Introduction to Psychology Biological Basis of Behavior Unit

Introduction to Psychology Biological Basis of Behavior Unit 2

Structure of the Neuron Soma (Cell Body): The central part of the neuron, contains the nucleus ◦ Regulates cell functioning Dendrites: the branching part of the neuron that receives messages from other neurons and relays them to the cell body

Structure of the Neuron Axon: The long, cable-like extension that delivers messages to other neurons Myelin Sheath: Layer of fatty tissue that insulates the axon and helps speed up message transmission ◦ Multiple Sclerosis: Deterioration of myelin leads to slowed communication with muscles and impaired sensation in limbs

Structure of the Neuron Synapse: The gap between two neurons allowing communication ◦ Chemical Synapse utilizes Neurotransmitters ◦ Electrical Synapse utilizes Action Potentials Speed of electrical synapses depends on myelin presence Unmyelinated neurons transmit approximately 2 meters per section Myelinated neurons transmit approximately 120 meters per section

Six Primary Neurotransmitters 1. Acetylcholine –Firing of neurons 2. GABA- Keeps neurons from firing 3. Norepinephrine- Inhibits firing of neurons in the CNS 4. Dopamine- Inhibitor –helps to control voluntary movement affects sleep, mood, attention and learning 5. Serotonin- Primarily inhibits, regulates sleep, mood, attention and learning 6. Endorphins- Stimulates firing of neurons, shields body from pain and elevates feeling of pleasure

The Nervous System A. B. C. D. E. F. G. Central Nervous System Peripheral Nervous System Somatic Nervous System Autonomic Nervous System Sympathetic Nervous System Parasympathetic Nervous System Non emergency functions

Nervous System

Structure of the Cortex Cerebral Cortex divided into lobes, or regions of the brain ◦ Each lobe is (roughly) responsible for different higher-level functions, but remember that they do not work merely in isolation.

Structure of the Cortex Occipital Lobe: brain lobe at the back of the head ◦ responsible primarily for vision; separate areas specify visual properties such as shape, color, and motion

Structure of the Cortex Parietal Lobe: brain lobe at the top and center/rear of the head ◦ involved in registering spatial location, attention, and motor control ◦ also involved in arithmetic Einstein’s parietal lobes were found to be about 15% bigger than average (Witelson et al. , 1999)

Structure of the Cortex Temporal Lobe: the brain lobe under the temples, in front of the ears ◦ many functions, including processing sounds, committing information to memory, and comprehending language

Structure of the Cortex Frontal Lobe: the brain lobe located behind the forehead ◦ the seat of planning, memory search, motor control, reasoning, emotions, and many other functions ◦ In many ways, the frontal lobe is what makes us uniquely human.

Introduction to Psych Corpus Callosum ◦ Fibers that connect the two hemispheres ◦ Allow close communication between left and right hemisphere Each hemisphere appears to specialize in certain functions Epilepsy Neurons somewhere in brain emits abnormal rhythmic spontaneous impulses

Brain Scans CT or CAT Scan –X rays pass through the head; dyes in the blood increase contrast between fluids and brain cells PET Scan- Position-emission tomography- high resolution image of brain activity by recording radioactivity emitted from injected chemicals FMRI –Functional Magnetic Resonance Imaging – magnetic detectors outside the head to record

The Effects of Localized Brain Damage The Visual System Damage to primary cortex –completely blind Damage to Inferior Temporal Cortex –face blindness Damage to part of color pathway loss of color constancy-ability to recognize changes in light

Unilateral Neglect Damage to parietal lobe leads neglect or disregard to the opposite side of the body Individuals may put clothing on one side of the body and insist that the other side belongs to someone else

Memory Loss Brain Damage Small Portion of the frontal cortex Delayed response Signal from one side and delay happens Impairment in monkeys

Connections between eye and brain Part of the right and left eye see almost the same view of the world Left retina to the left hemisphere of cerebral cortex and vice versa

