Chapter 3: The Biology of Behavior

BRIEF CHAPTER OUTLINE

Genes and Behavior

The Complex Connection Between Genes and Behavior

Polygenic Influence on Behavior

Genes and the Environment

Twin Studies

Adoption Studies

Twin-Adoption Studies

Gene-by-Environment Studies

Epigenetics: How the Environment Changes Gene Expression

The Nervous System

Organization of the Nervous System

The Cells of the Nervous System: Glial Cells and Neurons

The Structure and Types of Neurons

Neural Communication: The Action Potential

Communication Between Neurons: Neurotransmission

Common Neurotransmitters

Summary of the Steps in Neural Transmission

The Brain

Evolution of the Human Brain

Overview of Brain Regions

Hindbrain

Midbrain

Forebrain

The Limbic System

The Cerebrum and the Cerebral Cortex

Cerebral Hemispheres

Communication Between the Hemispheres

Brain Plasticity and Neurogenesis

Breaking New Ground: Neurogenesis in the Adult Brain

Psychology in the Real World: Using Progesterone to Treat Brain Injury

Measuring the Brain

Electroencephalography

Magnetic Resonance Imaging (MRI) and Functional MRI (fMRI)

Positron Emission Tomography (PET)

The Endocrine System

Making Connections in the Biology of Behavior: What Esref Armagan’s Story Reveals about the Brain

Chapter Review

EXTENDED CHAPTER OUTLINE

GENES AND BEHAVIOR

· Heredity influences much of behavior and experience.

· DNA (deoxyribonucleic acid): a large coiled molecule that resides in every cell in the body, except red blood cells; contains all the information needed for human development and function.

· Chromosomes: DNA is packaged with proteins to form structures called chromosomes.

· Genes: small segments of DNA that contain the blueprints or plans for the production of proteins. Genes influence specific characteristics, such as height or hair color, by directing the synthesis of proteins.

· Genome: all of the genetic information contained in most of our cells.

· Genes occur in pairs of alleles, which are different forms of each other. We inherit one allele from each one of our parents. Each gene in an allele pair can produce different characteristics.

· Dominant genes: show their effect even if there is only one copy of that gene in the pair. So if you have one brown and one blue eye allele, chances are you will have brown eyes.

· Recessive genes show their effects only when both alleles are the same. For example, a person will have blue eyes only if he or she inherits an allele for blue eyes from each parent.

· Behavioral genetics: an area that looks at nature versus nurture in given traits.

· Four principles of behavioral genetics are especially relevant in psychology:

The Complex Connection Between Genes and Behavior

· Genes seldom make behaviors a certainty. Typically, a specific gene plays only a small part in creating a given behavior, and genetic influence itself is only part of the story.

Polygenic Influence on Behavior

· The second principle of behavioral genetics is that traits tend to be influenced by many genes.

· Monogenic transmission: passing on of traits determined by a single gene. Example: Huntington’s disease.

· Polygenic transmission: many genes interact to create a single characteristic. Examples: skin color, personality traits, height, and weight.

· CONNECTION: Genetics influence about 50% of the differences in performance on intelligence tests, leaving about the same amount to be explained by non-genetic influences (see Chapter 10).

Genes and the Environment

· Heritability: the extent to which a characteristic is influenced by genes.

· Researchers use twin studies, adoption studies, twin-adoption studies, and gene-by-environment studies to study heritability.

Twin Studies

· Fraternal twins: two different eggs fertilized by two different sperm, as are any two siblings.

· Identical twins: a single fertilized egg that splits into two independent cells.

· Twin studies: compare pairs of fraternal and identical twins. Fraternal twins share half as many genes on average as identical twins (50% compared to 100%). If a trait is genetically influenced, identical twins should be more similar in that trait than fraternal twins would be. If genetics plays no role, identical twins will be no more alike than fraternal twins in that specific trait.

Adoption Studies

· Adoption studies: compare adopted individuals to their biological and adoptive parents. Adopted children share none of their genes but most of their environment with their adopted families.

· If environment is most influential, people will be more similar on a trait to their adoptive parents than to their biological parents. But if genetics is more influential, people will be more similar to their biological parents than to their adoptive parents.

Twin-Adoption Studies

· Twin-adoption studies: study twins, both identical and fraternal, who were raised apart (adopted) and those who were raised together.

Gene-by-Environment Studies

· Gene-by-environment interaction research: directly measures genetic similarity in parts of the genome itself.

· Researchers locate a genetic marker, a variant sequence of DNA that is present in some people and not in others. They then assess crucial environmental experiences in people with and without the genetic marker, such as trauma and stress. Finally, they determine whether individuals with the genetic marker who were raised in a particular environment are more or less likely to develop some trait, such as extraversion, violence, intelligence, or schizophrenia.

· Polymorphism: Individuals differ not so much in whether or not they have a gene, but rather in the form the gene takes.

· CONNECTION: How do stress and abuse interact with genes to increase vulnerability to depression? (See Chapter 15.)

Nature-Nurture Pointer: Living in an abusive or stressful environment is more likely to lead to depression in individuals who have a short form of a specific gene.

Epigenetics: How the Environment Changes Gene Expression

· Environmental events influence how and when genes are activated or deactivated.

· Epigenetics: occurs when there is a change in the way genes get expressed—that is, are activated or deactivated—without changing the sequence of DNA.

Nature-Nurture Pointer: A mother’s behavior may influence the expression of genes in her offspring.

THE NERVOUS SYSTEM

Organization of the Nervous System

· Central nervous system (CNS): includes the brain and spinal cord.

· Peripheral nervous system: consists of all the other nerve cells in the body, including the somatic nervous system and the autonomic nervous system.

· Somatic nervous system: transmits sensory information to the brain and spinal cord and from the brain and spinal cord to the skeletal muscles.

· Autonomic nervous system (ANS): serves the involuntary systems of the body, such as the internal organs and glands.

· The ANS has two main branches:

o Sympathetic nervous system: responsible for flight-or-fight response; that is, it activates bodily systems in times of emergency. The main function of the sympathetic nervous system is activating the body; for example, by increasing the heart rate, dilating the pupils of the eyes, and inhibiting digestion.

o Parasympathetic nervous system: The function of the parasympathetic branch of the ANS is largely one of relaxation or returning the body to a less active, restful state.

The Cells of the Nervous System: Glial Cells and Neurons

· The central nervous system is made up of two types of cells: glial cells and neurons.

· Glial cells hold the CNS together. Specifically, they provide structural support, promote efficient communication between neurons, and remove cellular debris.

· Neurons: cells that process and transmit information throughout the nervous system. Within the brain, neurons receive, integrate, and generate messages. By most estimates, there are more than 10 billion neurons in the human brain. Each neuron has approximately 10,000 connections to other neurons, making for literally trillions and trillions of neural connections in the human brain!

