Nervous System and Brain Stem
Biopsychology: A specialty that studies the interaction of biology, behavior, and mental processes. Evolution: The gradual process of biological change that occurs in a species as it adapts to its environment new generations change as they adapt to changing environments Evolution has fundamentally shaped psychological processes because it favors genetic variations that produce adaptive behavior Charles Darwin:Wondered if animals were related and if all creations, even humans, could share a common ancestry made the controversial case for the evolution of life
Natural selection:The driving force behind evolution, the fittest organisms are selected by the environment, the best adapted will flourish and the least adapted will die out. Darwin never said humans came from monkeys, but that they both had a common ancestor Genetics and inheritance: Genotype: Genetic Makeup
Phenotype: Physical and behavioral characteristics (observable characteristics) not all biological, also can be changed by nutrition, disease, stress, and poor medical care causing birth defects Genome: Set of genetic information contained within a cell DNA:A complex molecule that stores biological information Genes: The words that make up the instruction manual (genome) Chromosomes:Tightly coiled structures in which genes are organized, consist of DNA Nucleotides: letters that form genes, there are 4
Sex chromosomes: The X and Y chromosomes that determine physical sex characteristics XX-female XY-male , fathers determine sex Genes influence our psychological characteristics
Never attribute psychological characteristics to genetics alone, even identical twins Race and human variations: Certain features of skin color and other physical characteristics are common among people who trace their ancestry to the same part of the world tropical ancestry have darker skin to protect them from the sun, and lighter skin for less sunny places There are no genetic differences for races, race is more of a socially defined term Preimplantation Genetic Diagnosis: Testing fetus at a very oung age to ensure a genetically healthy fetus Some of these clinics also offer gender selection and ‘savior siblings’ How does the body communicate internally?
The nervous system reacts first:accelerate your heart rate and tense your muscles for action Endocrine system sends follow-up messages:send hormones which also accelerate heart and tense muscles they work together in stressful and happier situations and even during low arousal states the brain is the chief that manages the cooperation of the nervous and endocrine systems
The brain coordinates the bodys 2 communication systems, the nervous and endocrine, which use similar chemical processes to communicate with targets throughout the body Neuron (nerve cell) : cell that receives and transmits information to other cells of the body, bundles are called nerves Sensory neuron (afferent neurons): A cell that carries messages towards the brain from sense receptors Motor neuron (efferent neurons): A cell that carries messages away from the brain to the muscles and glands
Interneurons: A cell that relays messages between nerve cells, especially in the brain and spinal cord Dendrites: Branched fibers that extend outward from the cell body and carries information into the neuron Soma: part of the cell containing the nucleus or cell body, houses chromosomes Axon: An extending fiber that conducts information from the soma to the terminal buttons Resting potential: The electrical charge of the axon in its inactive state, when neuron is ready to ‘fire’
Action potential: When the neuron ‘fires’ due to a change in electrical charge across the cell membrane of axon All or none principle: action potential in the axon occurs either completely or not at all when many neurons fire too easily the result can be epileptic seizure Synapse:gap that serves as a communications link between neurons or between neurons and muscles or glands they serve Terminal buttons:Tiny bulb like structures at the end of the axon that carry the message into the synapse Synaptic transmission: The relaying of information across the synapse Neurotransmitter: Chemical messenger that relays neural messages across the synapse, many are also hormones Reuptake:The process by which unused neurotransmitters are drawn back into the vesicles of their originating neuron 7 important neurotransmitters:
