Chapter 2: Neurobiology Review

Tripken Ch. 2 St. Guide Neuro Bio Neurobiology The Neuron What is a Neuron? A neuron is a nerve cell. The brain is made up of about 100 billion neurons. Soma (cell body): Contains nucleus and support systems Dendrites: Tree-like branches that receive information from other neurons Axon: Long fiber that passes info to other neurons Myelin: Fatty substance on some axons--speeds up neural transmissions Terminal Branches of Axon: Form junctions with other cells and contain synaptic vesicles Synaptic vesicles: sac-like structures that contain neurotransmitters Synapse: The tiny gap between the sending and receiving neurons Neural Networks: Clusters of neurons that work together and become strengthened with use. Neurons are similar to other cells in the body in some ways such as: 1. Neurons are surrounded by a membrane. 2. Neurons have a nucleus that contains genes. 3. Neurons contain cytoplasm, mitochondria and other "organelles". However, neurons differ from other cells in the body in some ways such as: 1. Neurons have specialized projections called dendrites and axons. Dendrites bring information to the cell body and axons take information away from the cell body. 2. Neurons communicate with each other through an electrochemical process. 3. Neurons form specialized connections called "synapses" and produce special chemicals called "neurotransmitters" that are released at the synapse. It has been estimated that there are 1 quadrillion synapses in the human brain. That's 1015 or 1,000,000,000,000,000 synapses! This is equal to about a half-billion synapses per cubic millimeter. (Statistic from Changeux, J-P. and Ricoeur, P., What Makes Us Think?, Princeton: Princeton University Press, 2000, p. 78) Page 1 Tripken SG 2 Neural Communication: Neurons communicate via an electrochemical process Electrical Process Resting Potential: Neuron is at rest and is said to be Polarized (-70 milivolts). The inside of the cell is more negative than the surrounding fluid. Action Potential: When stimulated at or above threshold, the cell becomes depolarized (+50 milivolts)as positively charged sodium ions rush into the cell. The neuron has now "fired". It is an all-or-nothing response. The cell then returns to its polarized state. Refractory Period: For 1/1000 of a second after firing, the cell cannot fire again. This is Somewhat like a camera flash recharging itself. Page 2 Tripken SG 2 Chemical Process 1. When the action potential reaches the terminal buttons on the ends of the terminal branches, it causes the synaptic vesicles to release neurotransmitters into the synapse. 2. The neurotransmitters then bind to receptor sites on the receiving neuron (like a key fitting into a lock). Some neurotransmitters are excitatory (create a new action potential) while others are inhibitory. Page 3 Tripken SG 2 3. After neurotransmitters have done their job, they may be destroyed by other chemicals released into the synapse. Or, reuptake may occur. Reuptake: Neurotransmitters are reabsorbed by the sending neuron and recycled for future use. Reputake of Neurotransmitters – re-absorption of neurotransmitters in the synaptic cleft is disallowed, allowing them to go to other areas of need. Blocking Neurotransmitter receptors – This is used when amounts of neurotransmitters needs to be lowered. Mimicking Neurotransmitters – Chemicals within the drugs are so similar to neurotransmitters, they are allowed into receptor areas in the postsynaptic neuron. How Do Drugs Work? For a drug to affect our behavior, it has to get into our bloodstream through ingestion (eating or drinking the substance); inhalation (heating or burning the substance and breathing the fumes); absorption through the mucous membranes of the mouth or nose; or injection with a hypodermic needle. Once in our bloodstream, psychoactive drugs influence our behavior by altering the functioning of the central nervous system (CNS). Then, over a period of hours, the influence of the drug gradually wears off as the liver produces enzymes that metabolize the drug. Drugs and Neurotransmitters Psychoactive drugs may be categorized according to their effects on the central nervous system. In this module we’ll consider two major groups: stimulants, which enhance the activity of the CNS, and depressants, which slow down or impair the activity of the CNS. We’ll also briefly discuss marijuana, which represents a third class of drugs: hallucinogens. Although psychoactive drugs influence the central nervous system in a variety of ways, in this module we’ll focus on the most important mechanism, namely the way that drugs alter the action of certain neurotransmitters at the synapses (spaces or junctions) between neurons. We’ll present a