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Copyright © Macmillan education 2015

Chapter 2: Biology and behavior

D E B O R A H M . L I G H T M I S T Y G . H U L L C O C O B A L L A N T Y N E

Courtesy Dr. Julie Gralow


LEARNING OBJECTIVES: Part 1

LO 1 Define neuroscience and explain its contributions to our understanding of behavior.

LO 2 Label the parts of a neuron and describe an action potential.

LO 3 Illustrate how neurons communicate with each other.

LO 4 Summarize various neurotransmitters and the roles they play in human behavior.

LO 5 Recognize the connections between the central and peripheral nervous systems.


LEARNING OBJECTIVES: Part 2

LO 6 Evaluate pseudo psychology and its relationship to critical thinking.

LO 7 Describe how psychologists use the scientific method.

LO 8 Summarize the importance of a random sample.

LO 9 Recognize the forms of descriptive research.

LO 10 Explain how the experimental method relates to cause and effect.

LO 11 Demonstrate an understanding of research ethics.

LO 12 Compare and contrast tools scientists use to study the brain.

LO 13 Identify the lobes of the cortex and explain their functions.

LO 14 Recognize the association areas and identify their functions.

LO 15 Distinguish the structures and functions of the limbic system.

LO 16 Distinguish the structures and functions of the brainstem and cerebellum.


Biology and Behavior: Studying the Last Frontier – Part 1

Neuroscience

Involves study of the brain and nervous system

Biological psychology

Focuses on how the brain and other biological systems influence human behavior

Contributions

Examination of extent of experience-induced neural plasticity



Brandon Burns poses for a photo at the Marine Corps Recruit Depot in Parris Island, South Carolina in the fall of 2003. The following year, he was shot in the head by an enemy sniper in the Battle of Fallujah.

Doctors concluded that some parts of his brain were no longer viable. “They removed part of my skull and dug out the injured part of my brain,” and now, Brandon says, “one third of my brain is gone.”

What were the consequences of his injury?


The Neuron


Can you identify the structure of a typical neuron?

Cell body

Dendrites

Axon

Terminal buds

Myelin sheath

Synapse


Biology and Behavior

Glia to the Rescue

A scanning electron micrograph shows neurons (green) and glia (orange).

Glial cells serve as the “glue” of the nervous system, providing cohesion and support for the neurons. Thomas Deerinck, NCMIR

Some classes of glial cells

Microglia

Astrocytes

Schwann


Communication Within Neurons



COMMUNICATION WITHIN AND BETWEEN

Resting potential

Electrical potential of cell at rest

Solutions on either side of the membrane wall come into equilibrium; slightly more negative charge inside




Action potential

Involves spike in electrical energy that passes through the axon of a neuron, the purpose of which is to convey information

Is all-or-none

Every time a segment of the axon fires

Positive sodium ions flood in from the outside of the cell, while the prior segment returns to its resting potential, all along the length of the axon to its end




Excitatory signals

Occur when enough combine, sending neurons signal the receiving neuron to pass along message

Inhibitory signals

Inhibit neuron from releasing a signal through the axon


Biology and Behavior: Communication Within and Between

Myelin sheath insulates and protects the tiny spikes in electricity happening inside the axon.

Action potential “skips” over the segments of myelin, hopping from one node to the next, instead of traversing the entire length of the axon.

MYELIN

Protein that envelops and insulates the axon, facilitating faster transmission of the impulse.



COMMUNICATION BETWEEN

Neurotransmitters

Chemical messengers that neurons use to communicate at the synapse

Receptor sites

Location where neurotransmitters attach on the receiving side of the synaptic gap

Reuptake

Process by which neurotransmitters are reabsorbed by the sending terminal bud


Biology and Behavior: The Synapse

The Synapse

Axon terminal of a sending neuron interacts with the dendrites of a receiving neuron by releasing chemical messengers (neurotransmitters) into the synapse.

Once the neurotransmitters migrate across the gap and latch onto the dendrite’s receptor sites, the message has been conveyed.