Dopamine:Produces feeling of pleasure or reward, imbalances cause schizophrenia and Parkinson, cocaine, amphatamine, and alcohol affect the action of this transmitter Serotonin:Regulates, sleep, dreams, mood, pain, appetite, sex drive, imbalances cause depression, anxiety, OCD, Prozac and LSD affect the action of this transmitter Norepinnephrine:controls heart rate, sleep, stress, sexual responsiveness, appetite, imbalances cause high blood pressure, depression, Tricyclic, anti depressants, and beta blockers affect the action of this transmitter Acetycholine:involved in learning and memory, imbalances cause muscular disorders, alzheimers, nicotine, black widow spider venom, botulism toxin, barbiturates affect the action of this transmitter
GABA:Inhibitory transmitter, inbalances cause anxiety and epilepsy, minor tranquilizers and alcohol affect the action of this transmitter Glutamate:Excitatory transmitter, excess release of glutamate causes brain damage after stroke, PCP affects the action of this transmitter Endorphins:Pleasurable sensations and control of pain, imbalances come from opiate addiction, opiates like morphine, heroin, and methadone effect the action of this transmitter Plasticity: the nervous systems ability to change or adapt as a result of an experience or physical damage plasticity can not compensate for extensive injurys just as paralyzed individuals may implant computer chips in the brain to restore some forms of control
Glial cells: A cell that provides structural support for neurons, also provide the myelin sheath of the axon for some neurons nervous system: Network of neurons in the body, including the central nervous system, peripheral nervous system, and their subdivisions Central nervous system:brain and spinal cord Reflex:simple unlearned response triggered by stimuli done by spinal cord Contralateral:Each side of the brain communicates with the opposite side of the body Peripheral Nervous system:Connects the central nervous system with the rest of the body (somatic and autonomic) Somatic nervous system: Carries sensory information to the brain and voluntary messages to the muscles
Autonomic nervous system: Sends communications between the brain and the internal organs and glands Sympathetic division: ends messages to internal organs and glands that help us respond to stressful or emergency situations Parasympathetic: monitors the routine operations of the internal organs and returns body to calmer functioning after arousal by the sympathetic division
The endocrine system: The hormone system, chemical messenger system including pituitary, thyroid, adrenals, pancreas, ovaries, and testes in a crisis this system releases epinephrine or adrenalin sustaining the bodies fight or flight reaction Hormones: chemical messengers used by the endocrine system and the nervous system
Hormonal functions of major endocrine glands: Anterior Pituitary: ovaries and testes, breast milk production, metabolism, reactions to stress Posterior Pituitary: conservation of water in the body, breast milk secretion, uterus contractions Thyroid: metabolism, physical growth and development Parathyroid: calcium levels in the body Pancreas: glucose (sugar) metabolism
Adrenal glands: fight or flight response, metabolism, sexual desire (especially in women) Ovaries: development of female sexual characteristics, production of eggs or ova Testes: development of male sexual characteristics, sperm production, sexual desire in men Pituitary gland: the ‘master gland’ that oversees all these endocrine responses Agonists: drugs or other chemicals that enhance or mimic the effects of neurotransmitters antagonists: drugs or other chemicals that inhibit the effects of neurotransmitters
Neural pathways: bundles of nerve cells that follow generally the same route and employ the same neurotransmitter How does the brain produce behavior and mental processes? Thoughts and feelings originate from the brain (love doesn’t come from the heart) brain is a collection of distinct modules that work together like the components of a computer the brain is composed of many specialized modules that work together to create mind and behavior EEG(Electroencephalograph):A device for recording brain waves, typically by electrodes places on the scalp. The recording is an EEG Can reveal abnormal waves which cause epilepsy not very precise
Wilder Pen field mapped the brain with electric probes which showed him that the brain’s surface had distinct areas with distinct functions Brain Scans: help neurosurgeons to locate abnormalities such as tumors or stroke related damage without opening the skull CT(computerized tomography):uses x-rays taken of the brain at different angles and then combined into an image PET(positron emission tomography):Imaging technique that relies on the detection of radioactive sugar consumed by active brain cells
