chapter 3: biopsychology sw - cnx

Chapter 3: Biopsychology SW

By:Stephen E. Wisecarver

Chapter 3: Biopsychology SW

By:Stephen E. Wisecarver

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Table of Contents

1 3.0 Introduction to Biopsychology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.1 Human Genetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 3.2 Parts of the Nervous System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 3.3 The Brain and Spinal Cord . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 3.4 The Endocrine System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Attributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

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Chapter 1

3.0 Introduction to Biopsychology1

Figure 1.1: Di�erent brain imaging techniques provide scientists with insight into di�erent aspectsof how the human brain functions. Left to right, PET scan (positron emission tomography), CT scan(computed tomography), and fMRI (functional magnetic resonance imaging) are three types of scans.(credit �left�: modi�cation of work by Health and Human Services Department, National Institutes ofHealth; credit �center": modi�cation of work by "Aceofhearts1968"/Wikimedia Commons; credit �right�:modi�cation of work by Kim J, Matthews NL, Park S.)

Have you ever taken a device apart to �nd out how it works? Many of us have done so, whether to attempt arepair or simply to satisfy our curiosity. A device's internal workings are often distinct from its user interfaceon the outside. For example, we don't think about microchips and circuits when we turn up the volume ona mobile phone; instead, we think about getting the volume just right. Similarly, the inner workings of thehuman body are often distinct from the external expression of those workings. It is the job of psychologists to�nd the connection between these�for example, to �gure out how the �rings of millions of neurons becomea thought.

1This content is available online at <http://cnx.org/content/m55747/1.1/>.


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2 CHAPTER 1. 3.0 INTRODUCTION TO BIOPSYCHOLOGY

This chapter strives to explain the biological mechanisms that underlie behavior. These physiologicaland anatomical foundations are the basis for many areas of psychology. In this chapter, you will learn howgenetics in�uence both physiological and psychological traits. You will become familiar with the structureand function of the nervous system. And, �nally, you will learn how the nervous system interacts with theendocrine system.

1.1 References

Arnst, C. (2003, November). Commentary: Getting rational about health-care rationing. Bloomberg

Businessweek Magazine. Retrieved from http://www.businessweek.com/stories/2003-11-16/commentary-getting-rational-about-health-care-rationing

Berridge, K. C., & Robinson, T. E. (1998). What is the role of dopamine in reward: Hedonic impact,reward learning, or incentive salience? Brain Research Reviews, 28, 309�369.

Chandola, T., Brunner, E., & Marmot, M. (2006). Chronic stress at work and the metabolic syndrome:A prospective study. BMJ, 332, 521�524.

Comings, D. E., Gonzales, N., Saucier, G., Johnson, J. P., & MacMurray, J. P. (2000). The DRD4 geneand the spiritual transcendence scale of the character temperament index. Psychiatric Genetics, 10, 185�189.

Confer, J. C., Easton, J. A., Fleischman, D. S., Goetz, C. D., Lewis, D. M. G, Perilloux, C., & Buss,D. M. (2010). Evolutionary psychology: Controversies, questions, prospects, and limitations. American

Psychologist, 65, 110�126.Gaines, C. (2013, August). An A-Rod suspension would save the Yankees as much as $37.5 million in

2014 alone. Business Insider. Retrieved from http://www.businessinsider.com/an-a-rod-suspension-would-save-the-yankees-as-much-as-375-million-in-2014-2013-8

Gardner, E. L. (2011). Addiction and brain reward and antireward pathways. Advances in PsychosomaticMedicine, 30, 22�60.

George, O., Le Moal, M., & Koob, G. F. (2012). Allostasis and addiction: Role of the dopamine andcorticotropin-releasing factor systems. Physiology & Behavior, 106, 58�64.

Glaser, R., & Kiecolt-Glaser, J. K. (2005). Stress-induced immune dysfunction: Implications for health.Nature Reviews Immunology, 5, 243�251.

Gong, L., Parikh, S., Rosenthal, P. J., & Greenhouse, B. (2013). Biochemical and immunological mech-anisms by which sickle cell trait protects against malaria. Malaria Journal. Advance online publication.doi:10.1186/1475-2875-12-317

Hardt, O., Einarsson, E. Ö., & Nader, K. (2010). A bridge over troubled water: Reconsolidation as alink between cognitive and neuroscienti�c memory research traditions. Annual Review of Psychology, 61,141�167.

Macmillan, M. (1999). The Phineas Gage Information Page. Retrieved fromhttp://www.uakron.edu/gage

March, J. S., Silva, S., Petrycki, S., Curry, J., Wells, K., Fairbank, J., . . . Severe, J. (2007). The treatmentfor adolescents with depression study (TADS): Long-term e�ectiveness and safety outcomes. Arch Gen

Psychiatry, 64, 1132�1143.Mustanski, B. S., DuPree, M. G., Nievergelt, C. M., Bocklandt, S., Schork, N. J., & Hamer, D. H. (2005).

A genome wide scan of male sexual orientation. Human Genetics, 116, 272�278.National Institute on Drug Abuse. (2001, July). Anabolic steroid abuse: What are

the health consequences of steroid abuse? National Institutes of Health. Retrieved fromhttp://www.drugabuse.gov/publications/research-reports/anabolic-steroid-abuse/what-are-health-consequences-steroid-abuse

Squire, L. R. (2009). The legacy of patient H. M. for neuroscience. Neuron, 61, 6�9.Tienari, P., Wynne, L. C., Sorri, A., et al. (2004). Genotype�environment interaction in schizophrenia

spectrum disorder: long-term follow-up study of Finnish adoptees. British Journal of Psychiatry, 184, 216�222.


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University of Utah Genetic Science Learning Center. (n.d.). What are genetic disorders? Retrieved fromhttp://learn.genetics.utah.edu/content/disorders/whataregd/


4 CHAPTER 1. 3.0 INTRODUCTION TO BIOPSYCHOLOGY


Chapter 2

3.1 Human Genetics1

Psychological researchers study genetics in order to better understand the biological basis that contributes tocertain behaviors. While all humans share certain biological mechanisms, we are each unique. And while ourbodies have many of the same parts�brains and hormones and cells with genetic codes�these are expressedin a wide variety of behaviors, thoughts, and reactions.

Why do two people infected by the same disease have di�erent outcomes: one surviving and one succumb-ing to the ailment? How are genetic diseases passed through family lines? Are there genetic components topsychological disorders, such as depression or schizophrenia? To what extent might there be a psychologicalbasis to health conditions such as childhood obesity?

This is precisely the situation that Charles Darwin describes in the theory of evolution by naturalselection (). In simple terms, the theory states that organisms that are better suited for their environmentwill survive and reproduce, while those that are poorly suited for their environment will die o�. In ourexample, we can see that as a carrier, Luwi's mutation is highly adaptive in her African homeland; however,if she resided in the United States (where malaria is much less common), her mutation could prove costly�with a high probability of the disease in her descendants and minor health problems of her own.