Parts of the Brain and how damage affects them Medulla and Pons Sensory input from head and sends impulses from motor control of head Axons control heart rate other life preserving functions Systems that regulate brain arousal (reticular formation) Malfunction in one of these systems may lead to sleepiness or being persistently aroused Cerebellum Cerebral Cortex Rapid sequences of action Important behaviours involve timing Damage makes muscle movements slower and more thought out Corpus Callosum –sensation and motor control on opposite side of body

Parts of the Brain and how damage affects them Primary Cortex Neurons sensitive to touch Damage cause complete blindness Inferior Temporal Cortex Part of visual system Damage may cause face blindness Parietal lobe Body senses –touch, pain, and temperature, awareness of the location of body parts Damage may cause unilateral neglect Temporal lobe Hearing complex aspects of vision, and language comprehension Damage results in impariment in individuals ability to understand what someone is saying or remebering objects

Genetics Zygote- Fertilized Egg ◦ Monozygotic vs Dizygotic Twins Genes are made up of DNA a chemical that controls RNA Homozygous- Two genes where the pairs are the same Heterozygous- Two genes where the pairs are different Identifying Genes Researchers have found some genes to contribute to Alzheimer's and Huntington's disease Researching Hereditability Ranges from 0 to 1 Measure of 1 indicates all variance id due to heredity Measure of 0 suggests none is due to heredity

Genetics Interactions between Heredity and the Environment PKU-Phenylketonuria inherited condition leads to retardation Evolution Changes in gene frequency species Selective Breeding: Artificial selection of animals and plants Natural selection: Individuals with certain charcteristics reproduce more successfully Socio-biology attempts to connect social behaviour of species to its biology

Genetics The Visual Senses Stimuli Receptors

Genetics Heredity - transmission of trait from one generation to next Chromosomes ◦ Pairs of thread like bodies that contain genes Deoxyribonucleic acid (DNA) ◦ Organic molecule arranged in a doublehelix ◦ Contains the “code of life”

Genetic Concepts Nucleic Acids ◦ DNA ◦ RNA Chromosomes ◦X ◦Y ◦ Karyotype Chromosomal Maps

Genetic Concepts Genotype : What is in the DNA Phenotype: What is observable as a result of the genotype Carrier vs Expressed Genetics Multifactorial & Polygenic Factors

Gene-Environment Interaction Twin Studies! ◦ Monozygotic Twins ◦ Dizygotic Twins

Genetic Abnormalities Down’s Syndrome aka Trisomy 21 ◦ Three copies of Chromosom 21 present ◦ Characteristics: Thick tongue Round face Slanted eyes Short limbs Cognitive delays, occasional mental retardation More prone to dementias and age-related disease early in life

Genetic Abnormalities Phenylketonuria aka PKU ◦ Metabolic disorder leading to inability to digest proteins ◦ 1/5, 000 US births ◦ Recessive linked ◦ Dietary treatment available ◦ Can be detected prenatally and through standard newborn testing

Genetic Abnormalities Huntington’s Disease ◦ Dominant linked ◦ Symptoms begin around age 35 ◦ Manifests as mental illness and extreme aggression ◦ Typically ends in suicide ◦ Can be screened for in genetic testing

Sex-Linked Abnormalities Kleinfelter Syndrome: XXY Chromosomal Pattern ◦ Seemingly male appearance with an absence of secondary sex characteristics typically present at puberty ◦ Learning disabilities, language deficits, and anger issues are common

Sex-Linked Abnormalities Fragile X Syndrome: Part of the X is thinly attached and prone to breaking ◦ One gene mutation replicates over 200 times (normal range is 30) ◦ Enlargement of the head and ears are typically present ◦ Males may have enlarged scrotum and testicle ◦ May lead normal lives (20%) ◦ Mild retardation (30%) ◦ Severe retardation (47%)