simplified version of the story, focusing especially on the neurotransmitter called dopamine. Understanding how drugs affect the action of dopamine is one of the keys to understanding drug addiction. It should also facilitate your understanding of how drugs affect other neurotransmitters. You’ll learn more about how these drugs work later in this module. Page 4 Tripken SG 2 Drugs that mimic or facilitate the action of a particular neurotransmitter are called agonists. Drugs that oppose or block the action of a particular neurotransmitter are called antagonists. Neurotransmitters Acetylcholine (Ach): Muscle movement, learning, and memory. An undersupply is involved in Alzheimer's disease. Dopamine: Involved in learning, attention, and emotion. An Excess dopamine is involved in schizophrenia. Serotonin: Affects mood, hunger, sleep, and arousal. An undersupply is linked to depression. Norepinephrine: Helps control alertness and arousal. An undersupply can lead to depression. An oversupply can lead to manic symptoms. GABA (gamma-aminobutytic acid): Major inhibitory neurotransmitter. An undersupply can lead to Page 5 Tripken SG 2 tremors, seizures, and insomnia. Glutamate: Major excitatory neurotransmitter; involved in memory. Oversupply can overstimulate the brain leading to migraines (this is why some people avoid MSG in food). Endorphins: natural opiate-like neurotransmitter linked to pain control and pleasure. Drugs and Neurotransmitters Agonists: Drugs that are so similar to a neurotransmitter that they can mimic its effects-or-they may block reuptake of a neurotransmitter. Antagonists: Drugs that inhibit a neurotransmitters release-or-they may occupy the receptor site on the receiving neuron, thus blocking the neurotransmitter form binding. How do drugs affect each of the above neurotransmitters? Examples: Drug Effects Alcohol – depressant; stimulates GABA receptors, leading to a reduction of anxiety and a loss of inhibitions. Marijuana – There is a specific receptor for THC (tetra-hydro-cannabinol) throughout the brain, including the hippocampus, cerebellum and limbic system. Hallucinogens – Increase the amount of dopamine in the auditory and visual cortex areas and inhibits flow to the prefrontal cortex with mescaline. With LSD (acid) and Psilocybin ('shrooms), seratonin receptors are blocked. LSD Psilocybin Mescaline Ecstasy Stimulants – Increase the production of dopamine as well as blocking its reuptake, sending it to other magical areas affecting sensation, mood, and motor skills. Amphetamines Cocaine Caffeine Nicotine Opiates – mimick the function of naturally produced endorphins in the body. It has its own receptors within the brain, and continual use can lead to a decrease in naturally produced endorphins, leading to severe withdrawal and addictions. It also causes constipation. Opium Morphine Heroin Abnormal Psychological Issues … how neurotransmitters are affected (SEE ABOVE IN THE CHART) Schizophrenia – ??? Anxiety disorders –??? Mood disorders (depression and bipolar) – ??? The Nervous System Page 6 Tripken SG 2 I. Central Nervous System a) Brain b) Spinal Cord II. Peripheral Nervous System a) Somatic (skeletal) nervous system: Voluntary behaviors b) Autonomic: Self-regulation of internal organs and glands. 1. sympathetic NS: arousing Pupils dilate, HR, BP, respiration increase, and digestive processes slow down. Fight or flight response. Sympathetic Nervous System – Increase in physiological reactions, usually part of fight-or-flight responses. 2. parasympathetic NS: calming-opposite of sympathetic nervous system response. Parasympathetic Nervous System – Brings it all back down. Three types of Neurons 1. Sensory (afferent) neurons of the peripheral NS take incoming sensory information to the spinal cord and brain / Afferent neurons – Send information from the body to the brain. 2. Motor (efferent) neurons take information from the spinal cord out to muscles and glands. Efferent neurons – Send information from the body to the brain. 3. Interneurons are neurons in the central NS (brain & spinal cord). They communicate with each other and connect the sensory and motor neurons. Page 7 Tripken SG 2 The Simple Reflex A simple reflex involves afferent (sensory) neurons carrying sensory information to the spinal cord. Interneurons connect the afferent neurons to the efferent (motor) neurons. A reflex does not involve the brain. Studying the Brain-Phineas Gage Lesions: Destruction of brain tissue EEG (electroencephalogram): amplified recordings of brain wave activity. CT (computerized tomography) scan: X-ray photos of slices of the brain. CT (or CAT) scans show structures within the brain but not functions of the brain. PET (positron emission tomography): visual display of brain activity that detects where a radioactive form of glucose is being used while the brain performs certain tasks. MRI (magnetic resonance imaging): technique that uses magnetic fields and radio waves to see structures within the brain. fMRI (functional MRI): allows us to see where oxygen is being used in the brain while various tasks are being performed. Page 8 Tripken SG 2 Structure and Function of the Brain Brainstem: Oldest area of the brain. Also called the reptilian brain. 