2.1 Genetic Variation

Genetic variation, the genetic di�erence between individuals, is what contributes to a species' adaptation toits environment. In humans, genetic variation begins with an egg, about 100 million sperm, and fertilization.Fertile women ovulate roughly once per month, releasing an egg from follicles in the ovary. The egg travels,via the fallopian tube, from the ovary to the uterus, where it may be fertilized by a sperm.

The egg and the sperm each contain 23 chromosomes. Chromosomes are long strings of genetic materialknown as deoxyribonucleic acid (DNA). DNA is a helix-shaped molecule made up of nucleotide basepairs. In each chromosome, sequences of DNA make up genes that control or partially control a numberof visible characteristics, known as traits, such as eye color, hair color, and so on. A single gene may havemultiple possible variations, or alleles. An allele is a speci�c version of a gene. So, a given gene may codefor the trait of hair color, and the di�erent alleles of that gene a�ect which hair color an individual has.

When a sperm and egg fuse, their 23 chromosomes pair up and create a zygote with 23 pairs of chromo-somes. Therefore, each parent contributes half the genetic information carried by the o�spring; the resultingphysical characteristics of the o�spring (called the phenotype) are determined by the interaction of geneticmaterial supplied by the parents (called the genotype). A person's genotype is the genetic makeup of thatindividual. Phenotype, on the other hand, refers to the individual's inherited physical characteristics ().

Most traits are controlled by multiple genes, but some traits are controlled by one gene. A characteristiclike cleft chin, for example, is in�uenced by a single gene from each parent. In this example, we will callthe gene for cleft chin �B,� and the gene for smooth chin �b.� Cleft chin is a dominant trait, which means



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6 CHAPTER 2. 3.1 HUMAN GENETICS

that having the dominant allele either from one parent (Bb) or both parents (BB) will always result in thephenotype associated with the dominant allele. When someone has two copies of the same allele, they aresaid to be homozygous for that allele. When someone has a combination of alleles for a given gene, theyare said to be heterozygous. For example, smooth chin is a recessive trait, which means that an individualwill only display the smooth chin phenotype if they are homozygous for that recessive allele (bb).

Imagine that a woman with a cleft chin mates with a man with a smooth chin. What type of chinwill their child have? The answer to that depends on which alleles each parent carries. If the woman ishomozygous for cleft chin (BB), her o�spring will always have cleft chin. It gets a little more complicated,however, if the mother is heterozygous for this gene (Bb). Since the father has a smooth chin�thereforehomozygous for the recessive allele (bb)�we can expect the o�spring to have a 50% chance of having a cleftchin and a 50% chance of having a smooth chin (Figure 2.1).

Figure 2.1: (a) A Punnett square is a tool used to predict how genes will interact in the productionof o�spring. The capital B represents the dominant allele, and the lowercase b represents the recessiveallele. In the example of the cleft chin, where B is cleft chin (dominant allele), wherever a pair containsthe dominant allele, B, you can expect a cleft chin phenotype. You can expect a smooth chin phenotypeonly when there are two copies of the recessive allele, bb. (b) A cleft chin, shown here, is an inheritedtrait.


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Figure 2.2: In this Punnett square, N represents the normal allele, and p represents the recessiveallele that is associated with PKU. If two individuals mate who are both heterozygous for the alleleassociated with PKU, their o�spring have a 25% chance of expressing the PKU phenotype.

Where do harmful genes that contribute to diseases like PKU come from? Gene mutations provide onesource of harmful genes. A mutation is a sudden, permanent change in a gene. While many mutations canbe harmful or lethal, once in a while, a mutation bene�ts an individual by giving that person an advantageover those who do not have the mutation. Recall that the theory of evolution asserts that individuals bestadapted to their particular environments are more likely to reproduce and pass on their genes to futuregenerations. In order for this process to occur, there must be competition�more technically, there must



be variability in genes (and resultant traits) that allow for variation in adaptability to the environment.If a population consisted of identical individuals, then any dramatic changes in the environment woulda�ect everyone in the same way, and there would be no variation in selection. In contrast, diversity ingenes and associated traits allows some individuals to perform slightly better than others when faced withenvironmental change. This creates a distinct advantage for individuals best suited for their environmentsin terms of successful reproduction and genetic transmission.

2.2 Gene-Environment Interactions

Genes do not exist in a vacuum. Although we are all biological organisms, we also exist in an environment thatis incredibly important in determining not only when and how our genes express themselves, but also in whatcombination. Each of us represents a unique interaction between our genetic makeup and our environment;range of reaction is one way to describe this interaction. Range of reaction asserts that our genes set theboundaries within which we can operate, and our environment interacts with the genes to determine wherein that range we will fall. For example, if an individual's genetic makeup predisposes her to high levels ofintellectual potential and she is reared in a rich, stimulating environment, then she will be more likely toachieve her full potential than if she were raised under conditions of signi�cant deprivation. According to theconcept of range of reaction, genes set de�nite limits on potential, and environment determines how muchof that potential is achieved.

In another approach to gene-environment interactions, the �eld of epigenetics looks beyond the genotypeitself and studies how the same genotype can be expressed in di�erent ways. In other words, researchersstudy how the same genotype can lead to very di�erent phenotypes. As mentioned earlier, gene expressionis often in�uenced by environmental context in ways that are not entirely obvious. For instance, identicaltwins share the same genetic information (identical twins develop from a single fertilized egg that split,so the genetic material is exactly the same in each; in contrast, fraternal twins develop from two di�erenteggs fertilized by di�erent sperm, so the genetic material varies as with non-twin siblings). But even withidentical genes, there remains an incredible amount of variability in how gene expression can unfold overthe course of each twin's life. Sometimes, one twin will develop a disease and the other will not. In oneexample, Ti�any, an identical twin, died from cancer at age 7, but her twin, now 19 years old, has never hadcancer. Although these individuals share an identical genotype, their phenotypes di�er as a result of howthat genetic information is expressed over time. The epigenetic perspective is very di�erent from range ofreaction, because here the genotype is not �xed and limited.

Genes a�ect more than our physical characteristics. Indeed, scientists have found genetic linkages to anumber of behavioral characteristics, ranging from basic personality traits to sexual orientation to spirituality(for examples, see Mustanski et al., 2005; Comings, Gonzales, Saucier, Johnson, & MacMurray, 2000). Genesare also associated with temperament and a number of psychological disorders, such as depression andschizophrenia. So while it is true that genes provide the biological blueprints for our cells, tissues, organs,and body, they also have signi�cant impact on our experiences and our behaviors.

Let's look at the following �ndings regarding schizophrenia in light of our three views of gene-environmentinteractions. Which view do you think best explains this evidence?

In a study of people who were given up for adoption, adoptees whose biological mothers had schizophreniaand who had been raised in a disturbed family environment were much more likely to develop schizophreniaor another psychotic disorder than were any of the other groups in the study:

• Of adoptees whose biological mothers had schizophrenia (high genetic risk) and who were raised indisturbed family environments, 36.8% were likely to develop schizophrenia.

• Of adoptees whose biological mothers had schizophrenia (high genetic risk) and who were raised inhealthy family environments, 5.8% were likely to develop schizophrenia.

• Of adoptees with a low genetic risk (whose mothers did not have schizophrenia) and who were raisedin disturbed family environments, 5.3% were likely to develop schizophrenia.