Sex-Linked Abnormalities Turner’s Syndrome: XO Genetic mutation, only one chromosome present ◦ Learning disabilities (particularly math/science/logical reasoning) ◦ Flat affect and difficulty recognizing emotions ◦ Short stature ◦ Secondary sex characteristics and puberty changes do not develop ◦ “Webbed” neck sometimes present

Behavior Genetics Study of behavior from a genetic perspective Animal behavior genetic studies include: ◦ Strain studies ◦ Selection studies

Human Behavior Genetics Family studies ◦ Assume that close family members share more of a trait than non-relatives ◦ Used to assess the heritability of psychological disorders or traits Twin studies ◦ Used to determine how heritable a trait or disorder may be ◦ Identical twins would have highest heritability

Human Behavior Genetics Adoption studies ◦ Used to assess the influence of environment Molecular genetics ◦ Direct study of the genetic code

Structure and Function of the Human Eye

Disorders involving Vision Presbyopia –decreased flexibility in lens difficulty focusing on nearby objects Myopia –elongation of eyeballs- far objects Hyperopia – flattened eyeballs- farsighted Glaucoma- increased pressure in eyeball leading to optic nerve damage Cataract- lend becomes cloudy

The Visual Receptors Neurons in the retina specialized to respond to small quantities of light Cones –Color, daytime, detailed Vision 5 to 10% visual receptors – 6 million per eye Rods – receptors adopted vision in dim light – 100 million per eye

Visual Pathways Bipolar Cells –make contact with other neurons Ganglion Cells- receive input from bipolar cells Optic Nerve- Ganglion cell axions join to form the optic nerve

Color Vision Trichromatic Theory aka Young-Helmoltz Theory Three primary colors 3 types of Cones Blue Cones-Sensitive to short wavelengths Green Cones- Sensitive to medium wavelengths Red Cones- respond to long wavelengths

Color Vision Four basic primary colors ◦ ◦ Blue Green Red Yellow Erwald Hering – opponent process theory ◦ Negative after images ◦ Color Constancy ◦ Retinex Theory Color perceived through cerebral cortex Colorblindness ◦ 4% ◦ Most common is red green distinguishing ◦ More common in men

Color Vision

Hearing Process of Hearing: ◦ Auricle directs sound waves to the external auditory canal ◦ Sound waves strike the tympanic membrane causing vibrations. Low-frequency sounds cause slow vibrations High-frequency cause fast vibrations ◦ Vibrations cause the malleus to vibrate, which vibrates the incus, which vibrates the stapes. ◦ Movement of the stapes pushes the membrane of oval window open & closed.

Hearing Process of Hearing: ◦ Vibrations of the oval window cause the perilymph of the cochlea to move in waves. ◦ Waves move to the scala vestibuli, the scala tympani, then to the round window. ◦ The waves cause the round window to bulge into the middle ear & the walls fo the scala vestibuli & scala tympani to change. ◦ Wall changes cause pressure waves in the endolymph inside the cochlear duct. ◦ Waves in the cochlear duct cause vibration of the basilar membrane. ◦ Cochlear waves move the organ of Corti hairs against the tectorial membrane.

Hearing Process of Hearing: ◦ Tectorial membrane vibrations cause receptor potentials, then nerve impulses, via opening potassium channels. ◦ Auditory Pathway travels from the first-order sensory neurons in the cochlear branch of the vestibulocochlear nerves (CN 8) to the medulla oblongata. ◦ Signal travels from the medulla oblongata to the midbrain, to the thalamus, then the temporal lobe for conscious perception.

Hearing Tuning: Basilar membrane is divided into pitches. ◦ High intensity sound waves create longer vibrations & creates an interpretation of high pitch. ◦ Low intensity sound waves create shorter vibrations & creates an interpretation of low pitch.