Reuptake

Occurs when neurotransmitters are reabsorbed by the sending bud

Diffusion

Occurs when neurotransmitters are not reabsorbed and drift out of the synaptic gap


Communication Between Neurons



NEUROTRANSMITTERS

Acetylcholine

Relays messages from motor neurons to muscles, enabling movement; involved in memory

Too much = spasms; too little = paralysis

Glutamate

Makes neurons fire; central role in memory and learning

Too much = strokes; too little = symptoms of schizophrenia

GABA

Inhibits neurotransmitter firing; contributes to motor control, vision



NEUROTRANSMITTERS

Norepinephrine

Has variety of effects in CNS; helps body prepare for stress

Serotonin

Plays key role in controlling appetite, aggression, and mood; regulates sleep and breathing

Dopamine

Plays role in modulating mood; plays central role in positive reinforcement and dependency



NEUROTRANSMITTERS

Endorphins

Regulates secretion of other neurotransmitter; naturally produced opioids; reduces pain and elevates mood

Agonists

Interfere at level of synapse; increase normal neurotransmitter activity

Antagonists

Interfere at level of synapse; decrease normal neurotransmitter activity


Biology and Behavior: Neurotransmitters

Caffeine

Blocks receptors for adenosine

Increases activity in branch of nervous system serving the body


SHOW WHAT YOU KNOW – Part 1

1. Many axons are surrounded by a ______ , which is a fatty substance that insulates the axon.

2. When Brandon was injured, _____ played an important role in his recovery by defending against infection and inflammation of the brain, as well as holding neurons together and maintaining the structure of the nervous system.

a. glial cells

b. dendrites

c. action potentials

d. sodium ions



3. ________ are released into the ________ when an action potential reaches the branches of the terminal buds.

a. Sodium ions; synaptic gap

b. Neurotransmitters; synaptic gap

c. Potassium ions; cell membrane

d. Neurotransmitters; sodium gates

4. Neural communication is very complicated. Draw a diagram depicting the process of neural communication, then explain it to yourself while looking at what you have drawn.


The Supporting Systems: Infrastructure

Brain needs supporting infrastructure to carry out directives and relay essential information from outside

Central nervous system (CNS)

Peripheral nervous system (PNS)


The Supporting Systems: Overview of the Nervous System

The nervous system is made up of the central nervous system, which includes the brain and spinal cord, and the peripheral nervous system.

moodboard/Alamy


The Supporting Systems: Part 1

Spinal cord

Includes bundle of neurons

Allows communication between the brain and the peripheral nervous system

Connects with the body’s muscles, glands, and organs


The Supporting Systems: Part 2

Sensory neurons

Receive information about the environment from the sensory systems and convey this to the brain for processing

Motor neurons

Carry information from CNS to produce movement; provide mechanism regulated by spinal cord and brain

Interneurons

Resides in brain and spinal cord; act as bridges connecting sensory and motor neurons


THE SPINAL CORD AND REFLEX ARC

Without any input from the brain, the spinal cord neurons are capable of creating some simple reflexive behavior.

While the spinal reflex occurs, sensory neurons also send messages to the brain, letting it know what has happened.


Try This

Test your knowledge of the reflex arc using Brandon as an example. As you recall, Brandon’s brain injury led to paralysis on the right side of his body.

What do you think would happen if a doctor tapped on his right knee—would he experience a reflex?


What Lies Beyond: The Peripheral Nervous System – Part 1

Peripheral nervous system

Includes all neurons not in CNS

Involves neurons that are bundled together to carry signals throughout body

Nerves

Act as primary communication system for PNS

Supply CNS with information about body’s environment



SOMATIC NERVOUS SYSTEM

Characteristics

Involves branch of the parasympathetic nervous system

Includes sensory nerves and motor nerves

Gathers information from sensory receptors

Controls the skeletal muscles responsible for voluntary movement



AUTONOMIC NERVOUS SYSTEM

Characteristics

Regulates involuntary activity

Has two divisions involved in physiological responses to stress or crisis situations

Sympathetic nervous system

Parasympathetic nervous system


The Sympathetic and Parasympathetic Nervous System


What Lies Beyond: The Peripheral Nervous System

TEND AND BEFRIEND

Female response to stress

Many women have inclination to direct energy toward nurturing and forging social bonds as a stress response.