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• Of adoptees with a low genetic risk (whose mothers did not have schizophrenia) and who were raisedin healthy family environments, 4.8% were likely to develop schizophrenia (Tienari et al., 2004).

The study shows that adoptees with high genetic risk were especially likely to develop schizophrenia only ifthey were raised in disturbed home environments. This research lends credibility to the notion that bothgenetic vulnerability and environmental stress are necessary for schizophrenia to develop, and that genesalone do not tell the full tale.

2.3 Summary

Genes are sequences of DNA that code for a particular trait. Di�erent versions of a gene are called alleles�sometimes alleles can be classi�ed as dominant or recessive. A dominant allele always results in the dominantphenotype. In order to exhibit a recessive phenotype, an individual must be homozygous for the recessiveallele. Genes a�ect both physical and psychological characteristics. Ultimately, how and when a gene isexpressed, and what the outcome will be�in terms of both physical and psychological characteristics�is afunction of the interaction between our genes and our environments.

2.4 Review Questions

Exercise 2.1 (Solution on p. 11.)

A(n) ________ is a sudden, permanent change in a sequence of DNA.

a. alleleb. chromosomec. epigeneticd. mutation


________ refers to a person's genetic makeup, while ________ refers to a person's physicalcharacteristics.

a. Phenotype; genotypeb. Genotype; phenotypec. DNA; gened. Gene; DNA


________ is the �eld of study that focuses on genes and their expression.

a. Social psychologyb. Evolutionary psychologyc. Epigeneticsd. Behavioral neuroscience


Humans have ________ pairs of chromosomes.

a. 15b. 23c. 46d. 78



2.5 Critical Thinking Questions


The theory of evolution by natural selection requires variability of a given trait. Why is variabilitynecessary and where does it come from?


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Solutions to Exercises in Chapter 2

Solution to Exercise 2.1 (p. 9)DSolution to Exercise 2.2 (p. 9)BSolution to Exercise 2.3 (p. 9)CSolution to Exercise 2.4 (p. 9)BSolution to Exercise 2.5 (p. 10)Variability is essential for natural selection to work. If all individuals are the same on a given trait, therewill be no relative di�erence in their reproductive success because everyone will be equally adapted to theirenvironments on that trait. Mutations are one source of variability, but sexual reproduction is anotherimportant source of variation given that individuals inherit half of their genetic makeup from each of theirparents.


Chapter 3

3.2 Parts of the Nervous System1

The nervous system can be divided into two major subdivisions: the central nervous system (CNS)and the peripheral nervous system (PNS), shown in Figure 3.1. The CNS is comprised of the brain andspinal cord; the PNS connects the CNS to the rest of the body. In this section, we focus on the peripheralnervous system; later, we look at the brain and spinal cord.



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14 CHAPTER 3. 3.2 PARTS OF THE NERVOUS SYSTEM

Figure 3.1: The nervous system is divided into two major parts: (a) the Central Nervous System and(b) the Peripheral Nervous System.

3.1 Peripheral Nervous System

The peripheral nervous system is made up of thick bundles of axons, called nerves, carrying messages backand forth between the CNS and the muscles, organs, and senses in the periphery of the body (i.e., everythingoutside the CNS). The PNS has two major subdivisions: the somatic nervous system and the autonomicnervous system.

The somatic nervous system is associated with activities traditionally thought of as conscious orvoluntary. It is involved in the relay of sensory and motor information to and from the CNS; therefore,it consists of motor neurons and sensory neurons. Motor neurons, carrying instructions from the CNS tothe muscles, are e�erent �bers (e�erent means �moving away from�). Sensory neurons, carrying sensoryinformation to the CNS, are a�erent �bers (a�erent means �moving toward�). Each nerve is basically atwo-way superhighway, containing thousands of axons, both e�erent and a�erent.

The autonomic nervous system controls our internal organs and glands and is generally considered tobe outside the realm of voluntary control. It can be further subdivided into the sympathetic and parasym-pathetic divisions (Figure 3.2). The sympathetic nervous system is involved in preparing the body forstress-related activities; the parasympathetic nervous system is associated with returning the body to


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routine, day-to-day operations. The two systems have complementary functions, operating in tandem tomaintain the body's homeostasis. Homeostasis is a state of equilibrium, in which biological conditions(such as body temperature) are maintained at optimal levels.

Figure 3.2: The sympathetic and parasympathetic divisions of the autonomic nervous system have theopposite e�ects on various systems.

The sympathetic nervous system is activated when we are faced with stressful or high-arousal situations.The activity of this system was adaptive for our ancestors, increasing their chances of survival. Imagine, for



example, that one of our early ancestors, out hunting small game, suddenly disturbs a large bear with hercubs. At that moment, his body undergoes a series of changes�a direct function of sympathetic activation�preparing him to face the threat. His pupils dilate, his heart rate and blood pressure increase, his bladderrelaxes, his liver releases glucose, and adrenaline surges into his bloodstream. This constellation of phys-iological changes, known as the �ght or �ight response, allows the body access to energy reserves andheightened sensory capacity so that it might �ght o� a threat or run away to safety.

While it is clear that such a response would be critical for survival for our ancestors, who lived in aworld full of real physical threats, many of the high-arousal situations we face in the modern world are morepsychological in nature. For example, think about how you feel when you have to stand up and give apresentation in front of a roomful of people, or right before taking a big test. You are in no real physicaldanger in those situations, and yet you have evolved to respond to any perceived threat with the �ght or�ight response. This kind of response is not nearly as adaptive in the modern world; in fact, we su�ernegative health consequences when faced constantly with psychological threats that we can neither �ghtnor �ee. Recent research suggests that an increase in susceptibility to heart disease (Chandola, Brunner, &Marmot, 2006) and impaired function of the immune system (Glaser & Kiecolt-Glaser, 2005) are among themany negative consequences of persistent and repeated exposure to stressful situations.

Once the threat has been resolved, the parasympathetic nervous system takes over and returns bodilyfunctions to a relaxed state. Our hunter's heart rate and blood pressure return to normal, his pupils constrict,he regains control of his bladder, and the liver begins to store glucose in the form of glycogen for future use.These processes are associated with activation of the parasympathetic nervous system.

3.2 Summary

The brain and spinal cord make up the central nervous system. The peripheral nervous system is comprisedof the somatic and autonomic nervous systems. The somatic nervous system transmits sensory and motorsignals to and from the central nervous system. The autonomic nervous system controls the function ofour organs and glands, and can be divided into the sympathetic and parasympathetic divisions. Sympa-thetic activation prepares us for �ght or �ight, while parasympathetic activation is associated with normalfunctioning under relaxed conditions.



Our ability to make our legs move as we walk across the room is controlled by the ________nervous system.

a. autonomicb. somaticc. sympatheticd. parasympathetic


If your ________ is activated, you will feel relatively at ease.

a. somatic nervous systemb. sympathetic nervous systemc. parasympathetic nervous systemd. spinal cord


The central nervous system is comprised of ________.