· Three major principles of how neurons communicate with other neurons:

1. Neurons are the building blocks of the nervous system. All the major structures of the brain are composed of neurons.

2. Information travels within a neuron in the form of an electrical signal by action potentials.

3. Information is transmitted between neurons by means of chemicals called neurotransmitters.

The Structure and Types of Neurons

· Neurons are the building blocks of the nervous system. All the major structures of the brain are composed of neurons.

· Three major parts of the neuron: cell body, dendrites, and axon.

1. Soma: the cell body - contains a nucleus and other components needed for cell maintenance and function. Within the nucleus itself are the genes that direct neural change and growth.

2. Axon: a long projection from the soma, which transmits electrical impulses toward the adjacent neuron.

3. Dendrites: fingerlike projections that receive incoming messages from other neurons.

· Myelination: the axons of some neurons become wrapped in a fatty myelin sheath. Just like rubber around an electrical wire, the myelin sheath insulates the axon so that the impulse travels more efficiently.

· Synapse: the junction between the axon and the adjacent neuron.

· Terminal button: located at the end of the axon; contains tiny sacs of neurotransmitters.

· When an electrical impulse reaches the terminal button, it triggers the release of neurotransmitter molecules into the gap between neurons, known as the synaptic cleft.

· Three kinds of neurons:

1. Sensory neurons: receive incoming sensory information from the sense organs (eye, ear, skin, tongue, and nose).

2. Motor neurons: take commands from the brain and carry them to the muscles of the body.

· One type of motor neuron that is active when we observe others making an action as well as when performing the same action are mirror neurons, and they appear to play an important role in learning.

3. Interneurons are neurons that communicate only with other neurons. Most interneurons connect neurons in one part of the brain with neurons in another part. Interneurons are the most common kind of neuron in the brain, outnumbering sensory and motor neurons by at least 10 to 1.

Neural Communication: The Action Potential

· Neural communication is a two-step process.

1. An impulse travels one way from the dendrites along the axon and away from the soma, a process that is both electrical and chemical; this is known as an action potential.

2. The impulse releases chemicals at the tips of the neurons, which are released into the synaptic cleft to transmit the message to another neuron. This is known as neurotransmission.

· Action potential: the positively charged impulse that moves down an axon.

· This happens by virtue of changes in the neuron itself. The neuron, like all cells in the body, is surrounded by a membrane separating the fluid inside the cell from the fluid outside the cell.

· This membrane is somewhat permeable, which means that it lets only certain particles move through it. The fluid inside and outside the cell contains chemically charged particles called ions.

· When a neuron is in the resting state, the electrical charge inside the axon is -70 millivolts (mV), where the minus sign indicates that the charge is negative. This value is the resting potential of the neuronal membrane.

· Neurons do not stay at rest, however. An incoming impulse can temporarily change the potential.

· While the neuron is returning to its resting state, it temporarily becomes super negatively charged. During this brief period, known as the refractory period, the neuron cannot generate another action potential.

· We can summarize the electrical changes in the neuron from resting to action potential to refractory period and back to the resting state as follows:

1. Resting potential is -70mV.

2. If an incoming impulse causes sufficient depolarization, voltage-dependent sodium channels open and sodium ions flood into the neuron.

3. The influx of positively charged sodium ions quickly raises the membrane potential to +40 mV. This surge in positive charge inside the cell is the action potential.

4. When the membrane potential reaches +40 mV, the sodium channels close and potassium channels open. The outward flow of positively charged potassium ions restores the negative charge inside the cell.

· How fast are action potentials, anyway? About 100 feet per second!

· Thresholds – a point of no return; once the charge inside the neuron exceeds this threshold, the action potential fires and it always fires with the same intensity. This is known as the all-or-none principle. In other words, an action potential either fires or it does not. There is no halfway. If the depolarization threshold is not reached, there is no action potential.

Communication Between Neurons: Neurotransmission

· The arrival of an action potential at the terminal buttons of a neuron triggers the second phase in neural transmission – the release of neurotransmitters into the synaptic cleft to pass on the impulse to other neurons.

· Neurotransmitters are packaged in sacs called synaptic vesicles in the terminal button.

· Not all of the neurotransmitter molecules that are released into the synaptic cleft bind with receptors. Usually, excess neurotransmitter remains in the synaptic cleft and needs to be removed.

· There are two ways to remove excess neurotransmitter from the synaptic cleft:

· Enzymatic degradation: enzymes specific to that neurotransmitter bind with the neurotransmitter and destroy it.

· Reuptake: returns excess neurotransmitter to the sending, or pre-synaptic, neuron for storage in vesicles and future use.

· After a neurotransmitter has bound to a receptor on the postsynaptic neuron, a series of changes occur in that neuron’s cell membrane. These small changes in membrane potential are called graded potentials. These are not all-or-none like action potentials. Rather, they affect the likelihood that an action potential will occur in the receiving neuron.

· Some neurotransmitters excite and others inhibit.

Common Neurotransmitters

· Within the past century, researchers have discovered at least 60 distinct neurotransmitters and learned what most of them do. Of the known neurotransmitters, the ones that have the most relevance for the study of human thought and behavior are acetylcholine, epinephrine, norepinephrine, dopamine, serotonin, GABA, and glutamate.

· Neurotransmitters are found only in the brain. They are synthesized inside the neuron for the purpose of neurotransmission.

· Acetylcholine (ACh): controls muscle movement and plays a role in mental processes such as learning, memory, attention, sleeping, and dreaming.

· Dopamine: released in response to behaviors that feel good or are rewarding to the person or animal. Because dopamine activity makes us feel good, many drug addictions involve increased dopamine activity.

· Epinephrine and norepinephrine: primarily have energizing and arousing properties. Epinephrine was formerly called “adrenaline.” Both epinephrine and norepinephrine are produced in the brain and by the adrenal glands that rest on the kidneys.

· Serotonin: involved in dreaming and in controlling emotional states, especially anger, anxiety, and depression. People who are generally anxious and/or depressed often have low levels of serotonin.

· CONNECTION: Common treatments for depression, which is thought to result in part from a deficiency of the neurotransmitter serotonin, block the reuptake of serotonin at the synapse, making more of it available for binding with postsynaptic neurons (see Chapter 16).

· Gamma-aminobutyric acid, or GABA: a major inhibitory neurotransmitter in the brain. Remember that inhibitory neurotransmitters tell the postsynaptic neurons NOT to fire. It slows CNS activity and is necessary for the regulation and control of neural activity. Without GABA, the central nervous system would have no “brakes” and could run out of control.

· Glutamate: the brain’s major excitatory neurotransmitter. Glutamate is important in learning, memory, neural processing, and brain development. More specifically, glutamate facilitates growth and change in neurons, and the migration of neurons to different sites in the brain, all of which are basic processes of early brain development.