1. Medulla: the base of the brainstem; controls heartbeat and breathing. 2. Reticular Formation: A neural network within the brainstem; important in arousal including sleep. Thalamus: Sits on top of the brainstem; received all incoming sensory information (except smell) and sends it to the appropriate part of the brain for further processing. Cerebellum: The "little brain" attached to the back of the brainstem; it helps coordinate voluntary movement and balance. The Limbic System: A doughnut-shaped structure between the brainstem and the cerebral hemispheres. It is considered the "seat of emotion" and is also involved in motivated behavior like eating, drinking, and sex. 1. Amygdala: Involved in rage and fear as well as emotional memories. 2. Hippocampus: Involved in memory 3: Hypothalamus: Involved in eating, drinking, and sexual behavior. It also controls the endocrine (hormonal system) via the pituitary gland. It is sometimes referred to as "the pleasure center" of the brain. Cerebral Cortex: The intricate fabric of interconnected neural cells that covers the cerebral hemispheres. The ultimate information-processing center of the brain. Lobes of the Brain Page 9 Tripken SG 2 Frontal Lobes: Contain the motor cortex which control voluntary movement. In the LEFT frontal lobe is Broca's Area which controls our ability to speak. Parietal Lobes: Contain the somatosensory cortex which registers bodily sensations (touch). Temporal Lobes: Contain the primary auditory cortex (audition) and areas for the senses of smell (olfaction) and taste (gustatory sense). The LEFT temporal lobe contains Wernicke's Area which control language comprehension and expression. Occipital Lobes: Contains the Primary Visual Cortex. Association Areas: Areas of the cortex not involved in sensory or motor functions. They are involved in higher mental functions such as learning, remembering, thinking, planning, and language. About 75-80% of the brain is composed of association areas. Hemispheres of the Brain Virtually all activities require BOTH hemispheres. However, the Left Hemisphere receives sensory information from the right side of the body and controls movement of the right side of the body. It is also involved in language, science, math, etc. The Right Hemisphere receives sensory information from the left side of the body and control movement of the right side of the body. It is involved in music, artistic ability, and spatial skills. Split Brain Research: Review information in your text and check it out: Page 10 Tripken SG 2 ENDOCRINE SYSTEM: Hypothalamus: Controls pituitary gland Pituitary: Secretes growth hormone and many other hormones that affect other glands. Thyroid: Affects metabolism Parathyroids: Regulate calcium levels in the blood Adrenal Glands: Secrete the hormones epinephrine and norepinephrine which trigger the "fight or flight" response. Pancreas: Regulates glucose levels in the blood through the release of insulin. Ovaries and Testes: Secrete female and male sex hormones. Endocrine system – system of all the glands and their chemical messages taken together Hormones – chemical regulators that control bodily processes such as emotional responses, growth, and sexuality Pituitary gland – the master gland of the body that activates other glands and controls the growth hormone Growth hormone – hormone that regulates the growth process Thyroid gland – controls and regulates the speed of bodily processes called metabolism Metabolism – the speed at which the body operates of the speed at which it uses up energy Adrenal glands – glands that release the hormone that causes excitement in order to prepare the body for an emergency Adrenaline – chemical that prepares the body for emergency activity by increasing blood pressure, breathing rate, and energy level Page 11 Tripken SG 2 Reviewing the Biological Processes of the Brain Big Picture CNS PNS Somatic Nervous System Autonomic Nervous System Sympathetic Nervous System Parasympathetic Nervous System Function Central Nervous System – brain and spinal cord Peripheral Nervous System – any neurons that extend past CNS The muscles and functions you can control Regulates glands, blood vessels and flow, internal organs Breaking it down Medulla BRAIN FUNCTIONS