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a. sympathetic and parasympathetic nervous systemsb. organs and glandsc. somatic and autonomic nervous systemsd. brain and spinal cord


Sympathetic activation is associated with ________.

a. pupil dilationb. storage of glucose in the liverc. increased heart rated. both A and C



What are the implications of compromised immune function as a result of exposure to chronicstress?


Examine Figure 3.2, illustrating the e�ects of sympathetic nervous system activation. How wouldall of these things play into the �ght or �ight response?




Solution to Exercise 3.1 (p. 16)BSolution to Exercise 3.2 (p. 16)CSolution to Exercise 3.3 (p. 16)DSolution to Exercise 3.4 (p. 17)DSolution to Exercise 3.5 (p. 17)Chronic stress can lead to increased susceptibility to bacterial and viral infections, and potentially anincreased risk of cancer. Ultimately, this could be a vicious cycle with stress leading to increased risk ofdisease, disease states leading to increased stress and so on.Solution to Exercise 3.6 (p. 17)Most of these e�ects directly impact energy availability and redistribution of key resources and heightenedsensory capacity. The individual experiencing these e�ects would be better prepared to �ght or �ee.


Chapter 4

3.3 The Brain and Spinal Cord1

The brain is a remarkably complex organ comprised of billions of interconnected neurons and glia. It isa bilateral, or two-sided, structure that can be separated into distinct lobes. Each lobe is associated withcertain types of functions, but, ultimately, all of the areas of the brain interact with one another to providethe foundation for our thoughts and behaviors. In this section, we discuss the overall organization of thebrain and the functions associated with di�erent brain areas, beginning with what can be seen as an extensionof the brain, the spinal cord.

4.1 The Spinal Cord

It can be said that the spinal cord is what connects the brain to the outside world. Because of it, the braincan act. The spinal cord is like a relay station, but a very smart one. It not only routes messages to andfrom the brain, but it also has its own system of automatic processes, called re�exes.

The top of the spinal cord merges with the brain stem, where the basic processes of life are controlled,such as breathing and digestion. In the opposite direction, the spinal cord ends just below the ribs�contraryto what we might expect, it does not extend all the way to the base of the spine.

The spinal cord is functionally organized in 30 segments, corresponding with the vertebrae. Each segmentis connected to a speci�c part of the body through the peripheral nervous system. Nerves branch out fromthe spine at each vertebra. Sensory nerves bring messages in; motor nerves send messages out to the musclesand organs. Messages travel to and from the brain through every segment.

Some sensory messages are immediately acted on by the spinal cord, without any input from the brain.Withdrawal from heat and knee jerk are two examples. When a sensory message meets certain parameters,the spinal cord initiates an automatic re�ex. The signal passes from the sensory nerve to a simple processingcenter, which initiates a motor command. Seconds are saved, because messages don't have to go the brain, beprocessed, and get sent back. In matters of survival, the spinal re�exes allow the body to react extraordinarilyfast.

The spinal cord is protected by bony vertebrae and cushioned in cerebrospinal �uid, but injuries stilloccur. When the spinal cord is damaged in a particular segment, all lower segments are cut o� from the brain,causing paralysis. Therefore, the lower on the spine damage is, the fewer functions an injured individualloses.

4.2 The Two Hemispheres

The surface of the brain, known as the cerebral cortex, is very uneven, characterized by a distinctivepattern of folds or bumps, known as gyri (singular: gyrus), and grooves, known as sulci (singular: sulcus),



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20 CHAPTER 4. 3.3 THE BRAIN AND SPINAL CORD

shown in Figure 4.1. These gyri and sulci form important landmarks that allow us to separate the brain intofunctional centers. The most prominent sulcus, known as the longitudinal �ssure, is the deep groove thatseparates the brain into two halves or hemispheres: the left hemisphere and the right hemisphere.

Figure 4.1: The surface of the brain is covered with gyri and sulci. A deep sulcus is called a �ssure, suchas the longitudinal �ssure that divides the brain into left and right hemispheres. (credit: modi�cation ofwork by Bruce Blaus)

There is evidence of some specialization of function�referred to as lateralization�in each hemisphere,mainly regarding di�erences in language ability. Beyond that, however, the di�erences that have been foundhave been minor. What we do know is that the left hemisphere controls the right half of the body, and theright hemisphere controls the left half of the body.

The two hemispheres are connected by a thick band of neural �bers known as the corpus callosum,consisting of about 200 million axons. The corpus callosum allows the two hemispheres to communicate witheach other and allows for information being processed on one side of the brain to be shared with the otherside.

Normally, we are not aware of the di�erent roles that our two hemispheres play in day-to-day functions,but there are people who come to know the capabilities and functions of their two hemispheres quite well.In some cases of severe epilepsy, doctors elect to sever the corpus callosum as a means of controlling thespread of seizures (Figure 4.2). While this is an e�ective treatment option, it results in individuals who havesplit brains. After surgery, these split-brain patients show a variety of interesting behaviors. For instance,a split-brain patient is unable to name a picture that is shown in the patient's left visual �eld because the


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information is only available in the largely nonverbal right hemisphere. However, they are able to recreatethe picture with their left hand, which is also controlled by the right hemisphere. When the more verbal lefthemisphere sees the picture that the hand drew, the patient is able to name it (assuming the left hemispherecan interpret what was drawn by the left hand).

Figure 4.2: (a, b) The corpus callosum connects the left and right hemispheres of the brain. (c) Ascientist spreads this dissected sheep brain apart to show the corpus callosum between the hemispheres.(credit c: modi�cation of work by Aaron Bornstein)

4.3 Forebrain Structures

The two hemispheres of the cerebral cortex are part of the forebrain (Figure 4.3), which is the largest partof the brain. The forebrain contains the cerebral cortex and a number of other structures that lie beneaththe cortex (called subcortical structures): thalamus, hypothalamus, pituitary gland, and the limbic system(collection of structures). The cerebral cortex, which is the outer surface of the brain, is associated withhigher level processes such as consciousness, thought, emotion, reasoning, language, and memory. Eachcerebral hemisphere can be subdivided into four lobes, each associated with di�erent functions.



Figure 4.3: The brain and its parts can be divided into three main categories: the forebrain, midbrain,and hindbrain.

4.3.1 Lobes of the Brain

The four lobes of the brain are the frontal, parietal, temporal, and occipital lobes (Figure 4.4). The frontallobe is located in the forward part of the brain, extending back to a �ssure known as the central sulcus. Thefrontal lobe is involved in reasoning, motor control, emotion, and language. It contains the motor cortex,which is involved in planning and coordinating movement; the prefrontal cortex, which is responsible forhigher-level cognitive functioning; and Broca's area, which is essential for language production.


23

Figure 4.4: The lobes of the brain are shown.

People who su�er damage to Broca's area have great di�culty producing language of any form (Fig-ure 4.4). For example, Padma was an electrical engineer who was socially active and a caring, involvedmother. About twenty years ago, she was in a car accident and su�ered damage to her Broca's area. Shecompletely lost the ability to speak and form any kind of meaningful language. There is nothing wrongwith her mouth or her vocal cords, but she is unable to produce words. She can follow directions but can'trespond verbally, and she can read but no longer write. She can do routine tasks like running to the marketto buy milk, but she could not communicate verbally if a situation called for it.

