine System • Brain Structure and Function • Brain Hemisphere Organization • Behavioral Genetics
Biological Psychology Origins: Phrenology: Franz Gall (Early 1800’s) He Was Right: • Mental processes found in parts of brain • Larger brains = more intelligent behavior But He Was So Wrong: • Phrenology: bumps on skull indicate mental abilities/character traits.
The Neuron: Basic Hardware Nerve cells specialized in communication Building blocks of the nervous system Receive, integrate, transmit info 86 billion
Anatomy of a Neuron Soma: Cell body – keeps cell alive Nucleus: Contains DNA and coordinates cellular activity Dendrites: receive information from other neurons and relay it to the cell body Axons: carries information to other neurons, muscles or glands. Can be very long – even up to one meter Myelin Sheath: insulating material that encases some axons. In peripheral nervous system, made of Schwann cells. In central nervous system, made of oligodendroglial cells. Nodes of Ranvier: gap in myelin that facilitates transmission of nerve impulses Terminal Branches: forms junctions with other cells Terminal Buttons: contains synaptic vesicles that secrete chemicals called neurotransmitters
Multiple Sclerosis Immune system attacks myelin Impulses are transmitted more slowly People with MS have varying symptoms and incapacitation No cure right now, but stem cell transplantation shows promise
Types of Neurons
HOW NEURONS COMMUNICATE
What Causes an Action Potential (electrical signal)? Dendrites pick up chemical signals from neuron Signals affect polarization of the cell Excitatory signals (FIRE!) decrease polarization Inhibitory signals (HOLD FIRE!) increase polarization If threshold is reached, action potential occurs
Summary of the Action Potential • Electric impulse down axon • Causes axon terminals to release neurotransmitters • Goes by all-or-none principle; always has same force • Occurs when threshold (-55 millivolts) reached • Charge inside neuron changes from -70 millivolts to +40 millivolts • Jumps along the Nodes of Ranvier (speeds transmission).
Refractory Period • Occurs after action potential. • New action potential cannot be initiated. • Imbalance in ions rectified as the sodium potassium pump moves sodium ions back outside and potassium ions back inside until resting potential is met.
Synaptic Transmission Between Neurons • Area between one neuron’s axon terminal and another’s dendrites is the synapse. • Action potential triggers release of neurotransmitters, which cross the synaptic gap & bind to receptors on the receiving neuron (lock and key) • Excess neurotransmitters are reabsorbed by the terminal buttons of the sending neuron in a process called reuptake.
Postsynaptic Potentials Voltage Change at Receptor Site on Postsynaptic Cell Membrane Excitatory PSP Inhibitory PSP • POSITIVE voltage • NEGATIVE voltage shift that INCREASES the likelihood that the postsynaptic neuron will fire action potentials. shift that DECREASES the likelihood that the postsynaptic neuron will fire action potentials
Neurotransmitters • Released by motor Acetylcholine (ACh) Associated Disorders: Alzheimer’s Disease neurons controlling skeletal muscles • Botox blocks ACh receptors. • Contributes to regulation of attention, arousal, sleeping, dreaming, learning, and memory. • Some ACh receptors stimulated by nicotine.
Neurotransmitters • Contributes to control of Dopamine (DA) Associated Disorders: Parkinson’s (low) Schizophrenia (high) Addiction voluntary movement. • Regulates motivation, pleasure, and emotional arousal. • Cocaine and amphetamines elevate activity at DA synapses. • Too much associated with hallucinations.
Neurotransmitters Norepinephrine (NE) (Noradrenaline) Associated Disorders: Depression (low) • Mood and arousal • States of vigilance (heightened awareness of danger) • Produces excitatory PSP
Neurotransmitters Serotonin Associated Disorders: Depression (low) Eating Disorders/OCD (low) Mania (high) • Involved in regulation of sleep and wakefulness, eating, aggression.