· CONNECTION: Glutamate doesn’t function properly in people with schizophrenia, and so they become confused. Restoring glutamate function is the focus of new treatments for schizophrenia. (See Chapters 15 and 16.)

Summary of the Steps in Neural Transmission

· The information in neural transmission always travels in one direction in the neuron –

from the dendrites to the soma to the axon to the synapses. This process begins with information received from the sense organs, which generates a nerve impulse.

· The dendrites are the first to receive a message from other neurons. That message, in the form of an electrical and chemical impulse, is then integrated in the soma. While being integrated in the soma, they do not yet create an action potential. They need to be tallied or summed.

· If the excitatory messages pass the threshold intensity, an action potential will occur, sending the nerve impulse down the axon. If the inhibitory messages win out, the likelihood of the postsynaptic neuron firing goes down.

· When the nerve impulse, known as the action potential, travels down the axon in a wave-like fashion, it jumps from one space in the axon’s myelin sheath to the next. The nerve impulse travels down the axon because channels are opening and closing in the axon’s membrane. Passing in and out of the membrane are ions, mostly sodium and potassium.

· This impulse of opening and closing channels travels wave-like down the length of the axon, where the electrical charge stimulates the release of neurotransmitter molecules in the cell’s synapses and terminal buttons.

· The neurotransmitters are released into the space between neurons known as the synaptic cleft. Neurotransmitters released by the pre-synaptic neuron then connect with receptors in the membrane of the postsynaptic neuron.

· This connection or binding of neurotransmitter to receptor creates electrical changes in the postsynaptic neuron’s cell membrane, at its dendrites. Some neurotransmitters tend to be excitatory (for example, glutamate) and increase the likelihood of an action potential. Others tend to be inhibitory (for example, GABA) and decrease the likelihood of an action potential.

· The transmission process is repeated in postsynaptic neurons, which now become pre-synaptic neurons.

THE BRAIN

· The brain is a collection of neurons and glial cells that controls all the major functions of the body; produces thoughts, emotions, and behavior; and makes us human.

Evolution of the Human Brain

· The human brain has been shaped, via natural selection, by the world in which humans have lived.

· It is worth noting here that brains do not fossilize to allow a present-day analysis, but the skulls that hold them do. By looking at the size and shape of skulls from all animals and over very long time periods, scientists can glean something about how and when human brains evolved.

· The earliest ancestors of humans appeared in Africa about 6 million years ago. One of our closest evolutionary relatives, the Neanderthals (Homo neanderthalensis) lived from about 350,000 to 28,000 years ago, when they were replaced by our species (Homo sapiens).

· Neanderthals had brains slightly larger on average than modern humans. Nevertheless, these folks did not produce highly complex tools, may have had very rudimentary language, and never made symbolic pieces of art (at least, none that has been found). In other words, their brains were modern in size but not modern in function.

· It is possible, therefore, that the human brain took up to 100,000 years to become fully wired and complex, all the while staying the same overall size.

Overview of Brain Regions

· The three major regions of the brain, in order from earliest to develop to newest, are the hindbrain, the midbrain, and the forebrain.

Hindbrain

· The oldest brain region is the hindbrain, the region directly connected to the spinal cord. Hindbrain structures regulate breathing, heart rate, arousal, and other basic functions of survival. There are three main parts of the hindbrain: the medulla, the pons, and the cerebellum.

1. The medulla regulates breathing, heart rate, and blood pressure. It also is involved in various kinds of reflexes, such as coughing, swallowing, sneezing, and vomiting.

Reflexes are inborn and involuntary behaviors that are elicited by very specific stimuli.

2. Pons means “bridge,” and the pons indeed serves as a bridge between lower brain regions and higher midbrain and forebrain activity.

3. The cerebellum, or “little brain,” contains more neurons than any other single part of the brain. It is responsible for body movement, balance, coordination, and fine motor skills like typing and piano playing. The cerebellum is important in cognitive activities such as learning and language.

Midbrain

· The next brain region to evolve after the hindbrain is the smallest of the three major areas. Different parts of the midbrain control the eye muscles, process auditory and visual information, and initiate voluntary movement of the body. The midbrain, the medulla, and the pons together are sometimes referred to as the brain stem.

· Running through both the hindbrain and the midbrain is a network of nerves called the reticular formation. This is crucial in arousal: both waking up and falling asleep.

Forebrain

· The last major brain region to evolve is the largest part of the human brain, the forebrain. It consists of the cerebrum and numerous other structures, including the thalamus and the limbic system. Areas in the forebrain control cognitive, sensory, and motor function, and regulate temperature, reproductive functions, eating, sleeping, and the display of emotions.

· Most forebrain structures are bilateral; that is, there are two of them, one on each side of the brain.

· Thalamus: receives input from the ears, eyes, skin, or taste buds, and relays sensory information to the part of the cerebral cortex most responsible for processing that specific kind of sensory information.

The Limbic System

· In the middle of the brain directly around the thalamus lies a set of structures important in emotion and motivation that are referred to as the limbic system. This system includes the hypothalamus, the hippocampus, the amygdala, and the cingulate gyrus.

· Hypothalamus: the master regulator of almost all major drives and motives we have, including hunger, thirst, temperature, and sexual behavior. It controls the pituitary gland, and thus, the production of hormones.

· Hippocampus: key in memory systems. Sensory information from the eyes, ears, skin, nose, and taste buds goes to the hippocampus. If these events are important enough, they are established as lasting memories.

· CONNECTION: Psychologists learned how essential the hippocampus is in memory and learning through a case study of “H.M.,” who had these structures surgically removed. (See Chapter 7 and Chapter 8.)

· Amygdala: a small, almond-shaped structure located directly in front of the hippocampus. Anatomically, the amygdala has connections with many other areas of the brain, including the following structures that appear to be involved in emotion and memory: the hypothalamus, which controls the autonomic nervous system; the hippocampus, which plays a crucial role in memory; the thalamus, which contains neurons that receive information from the sense organs; and the cerebral cortex.

· By virtue of its prime location, the amygdala plays a key role in determining the emotional significance of stimuli, especially when they evoke fear.

· CONNECTION: Test your ability to recognize emotion in the facial expressions of others and learn more about the role of the amygdala in emotion (see Chapter 11).

· Basal ganglia: a collection of structures surrounding the thalamus involved in voluntary motor control.

· Cingulate gyrus: a belt-like structure in the middle of the brain. Portions of the cingulate gyrus, in particular the front part, play an important role in attention and cognitive control.

The Cerebrum and Cerebral Cortex

· The uppermost portion of the brain, the cerebrum is folded into convolutions and divided into two large hemispheres.

· The outer layer is called the cerebral cortex. The cortex is only about one-tenth to one-fifth of an inch thick, yet it is in this very thin layer of brain that much of human thought, planning, perception, and consciousness take place.