MRI(magnetic resonance imaging): Imaging technique that relies on cell’s responses in a high-intensity magnetic field fMRI(functional magnetic resonance imaging):form of MRI that records brain structure and activity PET and fMRI show which parts of the brain are active during a particular task MRI ecvelsat distinguishing the fine details of brain structures non of these can detect processes that occur only briefly (shift in attention, startle response) no scanning technique gives biopsychologists a perfectly clear view of all of the brains activity Three layers of the brain Brain stem: the most primitive of the brains three major layers, includes medulla, pons, and reticular formation medulla:Controls breathing and heart rate
Pons:Regulates brain activity during sleep or dreaming Reticular formation:keeps the brain alert and attentive to new stimulation Limbic system:middle layer, involved in emotion and memory, includes thee hippocampus,amygdalaa, hypothalamus, and some pleasure centers Hippocampus:Establishes long term memories amydala:memory and emotion, particularly fear and aggression Hypothalamus:Brains blood testing lab, constantly monitors blood to determine condition of the bod
Thalamus: brain’s central ‘relay station’, all messages that enter or exit the brain go through the thalamus controls sleep and awake states of consciousness cerebrum cerebellum:the ‘little brain’ attached to the brain stem, responsible for oordinated movements cerebral hemispheres:large symmetrical halves of the brain located atop the brain stem cerebral cortex:Thin gray matter covering the cerebral hemispheres, carries on major portion of higher mental processes like thinking and perceiving corpus callosum: the band of nerve cells connecting and enabling communication between the two cerebral hemispheres
The frontal lobes:cortical regions at the front of the brain especially involved in movement and in thinking motor cortex: A narrow vertical strip of cortex in the frontal lobes, controls voluntary motor movement Mirror neuron:A class of neuron that fires in response to ‘mirroring’ observation of another person’s actions or emotions The left frontal lobes: production of speech
The parietal lobes:Involved in touch sensation and perceiving spatial relationships Somatosensory cortex: A strip of the parietal lobe involved in sensations of touch The temporal lobes:Cortical lobes that process hearing, including speech, involved in storing long term memories Occipital lobes: The cortical regions that house the visual cortex Visual cortex: The visual processing area of cortex in the occipital and temporal lobes Association Cortex: Critical regions throughout the brain that combine information from various other parts of the brain
Cerebral Dominance:The tendency of each brain hemisphere to exert control over different functions, such as language or perception of spatial relationships The left side is more active in language and speech the right side is for visual and spatial and interprets others emotional responses and their nonverbal communication signals the right frontal lobes control the negative emotions such as fear and anger the left frontal lobes control the positive emotions such as joy cerebral dominance patterns are not always the same from one person to another men on average have slightly larger brains, thought to be part of body size and not much other importance CH 3
Sensation: The process by which stimulation of a sensory receptor produces neural impulses that the brain interprets as a sound, sight, taste, touch, or smell Perception: A mental process that elaborates and assigns meaning to the incoming sensory patterns The brain senses the world indirectly because the sense organs convert stimulation into the language of the nervous system (neural messages) 3 attributes common to all senses: transduction-process that converts information carried by the stimulus , such as light or sound waves, into the form of neural messages sensory adaption-loss of responsiveness in receptor cells after stimulation has remained unchanged for a while thresholds bsolute threshold-minimum amount of physical energy needed to produce a sensory experience (how soft can music be and still be heard) if it is above your thresholds, you sense it varies from person to person and varies in an individual depending on mental alertness and physical condition difference threshold (JND)-minimum amount by which a stimulus can be changed and the difference be detected half the time large when the stimulus intensity is high and small when low Webers law: The size of the JND is proportional to the intensity of the stimulus We are built to detect changes in stimulation and relationships among stimuli Signal detection theory: Theory that states that sensation depends on the characteristics of the stimulus, the background stimulation, and the detector.