How Antidepressants Might Work SSRI-selective serotonin reuptake inhibitor SNRI-selective serotonin & norepinephrine reuptake inhibitor SSRI – Prozac, Lexapro, Zoloft, Paxil. SNRI – Cymbalta, Effexor
Neurotransmitters GABA (gammaaminobutyric acid) Associated Disorders: Seizures (too little) Insomnia (too little) • Produces inhibitory PSP • Regulation of anxiety
Neurotransmitters • Major excitatory neurotransmitter in the brain. Associated • Involved in learning and memory. Disorders: Seizures (too much) • Oversupply results in overstimulation. Glutamate Migraines (too much)
Neurotransmitters Endorphins Associated Disorders: Opiate addiction (overuse of opiates decreases endorphin supply…more pain when addicted) • Released during exercise, excitement, and sex. • Produces well-being and euphoria. • Resemble opiates in structure and effect. • Dulls experience of pain.
Brain Plasticity Brain and Spinal Cord cells cannot regenerate, BUT brain structure and function are flexible. Experience Can Sculpt Structure • 3 months of LSAT preparation produced structural changes in brain crucial to reasoning. • Subjects given 3 months to practice and master jugging showed structural changes in brain areas known to handle processing of visual and motor tasks. Damage/Destruction of Sensory Pathways Can Lead to Neural Reorganization • Scientists amputated their finger of owl monkey, and the part of the brain that formerly responded to the third finger became responsive to the second and fourth fingers. The Adult Brain Can Generate New Neurons • Neurogenesis (formation of new neurons) takes place in olfactory bulb and hippocampus. • Can migrate to other areas where they sprout axons and form synapses with existing neurons. • Important in learning and memory. The Miracle of Plasticity
Central Nervous System • Brain • We use more than 10%! • Spinal Cord • Spinal Reflexes Conducts sensory info from PNS to brain. • Conducts motor information from brain to PNS •
Peripheral Nervous System Consists of neural pathways that bring information to and from brain. Connects CNS to organs and muscles Autonomic Somatic • Sympathetic • Afferent Peripheral Nervous System • Parasympathetic • Efferent
Branches of the Autonomic Nervous System Sympathetic division—mobilizes the body to react in the face of threat; fight or flight Parasympathetic division—demobilizes the body to conserve energy; calms the body down after a stress reaction
Internal Brain Structures: Brain Stem Includes: • Pons, Medulla, and Midbrain Controls: • Breathing, heartrate, swallowing, blood pressure, whether you are awake or asleep. Cerebellum Controls: • Movement • Posture/timing Damage: Loss of coordination, tremor, difficulty walking, dizziness, slurred speech *Alcohol depresses cerebellar functions.
Cerebral Cortex • Seat of complex thought, detailed perceptions, & complex behaviors. • Two hemispheres connected by corpus callosum. • Interconnected neural cells that cover cerebral hemispheres.