· The cerebrum is composed of four large areas called lobes, each of which carries out distinct functions.

1. The frontal lobes: in the front of the brain, they make up one-third of the area of the cerebral cortex. The frontal lobe carries out many important functions, including attention, holding things in mind while we solve problems, planning, abstract thinking, control of impulses, creativity, and social awareness. The frontal lobes are more interconnected with other brain regions than any other part of the brain and therefore are able to integrate much brain activity.

· Primary motor cortex: one important region of the frontal lobe, descending from the top of the head toward the center of the brain; electrical stimulation to this area causes different parts of the body to move.

· The frontal lobes are also the “youngest” part of the brain, evolving to a greater extent in modern humans than in any other species. Similarly, the frontal lobes are the last part of the brain to finish developing in individuals; they do not become mature until we reach our early 20s.

2. The parietal lobes: make up the top and rear sections of the brain and play an important role in the sensation and perception of touch. The front-most portion of the parietal lobes is the somatosensory cortex. When different parts of the body are touched, different parts of this strip of cortex are activated.

3. The temporal lobes: lie directly below the frontal lobe and parietal lobe and right behind the ears. The temporal lobes have many different functions, but the main one is hearing. Home of the auditory cortex, it is in this region where sound information arrives from the thalamus for processing. The temporal lobes also house and connect with the hippocampus and amygdala, and so it is also involved in memory and emotion.

4. The occipital lobes: Located in the back of the brain, the optic nerve travels from the eye to the thalamus and then to the occipital lobes—specifically, to the primary visual cortex. Visual information is processed in the visual cortex.

· Insula: a small structure that resides deep inside the cerebrum, in the area that separates the temporal lobe from the parietal lobe. The insula is active in the perception of bodily sensations, emotional states, empathy, and addictive behavior.

Cerebral Hemispheres

· The human cerebrum is split down the middle into two hemispheres that differ in shape, size, and function.

· The left hemisphere: processes information in a more focused and analytic manner; responsible for language

· The right hemisphere integrates information in a more holistic, or broader, manner.

· Corpus callosum: a thick band of nerve fibers connecting the two hemispheres of the brain, allowing communication between them.

· Aphasia: a deficit in the ability to speak or comprehend language.

· Broca’s area: responsible for the ability to produce speech.

· Wernicke’s area: responsible for speech comprehension. Damage results in fluent, grammatical streams of speech that lack meaning.

Communication Between the Hemispheres

· All communication between the two hemispheres occurs when information travels via the corpus callosum.

· Previous medical evidence had suggested that cutting the bundle of nerves between the two hemispheres could stop epileptic seizures.

· In performing this surgery, they found that not only did the man’s seizures stop, but there was no noticeable change in his personality or intelligence. However, they found the man could not name things that were presented to his left visual field, but he could do so with things presented to his right visual field.

· Language—both speech and comprehension—resides in the left hemisphere of the human brain.

· Information from our right visual field (the right portion of the visual scope of each eye) goes to the left occipital cortex, while information from the left visual field (the left portion of the visual scope of each eye) goes to the right occipital cortex.

· This case shows that we can know something even if we cannot name it.

Brain Plasticity and Neurogenesis

· Since the 1990s, numerous principles of brain plasticity have emerged.

· Neuroplasticity: the brain’s ability to adopt new functions, reorganize itself, or make new neural connections throughout life, as a function of experience.

· Almost every major structure of the neuron is capable of experience-based change.

· Not all regions of the brain are equally plastic. For example, the part of the brain most involved in learning, the hippocampus, is more plastic than just about any other part of the brain.

· Brain plasticity varies with age, being strongest in infancy and early childhood and gradually decreasing with age.

· CONNECTION: If a person is not exposed to language much before mid to late childhood, the ability to speak is limited because the brain loses some of its plasticity as we age. (See Chapter 9.)

Nature-Nurture Pointer: Throughout life, the brain can adopt new functions, reorganize itself, or make new neural connections, as a function of experience.

· Neurogenesis: the process of developing new neurons.

· Aborization: The growth and formation of new dendrites.

· Synaptogenesis: the formation of entirely new synapses or connections with other neurons that is the basis of learning.

Nature-Nurture Pointer: In blind people, the brain compensates for deficits in vision by reorganizing and rewiring the visual cortex to process sound.

Breaking New Ground: Neurogenesis in the Adult Brain

· See “Breaking New Ground” section for detailed explanation.

Psychology in the Real World: Using Progesterone to Treat Brain Injury

· In his early research with brain-damaged rats, Stein saw that many (though not all) of the female rats recovered faster than males. He wondered if female sex hormones might be responsible for the difference in recovery times.

· Further studies helped Stein show that progesterone, a female sex hormone that is released in significant amounts during pregnancy and has a protective effect on the fetus, may help heal the injured brain.

· His progressive, cumulative finding was that progesterone helps the brain repair itself after injury.

· Wright, Kellermen, Stein, and colleagues (2007) studied 100 people who came into the emergency room with traumatic brain injury. Patients were randomly assigned either to get treatment as usual or to get a large amount of progesterone. The researchers found that 30 days after injury, those who had received progesterone therapy were more likely to have survived and recovered than those on standard therapy.

· Progesterone can protect or rebuild the blood-brain barrier (a membrane that protects the brain from chemicals circulating in the bloodstream), reduce or offset fluid accumulation and swelling of the brain after injury, and limit neuron death. Furthermore, progesterone, a steroid, is released by neurons in the brains of men and women.

· These substances may play an important role in neuroplasticity; progesterone therapy shows great promise as a treatment for brain injury, a devastating condition that previously held a very poor prognosis for nearly all those who sustained such injuries.

MEASURING THE BRAIN

· To be able to look into the brain as it is working was a long-time fantasy of philosophers and scientists. In the last few decades, this has become possible. At least three distinct techniques are now commonly used to measure brain activity in psychological research.

Electroencephalography

· Electroencephalography (EEG): used to record the electrical activity of the brain by placing electrodes on a person’s scalp. EEG is superior to other brain imaging techniques in showing when brain activity occurs. It is not very accurate at indicating precisely where activity occurs.

· Event-related potential (ERP): a special technique that takes electrical activity from raw EEG data to measure cognitive processes. As it is based on EEG, ERPs provide excellent temporal resolution (they show brain activity linked with psychological tasks almost immediately in time) but poor spatial resolution.

Magnetic Resonance Imaging (MRI) and Functional MRI (fMRI)

· MRI stands for magnetic resonance imaging: uses magnetic fields to produce very finely detailed images of the structure of the brain and other soft tissues. MRI does not tell us anything about activity, just structures.