Sensory Adaptation: Loss of responsiveness in receptor cells after stimulation has remained unchanged for a while (adjusting to the temperature of a cold pool) The sense all operate in much the same way, but each extracts different information and sends it to its own specialized processing region in the brain Vision: Retina:The thin light-sensitive layer at the back of the eyeball. The retina contains millions of photoreceptor and other nerve cells the retina is where the transduction of light into neural signals occurs Photoreceptors: Light sensitive cells (neurons) in the retina that concert light energy to neural impulses, these receptors are as far as light gets into the visual system. Rods: Photoreceptors in the retina sensitive to dark lighting but not to color
Cones: photoreceptor in the retina sensitive to colors but not dim light Fovea-tiny area of sharpest vision in the retina ipolar cells-collect impulses from photoreceptors and send them to the ganglion cells optic nerve-the bundle of neurons that caries visual information from the retina to the brain blind spot- the point where the optic nerve exits the eye and there are no photoreceptors, anything in this area cannot be seen visual cortex creates visual images from the information received from the eyes in this cortex, brain turns neural impulses into visual sensations of color, form, boundary, and movement brightness- A sensation caused by intensity(amplitude) of light waves color-(hue) not a property of things in the external world , a psychological sensation created in the brain from information from the eyes from the wavelength of visual light
Electromagnetic spectrum-the entire range of electromagnetic energy, including radio waves, x rays, microwaves, and visible light visible spectrum-the tiny part of electromagnetic spectrum to which our eyes are sensitive, may be different from our own trichromatic theory-the idea that colors are sensed by three different types of cones sensitive to light in the red blue and green wavelengths, this theory explains color processing in the cones of the retina opponent-process theory-the idea that cells in the visual system process colors in complementary pairs, such as red or green , yellow or blue, this theory explains color sensation from the bipolar cells onward in the visual system afterimages-sensations that linger after the stimulus is removed, most are negative after images, which appear in reversed colors color blindness-genetic disorder that prevents an individual from discriminating certain colors, most common form is red green color blindness
Hearing: Frequency-highness or lowness of sound, pitch amplitude-the physical strength of a wave. Height of the wave , when turning down vol, your turning down amplitude, loudness timbre-complex quality of a sound wave, helps you distinguish different voices how we hear: sound waves are relayed to the inner ear, vibrating waves make their way through the ear canal to the ear drum or tympanic membrane, vibrates middle ear, sends to cochlea cochlea-main organ of hearing focuses he vibrations on the basilar membrane basilar membrane converts vibrations into neural messages neural messages travel to the auditory cortex in the brain Hearing loss-from damage of the hair cells in the cochlea Vision-stimulus is light waves, receptor is rods and cones
Hearing-stimulus is sound waves, receptor is hair cells in basilar membrane Skin senses-stimulus is external contact, receptor is nerve endings in skin Smell-stimulus is volatile substances, receptor is hair cells in olfactory epithelium Taste-stimulus is soluble substances, receptor is taste buds on tongue Pain- stimulus is extreme stimuli, receptors are pain receptors Kinesthatic and vestibular senses-stimulus is body position, movement and balance, receptors are hair cells in semicircular canals and neurons connected to muscles joints and tendons Vestibular senses-the sense of body orientation with respect to gravity, associated with inner ear and in fact is carried to the brain on a Branch of the auditory nerve Kinesthetic sense-the sense of body position and movement of body parts relative to each other
Smell: olfaction-sense of smell pheromones-chemical signals released by organisms to communicate with other members of their species. Often used by animals as sexual attractants, unclear if humans use them Taste: Gustation-the sense of taste
Skin senses: sensory system for processing touch, warmth, cold, texture, and pain synesthesia-the mixing of sensations across sensory modalities, as in tasting shapes or seeing colors associated with numbers Phantom limbs-sensations experienced by people who have lost a limb coming from the missing body part Gate control theory-an explanation for pain control that proposes we have a neural ‘gate’ that can, under some circumstances, block incoming pain signals if you experience pain you can take drugs like aspirin or you can get morphine which suppresses the pain messages in the spinal cord placebo-appears to be a drug, but is not (sugar pill) placebo effect-a response to a placebo caused by the belief that it is a real drug Perception gives meaning to sensation, so perception produces an interpretation of the world, not a perfect representation of it
Percept: The meaning product of perception, often an image that has been associated with concepts, memories of events, emotions, and motives What pathway-A neural pathway, projecting from the primary visual cortex to the temporal lobe, which involves identifying objects where pathway-A neural pathway the projects visual information to the parietal lobe, responsible for locating objects in space blindsight-being conscious of information in the what pathway but not necessarily in the where pathway feature detectors-cells in the cortex that specialize in extracting certain features of a stimulus binding problem:
how the brain combines the results from many senses into a single percept top-down process: memories and past experiences in our brain tell perception bottom up process: the sensed characteristics in the stimuli exert strong influence on our perceptions perceptual constancy-the ability to recognize the same object as remaining ‘constant’ under different conditions, such as distance or location inattentional blindness-a failure to notice changes occurring in ones visual field, caused by narrowing the focus of ones attention change blindness-failure to notice that a visual scene has changed from the way it had appeared previously, requires comparing a scene to one from the past illusion-incorrect perception of a stimulus pattern especially one that fools others ambiguous figures-images that can be interpreted in more than one way.