Internal Structures: Additional Ones to Know
Limbic system Hippocampus Function: • Memory storage and formation • Spatial navigation Damage: • Memory impairment H. M. Case Study Amygdala Function: • Fear/emotion processing • Learning/reward processing Damage: • Fear response • Loss of emotional control • Deficits in recognizing emotions Hypothalamus Function: • Hunger/thirst/body temp • Perspiration/bp/heartrate • Shivering Damage: • Excessive eating • Aggression • Self-mutilation • Overactive sex drive **works with endocrine system
Pituitary Gland Function: • “Master Gland” • Release of growth/oxytocin **Part of Endocrine System Corpus Collosum Function: • Connects left and right hemispheres Damage: • Split-brain
Lobes of the Brain Frontal Lobe Function: • Voluntary motor control • Decision-making • Cognition • Intelligence • Language Processing Damage: • Paralysis • Mood changes • Atypical social skills/personality traits Parietal Lobe Function: • Integration of sensory information • Pain/touch recognition • Spatial processing • Number representation Damage: • Can’t locate or recognize objects or body parts. • Lack of coordination • Disorientation Hemi-Spatial Neglect
Lobes of the Brain Temporal Lobe Function: • Facial/object recognition • Perception (hearing, smell) • Understanding language • Learning/memory Damage: • Can’t understand speech, faces, objects • Persistent talking • Memory loss • Abnormal sexual behavior/aggression Occipital Lobe Function: • Vision Damage: • Hallucinations • Blindness • Can’t see color, motion, orientation • Synesthesia
Association Areas
Prefrontal Cortex (Frontal Lobe) Motor Cortex (Frontal Lobe) Function: • Decision-making • Inhibition • Intelligence • Social Skills Damage: • Lack of inhibition • Impairments in voluntary movement • Memory dysfunction Phineas Gage Function: • Coordinate/initiate movement Damage: • Distorted body image • Motor-learning deficits • Speech impairment Somatosensory Cortex (Parietal Lobe) Auditory Cortex (Temporal Lobe) Function: • Sensory processing/integration Damage: • Can’t recognize objects by touch • Phantom limb pain • Hemispatial neglect Function: • Ability to hear (process volume and pitch Damage: • Partial or complete loss of hearing
Speech Areas in Left Hemisphere
Speech Areas in Left Hemisphere • Broca’s aphasia: results from damage to Broca’s area in the primary motor cortex (left frontal lobe). Trouble finding words, but comprehension remains intact. https: //www. youtube. com/watch? v=JWC-c. VQm. Em. Y • Wernicke’s Area (temporal Lobe): Damage to Wernicke’s area in left temporal lobe produces inability to comprehend speech. They can speak, but it may be nonsensical. https: //www. youtube. com/watch? v=3 oef 68 Yab. D 0
Endocrine System: Another Way to Communicate • Endocrine system– glands that secrete chemicals into the bloodstream that help control bodily function. • Nervous system uses neurotransmitters; endocrine system uses hormones. • The Messengers: Hormones-- chemical substances released into the bloodstream by the endocrine glands
Who’s In Control? Many parts of the endocrine system are under CNS control Neural activation hypothalamus to secrete a particular releasing factor pituitary gland releases specific hormone Pituitary gland (“master gland”) governs release of hormones from the rest of the endocrine glands responsible for major bodily processes Brain Pituitary Other Glands Hormones Body
Key Hormones • Growth: secreted by pituitary • Oxytocin: secreted by pituitary • “love” hormone • Associated with social behavior, bonding, sexual behavior, trust • Adrenaline (epinephrine) and noradrenaline (norepinephrine) • Secreted by adrenal gland as part of fight or flight response • Insulin: Secreted by pancreas • Regulates amount of glucose in blood • Lack causes a form of diabetes • Testosterone: secreted in gonads (men have more) • Associated with aggression, sex drive, fat distribution, muscle mass • Estrogen: secreted in gonads (women have more) • Associated with reproduction, menstrual cycle, female sex characteristics
Brain Hemisphere Organization Each hemisphere’s primary connections are on opposite sides of the body. • Corpus Collosum ensures that information is transferred from one side to the other. Corpus Collosum: band of nerve fibers that connect the left and right hemisphere. • For sensory and motor information: left hemisphere control the right side of the body and the right hemisphere controls the left. • For vision, stimuli in right half of visual field go to receptors in left side of the eye, and vice versa. • For auditory stimulation, sounds presented in the left ear are registered in right hemisphere first, and vice versa.
Brain Hemisphere Organization Lateralization: left and right hemispheres serve different functions Left Hemisphere Right Hemisphere • Superiority on nonverbal processing tasks: • Spatial • Musical • Visual Recognition • Perception of Emotions • New Stimuli • Self-Awareness • Superiority on verbal processing: • Language • Speech • Reading • Writing • Prioritizes the Expected Two sides are constantly collaborating. Quality of collaboration is important. Einstein’s brilliance could have been due to exceptional right/left brain connectivity.