Think Again

MALE BRAIN, FEMALE BRAIN

Studies suggest gender stereotypes can influence performance in math and science.

Research also shows that male and female brains are far more alike than they are different, but...

Certain regions of the limbic cortex and the frontal lobes were larger in women.

Areas of the parietal cortex, the amygdala, and hypothalamus were larger in men.

So is nature or nurture responsible for gender imbalance in math and science?


The Endocrine System and Its Slowpoke Messengers

ENDOCRINE SYSTEM

1. Hormones

2. Pituitary gland

3. Thyroid gland

4. Adrenal glands

Can you define each of these?


The Endocrine System


The Endocrine System and Its Slowpoke MessengersOther Endocrine Glands and Organs

Pineal gland

Secretes melatonin

Pancreas

Secretes insulin

Ovaries and testes

Secrete sex hormones



1. ________ carry information from the central nervous system to activate various parts of the body, such as muscles and glands.

a. Interneurons

b. Dendrites

c. Sensory neurons

d. Motor neurons



2. When a stimulus causes an involuntary response, we refer to it as a reflex arc. The simple communication pathway goes from a sensory neuron through interneurons in the _____ and back out through motor neurons.

a. brain

b. spinal cord

c. axon hillock

d. nodes of Ranvier



3. The ________ gland, located in the center of the brain, just under the hypothalamus, is in charge of the endocrine system.

4. When confronted with a potentially threatening situation, the sympathetic nervous system sometimes prepares for “fight or flight” and/or “tend and befriend.” How would you explain these two very different responses using the evolutionary perspective?


The Hemispheres

RIGHT BRAIN, LEFT BRAIN: THE TWO HEMISPHERES

Cerebrum

Includes largest, most highly developed part of brain

Involved in intelligence, personality, thinking, perceiving, planning and organization, language, sensation, motor functions

Divided into right and left hemispheres and covered by corpus callosum


Two Hemispheres

The right hemisphere controls the left side of the body, and the left hemisphere controls the right.

This explains why Brandon, who was shot on the left side of his head, suffered paralysis and loss of sensation on the right half of his body.

The cerebrum looks like a walnut with its two wrinkled halves. Regions of the left and right hemispheres specialize in different activities, but the two sides of the brain are constantly communicating and collaborating. Science Source/Photo Researchers, Inc. Colorization by: Eric Cohen


The Hemispheres: Hemispherectomy

Christina Santhouse relaxes with her mother at Johns Hopkins, where she had a dramatic brain surgery known as a hemispherectomy.

Prior to the operation, Christina experienced over 100 seizures a day.


The Hemispheres: Split Brain

Hemispherectomies

Exceptionally rare; last resort

Callostomies (Split-brain operations)

Right and left hemisphere disconnected

MRI SCAN

Both hemispheres Intact

After hemispherectomy


The Split-Brain Experiment

The image to the right shows a top view of the corpus callosum, the bundle of neurons linking the right and left hemispheres. When the corpus callosum is severed, we can easily see functional differences between the two sides of the brain. Studies of people who have undergone this procedure are shown here.

Terence H. Williams, Nedzad Gluhbegovic/Wolters Kluwer


The Hemispheres: Lateralization

Generalization

Left hemisphere plays a crucial role in language processing and right hemisphere plays a crucial role in managing visual spatial tasks.

But

Hemispheres constantly integrate and share information.


The Hemispheres: Language and the Left

Handedness and dominance

Left hemisphere controls language in most people; does not necessarily correspond to handedness.

Language dominance

Broca’s area

Wernicke’s area


Speak Again

Brandon works on his pronunciation in front of a mirror during a speech therapy session at the Memphis VA hospital. You can see the extent of his injury on the left side of his head. Upon awakening from his coma, Brandon could not articulate a single word. Today, he can hold his own in complex conversations.