No right way to see an ambiguous figure Gestalt psychology: believed that much of perception is shaped by innate factors built into the brain figure- a part of a pattern that stands out against the ground ground-part of a pattern that does not command attention-background closure-gestalt principle that identifies the tendency to fill in gaps in figures and to see incomplete figures as complete Laws of perceptual grouping-the gestalt principles of similarity, proximity, continuity, and common fate.
Suggest how our brains prefer to group stimulus elements together to form a percept Law of similarity-gestalt principle, we tend to group similar objects together in out perceptions Law of proximity-gestalt principle, we tend to group objects together when they are near each other Law of continuity-gestalt principle, we prefer perceptions of connected and continuous figures to disconnected and disjointed ones Law of common fate-gestalt principle, we tend to group similar objects together that share a common motion of destination Law of
Pragnanz- Gestalt principle, the simplest organization, requiring the least cognitive effect, will emerge as a figure, full figures such as a closed circle Learning based inference- the view that perception is primarily shaped by learning rather by innate factors perceptual set-readiness to detect a particular stimulus in a given context someone afraid interprets an unfamiliar sound as a threat, set of words, word missing binocular cues-information taken in by both eyes that aids in depth perception, including binocular convergence and retinal disparity Monocular cues-information about depth that relies on the input of just one eye and includes relative size, light and shadow, relative motion and atmospheric pressure CH 8
Cognitive Neuroscience-An interdisciplinary field involving cognitive psychology, neurology, biology, computer science, linguistics, and other specialists who are interested in the connection between mental processes and the brain Nonconscious process-Any brain process that does not involve conscious processing, including both preconscious memories and unconscious processes can perform many jobs at the same time (walk, chew gum, breath) Consciousness-The process by which the brain creates mental model of our experience, most common consciousness occurs during wakefulness, although there can be altered states Attention- a process by which consciousness focuses on a single item of ‘chunk’ in working memory Tools for studying consciousness- fMRI, EEG, PET Freud’s levels of consciousness:
Preconscious- A special unconscious storehouse for information no currently in conscious but readily available to the conscious (like your phone number) The unconscious-A part of the mind that processes below the level or awareness, emotional memories, desires, and feelings that would be threatening if brought back to consciousness James stream of consciousness-walking consciousness is like a flowing stream carrying ever changing sensations, perceptions, thoughts, memories, feelings, and desires, this stream includes awareness of ourselves and of stimulation from our environment, can also include physical sensations from within like hunger or pain James said consciousness has 2 levels :an area of focus for what we are focusing our attention on, and a peripheral conscious to encompass the feelings that give meaning to our focus The computer metaphor-likens consciousness to the information and images that appear on a computer screen nonconscious is the electronic activity behind the scene, which most of the time operates in parallel with consciousness Three important functions of the consciousness:
Consciousness restricts our attention-(restriction) because it processes information serially, it limits what you notice and think about,keeps your brain from being overwhelmed by stimulation cannot read while listening to music consciousness provides a mental ‘meeting place’-(combination) meeting place where sensation can combine with memory, emotions, motives, and a host of other psychological processes (perception) consciousness allows us to create a mental model of the world-(manipulation) a model we can manipulate in our minds, we don’t just operate in the moment, we make a model that draws on memory and brings the past and the future into awareness.