· Functional MRI (fMRI): tells us where activity in the brain is occurring during particular tasks by tracking blood oxygen use in brain tissue. It is not entirely clear exactly how directly fMRI images reflect underlying neural activity, although some studies suggest a fairly direct correlation with processing in certain cortical areas.

Positron Emission Tomography (PET)

· Positron Emission Tomography (PET): measures blood flow to brain areas in the active brain. From these measurements, researchers and doctors can determine which brain areas are active during certain situations.

THE ENDOCRINE SYTEM

· In the endocrine system, glands secrete chemicals called hormones, which travel through the bloodstream to tissues and organs all over the body and regulate body functions like metabolism, growth, reproduction, mood, and other processes.

· The hypothalamus is not a gland but is depicted as part of the endocrine system because it controls the pituitary gland.

· Pituitary gland: the master gland of the body, because it controls the release of hormones from glands elsewhere in the body.

· Thyroid: a gland that sits in the neck region and releases hormones that control the rate of metabolism.

· Metabolism is the process by which the body converts nutritional substances into energy.

· Pancreas: release hormones, including insulin, that play a vital role in regulating the blood sugar levels.

· The sex glands (ovaries and testes) release sex hormones that lead to development of sex characteristics (such as body hair and breast development), sex drive, and other aspects of sexual maturation.

· Adrenal glands: release hormones in response to stress and emotions.

o Catecholamines: a class of chemicals that includes the neurotransmitters dopamine, norepinephrine, and epinehprhine.

o Cortisol: is responsible for maintaining the activation of bodily systems during prolonged stress.

MAKING CONNECTIONS: What Esref Armagan’s Story Reveals about the Brain

· See “Making the Connections” section for detailed explanation.

KEY TERMS

aborization: the growth and formation of new dendrites.

acetylcholine (ACh): a neurotransmitter that controls muscle movement and plays a role in mental processes such as learning, memory, attention, sleeping, and dreaming.

action potential: the impulse of positive charge that runs down an axon.

adoption studies: research into hereditary influence in which adopted people are compared to their biological and adoptive parents.

adrenal glands: structures that sit atop each kidney; they release hormones important in stress, emotions, regulation of heart rate, blood pressure, and blood sugar regulation.

alleles: pairs or alternate forms of a gene.

all-or-none principle: the idea that once the threshold has been crossed, an action potential either fires or it does not; there is no half-way.

amygdala: a small, almond-shaped structure located directly in front of the hippocampus; has connections with many important brain regions and is important for processing emotional information, especially that related to fear.

aphasia: deficit in the ability to speak or comprehend language.

autonomic nervous system (ANS): all the nerves of the peripheral nervous system that serve involuntary systems of the body, such as the internal organs and glands.

axon: a long projection that extends from a neuron’s soma; it transmits electrical impulses toward the adjacent neuron and stimulates the release of neurotransmitters.

basal ganglia: a collection of structures surrounding the thalamus involved in voluntary motor control.

behavioral genetics: the scientific study of the role of heredity in behavior.

Broca’s area: an area in the left frontal lobe responsible for the ability to produce speech.

catecholamines: a class of chemicals released from the adrenal glands that function as hormones and as neurotransmitters; they control ANS activation and include the neurotransmitters dopamine, norepinephrine, and epinephrine

central nervous system (CNS): the part of the nervous system that comprises the brain and spinal cord.

cerebellum: a hindbrain structure involved in body movement, balance, coordination, fine-tuning motor skills, and cognitive activities such as learning and language.

cerebral cortex: the thin outer layer of the cerebrum, in which much of human thought, planning, perception, and consciousness takes place.

cerebrum: each of the large halves of the brain that are covered with convolutions, or folds.

chromosomes: coiled-up threads of DNA.

cingulate gyrus: a belt-like structure around the corpus callosum that plays an important role in attention and cognitive control.

contralaterality: the fact that one side of the brain controls movement on the opposite side.

corpus callosum: the nerve fibers that connect the two hemispheres of the brain.

cortisol: a hormone released by the adrenal glands; responsible for maintaining the activation of bodily systems during prolonged stress.

dendrites: fingerlike projections from a neuron’s soma that receive incoming messages from other neurons.

DNA (deoxyribonucleic acid): a large molecule that contains genes.

dominant genes: genes that show their effects even if there is only one copy of that gene in the pair.

dopamine: a neurotransmitter released in response to behaviors that feel good or are rewarding to the person or animal; also involved in voluntary motor control.

electroencephaolography (EEG): a method for measuring brain activity in which the electrical activity of the brain is recorded from electrodes placed on a person’s scalp.

endocrine system: bodily system of glands that secrete and regulate hormones.

enzymatic degradation: a way of removing excess neurotransmitter from the synapse, in which enzymes specific for that neurotransmitter bind with the neurotransmitter and destroy it.

epigenesis: change in the way genes are turned on or off without a change in the sequence of DNA.

epinephrine: also known as adrenaline, a neurotransmitter that arouses bodily systems (such as increasing heart rate).

event-related potential (ERP): a special technique that extracts electrical activity from raw EEG data to measure cognitive processes.

fraternal twins: twins that develop from two different eggs fertilized by two different sperm.

functional magnetic resonance imaging (fMRI): a brain imaging technique that uses magnetic fields to produce very finely detailed images of the activity of areas of the brain and other soft tissues.

GABA (gamma-aminobutyric acid): a major inhibitory neurotransmitter in the brain that tells post-synaptic neurons not to fire; it slows CNS activity and is necessary to regulate and control neural activity.

gene-by-environment interaction research: a method of studying heritability by comparing genetic markers that allows researchers to assess how genetic differences interact with environment to produce certain behaviors in some people but not in others.

genes: small segments of DNA that contain information for producing proteins.

genome: all the genetic information in DNA.

glial cells: the cells of the central nervous system that provide structural support, promote efficient communication between neurons, and serve as scavengers, removing cellular debris.

glutamate: a major excitatory neurotransmitter in the brain that increases the likelihood that a postsynaptic neuron will fire; important in learning, memory, neural processing, and brain development.

graded potentials: small changes in membrane potential that by themselves are insufficient to trigger an action potential.

heritability: the extent to which a characteristic is influenced by genetics.

hippocampus: a limbic structure that wraps itself around the thalamus; plays a vital role in learning and memory.

hormones: chemicals, secreted by glands, that travel in the bloodstream and carry messages to tissues and organs all over the body.

hypothalamus: a limbic structure; the master regulator of almost all major drives and motives we have, such as hunger, thirst, temperature, and sexual behavior; also controls the pituitary gland.

identical twins: twins that develop from a single fertilized egg that splits into two independent cells.

insula: a small structure inside the cerebrum that plays an important role in the perception of bodily sensations, emotional states, empathy, and addictive behavior.

interneurons: neurons that communicate only with other neurons.

ions: chemically charged particles that predominate in bodily fluids; found both inside and outside cells.