Probably the most famous case of frontal lobe damage is that of a man by the name of Phineas Gage.On September 13, 1848, Gage (age 25) was working as a railroad foreman in Vermont. He and his crewwere using an iron rod to tamp explosives down into a blasting hole to remove rock along the railway'spath. Unfortunately, the iron rod created a spark and caused the rod to explode out of the blasting hole,into Gage's face, and through his skull (Figure 4.5). Although lying in a pool of his own blood with brainmatter emerging from his head, Gage was conscious and able to get up, walk, and speak. But in the monthsfollowing his accident, people noticed that his personality had changed. Many of his friends described himas no longer being himself. Before the accident, it was said that Gage was a well-mannered, soft-spokenman, but he began to behave in odd and inappropriate ways after the accident. Such changes in personalitywould be consistent with loss of impulse control�a frontal lobe function.

Beyond the damage to the frontal lobe itself, subsequent investigations into the rod's path also identi�ed



probable damage to pathways between the frontal lobe and other brain structures, including the limbicsystem. With connections between the planning functions of the frontal lobe and the emotional processes ofthe limbic system severed, Gage had di�culty controlling his emotional impulses.

However, there is some evidence suggesting that the dramatic changes in Gage's personality were exagger-ated and embellished. Gage's case occurred in the midst of a 19th century debate over localization�regardingwhether certain areas of the brain are associated with particular functions. On the basis of extremely limitedinformation about Gage, the extent of his injury, and his life before and after the accident, scientists tendedto �nd support for their own views, on whichever side of the debate they fell (Macmillan, 1999).

Figure 4.5: (a) Phineas Gage holds the iron rod that penetrated his skull in an 1848 railroad con-struction accident. (b) Gage's prefrontal cortex was severely damaged in the left hemisphere. The rodentered Gage's face on the left side, passed behind his eye, and exited through the top of his skull, beforelanding about 80 feet away. (credit a: modi�cation of work by Jack and Beverly Wilgus)

The temporal lobe is located on the side of the head (temporal means �near the temples�), and isassociated with hearing, memory, emotion, and some aspects of language. The auditory cortex, the mainarea responsible for processing auditory information, is located within the temporal lobe. Wernicke's area,


25

important for speech comprehension, is also located here. Whereas individuals with damage to Broca's areahave di�culty producing language, those with damage to Wernicke's area can produce sensible language,but they are unable to understand it (Figure 4.6).

Figure 4.6: Damage to either Broca's area or Wernicke's area can result in language de�cits. The typesof de�cits are very di�erent, however, depending on which area is a�ected.

The occipital lobe is located at the very back of the brain, and contains the primary visual cortex, whichis responsible for interpreting incoming visual information. The occipital cortex is organized retinotopically,which means there is a close relationship between the position of an object in a person's visual �eld andthe position of that object's representation on the cortex. You will learn much more about how visualinformation is processed in the occipital lobe when you study sensation and perception.

4.3.2 Other Areas of the Forebrain

Other areas of the forebrain, located beneath the cerebral cortex, include the thalamus and the limbicsystem. The thalamus is a sensory relay for the brain. All of our senses, with the exception of smell, arerouted through the thalamus before being directed to other areas of the brain for processing (Figure 4.7).



Figure 4.7: The thalamus serves as the relay center of the brain where most senses are routed forprocessing.

The limbic system is involved in processing both emotion and memory. Interestingly, the sense of smellprojects directly to the limbic system; therefore, not surprisingly, smell can evoke emotional responses inways that other sensory modalities cannot. The limbic system is made up of a number of di�erent structures,but three of the most important are the hippocampus, the amygdala, and the hypothalamus (Figure 4.8).The hippocampus is an essential structure for learning and memory. The amygdala is involved in ourexperience of emotion and in tying emotional meaning to our memories. The hypothalamus regulates anumber of homeostatic processes, including the regulation of body temperature, appetite, and blood pressure.The hypothalamus also serves as an interface between the nervous system and the endocrine system and inthe regulation of sexual motivation and behavior.


27

Figure 4.8: The limbic system is involved in mediating emotional response and memory.

4.4 Midbrain and Hindbrain Structures

The midbrain is comprised of structures located deep within the brain, between the forebrain and thehindbrain. The reticular formation is centered in the midbrain, but it actually extends up into theforebrain and down into the hindbrain. The reticular formation is important in regulating the sleep/wakecycle, arousal, alertness, and motor activity.

The substantia nigra (Latin for �black substance�) and the ventral tegmental area (VTA) are alsolocated in the midbrain (Figure 4.9). Both regions contain cell bodies that produce the neurotransmitterdopamine, and both are critical for movement. Degeneration of the substantia nigra and VTA is involved inParkinson's disease. In addition, these structures are involved in mood, reward, and addiction (Berridge &Robinson, 1998; Gardner, 2011; George, Le Moal, & Koob, 2012).



Figure 4.9: The substantia nigra and ventral tegmental area (VTA) are located in the midbrain.

The hindbrain is located at the back of the head and looks like an extension of the spinal cord. Itcontains the medulla, pons, and cerebellum (Figure 4.10). The medulla controls the automatic processes ofthe autonomic nervous system, such as breathing, blood pressure, and heart rate. The word pons literallymeans �bridge,� and as the name suggests, the pons serves to connect the brain and spinal cord. It also isinvolved in regulating brain activity during sleep. The medulla, pons, and midbrain together are known asthe brainstem.


29

Figure 4.10: The pons, medulla, and cerebellum make up the hindbrain.

The cerebellum (Latin for �little brain�) receives messages from muscles, tendons, joints, and structuresin our ear to control balance, coordination, movement, and motor skills. The cerebellum is also thought tobe an important area for processing some types of memories. In particular, procedural memory, or memoryinvolved in learning and remembering how to perform tasks, is thought to be associated with the cerebellum.Recall that H. M. was unable to form new explicit memories, but he could learn new tasks. This is likelydue to the fact that H. M.'s cerebellum remained intact.

4.5 Summary

The brain consists of two hemispheres, each controlling the opposite side of the body. Each hemispherecan be subdivided into di�erent lobes: frontal, parietal, temporal, and occipital. In addition to the lobesof the cerebral cortex, the forebrain includes the thalamus (sensory relay) and limbic system (emotion andmemory circuit). The midbrain contains the reticular formation, which is important for sleep and arousal,



as well as the substantia nigra and ventral tegmental area. These structures are important for movement,reward, and addictive processes. The hindbrain contains the structures of the brainstem (medulla, pons,and midbrain), which control automatic functions like breathing and blood pressure. The hindbrain alsocontains the cerebellum, which helps coordinate movement and certain types of memories.

Individuals with brain damage have been studied extensively to provide information about the role ofdi�erent areas of the brain, and recent advances in technology allow us to glean similar information byimaging brain structure and function. These techniques include CT, PET, MRI, fMRI, and EEG.