Regulates breathing and heart rate – hanging a person works b/c (if done correctly) it breaks this in half Involved in sleeping, waking and dreaming The “lesser brain” coordinates balance and coordination Relays all sensory information to specific perception areas of the brain, with the exception of smell Part of the “old brain” – it controls survival elements such as hunger, thirst, emotion, sex drive and reproduction. Works in conjunction with the pituitary gland. Secretes hormones as “directed” by the hypothalamus to regulate the body during a “primal” function Instantaneously evaluates sensory information from the thalamus and determines its emotional importance – helps to decide if something needs to be addressed immediately; the “fight or flight” brain section (PART OF THE LIMBIC SYSTEM) The gateway to all memory functions; also works with the reticular activating system to relate sensory input to what the brain already “knows” about it (PART OF THE LIMBIC SYSTEM) Pons Cerebellum Thalamus Hypothalamus Pituitary Gland Amygdala Hippocampus THE LOBES Occipital lobe Parietal lobe Temporal lobe Frontal lobe Corpus Callosum Left side of brain Right side of brain Roger Sperry Prepares the body for stress; builds energy/adrenaline Helps to bring the body back to a normal state Lower back of the brain; contains the visual cortex Top of the brain; contains the somatosensory cortex, which receives all info about pressure, pain, heat, etc., from the body. Sides of the brain; involved in memory storage, perception and emotion; contains the auditory cortex as well as Wernicke’s area, which processes language comprehension. Front of the brain (duh) and contains the motor cortex, which controls over 600 muscles all over the body. Also contains Broca’s area, which allows us to know how to speak. It also helps us think creatively and think rationally; dopamine that is supposed to reach this lobe is shut off during schizophrenia, making it impossible for the victim to tell what is real and what is hallucinatory. Serves as the network between the left/right sides of the brain. Rational and analytical thought Intuitive, creative, holistic thought Most well known split-brain psychologist; worked with cats and severed their corpus callosum to see what would happen Page 12 Tripken NEURONS Dendrites Cell body Axon Mylein sheath Synaptic cleft Plasticity Action potential NEUROTRANSMITTER S Serotonin Dopamine Acetycholine GABA Norepinephrine Epinephrine SEEING THE BRAIN CAT MRI PET SG 2 Information receptors Determines how/when a neuron is supposed to fire and emit a signal The “tail” of the neuron; sends info away from the cell body Made up of several glial cells, insulates the axon to make sure no random signals get in and no signals slip out The areas between the synaptic end bulbs and dendrites of another neuron where neurotransmitters are released and taken. The brain’s ability to recover from brain/nerve damage by possibly creating new pathways for previous messages This allows messages to flow from neuron to neuron as an electrical charge is created when positively charged sodium ions flow into a neuron and flows out as positively charged potassium charges. Affects appetite, perception, temperature regulation, pain suppression and mood – the neurotransmitter that is inhibited during DEPRESSION; increased by stimulants. Affects voluntary movement, learning, memory, emotion – the neurotransmitter that is overactive during SCHIZOPHRENIA; can be replicated by certain psychoactive drugs like THC (marijuana); also in low amounts for Parkinson’s victims Affects cognitition, muscle movement, memory and emotion An inhibitor; it is unable to reuptake into neurons when depressants such as alcohol are present in the blood system Increases heart rate, involved in dreaming, sleeping and emotion Secreted by the endocrine system; basically, it is adrenaline Computerized Axial Tomography – a cross-section shot Magnetic Resonance Imaging – picks up iron in the blood to show what parts of the brain are active Positron Emission Tomography – radioactive glucose injections show up in specific parts of the brain during activity or during abnormal behavior Conditions we’ve discussed are marked with an **(the rest you must “get” by the end of this course) … a potential essay question may ask you to take one of these and analyze their cause from different perspectives (biological, cognitive, etc.) Autism ** Alzheimer’s Anorexia Anxiety Attention Deficit Hyperactivity Disorder Aphasia Bipolar Depression Page 13 Tripken SG 2 Bulimia ** Depression Dissociative disorders (amnesia, multiple personality, fugue) Down syndrome Fetal Alcohol Syndrome Gender Identity Disorder Phobias Posttraumatic Stress Disorder Seasonal