Equilibrium: The sense of balance maintained by our inner ear. ◦ Static Equilibrium: Refers to our ability to keep our position in response to gravity. ◦ Dynamic Equilibrium: Refers to our ability to keep our body position in response to sudden movements.

Equilibrium Vestibular Apparatus: The receptor organ responsible for maintaining equilibrium. Typically maintained by the saccule & utricle within the vestibule of the inner ear. ◦ Macula: A small patch of hair cells on both the saccule & utricle. Contains around 50 stereocilia & a single motile kinocilium. ◦ Otolithic Membrane: Thick, gelatin-like layer of glycoproteins weighted down by otoliths (calcium crystals). ◦ Shifting the head causes changes in these structures that generate nerve signals.

Equilibrium Semicircular Ducts: The three ducts, each containing ampulla, help to maintain balance. ◦ Crista Ampularis: Mounds of hair on each ampulla. Cupula: Gelatinous material covering the crista ampularis. ◦ Changes in these structures help to maitain dynamic equilibrium.

Sensory Receptors Sensory receptors transmit 4 types of information: ◦ Modality: Refers to the type of stimulus or sensation it produces. E. g. vision, hearing, taste. ◦ Location: Determined by which afferent (sensory) nerve fiber are firing & gives the brain the ability to identify the site or location of the stimulus. ◦ Intensity: Determined by the number & kind of nerve fibers which are firing & the time intervals between action potentials. ◦ Duration: Refers to the way nerve fibers change their firing frequencies over time.

Classification of Sensory Receptors – General Somesthetic (General) Senses: Includes receptors in the skin, muscle, tendons, joint capsules, and viscera. ◦ Somatic Senses: Tactile senses, thermal sensations, pain sensations, proprioceptive sensations. ◦ Visceral Senses: Provides information about conditions within the internal organs. Special Senses: Limited to the head & innervated by the cranial nerves. ◦ Includes: Vision, hearing, equilibrium, taste & smell.

Classification of Sensory Receptors – Overlapping Systems Chemoreceptors: Respond to chemicals, including odor & taste. Thermoreceptors: Respond to temperature (heat & cold). Nociceptors: Pain receptors. Mechanreceptors: Respond to the physical deformation of the plasma membrane. ◦ E. g. caused by touch, pressure, stretch, tension, or vibration. Photoreceptors: Respond to light. Osmoreceptors: Respond to osmotic pressure. Proprioreceptors: Sense the body position, muscle tension, & movement in space.

Pain Sensation Nocioceptors: Pain sensory neurons found in every bodily tissue except the brain. Analgesia: The relief of pain. ◦ Oligopeptides: Chemicals released by the CNS that have analgesic qualities. AKA edogenous opiods. E. g. Endorphins & dynorphins.

Types of Pain Slow Pain: Dull, achey pain signals carried along an unmeylinated neuron. Fast Pain: Sharp, stabbing, sudden pain signals carried along a myelinated neuron. Superficial Somatic Pain: Pain felt by receptors in the skin. Deep Somatic Pain: Pain felt in the muscles, joints, tendons, and fascia. Visceral Pain: Pain sensation from the receptors in the visceral organs. Referred Pain: Pain caused by an organ or specific area but felt in other areas served by the same spinal nerve.

Kinesthesia: The perception of body movements. Proprioceptors: Sensory receptors that can sense the location of body parts, their movements, & muscle tension without visual input. ◦ Mostly done through the hair cells in the inner ear responsible for balance & equilibrium. Muscle reflexes. Spindles: Involved in our stretch

Smell Olfaction: The sense of smell. ◦ Located in the nose – around 20 million receptors! Olfactory Receptors: First-order neurons whose dendrites contain the olfactory hairs (cilia) that respond to chemicals. ◦ Only sensory receptor in contact with the outside world. ◦ Receptors are replaced every few months. ◦ Supported by… Basal stem cells, Columnar supporting cells and. . Olfactory glands (aka Bowman’s glands): Produce the mucus that moistens the epithelium. Olfactory Epithelium: Contains most of the olfactory receptors. Odorant: A chemical responded to by the olfactory hairs.