The ________ is a sensory relay station where all sensory information, except for smell, goesbefore being sent to other areas of the brain for further processing.

a. amygdalab. hippocampusc. hypothalamusd. thalamus


Damage to the ________ disrupts one's ability to comprehend language, but it leaves one'sability to produce words intact.

a. amygdalab. Broca's Areac. Wernicke's Aread. occipital lobe


A(n) ________ uses magnetic �elds to create pictures of a given tissue.

a. EEGb. MRIc. PET scand. CT scan


Which of the following is not a structure of the forebrain?

a. thalamusb. hippocampusc. amygdalad. substantia nigra



Before the advent of modern imaging techniques, scientists and clinicians relied on autopsies ofpeople who su�ered brain injury with resultant change in behavior to determine how di�erent areasof the brain were a�ected. What are some of the limitations associated with this kind of approach?


31


Which of the techniques discussed would be viable options for you to determine how activity inthe reticular formation is related to sleep and wakefulness? Why?




Solution to Exercise 4.1 (p. 30)DSolution to Exercise 4.2 (p. 30)CSolution to Exercise 4.3 (p. 30)BSolution to Exercise 4.4 (p. 30)DSolution to Exercise 4.5 (p. 30)The same limitations associated with any case study would apply here. In addition, it is possible that thedamage caused changes in other areas of the brain, which might contribute to the behavioral de�cits. Suchchanges would not necessarily be obvious to someone performing an autopsy, as they may be functional innature, rather than structural.Solution to Exercise 4.6 (p. 31)The most viable techniques are fMRI and PET because of their ability to provide information about brainactivity and structure simultaneously.


Chapter 5

3.4 The Endocrine System1

The endocrine system consists of a series of glands that produce chemical substances known as hormones(Figure 5.1). Like neurotransmitters, hormones are chemical messengers that must bind to a receptor in orderto send their signal. However, unlike neurotransmitters, which are released in close proximity to cells withtheir receptors, hormones are secreted into the bloodstream and travel throughout the body, a�ecting anycells that contain receptors for them. Thus, whereas neurotransmitters' e�ects are localized, the e�ects ofhormones are widespread. Also, hormones are slower to take e�ect, and tend to be longer lasting.



33

34 CHAPTER 5. 3.4 THE ENDOCRINE SYSTEM

Figure 5.1: The major glands of the endocrine system are shown.

Hormones are involved in regulating all sorts of bodily functions, and they are ultimately controlledthrough interactions between the hypothalamus (in the central nervous system) and the pituitary gland (inthe endocrine system). Imbalances in hormones are related to a number of disorders. This section exploressome of the major glands that make up the endocrine system and the hormones secreted by these glands.

5.1 Major Glands

The pituitary gland descends from the hypothalamus at the base of the brain, and acts in close associationwith it. The pituitary is often referred to as the �master gland� because its messenger hormones control allthe other glands in the endocrine system, although it mostly carries out instructions from the hypothalamus.In addition to messenger hormones, the pituitary also secretes growth hormone, endorphins for pain relief,


35

and a number of key hormones that regulate �uid levels in the body.Located in the neck, the thyroid gland releases hormones that regulate growth, metabolism, and ap-

petite. In hyperthyroidism, or Grave's disease, the thyroid secretes too much of the hormone thyroxine,causing agitation, bulging eyes, and weight loss. In hypothyroidism, reduced hormone levels cause su�erersto experience tiredness, and they often complain of feeling cold. Fortunately, thyroid disorders are oftentreatable with medications that help reestablish a balance in the hormones secreted by the thyroid.

The adrenal glands sit atop our kidneys and secrete hormones involved in the stress response, suchas epinephrine (adrenaline) and norepinephrine (noradrenaline). The pancreas is an internal organ thatsecretes hormones that regulate blood sugar levels: insulin and glucagon. These pancreatic hormones areessential for maintaining stable levels of blood sugar throughout the day by lowering blood glucose levels(insulin) or raising them (glucagon). People who su�er from diabetes do not produce enough insulin;therefore, they must take medications that stimulate or replace insulin production, and they must closelycontrol the amount of sugars and carbohydrates they consume.

The gonads secrete sexual hormones, which are important in reproduction, and mediate both sexualmotivation and behavior. The female gonads are the ovaries; the male gonads are the testis. Ovaries secreteestrogens and progesterone, and the testes secrete androgens, such as testosterone.

5.2 Summary

The glands of the endocrine system secrete hormones to regulate normal body functions. The hypothalamusserves as the interface between the nervous system and the endocrine system, and it controls the secretionsof the pituitary. The pituitary serves as the master gland, controlling the secretions of all other glands. Thethyroid secretes thyroxine, which is important for basic metabolic processes and growth; the adrenal glandssecrete hormones involved in the stress response; the pancreas secretes hormones that regulate blood sugarlevels; and the ovaries and testes produce sex hormones that regulate sexual motivation and behavior.



The two major hormones secreted from the pancreas are:

a. estrogen and progesteroneb. norepinephrine and epinephrinec. thyroxine and oxytocind. glucagon and insulin


The ________ secretes messenger hormones that direct the function of the rest of the endocrineglands.

a. ovaryb. thyroidc. pituitaryd. pancreas


The ________ gland secretes epinephrine.

a. adrenalb. thyroidc. pituitary


36 CHAPTER 5. 3.4 THE ENDOCRINE SYSTEM

d. master


The ________ secretes hormones that regulate the body's �uid levels.

a. adrenalb. pituitaryc. testisd. thyroid



Hormone secretion is often regulated through a negative feedback mechanism, which means thatonce a hormone is secreted it will cause the hypothalamus and pituitary to shut down the productionof signals necessary to secrete the hormone in the �rst place. Most oral contraceptives are made ofsmall doses of estrogen and/or progesterone. Why would this be an e�ective means of contraception?


Chemical messengers are used in both the nervous system and the endocrine system. Whatproperties do these two systems share? What properties are di�erent? Which one would be faster?Which one would result in long-lasting changes?


37


Solution to Exercise 5.1 (p. 35)DSolution to Exercise 5.2 (p. 35)CSolution to Exercise 5.3 (p. 35)ASolution to Exercise 5.4 (p. 36)BSolution to Exercise 5.5 (p. 36)The introduction of relatively low, yet constant, levels of gonadal hormones places the hypothalamus andpituitary under inhibition via negative feedback mechanisms. This prevents the alterations in both estrogenand progesterone concentrations that are necessary for successful ovulation and implantation.Solution to Exercise 5.6 (p. 36)Both systems involve chemical messengers that must interact with receptors in order to have an e�ect.The relative proximity of the release site and target tissue varies dramatically between the two systems.In neurotransmission, reuptake and enzymatic breakdown immediately clear the synapse. Metabolism ofhormones must occur in the liver. Therefore, while neurotransmission is much more rapid in signalinginformation, hormonal signaling can persist for quite some time as the concentrations of the hormone in thebloodstream vary gradually over time.