Affective Disorder ** Schizophrenia (esp. catatonic and paranoid) Somatoform disorders RETICULAR FORMATION (ACTIVATION) -- Deals with arousing the forebrain (deals with reasoning, sleeping, emotions) The info in this chart is important for you to read over…….it is valuable but you DO NOT need to commit it to memory!! BIOLOGICAL BASES OF BEHAVIOR THE HUMAN BRAIN The influence of biology (sometimes called the neuroscience or biopsychological perspective) is growing. Some researchers predict that someday psychology will be a specialty within the field of biology. The human brain consists of three major divisions; hindbrain, midbrain, and forebrain Major Division Subdivision Structures Neocortex; Basal Ganglia; Amygdala; Hippocampus; Telencephalon Lateral Ventricles Prosencephalon (Forebrain) Thalamus; Hypothalamus; Epithalamus; Third Diencephalon Ventricle Mesencephalon Mesencephalon Tectum; Tegmentum; Cerebral Aqueduct (Midbrain) Cerebellum; Pons; Fourth Ventricle Rhombencephalon Metencephalon (Hindbrain) Myelencephalon Medulla Oblongata; Fourth Ventricle Brain Structure 1. Hindbrain- structures in the top part of the spinal cord, controls basic biological functions that keep us alive. a. Medulla- controls blood pressure, heart rate, and breathing b. Pons- connects the hindbrain with the mid and forebrain, also involved in the control of facial expressions c. Cerebellum- portion of the lower brain that coordinates and organizes bodily movements for balance and accuracy. 2 Midbrain-between the hind and forebrain, coordinates simple movements with sensory information. 3 Forebrain- controls what we think of as thought and reason. a. Thalamus- portion of the lower brain that functions primarily as a central relay station for incoming and outgoing messages from the body to the brain and the brain to the body b. Hypothalamus- portion of the lower brain that regulates basic needs (hunger, thirst) and emotions such as pleasure, fear, rage, and sexuality c. Amygdala and Hippocampus- two arms surrounding the thalamus, important in how we process and perceive memory and emotion NOTE: The three parts above are grouped together and called the limbic system because they all deal with aspects of emotion and memory. Page 14 Tripken SG 2 Comparative Brain sizes: How big is the brain? How much does the brain weigh? The adult human brain weighs between 1300 g and 1400 g (about 3 lbs). A newborn human brain weighs between 350 and 400 g. For comparison: elephant brain = 6,000 g chimpanzee brain = 420 g rhesus monkey brain = 95 g beagle dog brain = 72 g cat brain = 30 g rat brain = 2 g Ways of studying the brain: Accidents, Lesions, Electroencephalogram, Computerized axial tomography, Magnetic resonance imaging (MRI), Positron emission tomography, Functional MRI, Neuroanatomy Page 15 Tripken Chapter 2 Study Guide and Answers SG 2 A) B) C) D) ___ 1. Which of the following was a major problem with phrenology? It was “ahead of its time” and no one believed it could be true. The brain is not neatly organized into structures that correspond to our categories of behavior. The brains of humans and animals are much less similar than the theory implied. All of the above were problems with phrenology. A) B) ___ 2. A biological psychologist would be more likely to study: how you learn to express emotions. how to help people overcome emotional disorders. C) life-span changes in the expression of emotion. D) the chemical changes that accompany emotions. ___ 3. Dr. Hernandez is studying neurotransmitter abnormalities in depressed patients. She would most likely describe herself as a: A) personality psychologist. B) phrenologist. C) psychoanalyst. D) biological psychologist. ___ 4. The axons of certain neurons are covered by a layer of fatty tissue that helps speed neural transmission. This tissue is: A) the glia. B) the myelin sheath. C) acetylcholine. D) an endorphin. A) B) ___ 5. The myelin sheath that is on some neurons: increases the speed of neural transmission. slows neural transmission. A) B) C) D) ___ 6. During an action potential, the electrical state of the axon becomes: polarized, as positively charged atoms are admitted. polarized, as negatively charged atoms are admitted. depolarized, as positively charged atoms are admitted. depolarized, as negatively charged atoms are admitted. A) B) C) D) ___ 7. In a resting state, the axon is: depolarized, with mostly negatively charged ions outside and positively charged ions inside. depolarized, with mostly positively charged ions outside and negatively charged ions inside. polarized, with mostly negatively charged ions outside and positively charged ions inside. polarized, with mostly positively charged ions outside and negatively charged ions inside. A) B) ___ 