The Hemispheres: Language Area and The Brain

1. Broca’s area

2. Wernicke’s area

Can you identify the role each structure plays in language production and comprehension?


The Hemispheres: The Role of The Right

Research: Right hemisphere

More proficient in some visual tasks

Critical for understanding abstract and humorous use of language

Better for following conversations that change topics

Important for recognizing faces



1. The left hemisphere excels in language and the right hemisphere excels in visual spatial tasks. This specialization of the two hemispheres is known as:

a. split-brain.

b. callostomy.

c. hemispherectomy.

d. lateralization.



2. A man involved in a car accident suffered severe brain trauma. As he recovered, it became clear he was having difficulty producing speech, even though he could understand what people were saying to him. It is very likely he had suffered damage to the left frontal lobe in a part of the brain referred to as:

a. Wernicke’s area.

b. Broca’s area.

c. the visual field.

d. the corpus callosum.



3. On rare occasions, medication does not work for people with severe seizures. In those cases, doctors might suggest a procedure known as a _____, which essentially disconnects the right and left hemispheres.

4. The corpus callosum enables information sharing between the two hemispheres. In some cases, surgeons sever the corpus callosum to prevent seizures from spreading between the two hemispheres. How would you explain to a middle school student why this surgical procedure is used and how it is helpful?


The Amazing Brain: Neuroplasticity

HUMAN STEM CELL

Brain undergoes constant alterations

Physical adaptation and repair—even after hemispherectomy

Growth of new connections and reorganization

Stem cells

Responsible for creating new neurons


Across the World

THE PLASTIC BRAINS OF OUR CHILDREN

Children and music

Chinese parents believe that piano instruction for their kindergarteners will help school performance.

American parents play classical music to fetuses and show DVDs to their infants and toddlers to promote brain development.

Are these parents right in their assumptions?


The Amazing Brain: Part 1

ALL IN YOUR HEAD

Are you a secretive person? How high is your self-esteem?

The answers to these questions lie on the surface of the skull, or so claimed nineteenth-century phrenologists.


The Amazing Brain: Part 2

TOOLS FOR STUDYING THE BRAIN

Electroencephalogram (EEG)

Computerized Axial Tomography (CAT scan or CT scan)

Positron Emission Tomography (PET)

Magnetic Resonance Imaging (MRI)

Functional Magnetic Resonance Imaging (fMRI)

What are the strengths and limitations of each of these tools?


Social Media and Psychology

FACEBOOK IN THE BRAIN

Facebook friends range from zero to 5000, averaging 245.

A preliminary study suggests friend volume may reflex something about a user’s brain.

There is a correlation between number of Facebook friends and density of gray matter in areas of brain known for social interaction and facial recognition.

So…are your Facebook friends a gray matter?


Electric Surprise

STIMULATING BRAIN CELLS MAY BE TRICKIER THAN

WE THOUGHT

Using a new type of optical imaging, Harvard Medical School researchers observed neurons as they were stimulated by an electrode.

Electrodes caused sparse strings of neurons, rather than a small sphere of surrounding neurons.

Findings suggests a much smaller margin of error during brain surgery and design of neural prosthetics.

Melinda Wenner. Reproduced with permission. Copyright © 2010 Scientific American, a division of Nature America, Inc. All rights reserved.



1. Scientists hope that in the future they will be able to discover how we can use stem cells to help people like Brandon and Christina. The goal would be for doctors to induce the process of _____ to restore the lost brain tissue.

a. ablation

b. agonists

c. neurogenesis

d. lateralization



2. You have been asked to set up an experiment to determine if playing classical music to infants leads to improved cognitive abilities. What would your independent and dependent variables be? How would your experimental and control groups be treated differently?

3. ________ are responsible for creating new neurons.