Bisecting the Brain: Split-Brain Research Split Brain Surgery (Vogel/Bogen): Sever Corpus Collosum to treat epilepsy. Everyday behavior was normal. BUT Sperry and Gazzaniga thought there was more to the story.
Chimeric Face Study (half-face components of a full face) Split-Brain Research Video
Dual Processing: The Power of the Unconscious Information is often simultaneously processes on separate conscious and unconscious tracks. Parallel Processing: Effortless processing mode. Used to solve simple problems or process information we have already learned. Sequential Processing: Forms representations of novel situations or solves difficult problems. Dual Processing is an example of the way modern psychologists perceive the unconscious.
States of Consciousness Subjective awareness of the world and the mind
Circadian Rhythms • Bodily fluctuations that occur in a 24 -hour cycle (body temperature, hormones, blood pressure, urine production, etc. ) • Many people peak in late afternoon or evening; gets earlier with age. • “Morning” or “night” person depends on your particular circadian rhythm.
Suprachiasmatic nucleus (SCN) • A structure in the hypothalamus that serves as our internal biological clock. • Sends messages to the pineal gland signaling release of melatonin. • Light is a zeitgeber (time giver)— resets our clock each morning.
SLEEP
Overview: Stages of Sleep • When we’re awake and alert, brain waves are beta waves (very fast). • When we’re awake but relaxed, the brain wave pattern is a bit slower—alpha waves. • Four distinct stages, plus REM (rapid eye movement) sleep • With each stage from 1 -4, brain waves become slower (measured by EEG).
NREM 1 Sleep • THETA waves • Lasts 10 -12 minutes • May experience “hallucinations” during this stage, such as sensations of falling: hypnagogic sensations (sensations without sensory stimulus) • Myoclonic jerk: sensation of muscles “jerking” back awake; occurs between stages 1 and 2 and results from brain sending bursts of electrical activity to the muscles after noticing breathing and heart rate are slowing
NREM 2 Sleep Lasts about 10 -25 minutes • Periodic appearance of sleep spindles (bursts of rapid, rhythmic brain wave activity) and K complexes (large waves that react to external stimuli while sleeping) • Sleep spindles develop around 6 weeks of age and may be the reason babies twitch in their sleep. • Respiration rate, heartrate, body temperature decline. •
NREM 3 and 4 sleep • Stage 3 is a transitional stage between light stage 2 and deep stage 4 • Large slow delta waves • Stage 4 lasts for 20 -30 minutes; hard to awaken from • Bedwetting and sleepwalking usually occur in this stage • NREM gets shorter as we age; why older adults feel poorly rested. • After NREM, we cycle back up through the stages and enter REM.
REM Sleep (paradoxical sleep) • Occurs about an hour after you first fall asleep • Brain waves become fast, saw-toothed for 10 minutes or so, similar to stage 1 sleep. • Heart rate rises, breathing becomes fast & irregular, and eyes move rapidly every 30 seconds or so. • Sleeper virtually paralyzed. • Most dreams occur here. • REM periods get longer throughout the night (2025% of total sleep is REM sleep). • REM Rebound: REM deprivation causes more REM sleep the next night.
Diagram of brain waves during sleep
Your Questions…Answered!! Anesthesia • Not sleep…EEG patterns resemble coma more than sleep cycles. • Characteristics: Unconsciousness, amnesia, pain numbing, and inability to move Understanding the Anesthetized Brain Ambien • Increases slow wave sleep, but not necessarily total sleep time.
§ Facilitates learning and strengthens memories (memory consolidation). § Sleep following learning is essential for memory consolidation. § Strengthens neural connections. • Fuels creative thinking. • Support growth (pituitary gland releases growth hormones at night). • Restore immune system and repair brain tissue
Sleep Deprivation • Results in a “sleep debt” that is related to : Decreases in immune system • Decreases in reaction time (susceptibility to accidents) • Depression • Poor decision-making • • Lack of REM sleep: aggression, memory problems. • Sleep deprivation is related to obesity (increases hunger hormones and decreases metabolic rate.