8. Which is the correct sequence in the transmission of a neural impulse? axon  dendrite  cell body  synapse C) synapse  axon  dendrite  cell body dendrite  axon  cell body  synapse D) dendrite  cell body  axon  synapse A) B) ___ 9. A neuron will generate action potentials more often when it: remains below its threshold. C) receives more excitatory than inhibitory inputs. receives an excitatory input. D) is stimulated by a neurotransmitter. C) regulates the release of neurotransmitters. D) does a. and c. ___ 10. A strong stimulus can increase the: A) speed of the impulse the neuron fires. B) intensity of the impulse the neuron fires. C) number of times the neuron fires. D) threshold that must be reached before the neuron fires. ___ 11. Several shy neurons send an inhibitory message to neighboring neuron Joni. At the same time, a larger group of party-going neurons send Joni excitatory messages. What will Joni do? A) fire, assuming that her threshold has been reached C) enter a refractory period B) not fire, even if her threshold has been reached D) become hyperpolarized ___ 12. Since Malcolm has been taking a drug prescribed by his doctor, he no longer enjoys the little pleasures of life, such as eating and drinking. His doctor explains that this is because the drug: A) triggers release of dopamine. C) triggers release of ACh. B) inhibits release of dopamine. D) inhibits release of ACh. ___ 13. The neurotransmitter acetylcholine (ACh) is most likely to be found: A) at the junction between sensory neurons and muscle fibers. Page 16 Tripken B) C) D) SG 2 at the junction between motor neurons and muscle fibers. at junctions between interneurons. in all of the above locations. ___ 14. Melissa has just completed running a marathon. She is so elated that she feels little fatigue or discomfort. Her lack of pain is probably the result of the release of: A) ACh. B) endorphins. C) dopamine. D) norepinephrine. ___ 15. The pain of heroin withdrawal may be attributable to the fact that: A) under the influence of heroin the brain ceases production of endorphins. B) under the influence of heroin the brain ceases production of all neurotransmitters. C) during heroin withdrawal the brain's production of all neurotransmitters is greatly increased. D) heroin destroys endorphin receptors in the brain. ___ 16. The effect of a drug that is an agonist is to: A) cause the brain to stop producing certain neurotransmitters. B) mimic a particular neurotransmitter. C) block a particular neurotransmitter. D) disrupt a neuron's all-or-none firing pattern. ___ 17. Parkinson's disease involves: A) the death of nerve cells that produce a vital neurotransmitter. B) impaired function in the right hemisphere only. C) impaired function in the left hemisphere only. D) excess production of the neurotransmitters dopamine and acetylcholine. ___ 18. Heartbeat, digestion, and other self-regulating bodily functions are governed by the: A) voluntary nervous system. B) autonomic nervous system. C) sympathetic division of the autonomic nervous system. D) somatic nervous system. ___ 19. Voluntary movements, such as writing with a pencil, are directed by the: A) sympathetic nervous system. C) parasympathetic nervous system. B) somatic nervous system. D) autonomic nervous system. ___ 20. Following Jayshree's near-fatal car accident, her physician noticed that the pupillary reflex of her eyes was abnormal. This may indicate that Jayshree's ________ was damaged in the accident. A) occipital cortex B) autonomic nervous system C) left temporal lobe D) cerebellum ___ 21. Your brother has been taking prescription medicine and experiencing a number of unpleasant side effects, including unusually rapid heartbeat and excessive perspiration. It is likely that the medicine is exaggerating activity in the: A) reticular formation. B) sympathetic nervous system. C) parasympathetic nervous system. D) amygdala. ___ 22. When Sandy scalded her toe in a tub of hot water, the pain message was carried to her spinal cord by the ________ nervous system. A) somatic B) sympathetic C) parasympathetic D) central ___ 23. Which is the correct sequence in the transmission of a simple reflex? A) sensory neuron  interneuron  sensory neuron C) sensory neuron  interneuron  motor neuron B) interneuron  motor neuron  sensory neuron D) interneuron  sensory neuron  motor neuron ___ 24. Which of the following are/is governed by the simplest neural pathways? A) emotions B) physiological drives, such as hunger C) reflexes D) movements, such as walking ___ 25. You are able to pull your hand quickly away from hot water before pain is felt because: A) movement of the hand is a reflex that involves intervention of the spinal cord only. B) movement of the hand does