PSYCH 104 (1).pdf

Lesson 1 2. Ontogenetic - how a structure or behavior The Major Issues in Biological develops, incl. the influences of genes, nutrition, experiences & their interactions Psychology...

Lesson 1 2. Ontogenetic - how a structure or behavior The Major Issues in Biological develops, incl. the influences of genes, nutrition, experiences & their interactions Psychology - ability to inhibit impulses develops gradually from infancy to adolescence Biological Explanations of Behavior The Mind - Brain Relationship 3. Evolutionary - reconstructs the The Genetics of Behavior evolutionary history of a structure or – Heredity and Environment behavior – The Evolution of Behavior - goosebumps (hair erection) makes a – Genes and Behavior frightened animal looks larger Biological Psychology is the study of the 4. Functional - describes why a structure or physiological, evolutionary and behavior evolved as it did developmental mechanisms of behavior and - a camouflaged appearance makes an experience. animal inconspicuous to predators thus biopsychology / psychobiology / aiding in its survival physiological psychology / behavioral neuroscience The Mind Brain Relationship The goal is to relate biology to issues of psychology Biological explanations of behavior raise Biological Psychology is not only a field the mind-brain problem: “What is the of study, but also a point of view relationship between the mind and the The proper way to understand behavior is brain?” in terms of how it evolved, and how the Dualism - the belief that mind and body functioning of the brain and other organs are different kinds of substances that exists controls behavior independently Research Questions: what genes, prenatal Rene Descartes proposed that mind and environment, or other biological factors brain interact at a single point in space, predispose people to psychological which he suggested was the pineal gland, the disorders? What enables humans to learn smallest unpaired structure found in the language easily? brain Nearly all current philosophers and Biological Explanations of Behavior scientists reject the idea of dualism because 1. Physiological - relates the behavior to the it conflicts with the law of conservation of activity of the brain and other organs. matter and energy: matter can transform into - e.g. low levels of dopamine cause a person energy or energy into matter, but neither one to experience involuntary movements in the appears out of nothing, or disappears into body nothing.  Because matter alters its course only when more than consciousness causes brain matter or energy acts upon it, a mind that is activity not composed of matter or energy could not make anything happen. Monism - in contrast, is the belief that the universe consists of only one kind of The Genetics of Behavior substance A gene is defined as a portion of a Various forms of monism are possible and chromosome, which is composed of a grouped into the following categories: double stranded molecule called Materialism - everything that exists is deoxyribonucleic acid (DNA) material or physical. All psychological A strand of DNA serves as a template for experiences can be explained in purely the synthesis of RNA which serves as a physical terms template for protein molecules. Mentalism - the view that only the mind Some of these proteins form part of the really exists and that the physical world structure of the body, while others regulate could not exists unless some mind were chemical reactions in the body. aware of it Identity Position - the view that mental homozygous - an identical pair of genes on processes and certain kinds of brain the 2 chromosomes activities are the same thing. “Every mental heterozygous - an unmatched pair of genes experience is a brain activity” or “mental dominant genes - show strong effect in activity is what happens in the brain” either homozygous or heterozygous conditions Can we be sure monism is correct? No. recessive genes - shows its effects only in But it is the most reasonable working homozygous conditions hypothesis. autosomal genes - are located on Stimulation of any brain area provokes an autosomal chromosomes experience. sex linked genes - are located on sex One cannot have a mental activity without chromosomes a brain activity. Y chromosome has genes for only 27 proteins while an X chromosome has genes The hard problem is why the mind exists at for about 1500 proteins all in a physical world. Why is there such a thing as consciousness, and how does it Sex Linked and Sex Limited Genes relate to brain activity? An example of a human sex linked gene is the recessive gene for red green color - Accdg. to the identity position: brain deficiency. Any man with this gene on his X activity does not cause consciousness any chromosome experiences this color deficiency because he has no other X chromosome. A woman can only be color genes / prenatal influence --> increase of deficient if she has that recessive gene on some tendency both of her X chromosomes. Sex limited genes (present in both sexes) How genes affect behavior are on autosomal chromosomes, but active The gene itself does not cause a condition, mainly on one sex. Examples include genes rather it produces a protein that under that control the amount of chest hair in men, certain circumstances increases the breast size in women, amount of crowing in probability of the condition. roosters and rate of egg production in hens. There are certain genes that control brain chemicals Hereditary and Environment Genes also effect behavior indirectly, by Every behavior requires both heredity and changing the way others in the environment environment. Take away either one, and treat you. nothing is