magnetic resonance imaging (MRI): a brain imaging technique that uses magnetic fields to produce very finely detailed images of the structure of the brain and other soft tissues.

medulla: a hindbrain structure that extends directly from the spinal cord; regulates breathing, heart rate, and blood pressure.

mirror neurons: nerve cells that are active when we observe others making an action as well as when we are performing the same action.

monogenic transmission: the hereditary passing on of traits determined by a single gene.

motor neurons: nerve cells that carry commands for movement from the brain to the muscles of the body.

myelin sheath: the fatty substance wrapped around some axons, which insulates the axon, making the nerve impulse travel more efficiently.

neurogenesis: the development of new neurons.

neurons: the cells that process and transmit information in the nervous system.

neuroplasticity: the brain’s ability to adopt new functions, reorganize itself, or make new neural connections throughout life, as a function of experience.

neurotransmitters: chemicals that transmit information between neurons, across the synapses.

norepinephrine: a neurotransmitter that plays an important role in the sympathetic nervous system, energizing bodily systems, and increasing mental arousal and alertness.

parasympathetic nervous system: the branch of the autonomic nervous system that usually relaxes or returns the body to a less active, restful state.

peripheral nervous system: the part of the nervous system that comprises all the nerve cells in the body outside of the central nervous system.

pituitary gland: the master gland of the body; among the numerous hormones it secretes are hormones that control the release of hormones from glands elsewhere in the body.

polygenic transmission: the process by which many genes interact to create a single characteristic.

pons: a hindbrain structure that serves as a bridge between lower brain regions and higher midbrain and forebrain activity.

positron emission tomography (PET): brain imaging technique that measures blood flow to areas in the active brain; indicates which brain areas are active during certain situations.

recessive gene: genes that show their effects only when both alleles are the same.

reflexes: inborn and involuntary behaviors—such as coughing, swallowing, sneezing, or vomiting—that are elicited by very specific stimuli.

refractory period: the span of time, after an action potential has been generated, when the neuron is returning to its resting state and the neuron cannot generate an action potential.

resting potential: the difference in electrical charge between the inside and outside of the axon when the neuron is at rest.

reticular formation: a network of nerve fibers that runs up through both the hindbrain and the midbrain; it is crucial to waking up and to falling asleep.

reuptake: a way of removing excess neurotransmitter from the synapse, in which excess neurotransmitter is returned to the sending, or pre-synaptic, neuron for storage in vesicles and future use.

sensory neurons: neurons that receive incoming sensory information from the sense organs (eye, ear, skin, tongue, nose).

serotonin: a neurotransmitter with wide ranging effects: involved in dreaming and in controlling emotional states, especially anger, anxiety, and depression.

soma: the cell body of the neuron.

somatic nervous system: nerve cells of the peripheral nervous system that transmit sensory information to the central nervous system (CNS) and those that transmit information from the CNS to the skeletal muscles.

sympathetic nervous system: the branch of the autonomic nervous system that activates bodily systems in times of emergency.

synapse: the junction between an axon and the adjacent neuron, where information is transmitted from one neuron to another.

synaptic vesicles: tiny sacs in the terminal buttons that contain neurotransmitters.

synaptogenesis: the formation of entirely new synapses or connections with other neurons.

terminal button: little knobs at the end of the axon that contain tiny sacs of neurotransmitters.

thalamus: a forebrain structure that receives inputs from the ears, eyes, skin, or taste buds, and relays sensory information to the part of the cerebral cortex most involved in processing that specific kind of sensory information.

twin studies: research into hereditary influence comparing pairs of fraternal and identical twins.

twin-adoption studies: research into hereditary influence on twins, both identical and fraternal, who were raised apart (adopted) and who were raised together.

Wernicke’s area: an area deep in the left temporal lobe responsible for the ability to speak in meaningful sentences and to comprehend the meaning of speech.

MAKING THE CONNECTIONS

Polygenic Influence on Behavior

CONNECTION: Genetics influence about 50% of the differences in performance on intelligence tests, leaving about the same amount to be explained by non-genetic influences. (See Chapter 10.)

· Discussion: The following link is to the Bouchard et al (1990) study on heritability of IQ. http://www.lrainc.com/swtaboo/taboos/tjbouc01.html. See the suggested reading for the full citation.

Gene-by-Environment Studies

CONNECTION: How do stress and abuse interact with genes to increase vulnerability to depression? (See Chapter 15.)

· Discussion: Here is a link to a great article in the Harvard Gazette on effects of long-term abuse on the development of the brain by William Cromie: http://www.hno.harvard.edu/gazette/2003/05.22/01-brain.html.

Common Neurotransmitters

CONNECTION: Common treatments for depression, which is thought to result in part from a deficiency of the neurotransmitter serotonin, block the reuptake of serotonin at the synapse, making more of it available for binding with postsynaptic neurons. (See Chapter 16.)

· Discussion: Here is a great link to the Zoloft commercial. It involves a simplified description of reuptake that students will respond to: http://www.youtube.com/watch?v=6vfSFXKlnO0

CONNECTION: Glutamate doesn’t function properly in people with schizophrenia, so they become confused. Restoring glutamate function is the focus of new treatments for schizophrenia. (See Chapters 15 and 16.)

· Discussion: a 1 hour 15 minute interview of Watson, the discoverer of DNA, discussing brain disorders such as schizophrenia, Alzheimer’s, and depression: “DNA and the Brain” an interview with James Watson: http://www.youtube.com/watch?v=Z6ZfrXHgiVY

The Limbic System

CONNECTION: Test your ability to recognize emotion in the facial expressions of others and learn more about the role of the amygdala in emotion. (See Chapter 11.)

· Discussion: A brief clip on how the limbic system and the amygdala work – including diagrams: http://www.youtube.com/watch?v=lZ4mdXAtnEs&feature=related

Brain Plasticity and Neurogenesis

CONNECTION: If a person is not exposed to language much before mid to late childhood, the ability to speak is limited because the brain loses some of its plasticity as we age. See Chapter 9.

· Discussion: You may want to take this opportunity to preview what’s to come and talk about feral children. For example, the case of Genie, a 13-year-old California girl who was severely neglected and raised with minimal human contact. Despite the efforts of the best linguists in the field at that time, she was never able to learn to speak and had moderately developed cognitive abilities.

Breaking New Ground: Neurogenesis in the Adult Brain

Evidence of Neuron Growth

· Three scientific events took place during the 1980s and 1990s that finally turned the tide of belief.

· First, a series of studies on birds showed exceptional neuronal growth in many areas of the adult avian brain, including the hippocampus.

· Second, there was increasing evidence for the formation of new synaptic connections in the brains of rats when they were raised in enriched environments.

· Third, in the1990s, researchers began to find solid evidence for neurogenesis in one particular region of the hippocampus in adult rats, monkeys, and humans.