not require intervention by the central nervous system. C) the brain reacts quickly to prevent severe injury. D) the autonomic division of the peripheral nervous system intervenes to speed contraction of the muscles of the hand. ___ 26. In the brain, learning occurs as experience strengthens certain connections in cell work groups called: A) action potentials. B) neural networks. C) endocrine systems. D) dendrites. Page 17 Tripken SG 2 ___ 27. Chemical messengers produced by endocrine glands are called: A) agonists. B) neurotransmitters. C) hormones. D) enzymes. ___ 28. I am a relatively slow-acting (but long-lasting) chemical messenger carried throughout the body by the bloodstream. What am I? A) a hormone B) a neurotransmitter C) acetylcholine D) dopamine ___ 29. The gland that regulates body growth is the: A) adrenal. B) thyroid. C) hypothalamus. D) pituitary. ___ 30. Epinephrine and norepinephrine are ________ that are released by the ________ gland. A) neurotransmitters; pituitary B) hormones; pituitary C) neurotransmitters; thyroid D) hormones; adrenal ___ 31. A bodybuilder friend suddenly seems to have grown several inches in height. You suspect that your friend's growth spurt has occurred because he has been using drugs that affect the: A) pituitary gland. B) thalamus. C) adrenal glands. D) medulla. ___ 32. The brain research technique that involves monitoring the brain's usage of glucose is called (in abbreviated form) the: A) PET scan. B) fMRI. C) EEG. D) MRI. ___ 33. The technique that uses magnetic fields and radio waves to produce computer images of structures within the brain is called: A) the EEG. B) a lesion. C) a PET scan. D) MRI. ___ 34. In primitive vertebrate animals, the brain primarily regulates ________; in lower mammals, the brain enables ________. A) emotion; memory B) memory; emotion C) survival functions; emotion D) reproduction; emotion ___ 35. The part of the human brain that is most like that of a fish is the: A) cortex. B) limbic system. C) brainstem. D) right hemisphere. ___ 36. Following a head injury, a person has ongoing difficulties staying awake. Most likely, the damage occurred to the: A) thalamus. B) corpus callosum. C) reticular formation. D) cerebellum. ___ 37. Moruzzi and Magoun caused a cat to lapse into a coma by severing neural connections between the cortex and the: A) reticular formation. B) hypothalamus. C) thalamus. D) cerebellum. ___ 38. Jessica experienced difficulty keeping her balance after receiving a blow to the back of her head. It is likely that she injured her: A) medulla. B) thalamus. C) hypothalamus. D) cerebellum. ___ 39. Dr. Frankenstein made a mistake during neurosurgery on his monster. After the operation, the monster “saw” with his ears and “heard” with his eyes. It is likely that Dr. Frankenstein “rewired” neural connections in the monster's: A) hypothalamus. B) cerebellum. C) amygdala. D) thalamus. ___ 40. Though there is no single “control center” for emotions, their regulation is primarily attributed to the brain region known as the: A) limbic system. B) reticular formation. C) brainstem. D) cerebellum. ___ 41. A scientist from another planet wishes to study the simplest brain mechanisms underlying emotion and memory. You recommend that the scientist study the: A) brainstem of a frog. B) limbic system of a dog. C) cortex of a monkey. D) cortex of a human. ___ 42. If Dr. Rogers wishes to conduct an experiment on the effects of stimulating the reward centers of a rat's brain, he should insert an electrode into the: A) thalamus. B) sensory cortex. C) hypothalamus. D) corpus callosum. ___ 43. Beginning at the front of the brain and moving toward the back of the head, then down the skull and back around to the front, which of the following is the correct order of the cortical regions? A) occipital lobe; temporal lobe; parietal lobe; frontal lobe C) frontal lobe; occipital lobe; temporal lobe; parietal lobe B) temporal lobe; frontal lobe; parietal lobe; occipital lobe D) frontal lobe; parietal lobe; occipital lobe; temporal lobe ___ 44. The visual cortex is located in the: Page 18 Tripken SG 2 A) occipital lobe. B) temporal lobe. C) frontal lobe. D) parietal lobe. ___ 45. Raccoons have much more precise control of their paws than dogs do. You would expect that raccoons have more cortical space dedicated to “paw control” in the ________of their brains. A) frontal lobes B) parietal lobes C) temporal lobes D) occipital lobes ___ 46. Research has found that the amount of representation in the motor cortex reflects the: A) size of the body parts. B) degree of precise control required by each of the parts. C) sensitivity of the body region. D) area of the occipital lobe being stimulated by the environment. ___ 47. In