possible. Eg. People deemed as attractive are more Do the observed differences among confident individuals depend more on differences in heredity or differences in environment? The Evolution of Behavior Many researchers utilized monozygotic Evolution is a change over generations in and dizygotic twin studies to determine the frequencies of various genes in a contributions of heredity and environment, population. It includes any change in gene as well as on adopted children. frequency regardless of whether it helps / Biochemical methods have identified harms species in the long run. certain genes to be linked to conditions / Any gene that is consistently associated behaviors including loneliness, neuroticism, with reproductive success will become more TV watching, and social attitudes. prevalent in later generations. Heredity vs. prenatal influences Biological children of parents with Artificial selection - a technique used by criminal records are likely to have similar breeders when they choose individuals with problems even when they are adopted by desired traits and makes them parents of excellent parents. next generation The biological parents gave them their Natural selection (Darwin, 1859): genes and also their prenatal environment individuals more successful than others in (poor diets, poor medical care, smoked, finding food, escaping enemies, attracting drank or used drugs) mates, protecting their offspring, then their Genes can also influence behavior genes will become more prevalent in later indirectly by changing your environment generations (multiplier effect, Dickens & Flynn, 2001) Evolutionary Psychology Evolutionary Psychology deals with how behaviors have evolved, especially social behaviors Is there a gene for altruistic behavior? Among non-humans, altruism toward non-relatives is rare in most species. (Eg. chimpanzees, crows) Altruisitic groups survive better than less cooperative ones (Bowles,2006) Reciprocal altruism - individuals help those who will return the favor (or extend help to others) Kin selection - in both humans and non-humans altruistic behavior is more common towards relatives than toward unrelated individuals Biological Explanations of behavior: physiological, ontogenetic, evolutionary, functional Biological explanations of behavior do not assume that the individual understands the purpose or function of the behavior Dualism vs. Monism - try to explain mind-brain relationship No one has found a way to answer the “hard problem:” why brain activity is related to mental experience at all. Most behavioral variations reflect the combined influences of many genes and many environmental factors. Heritability is an estimate of the amount of variation that is due to genetic variation as opposed to environmental variation  Every sensory neuron is afferent to the NS, Lesson 2 every motor neuron is efferent to the NS The Cells of the Nervous System Neuroglia Glia (from the Greek word meaning 'glue') The nervous system is composed of 2 hold the neurons together and provide a kinds of cells: neurons and glia (neuroglia) supportive framework for the NS; they are Neurons - receive information and smaller but more numerous than neurons transmits it to other cells astrocytes -wrap around presynaptic Glia - do not transmit information over terminals of a group of functionally related long distances as neurons do, although they axons do exchange chemicals with adjacent microglia - remove waste material viruses, neurons; provide supportive framework for fungi, microorganisms the NS Types of Glia Anatomy of the Neuron oligodendrocytes & Schwann cells - build dendrites - branching fibers that receive myelin sheaths that insulate the vertebrate information axons cell body/soma - contains the nucleus, radial glia - guide migration of neurons ribosomes, mitochondria; covered with during embryonic development synapses at its surface axon - thin fiber that sends info to other The Blood-Brain Barrier neurons or an organ / muscle; has branches Although the brain, like any other organs, at the end (presynaptic teminal) needs to receive nutrients from the blood, myelin sheath - covers the axon many chemicals cannot cross from the blood to the brain. Types of Neurons When the immune system identifies a Motor Neuron - has its soma in the spinal virus, they kill it & the cell that contain it, cord; it receives excitation from other however damaged neurons are not replaced neurons and conducts impulses along its To minimize risk of irreparable brain axon to a muscle damage, the body builds a wall along the Sensory Neuron - highly sensitive to a sides of the brain's blood vessels to keep out particular type of stimulation most viruses, bacteria, harmful chemicals (light/sound/touch) but also nutrients Interneuron - if a cell's dendrites and axons Any virus that enters the NS stays their for are contained within a single structure life (rabies / chicken pox / shingles / genital Afferent - brings information into a herpes) structure Chemicals that pass through the Efferent - carries information away from a blood-brain barrier are: oxygen, carbon structure dioxide, chemicals that dissolve in the fats of the membrane  glucose, amino acids, purines, choline, Otto Leowi, German physiologist, vitamins iron & a few hormones pass demonstrated it by stimulating the vagus through active transport, a protein mediated nerve of a frog thereby decreasing its heart process that expands energy to pump rate, he collected fluid from the heart & chemicals from the blood into the brain transferred it to another frog and produced a Adult neurons rely heavily on glucose the similar effect concluding that nerves send only nutrient that can cross blood-brain messages by releasing