Environmental Effects on Neuron Growth

· Gould and colleagues compared rates of neurogenesis and synaptic growth in the brains of primates living in naturalistic settings with those living in lab cages. The brains of the animals that lived in these environmentally complex settings showed brain growth in areas of thinking and feeling, higher rates of neurogenesis, and more connections between neurons.

· Another prominent researcher looked at using a technique that involves injecting people with a substance called BrdU, which is incorporated into dividing cells so that they can be identified. This is sometimes given to cancer patients as part of their therapy.

· After some patients who had been injected with BrdU died, Gage and Erikkson examined their hippocampus tissue. Based on the presence of BrdU, they found new cells in the adult human hippocampus.

· In the 1990s, the dogma of no new neural growth finally died. It took the accumulation of decades of empirical evidence about many species for neurogenesis to be accepted. But we now know that neurons and their dendrites and synapses change, grow, and die in both young and old animals—including humans—depending on the kind of stimulation they receive from the outside world.

MAKING CONNECTIONS: What Esref Armagan’s Story Reveals about the Brain

· Esref is a blind artist who paints using a Braille stylus (writing utensil) to sketch out his drawing by laying down bumps on paper. With his other hand, he follows the raised bumps to “see” what he has put down. No one helps him when he paints, and his paintings are entirely his own creations.

· He portrays perspective with uncanny realism, far beyond what any other blind painter has ever achieved. He says he learned this from talking with others as well as from feeling his way in the world. Armagan’s skill appears to have at least some inborn basis, given how early he started without receiving any instruction.

· Like many blind people, Armagan relies mostly on his sense of touch. Interestingly, he needs total silence while working. In many blind people, the so-called “visual” centers of the brain are used to process hearing (Röder et al., 2002). Maybe Armagan needs silence because he cannot afford to devote the precious resources of his mind’s eye to hearing.

· Armagan is one of the few blind people with the ability to accurately portray depth and perspective in his drawings and paintings. When asked to draw a cube and then rotate it once and then once again, he draws it in perfect perspective, with horizontal and vertical lines converging at imaginary points in the distance.

· Because he has been blind since birth, Armagan’s visual cortex has never received any visual input (light). But that part of his brain didn’t merely die or stop functioning. In many blind people, the visual cortex takes on hearing functions, enabling them to hear certain types of sounds better than sighted people can. Armagan’s occipital cortex indeed is very active when he paints, but he is receiving tactile (touch) and not visual input.

· There is evidence from neuroscientists who study blind people in general that this plasticity of the occipital lobes is the norm—it usually processes tactile information, verbal information, or both for blind people. The life, abilities, and brain of Armagan illustrate that the brain is both highly plastic and specialized.

NATURE-NURTURE POINTERS

Gene-by-Environment Studies

Nature-Nurture Pointer: A mother’s behavior may influence the expression of genes in her offspring.

o Discussion: Here is the link to the CDC’s site on FAS: http://www.cdc.gov/ncbddd/fas/. You may also want to discuss with students how things like smoking, drinking, and doing drugs are ill-advised. You may want to have the student health center at your university come by at some point in the semester to talk to students about safe sex and things they or their partner can do if they are pregnant to minimize negative effects on fetal development, like quitting smoking.

o You may also want to stress to students that today the general advice in the field is to avoid anything that may be teratogenic, as there is no data supporting what a safe level is for many of these stimuli.

Brain Plasticity and Neurogenesis

Nature-Nurture Pointer: Throughout life, the brain can adopt new functions, reorganize itself, or make new neural connections, as a function of experience.

o Discussion: Learning is one key way that we see this. Research has indicated that children after stroke have been able to show tremendous gains, even in language skills. Here is a link to an article and video clip: http://www.sciencedaily.com/videos/2005/0711-inside_the_brain.htm.

Nature-Nurture Pointer: In blind people, the brain compensates for deficits in vision by reorganizing and rewiring the visual cortex to process sound.

o Discussion: See the following full-text article by Gougoux et al. (2005) on this matter: http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.0030027&ct=1

Breaking New Ground: Neurogenesis in the Adult Brain

· Neurons are unique cells in the body. Unlike many other cells, including hair, blood, or skin cells, nerve cells do not grow and die on an hourly basis. Nor do they reproduce. The prevailing wisdom was that neurons are incapable of growth, at least after early childhood.

· Neuron doctrine: declared that neurons do not regenerate.

INNOVATIVE INSTRUCTION

Additional Discussion Topics

1. The problem with twin and adoption studies: You may want to point out to students that there are few twins separated at birth. Remind students of what we discussed in Chapter 2. Regarding sampling and anecdotal evidence: You may want to tie in the sampling error inherent in twin research as well as the limited number of subjects available in the general population. Ask students what they think would be a better alternative.

In terms of adoption data, remind students that few adoptees have been reunited with their birth parent, which does limit the generalizability of any results in these studies. Also point out those adoptive parents as a group differs widely from the general population. That is, they tend to one want kids badly & two have at least some funds to afford adoption. Thus, as a group they tend to be different from any other random sample of parents.

2. Epigenesis: Explain to students that many of the theories they will hear about throughout the term are epigenetic in nature (e.g., Piaget, Freud, the diathesis-stress model of abnormal behavior, and the neurodevelopmental hypothesis). It is important that students understand the dynamic relationship between all levels of experiential (i.e., nurture) and biological (i.e., nature) interaction.

3. Evolution: You may want to avoid asking students if they believe in evolution but rather focus on the theory and their understanding of how natural selection works. For example, recent media reports indicated that blondes are going extinct (see http://www.youtube.com/watch?v=ab1EixVFKZE and Suggested Websites for additional information). This seems crazy, but remember, blonde is a recessive trait. However, red hair is an even more recessive trait and has yet to go extinct. You may also want to point out that other traits are passed on via natural selection as well (e.g., preference for novelty). So the point here, is that there is an ebb and flow to all traits as environment (and culture) selects what traits are “in” and what traits are “out.”

4. Stem Cell Research: This is a good place to discuss the controversial issue of stem cell research and human cloning. You may want to outline the issues for those who are unfamiliar with current controversies (see the following site for suggested activities and videos: http://www.pbs.org/wgbh/nova/sciencenow/3209/04.html).

5. The Limbic System: The limbic system is instrumental in emotional functioning, so what happens when it is damaged? The text outlines the famous case of Phineas Gage but there are more recent, and scientific, outlines of this issue. For example, Bauman, Lavenex, Mason, Capitanio, and Amaral (2004) lesioned different portions of the limbic system in rhesus monkeys and found that specific parts of the limbic system are involved in specific emotional and social behaviors (e.g., the amaygdala is linked with avoiding potential danger). See http://cat.inist.fr/?aModele=afficheN&cpsidt=16223384 for more information.