Coma-An unconscious state, during which a person lacks the normal cycles of sleep and wakefulness, usually only lasts a few days (between vegetative and minimally conscious states) Consciousness fluctuates in cycles that correspond to our biological rhythms and to patterns of stimulation in our environmental Daydreaming-A common (and quite normal) variation of consciousness in which attention shifts to memories, expectations, desires, or fantasies and away from the immediate situation daydreaming is automatic when we are in a restful state or not focused on something Circadian Rhythms-A pattern that repeats every 24 hours such as sleep and wakefulness cycle, jet lag Main Events of sleep: REM sleep-stage that occurs approximately every 90 minutes, marked by bursts of rapid eye movement occurring under closed eye lids each REM period gets longer and longer Non-REM-the recurring periods, mainly associated with the deeper state of sleep, when a sleeper is not showing rapid eye movements Sleep paralysis- A condition in which a sleeper is unable to move any of the voluntary muscles except the eyes (normally occurs during REM) Stages of sleep: Stage 1:Slower theta waves, faster beta waves
Stage 2:Short burst of fast electrical activity that reliably signal the end of stage 1 Stage 3 &4:heart rate and breathing slow down , beta brain waves slow, delta waves appear DEEPEST sleep in stage 4 as stage 4 ends sleeper climbs back up the stages backwards REM sleep: fast beta waves, rapid eye movement, after REM sleeper slips back into stage 2 REM rebound- A condition of increased REM sleep caused by REM sleep deprivation Sleep debt-A sleep deficiency caused by not getting the amount of sleep required for optimal functioning Isrealites interpreted dreams as messages from the gods Egyptians tried to influence dreams by sleeping in temples dedicated to the god of dreaming Chinese are scared to dream because they think the soul wanders outside the body Freud’s theory of dreams: manifest content-the story line of a dream, taken at face value without interpretation latent content- the symbolic meaning or objects and events in a dream Activation synthesis theory- the theory that dreams begin with random electrical activation coming from the brain stem.
The storyline of dreams are the brains attempt to make sense of this random activity Insomnia- involving insufficient sleep, the inability to fall asleep quickly, frequent arousals, or early awakenings Sleep Apnea- A respiratory disorder in which the person intermittently stops breathing many times while asleep Night terrors-deep sleep episodes that seem to produce terror, what made the person scared is usually forgotten on awakening, usually found in children narcolepsy-a disorder of REM sleep, involving sleep-onset periods in sudden daytime REM-sleep attacks An altered state of consciousness occurs when some aspect of normal consciousness is modified by mental, behavioral, or chemical means Hypnosis-A state of awareness characterized by deep relaxation, heightened suggestibility, and focused attention Hypnotizability- susceptibility measured by a persons responsiveness to standardized suggestions hypnosis an be used for dental and medical uses, psychological treatment
Meditation-A state of consciousness often induces by focusing on a repetitive behavior, assuming certain body positions, and minimizing external stimulation Psychoactive drug-chemical that affects mental processes and behavior by its effect on the brain Hallucinogen-a drug that creates hallucinations or alters perception of the external environment and inner awareness Opiates-Highly addictive drug, derived from opium, that can produce a profound sense of sell being and has strong pain relieving properties Depressant-drug that slows down mental and physical activity by inhibiting transmission of nerve impulses in the brain (alcohol, barbiturates) Stimulants-speed up brain and mental and physical responses (cocain, amphetamine, nicotine, caffeine)
General Anesthetic-substance that suppresses consciousness and awareness of pain, some produce sedation and immobility Tolerance-the reduces effectiveness a drug has after repeated use psychical dependence-the body adjusts to and comes to need and drug for every day functioning addiction- a person continues to use a drug despite its adverse effects and many attempts to stop withdrawal-A pattern of uncomfortable or painful physical symptoms and cravings experienced by the user when the level of drug is decreased or the drug is eliminated psychological dependency-a desire to obtain or use a drug, even though there is no physical dependence