order to pinpoint the location of a tumor, a neurosurgeon electrically stimulated parts of the patient's sensory cortex. If the patient was conscious during the procedure, which of the following was probably experienced? A) “hearing” faint sounds C) movement of the arms or legs B) “seeing” random visual patterns D) a sense of having the skin touched ___ 48. Cortical areas that are not primarily concerned with sensory, motor, or language functions are: A) called projection areas. C) located mostly in the parietal lobe. B) called association areas. D) located mostly in the temporal lobe. ___ 49. The increasing complexity of animals' behavior was accompanied by a(n): A) increase in the size of the brainstem. C) increase in the size of the frontal lobes. B) decrease in the ratio of brain to body weight. D) increase in the amount of association area. ___ 50. Following a nail gun wound to his head, Jack became more uninhibited, irritable, dishonest, and profane. It is likely that his personality change was the result of injury to his: A) parietal lobe. B) temporal lobe. C) occipital lobe. D) frontal lobe. ___ 51. Damage to ________ will usually cause a person to lose the ability to comprehend language. A) the angular gyrus B) Broca's area C) Wernicke's area D) frontal lobe association areas ___ 52. Three-year-old Marco suffered damage to the speech area of the brain's left hemisphere when he fell from a swing. Research suggests that: A) he will never speak again. B) his motor abilities may improve so that he can easily use sign language. C) his right hemisphere may take over much of the language function. D) his earlier experience with speech may enable him to continue speaking. ___ 53. The nerve fibers that enable communication between the right and left cerebral hemispheres and that have been severed in split-brain patients form a structure called the: A) reticular formation. B) association areas. C) corpus callosum. D) parietal lobes. ___ 54. A split-brain patient has a picture of a knife flashed to her left hemisphere and that of a fork to her right hemisphere. She will be able to: A) identify the fork using her left hand. C) identify a knife using either hand. B) identify a knife using her left hand. D) identify a fork using either hand. ___ 55. Dr. Johnson briefly flashed a picture of a key in the right visual field of a split-brain patient. The patient could probably: A) verbally report that a key was seen. C) draw a picture of a key using the left hand. B) write the word key using the left hand. D) do none of the above. ___ 56. (Thinking Critically) Based on research, which of the following seems true about the specialized functions of the right and left hemispheres? A) They are more clear-cut in men than in women. B) They are more clear-cut in women than in men. C) Most complex tasks emerge from the activity of one or the other hemisphere. D) Most complex activities emerge from the integrated activity of both hemispheres. ___ 57. Which of the following is typically controlled by the right hemisphere? A) language B) learned voluntary movements C) arithmetic reasoning D) perceptual tasks Page 19 Tripken SG 2 ___ 58. Anton is applying for a technician's job with a neurosurgeon. In trying to impress his potential employer with his knowledge of the brain, he says, “After my father's stroke I knew immediately that the blood clot had affected his left cerebral hemisphere because he no longer recognized a picture of his friend.” Should Anton be hired? A) Yes. Anton obviously understands brain structure and function. B) No. The right hemisphere, not the left, specializes in picture recognition. C) Yes. Although blood clots never form in the left hemisphere, Anton should be rewarded for recognizing the left hemisphere's role in picture recognition. D) No. Blood clots never form in the left hemisphere, and the right hemisphere is more involved than the left in recognizing pictures. ___ 59. Which of the following is typically controlled by the left hemisphere? A) spatial reasoning B) word recognition C) the left side of the body D) perceptual skills ___ 60. Which of the following is not true regarding brain organization and handedness? A) If a person has a left-handed identical twin, odds are that he or she will also be left-handed. B) Right-handedness is far more common than left-handedness throughout the world. C) On average, right-handers live longer than left-handers. D) Left-handers are more common than usual among people with reading disabilities. Page 20 Tripken SG 2 Answer Key 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. B D D B A C D D C C A B B B A B A B B B B A C C A B C A D D A A D C C C A D D A B C D A A B D B D D C C C A A D D B B A Page 21 Tripken SG 2 Page 22