Sleep Disorders: Insomnia • Difficulty falling/staying asleep • The most common sleep disorder • Sedatives not the best treatment. • Cause dependence • Reduce REM sleep • Best treatment for chronic insomnia: combination of medication (limited time) combined with cognitive-behavioral therapy and following sleep guidelines. • If you can’t sleep, get up and do something else.
Sleep Disorders: Narcolepsy • Rare disorder in which sleep occurs at inappropriate and unexpected times • Sleep attacks lasting for a few minutes at random times • Cataplexy: falling down suddenly when narcoleptic attacks occur. Person falls into REM sleep, and muscles become paralyzed (occurs in almost half of those with narcolepsy)
Sleep disorders: Somnambulism • Sleepwalking • Associated with non-REM slow-wave sleep • Occurs at least once in 15 -40% of all children • About 3 -4% of adults sometimes sleepwalk.
Sleep Disorders: Night terrors • Could be related to sleepwalking • People (especially children between 4 -12 years old) awaken from deep sleep, mainly stage 4, with signs of intense arousal and powerful feelings of fear for 5 -20 minutes • No memory of any dreams associated with night terrors. • Nightmares are found during REM sleep; night terrors are in stage 4. Nightmares can be recalled; night terrors aren’t.
Sleep disorders: Sleep apnea • A disorder in which one actually stops breathing during sleep, causing the person to wake up multiple times a night Causes fatigue, depression, irritability, and inability to concentrate 1 in 25 people suffer from it, usually overweight men Risk factor for heart failure and stroke; highly correlated with heart disease, especially in middle-aged men. Suspected in cases of SIDS (“crib death”)
Sleep Disorders REM Behavior Disorder §Sleep paralysis does not occur during REM sleep. §Act out their dreams. §Associated with neurological problems/brainstem damage.
Dreams “dreaming permits each and every one of us to be quietly and safely insane every night of our lives” William C. Dement • Can be recalled more than 80% of the time if you’re awakened during REM (but recollection fleeting). • Forget 95 -99% of dreams • Feel emotion and sensation. • Thought is illogical. • Uncritical acceptance. • Average of 24 nightmares a year.
Lucid Dreaming • When you know you’re dreaming (associated with REM sleep) • Also refers to the ability to control what you dream about or the outcome of your dream (e. g. , may involve “special powers” in the dream, such as flying) • Sometimes you even have the ability to wake yourself up from a dream.
Dream Theories: Psychoanalytic View of Dreams • Freud (Interpretation of Dreams) • Dreams represent unconscious desires or impulses (some too taboo to be expressed) • Manifest Content: dreams apparent meaning. • Latent Content: dream’s true meaning.
Dream Theories: Activation-Synthesis Theory • Dreams are the subjective experience of random neural activity (static) in the brain that originates in the pons. • The visual and language centers of the cortex try to make sense of neural signals and weave a story about it. • Amygdala gets involved and adds emotional content.
Dream Theories: Information-Processing View • Allow reflection on emotional experiences and regulate emotions. • Allows us to form memories. • Creative thinking
Dual Processing: The Power of the Unconscious Information is often simultaneously processes on separate conscious and unconscious tracks. Parallel Processing: Effortless processing mode. Used to solve simple problems or process information we have already learned. Sequential Processing: Forms representations of novel situations or solves difficult problems. Dual Processing is an example of the way modern psychologists perceive the unconscious.
Meditation • A state of heightened awareness that bring mental processes under greater voluntary control. § Health Benefits of Meditation § Lower levels of stress hormones in the body § Enhanced immune system functioning § Improved cardiovascular health § Reductions in chronic pain § Enhanced sleep patterns
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