Smell Olfactory Epithelium: Contains most of the olfactory receptors. Hyposomia: The gradual loss of smell as we get older.

Process of Smelling Odorants (chemicals) bind to the Olfactory Receptors. ◦ Odorants must be water-soluble, volatile, & reach the minimum threshold to be detected. Olfactory receptors send a signal to the Olfactory Nerves (Cranial nerve 1). Signal continues to the Olfactory Bulbs (firstorder neuron) & synapses with the Olfactory Tract (second-order neuron). Signal is then transmitted to the brain, through the cortex & on to the thalamus to be perceived.

Taste Gustation: The chemically-based sense of taste. 5 Primary Tastes: ◦ ◦ ◦ Sweet: Least sensitivity. Sour Bitter: Most sensitive. Salty Umami: Meaty or Savory flavor. Flavor: A combination of taste, smell, and texture. MOST of taste perception is driven by scent.

Taste Buds: Small organs made up of several components that allow us to perceive taste. ◦ Over 10, 000 total, mostly on the tongue. ◦ Can be located on the papillae.

Taste Components of a taste bud: ◦ Gustatory Receptor Cells: Around 50 total in each taste bud. ◦ Taste Pore: A small opening in the top of the taste bud. ◦ Gustatory Hair: Projects through the taste pore to help trap chemicals to analyze.

Taste Papillae (elevations on the tongue that give it a rough texture). 4 types: ◦ Vallate Papillae: Twelve large circular papillae forming an inverted V at the back of the tongue. Each contains a few hundred taste buds. ◦ Fungiform Papillae: Mushroom-shaped papillae. Each contains around give taste buds. Found all over the tongue.

Taste ◦ Foliate Papillae: Found in the trenches on the sides of the tongue. These taste buds degenerate rapidly. ◦ Filiform Papillae: Threadlike papillae found all over the tongue. Contain no taste buds. Contain tactile receptors to detect texture. Increase friction between the tongue and food & move food around in the oral cavity.

Taste Tastant: Any chemical that stimulates our taste. ◦ Each tastant stimulates the receptors in a different way. ◦ G-Proteins: A specific protein some tastants must be linked to in order to reach threshold. Facial Nerve (CN 7) and Glossopharyngeal Nerve (CN 11) serve the tongue. Vagus Nerve (CN 10) serves the throat and epiglottis.

Taste Pathway of Taste Perception: ◦ Taste bud to the appropriate cranial nerve ◦ Cranial nerve to the gustatory nucleus in the medulla oblongata ◦ Medulla oblongata to the thalamus ◦ Thalamus to the gustatory cortex

Interpreting Sensation Absolute Threshold Difference Threshold Sensory Adaptation

Depth Perception Visual Consistency Shape Consistency Size Consistency

Depth Perception Binocular Cues ◦ Retinal Disparity ◦ Convergence ◦ Accommodation ◦ Binocular Parallax ◦ Binocular Disparity

Depth Perception Monocular Cues ◦ Relative Size & Height ◦ Linear Perspective ◦ Detail ◦ Interposition Visual Cliff

Depth Perception Monocular Cues ◦ Texture Gradient ◦ Motion Parallax ◦ Shadow ◦ Familiar Size Visual Cliff

Movement Perception Induced Movement Stroboscopic

Optical Illusions

Optical Illusions Ames Room

Sleep Circadian Rhythms ◦ Jet Lag ◦ Graveyard Shifts ◦ Shift Work Two Theories of the Purpose of Sleep: ◦ Repair & Restoration Theory ◦ Energy-Conservation Theory Freud’s Theory – Reveal unconscious thoughts & motivations Contemporary Theory ◦ Activation-Synthesis Theory ◦ Neurocognitive Theory