Activities

1. Have students look in the mirror and describe what they see (hair color, eye color, hair texture [straight, curly, etc.], and so on). Have them report the same information for their mother and father. Have them discuss genotypes and phenotypes and outline which of their phenotypic features are dominant and which are recessive. If they want their child to look like them, what phenotype will their partner need to display?

2. Students will have a hard time with understanding neural communication and the action potential. One way to demonstrate how this works is to have all the students stand up and hold hands. Then tell the first student on your left to squeeze the hand of the person next to them. As soon as they feel that squeeze, that next student should squeeze the hand of the person next to them and so on down the line. The last person in the row should raise their hand to indicate they received the signal. Have them practice first and then race! Explain that they are the axon for the neuron and each squeeze is propagating the signal to the terminal buttons. Whatever row was fastest was the row that was myelinated.

3. Ask students who they think they would mourn most: the loss of a pet, their mother, their father, a grandparent, a child, or a step-child. Ask them to explain their answer and link that response to evolutionary theory.

4. Have students go to http://www.pbs.org/wgbh/nova/miracle/program.html and select “Passing on your DNA.” Have them write a paragraph outlining the content of this 10-minute clip and relate it to their readings in this chapter. Have them also comment on the applicability of the content to their lives.

5. Try to help students remember the different parts of the brain and their functions with mnemonic devices (see Chapter 7 for the connection). For example, if they cannot recall that the hippocampus is instrumental in memory formation, have them think about a hippo roaming aimlessly (i.e., lost) on campus. Too bad his memory system didn’t help him remember his way. Another example is what the limbic system itself is for: it is involved in the four “F’s” of behavior: fight, flight, flee, and “reproduction” (students groan and giggle but will remember this for the test!). Ask them to come up with two of their own and share them with the class.

Suggested Films

1. Parent Trap (1998 or the original in 1961) is a good, G-rated film to discuss twin research.

2. Adaptation (2002) is another good film on twins.

3. A NOVA clip on epigensis and identical twins: http://www.pbs.org/wgbh/nova/sciencenow/3411/02.html

4. Louise Leakey discussing human origins: http://www.ted.com/index.php/talks/louise_leakey_digs_for_humanity_s_origins.html

5. NOVA clips on DNA, Cracking the Code of Life: http://www.pbs.org/wgbh/nova/genome/program.html

6. NOVA clips on the effects of learning on the brain, Of Mice and Memory: http://www.pbs.org/wgbh/nova/sciencenow/0301/02.html

7. NOVA clips on evolution, First Primates: http://www.pbs.org/wgbh/nova/sciencenow/0303/02.html

8. Living with Traumatic Brain Injury: http://www.youtube.com/watch?v=FgtHvBF4t-E

9. Neurons and How They Work (Discovery Channel): http://www.youtube.com/watch?v=0WUS3M3zlZY

10. Pinky and the brain singing about the parts of the brain – much more light-hearted than the other clips: http://www.youtube.com/watch?v=Li5nMsXg1Lk

Suggested Websites

1. A great site on different accounts of feral kids throughout history, including the case of Genie: http://www.feralchildren.com/en/showchild.php?ch=genie

2. An informative site on IQ with useful links: http://www.psych.utoronto.ca/users/reingold/courses/intelligence/cache/1198gottfred.html#link2

3. Natural selection of blondes: http://news.bbc.co.uk/1/hi/health/2284783.stm

4. A transcript of Steven Pinker discussing the evolution of the human mind: http://www.pbs.org/wgbh/evolution/library/07/2/l_072_03.html

5. A great site from Bryn Mawr on structures in the brain: http://serendip.brynmawr.edu/bb/kinser/Structure1.html

6. A great site from Harvard Medical – includes a Brain Atlas: http://www.med.harvard.edu/AANLIB/home.html

7. Brain facts and figures: http://www.hallym.ac.kr/~neuro/kns/tutor/facts.html

8. A neat chart on brain size by proportion from various species: http://www.highnorth.no/Library/Myths/br-si-bo.htm

9. A very basic website for kids on the brain parts: http://kidshealth.org/kid/htbw/brain.html

10. The center for Neuro Skills site on parts of the brain: http://www.neuroskills.com/brain.shtml

11. Here is an article on marijuana use and effects on the brain: http://www.reuters.com/article/latestCrisis/idUSN02271474

12. A nice overview of the brain: http://www.abta.org/sitefiles/sitepages/e3c6aceceeb3873e1722853ca6259c30.pdf

13. An atlas of the brain from the Lundback Institute: http://www.brainexplorer.org/brain_atlas/Brainatlas_index.shtml

14. This site has an activity page with some fun activities you may want to use in class: http://library.thinkquest.org/J002952F/favorite.htm

15. This has a lateral diagram of the brain and students can plug in the correct parts – it also has the answers posted: http://www.enchantedlearning.com/subjects/anatomy/brain/label/lateralbrain/label.shtml

Suggested Readings

Aggleton J.P. & Passingham, RE. (1981). Syndrome produced by lesions of the amygdala in monkeys (Macaca mulatta). Journal of Comparative Physiological Psychology. 95: 961-977.

Asimov, I. (1987). How Did We Find Out About The Brain?. New York: Walter and Company.

Baird A.A., Gruber S.A., & Fein, D.A. (1999). Functional magnetic resonance imaging of facial affect recognition in children and adolescents. Journal of the American Academy of Child and Adolescent Psychiatry, 38(2): 195-199.

Bouchard, T.J., Lykken, D.T., McGue, M., Segal, N.L., & Tellegen, A. (1990). Sources of human psychological differences: the Minnesota study of twins reared apart. Science, 250 (4978): 223-226.

Deacon, T. (1997). What Makes the Human Brain Different? Annual Review of Anthropology, 26: 337-357.

Eccles, J. (1973). The Understanding of the Brain. New York: McGraw-Hill.

Giedd J.N., Blumenthal J., & Jeffries, N.O. (1999). Brain development during childhood and adolescence: a longitudinal MRI study. Nature Neuroscience, 2 (10): 861-863.

Heinz, S., Baron, G., & Frahm, H. (1998). Comparative Size of Brains and Brain Components. Neurosciences: Comparative Primate Biology, 4: 223-228.

Miller, J.A. (1995). The Layered Look in Cortex. BioScience, 246: 7-16.

Roberts, M. & Hanaway, J. (1970). Atlas of the Human Brain in Section. Philadelphia: Lea and Febiger.

Sowell E.R., Thompson P.M., Holmes C.J., (1999). In vivo evidence for post-adolescent brain maturation in frontal and striatal regions. Nature Neuroscience, 2(10): 859-861

Thompson, P.M., Giedd, J.N., & Woods, R.P. (2000). Growth patterns in the developing brain detected by using continuum mechanical tensor maps. Nature, 404(6774): 190-193.