4. The brain is constantly undergoing alterations in response to experiences and is capable of a certain degree of physical adaptation and repair. This ability is known as:

a. neuroplasticity

b. phrenology

c. ablation

d. lateralization


Ways to Study the Living Brain


The Cortex: A Peek Beneath the Skull – Part 1

THE CORTEX

Cerebral cortex

Processes information and surrounds nearly all of the brain structure

Association areas

Involves region of cortex that integrates information from all over the brain

What does it require to study the brain?

Look at the above illustration for clues.


THE LOBES: UP CLOSE AND PERSONAL



Phineas Gage and the frontal lobes

In 1848, Gage was impaled by a 3-foot tamping rod through his cheek, brain, and skull and caused dramatic changes in his personality.

Fritsch and Hitzig and the motor cortex

By applying mild shock to dogs’ cortex, researchers demonstrated motor cortex region involvement in muscle movement.

Albert Einstein and the parietal lobes

Postmortem comparison of 35 male brain specimens and Einstein’s brain found the region of Einstein’s parietal lobe responsible for visual spatial cognition and mathematical thinking 15 percent larger than those of the control group.




Penfield

Used method similar to Fritsch and Hitzig, showing which points along the motor cortex and somatosensory cortex corresponded to parts of the body

Developed model often represented by oversimplified “homunculus”


PENFIELD’S MAPThe Motor and Somatosensory Cortex




Occipital lobes

Initial processing site for visual information

Primary visual cortex

Connects to optic nerve where visual information is received and interpreted



1. The major function of the _____ is to organize information among the other lobes of the brain.

a. parietal lobes

b. frontal lobes

c. corpus callosum

d. temporal lobes

2. The ________ integrate information from all over the brain, allowing us to learn, have abstract thoughts, and carry out complex behaviors.



3. This section introduces the lobes of the cortex and their associated functions. Create a way to remember the lobes and their specific functions using a rhyme or another memorization technique you know.

4. Phineas Gage suffered a horrific accident in the mid-1800s, when an explosion sent a metal rod through his brain and out the top of his skull. Which caused the sudden change in his personality following the accident?

a. damage to his occipital lobes

b. damage to his temporal lobes

c. damage to his frontal lobes

d. damage to his somatosensory cortex


Digging Below the Cortex

DRAMA CENTRAL: THE LIMBIC SYSTEM

Limbic system fuels basic drives and processes emotions and memories.


Digging Below the Cortex: Identify Functions

Hippocampus

Amygdala

Thalamus

Hypothalamus


Digging Below the CortexDeeper Yet: The Brainstem and Cerebellum

Brainstem

Includes the brain’s core

Extends from spinal cord to forebrain

Forebrain

Involves largest part of brain and includes cerebral cortex and limbic system

Midbrain

Involves brainstem part involved in arousal levels, responsible for generating movement patterns in response to sensory input


Digging Below the Cortex: Brainstem and Cerebellum

Reticular formation

Involves network of neurons running through the midbrain

Controls levels of arousal and quickly analyzes sensory information on its way to the cortex

Hindbrain

Pons

Medulla

Cerebellum

Involves muscle coordination and balance

May also affect fine distinctions in cognition


Amazing Brains: Amazing People

Three years after his traumatic brain injury, Brandon celebrated his marriage to Laura. The couple recently had their third child, a daughter named MacCrea Iona.

With her master’s degree in speech–language pathology, Christina now works full time in Pennsylvania’s public school system.



1. The _____ represents a group of interconnected structures that process emotions, memories, and basic drives.

a. left hemisphere

b. limbic system

c. corpus callosum

d. superior temporal sulcus

2. The specific part of the brain that processes basic emotions, such as fear and aggression and the memories associated with them, is the ______.



3. How might the specific structures of the limbic system, the brainstem, and the cerebellum come into play if you were out on a first date?

4. The primary role of the thalamus is to:

a. relay sensory information.

b. keep the body’s systems in a steady state.

c. generate movement patterns in response to sensory input.

d. regulate sleep–wake cycles.

biology and behavior - wordpress.com · lo 4 summarize various neurotransmitters and the roles they...

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