38 GLOSSARY

Glossary

A adrenal gland

sits atop our kidneys and secreteshormones involved in the stress response

allele

speci�c version of a gene

amygdala

structure in the limbic system involved inour experience of emotion and tyingemotional meaning to our memories

auditory cortex

strip of cortex in the temporal lobe that isresponsible for processing auditoryinformation

autonomic nervous system

controls our internal organs and glands

B Broca's area

region in the left hemisphere that isessential for language production

C central nervous system (CNS)

brain and spinal cord

cerebellum

hindbrain structure that controls ourbalance, coordination, movement, andmotor skills, and it is thought to beimportant in processing some types ofmemory

cerebral cortex

surface of the brain that is associated withour highest mental capabilities

chromosome

long strand of genetic information

computerized tomography (CT) scan

imaging technique in which a computercoordinates and integrates multiplex-rays of a given area

corpus callosum

thick band of neural �bers connecting thebrain's two hemispheres

D deoxyribonucleic acid (DNA)

helix-shaped molecule made of nucleotidebase pairs

diabetes

disease related to insu�cient insulinproduction

dominant allele

allele whose phenotype will be expressedin an individual that possesses that allele

E electroencephalography (EEG)

recording the electrical activity of thebrain via electrodes on the scalp

endocrine system

series of glands that produce chemicalsubstances known as hormones

epigenetics

study of gene-environment interactions,such as how the same genotype leads todi�erent phenotypes

F �ght or �ight response

activation of the sympathetic division ofthe autonomic nervous system, allowingaccess to energy reserves and heightenedsensory capacity so that we might �ghto� a given threat or run away to safety

forebrain

largest part of the brain, containing thecerebral cortex, the thalamus, and thelimbic system, among other structures

fraternal twins

twins who develop from two di�erent eggsfertilized by di�erent sperm, so theirgenetic material varies the same as innon-twin siblings

frontal lobe


GLOSSARY 39

part of the cerebral cortex involved inreasoning, motor control, emotion, andlanguage; contains motor cortex

functional magnetic resonance imaging(fMRI)

MRI that shows changes in metabolicactivity over time

G gene

sequence of DNA that controls or partiallycontrols physical characteristics

genetic environmental correlation

view of gene-environment interaction thatasserts our genes a�ect our environment,and our environment in�uences theexpression of our genes

genotype

genetic makeup of an individual

gonad

secretes sexual hormones, which areimportant for successful reproduction,and mediate both sexual motivation andbehavior

gyrus

(plural: gyri) bump or ridge on thecerebral cortex

H hemisphere

left or right half of the brain

heterozygous

consisting of two di�erent alleles

hindbrain

division of the brain containing themedulla, pons, and cerebellum

hippocampus

structure in the temporal lobe associatedwith learning and memory

homeostasis

state of equilibrium�biological conditions,such as body temperature, aremaintained at optimal levels

homozygous

consisting of two identical alleles

hormone

chemical messenger released by endocrineglands

hypothalamus

forebrain structure that regulates sexualmotivation and behavior and a number ofhomeostatic processes; serves as aninterface between the nervous system andthe endocrine system

I identical twins

twins that develop from the same spermand egg

L lateralization

concept that each hemisphere of the brainis associated with specialized functions

limbic system

collection of structures involved inprocessing emotion and memory

longitudinal �ssure

deep groove in the brain's cortex

M magnetic resonance imaging (MRI)

magnetic �elds used to produce a pictureof the tissue being imaged

medulla

hindbrain structure that controlsautomated processes like breathing,blood pressure, and heart rate

midbrain

division of the brain located between theforebrain and the hindbrain; contains thereticular formation

motor cortex

strip of cortex involved in planning andcoordinating movement

mutation

sudden, permanent change in a gene

O occipital lobe

part of the cerebral cortex associated withvisual processing; contains the primaryvisual cortex

P pancreas

secretes hormones that regulate bloodsugar


40 GLOSSARY

parasympathetic nervous system

associated with routine, day-to-dayoperations of the body

parietal lobe

part of the cerebral cortex involved inprocessing various sensory and perceptualinformation; contains the primarysomatosensory cortex

peripheral nervous system (PNS)

connects the brain and spinal cord to themuscles, organs and senses in theperiphery of the body

phenotype

individual's inheritable physicalcharacteristics

pituitary gland

secretes a number of key hormones, whichregulate �uid levels in the body, and anumber of messenger hormones, whichdirect the activity of other glands in theendocrine system

polygenic

multiple genes a�ecting a given trait

pons

hindbrain structure that connects thebrain and spinal cord; involved inregulating brain activity during sleep

positron emission tomography (PET)scan

involves injecting individuals with a mildlyradioactive substance and monitoringchanges in blood �ow to di�erent regionsof the brain

prefrontal cortex

area in the frontal lobe responsible forhigher-level cognitive functioning

R range of reaction

asserts our genes set the boundaries withinwhich we can operate, and ourenvironment interacts with the genes todetermine where in that range we will fall

recessive allele

allele whose phenotype will be expressedonly if an individual is homozygous forthat allele

reticular formation

midbrain structure important in regulatingthe sleep/wake cycle, arousal, alertness,and motor activity

S somatic nervous system

relays sensory and motor information toand from the CNS

somatosensory cortex

essential for processing sensoryinformation from across the body, such astouch, temperature, and pain

substantia nigra

midbrain structure where dopamine isproduced; involved in control ofmovement

sulcus

(plural: sulci) depressions or grooves inthe cerebral cortex

sympathetic nervous system

involved in stress-related activities andfunctions

T temporal lobe

part of cerebral cortex associated withhearing, memory, emotion, and someaspects of language; contains primaryauditory cortex

thalamus

sensory relay for the brain

theory of evolution by natural selection

states that organisms that are bettersuited for their environments will surviveand reproduce compared to those thatare poorly suited for their environments

thyroid

secretes hormones that regulate growth,metabolism, and appetite

V ventral tegmental area (VTA)

midbrain structure where dopamine isproduced: associated with mood, reward,and addiction

WWernicke's area

important for speech comprehension


INDEX 41

Index of Keywords and Terms

Keywords are listed by the section with that keyword (page numbers are in parentheses). Keywordsdo not necessarily appear in the text of the page. They are merely associated with that section. Ex.apples, � 1.1 (1) Terms are referenced by the page they appear on. Ex. apples, 1

A action potential, � 1(1)adrenal gland, � 1(1), � 5(33)adrenal glands, 35agonist, � 1(1)all-or-none, � 1(1)allele, � 1(1), � 2(5), 5amygdala, � 1(1), � 4(19), 26anabolic steroid, � 1(1), � 5(33)antagonist, � 1(1)auditory cortex, � 1(1), � 4(19), 24autonomic nervous system, � 1(1), � 3(13), 14axon, � 1(1)

B behavioral genetics, � 1(1), � 2(5)biological psychology, � 1(1)biopsychology, � 1(1)brain, � 1(1), � 4(19)brain imaging, � 1(1), � 4(19)brain scan, � 1(1), � 4(19)Broca's area, � 1(1), � 4(19)Broca's area, 22

C central nervous system, � 1(1), � 3(13)central nervous system (CNS), 13cerebellum, � 1(1), � 4(19), 29cerebral cortex, 19chromosome, � 1(1), � 2(5)Chromosomes, 5cleft chin, 5computerized tomography, � 1(1), � 4(19)corpus callosum, � 1(1), � 4(19), 20CT scan, � 1(1), � 4(19)