chemicals barrier, thiamine (vitamin B) is needed to use glucose Types of Neurotransmitters At a synapse, one neuron releases Synapses chemicals called neurotransmitters that At a synapse, a neuron releases affect a second neuron neurotransmitters (chemicals) that excite or amino acids - glutamate, GABA, glycine, inhibit another cell or alter its response to aspartate other input. neuropeptides - chain of amino acids A single release of neurotransmitter acetylcholine produces only a subthreshold response in the monoamines receiving cell. purines Transmission at synapses goes through gasses many steps, and interference at any of them can alter the outcome Nearly all drugs that affect behavior or experience do so by acting at synapses Charles Scott Sherington - physiologically demonstrated that communication between 1 neuron and the next differs from communication along a single axon by studying reflexes. Neurotransmitters can either be: Chemical Events at the Synapse EXCITATORY - cause neurons to fire action T.R. Elliott discovered that applying the potentials (electric signals) hormone adrenaline directly to the surface of INHIBITORY - prevent action potentials the heart, the stomach and pupils produces from being fired the same effects as those of the sympathetic nervous system. He suggested sympathetic Action potentials play an important role in nerves stimulate muscles by releasing a cell to cell communication. In muscle cell, similar chemical at a synapse the firing of an action potential can cause a muscle contraction Excitatory Neurotransmitters SEROTONIN - feelings of well-being and ADRENALINE (Epinephrine) - produced happiness in high stress or exciting situations stimulates increased heart rate, contracts regulates sleep-wake cycle & intestinal blood vessels, dilates airways, increase movements blood flow to the muscles and oxygen to the Low levels of serotonin has been linked lungs with depression and anxiety leads to a physical boost & heightened Antidepressants work by increasing awareness serotonin EpiPens used to treat allergic reaction, Exercise & light exposure can increase work by injecting adrenaline levels NORADRENALINE (Norepiniphrine) affects attention and responding actions in ACETYLCHOLINE - principal the brain neurotransmitter involved in thought, fight or flight response learning & memory contract blood vessels to increase blood flow it the body, it activates muscle action Patients with ADHD are often prescribed damage to acetylcholine producing areas in medication that increase levels of the brain has been linked with memory noradrenaline in the brain deficits associated with attention & enhancement of sensory perception upon waking Excitatory Neurotransmitters GLUTAMATE - most common neurotransmitter in the brain involved in cognitive functions: learning & memory regulates brain development & creation of nerve contacts Excitatory/ Inhibitory Neurotransmitters it is toxic to neurons in large quantities brain damage / strokes can lead to creation DOPAMINE - pleasure & satisfaction of harmful excess, killing brain cells associated with addiction, movement and motivation ENDORPHINS - are a range of compounds, Natural activities & synthetic substances formed from long chains of amino acids. can trigger release of dopamine related to positive symptoms of They are released in the brain during Schizophrenia exercise, excitement, pain, sexual activity  produces a feeling of well being & euphoria at least 20 types of endorphins have been identified in humans Certain foods (chocolate, spices) can also Made up of ductless glands stimulate release of endorphins Secretes hormones (chemical messengers) directly into blood stream Inhibitory Neurotransmitter Oversecretion and undersecretion of hormones may disrupt normal functioning GAMMA AMINOBUTYRIC ACID (GABA) affecting behavior - is a major inhibitory neurotransmitter in the brain calms firing nerves in the CNS increased levels improve mental focus and relaxation Low levels cause anxiety and has been linked to epilepsy GABA also contributes to motor control & vision Hormones of the Endocrine System HORMONES -are chemicals that are secreted by a gland or other cells and conveyed by the blood to other organs, whose activity it influences. neurotransmitters conveys messages directly from sender to the receiver (telephone) while hormones are like radio stations, they convey message to any receiver who is tuned in Pituitary gland Master Gland Controls the activities of other glands growth hormone Somatotrophin  Secretes Vasopressin an antidiuretic hormone which controls water secretion of kidneys Oxytocin– stimulates labor / breastfeeding / attachment Adrenal Glands Secretes Corticosteroids – regulate heartbeat, stress resistance & muscle development cortisol (stress hormone) Adrenaline or epinephrine – helps arouse body to cope with threats & stress -intensifies emotions such as fear & anxiety Secretes the hormone melatonin which regulates the sleep-wake cycle Melatonin is a mild sedative, signals the body when it is time to sleep may affect the onset of puberty & is also connected with aging Thyroid gland Islet of Langerhans Secretes Thyroxin controls metabolism Hyperthyroidism – increased metabolism = Found in the pancreas irritable and tired, excitability, insomnia, Secretes insulin that prevents the weight loss accumulation of sugar in the blood. Hypothyroidism – low levels of thyroxin, Under secretion of insulin=increase in can cause mental retardation in children blood sugar (hyperglycemia) known as cretinism Sex Glands Gonads of males (testes) produce testosterone that helps produce male secondary characteristics Sex Glands of females (ovaries) produce estrogen and progesterone