D Darwin, � 1(1), � 2(5), 5dendrite, � 1(1)deoxyribonucleic acid, � 1(1), � 2(5)deoxyribonucleic acid (DNA), 5diabetes, 35DNA, � 1(1), � 2(5)dominant allele, � 1(1), � 2(5), 6

E EEG, � 1(1), � 4(19)

Electroencephalography, � 1(1), � 4(19)endocrine system, � 1(1), � 5(33), 33epigenetics, � 1(1), � 2(5), 8evolution, � 1(1), � 2(5)evolutionary psychology, � 1(1), � 2(5)

F �ght or �ight, � 1(1), � 3(13), 16�ght or �ight response, 16fMRI, � 1(1), � 4(19)forebrain, � 1(1), � 4(19), 21, 25fraternal twin, � 1(1), � 2(5)fraternal twins, 8frontal lobe, � 1(1), � 4(19), 22functional magnetic resonance imaging, � 1(1),� 4(19)

G Gage, 23, 24gene, � 1(1), � 2(5)genes, 5, 8genetic environmental correlation, � 1(1),� 2(5)genetics, � 1(1), � 2(5)genotype, � 1(1), � 2(5), 5glia, � 1(1)glial cell, � 1(1)gonad, � 1(1), � 5(33)gonads, 35gyri, � 1(1), � 4(19), 19

H hemisphere, � 1(1), � 4(19)hemispheres, 20heterozygous, � 1(1), � 2(5), 6hindbrain, � 1(1), � 4(19), 28hippocampus, � 1(1), � 4(19), 26homeostasis, � 1(1), � 3(13), 15homozygous, � 1(1), � 2(5), 6hormone, � 1(1), � 5(33)hormones, 33hypothalamus, � 1(1), � 4(19), 26

I identical twin, � 1(1), � 2(5)identical twins, 8


42 INDEX

L lateralization, 20limbic system, � 1(1), � 4(19), 26longitudinal �ssure, � 1(1), � 4(19), 20

M magnetic resonance imaging, � 1(1), � 4(19)medulla, � 1(1), � 4(19), 28membrane potential, � 1(1)midbrain, � 1(1), � 4(19), 27Molaison, � 1(1), � 4(19)motor cortex, � 1(1), � 4(19), 22MRI, � 1(1), � 4(19)mutation, � 1(1), � 2(5), 7myelin sheath, � 1(1)

N natural selection, � 1(1), � 2(5)nature vs. nurture, � 1(1), � 2(5)nervous system, � 1(1), � 3(13), 13neuron, � 1(1)neurotransmitter, � 1(1)

O occipital lobe, � 1(1), � 4(19), 25

P pancreas, � 1(1), � 5(33), 35parasympathetic nervous system, 14parietal lobe, � 1(1), � 4(19)peripheral nervous system, � 1(1), � 3(13)peripheral nervous system (PNS), 13PET scan, � 1(1), � 4(19)phenotype, � 1(1), � 2(5), 5Phineas Gage, � 1(1), � 4(19)pituitary gland, � 1(1), � 5(33), 34polygenic, � 1(1), � 2(5)pons, � 1(1), � 4(19), 28positron emission tomography, � 1(1), � 4(19)prefrontal cortex, � 1(1), � 4(19), 22psychobiology, � 1(1)psychotropic, � 1(1)

Punnett square, 6, 7

R range of reaction, � 1(1), � 2(5), 8receptor, � 1(1)recessive allele, � 1(1), � 2(5), 6resting potential, � 1(1)reticular formation, � 1(1), � 4(19), 27reuptake, � 1(1)

S Schiavo, � 1(1), � 4(19)schizophrenia, 8semipermeable membrane, � 1(1)sickle-cell anemia, � 1(1), � 2(5)sodium-potassium pump, � 1(1)soma, � 1(1)somatic nervous system, � 1(1), � 3(13), 14somatosensory cortex, � 1(1), � 4(19)spinal cord, � 1(1), � 4(19), 19substantia nigra, � 1(1), � 4(19), 27sulci, � 1(1), � 4(19), 19sympathetic nervous system, � 1(1), � 3(13),14synapse, � 1(1)synaptic vesicle, � 1(1)

T temporal lobe, � 1(1), � 4(19), 24terminal button, � 1(1)thalamus, � 1(1), � 4(19), 25theory of evolution by natural selection, 5threshold of excitation, � 1(1)thyroid gland, � 1(1), � 5(33), 35trait, � 1(1), � 2(5)

V ventral tegmental area, � 1(1), � 4(19)ventral tegmental area (VTA), 27

W Wernicke's area, � 1(1), � 4(19)Wernicke's area, 24


ATTRIBUTIONS 43

Attributions

Collection: Chapter 3: Biopsychology SWEdited by: Stephen E. WisecarverURL: http://cnx.org/content/col11821/1.1/License: http://creativecommons.org/licenses/by/4.0/

Module: "3.0 Introduction to Biopsychology"By: Stephen E. WisecarverURL: http://cnx.org/content/m55747/1.1/Pages: 1-3Copyright: Stephen E. WisecarverLicense: http://creativecommons.org/licenses/by/4.0/Based on: IntroductionBy: OpenStax CollegeURL: http://cnx.org/content/m49029/1.4/

Module: "3.1 Human Genetics SW"Used here as: "3.1 Human Genetics"By: Stephen E. WisecarverURL: http://cnx.org/content/m55749/1.2/Pages: 5-11Copyright: Stephen E. WisecarverLicense: http://creativecommons.org/licenses/by/4.0/Based on: Human GeneticsBy: OpenStax CollegeURL: http://cnx.org/content/m48993/1.5/

Module: "3.3 Parts of the Nervous System SW"Used here as: "3.2 Parts of the Nervous System"By: Stephen E. WisecarverURL: http://cnx.org/content/m55750/1.1/Pages: 13-18Copyright: Stephen E. WisecarverLicense: http://creativecommons.org/licenses/by/4.0/Based on: Parts of the Nervous SystemBy: OpenStax CollegeURL: http://cnx.org/content/m49005/1.6/

Module: "3.4 The Brain and Spinal Cord SW"Used here as: "3.3 The Brain and Spinal Cord"By: Stephen E. WisecarverURL: http://cnx.org/content/m55756/1.1/Pages: 19-32Copyright: Stephen E. WisecarverLicense: http://creativecommons.org/licenses/by/4.0/Based on: The Brain and Spinal CordBy: OpenStax CollegeURL: http://cnx.org/content/m49006/1.7/


44 ATTRIBUTIONS

Module: "3.5 The Endocrine System SW"Used here as: "3.4 The Endocrine System"By: Stephen E. WisecarverURL: http://cnx.org/content/m55757/1.1/Pages: 33-37Copyright: Stephen E. WisecarverLicense: http://creativecommons.org/licenses/by/4.0/Based on: The Endocrine SystemBy: OpenStax CollegeURL: http://cnx.org/content/m49007/1.6/


Chapter 3: Biopsychology SWHuman genetics cells of the nervous system parts of the nervous system brain and spinal cord endocrinesystem

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chapter 3: biopsychology sw - cnx

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