Summary of Concepts
LO 1 Define neuroscience and explain its contributions to our understanding of behavior.
Neuroscience is the study of the nervous system and the brain, extending into a variety of disciplines and research areas. Our understanding of behavior is further explored in biological psychology, a subfield of psychology focusing on how the brain and other biological systems influence behavior. Neuroscience helps us explore physiological explanations for mental processes, searching for connections between behavior and the human nervous system, particularly the brain.
LO 2 Label the parts of a neuron and describe an action potential.
A typical neuron has three basic parts: a cell body, dendrites, and an axon. The dendrites receive messages from other neurons, and the branches at the end of the axon send messages to neighboring neurons. The messages are in the form of electrical and chemical activity. When a neuron fires, the action potential moves down the axon. Action potentials are all-or-none, meaning they either fire or do not fire.
LO 3 Illustrate how neurons communicate with each other.
Neurons communicate with each other via chemicals called neurotransmitters. An action potential moves down the axon and reaches the branches of the terminal buds, where the command to release neurotransmitters is conveyed. The neurotransmitters are released into the synapse. Most of these neurotransmitters drift across the gap and come into contact with receptor sites of the receiving neuron’s dendrites.
LO 4 Summarize various neurotransmitters and the roles they play in human behavior.
Neurotransmitters are chemical messengers that neurons use to communicate. There are many types of neurotransmitters, each with its own type of receptor site, including: acetylcholine, glutamate, GABA, norepinephrine, serotonin, dopamine, and endorphins. Neurotransmitters can influence mood, cognition, and many other processes and behaviors.
LO 5 Recognize the connections between the central and peripheral nervous systems.
The brain and spinal cord make up the central nervous system (CNS), which communicates with the rest of the body through the peripheral nervous system (PNS). There are three types of neurons participating in this back-and-forth communication: Motor neurons carry information from the CNS to various parts of the body such as muscles and glands; sensory neurons relay data from the sensory systems (for example, eyes and ears) to the CNS for processing; and interneurons, which reside exclusively in the CNS and act as bridges connecting sensory and motor neurons. Interneurons mediate the nervous system’s most complex operations. They assemble and process sensory input from multiple neurons and, in addition, connect what is happening now to our memory of experiences in the past. They also give rise to our thoughts and feelings, and direct our behaviors.
LO 6 Describe the organization and function of the peripheral nervous system.
The peripheral nervous system is divided into two branches: the somatic nervous system and the autonomic nervous system. The somatic nervous system controls the skeletal muscles, and the autonomic nervous system regulates involuntary processes within the body. The autonomic nervous system is made up of the sympathetic nervous system and the parasympathetic nervous system. The sympathetic nervous system initiates the fight-or-flight response. The parasympathetic nervous system is responsible for the rest-and-digest process.
LO 7 Evaluate the role of the endocrine system and how it influences behavior.
The endocrine system is a communication system that uses glands to convey messages and is closely connected with the nervous system. Its messages are conveyed by hormones, chemicals released into the bloodstream that can cause aggression and mood swings, as well as influence growth and alertness.
LO 8 Describe the functions of the two brain hemispheres and how they communicate.
The cerebrum includes virtually all parts of the brain except for the primitive brainstem structures. It is divided into two hemispheres: the right cerebral hemisphere and the left cerebral hemisphere. The left hemisphere controls most of the movement and sensation on the right side of the body. The right hemisphere controls most of the movement and sensation on the left side of the body. Language is processed primarily in the left hemisphere. Running between the two hemispheres is the corpus callosum, a band of fibers that connects the activities of the two hemispheres, allowing for communication between them.
LO 9 Explain lateralization and how split-brain operations affect it.
Each hemisphere excels in certain activities, which is known as lateralization. The left hemisphere excels in language and the right hemisphere excels in visual spatial tasks. Under certain experimental conditions, split-brain operation participants act as if they have two separate brains, each hemisphere exhibiting its own specialization.
LO 10 Identify areas in the brain responsible for language production and comprehension.
There are several areas in the brain that together are responsible for speech. Broca’s area is primarily responsible for speech production, and Wernicke’s area is primarily responsible for language comprehension.
LO 11 Define neuroplasticity and recognize when it is evident in brains.
Neuroplasticity refers to the ability of the brain to form new connections between neurons and adapt to changing circumstances, including structural changes in the brain. Vast networks of neurons have the ability to reorganize in order to adapt to the environment and an organism’s ever-changing needs—a quality that is particularly evident in the young.
LO 12 Compare and contrast tools scientists use to study the brain.
There are a variety of technologies used to study the brain. The EEG detects electrical impulses in the brain. The CT uses X-rays to create many cross-sectional images of the brain. The MRI uses pulses of radio frequency waves to produce more detailed cross-sectional images than does a CT scan; however, both study the structure of the brain. The PET uses radioactivity to track glucose consumption to construct a map of the brain. The fMRI also captures changes in activity in the brain. However, instead of tracking glucose consumption, it reveals patterns of blood flow in a particular area of the brain, which is a good indicator of how much oxygen is being used as a result of activity in that particular area.
LO 13 Identify the lobes of the cortex and explain their functions.
The outermost layer of the cerebrum is the cerebral cortex. The cortex is separated into different sections called lobes. The major function of the frontal lobes is to organize information among the other lobes of the brain. The frontal lobes are also responsible for higher-level cognitive functions, such as thinking and personality characteristics. The parietal lobes receive and process sensory information such as touch, pressure, temperature, and spatial orientation. Visual information goes to the occipital lobes, where it is processed. The temporal lobes are primarily responsible for hearing and language comprehension.
LO 14 Recognize the association areas and identify their functions.
The lobes include networks of neurons that specialize in certain activities: motor areas, sensory areas, and association areas. The motor areas direct movement, the sensory areas receive and analyze sensory stimuli, and the association areas integrate information from all over the brain, allowing us to learn, have abstract thoughts, and carry out complex behaviors.
LO 15 Distinguish the structures and functions of the limbic system.
The limbic system is a group of interconnected structures that play an important role in our experiences of emotion and our memories. The limbic system includes the hippocampus, amygdala, thalamus, and hypothalamus. In addition to processing emotions and memories, the limbic system fuels the most basic drives, such as hunger, sex, and aggression.
LO 16 Distinguish the structures and functions of the brainstem and cerebellum.
The brain’s ancient core consists of a stalklike trio of structures called the brainstem, extending from the spinal cord to the forebrain, which is the largest part of the brain and includes the cerebral cortex and the limbic system. Located at the top of the brainstem is the midbrain, and although there is some disagreement about which brain structures belong to the midbrain, most agree it plays a role in levels of arousal. The hindbrain includes areas of the brain responsible for fundamental life-sustaining processes.
action potential
adrenal glands
all-or-none
amygdala
association areas
autonomic nervous system
axon
biological psychology
Broca’s area
cell body
central nervous system (CNS)
cerebellum
cerebral cortex
cerebrum
corpus callosum
dendrites
endocrine system
forebrain
frontal lobes
glial cells
hindbrain
hippocampus
hormones
hypothalamus
interneurons
lateralization
limbic system
medulla
midbrain
motor cortex
motor neurons
myelin sheath
nerves
neurogenesis
neurons
neuroplasticity
neuroscience
neurotransmitters
occipital lobes
parasympathetic nervous system
parietal lobes
peripheral nervous system (PNS)
phrenology
pituitary gland
pons
receptor sites
reflex arc
resting potential
reticular formation
reuptake
sensory neurons
somatic nervous system
somatosensory cortex
spinal cord
split-brain operation
stem cells
sympathetic nervous system
synapse
temporal lobes
thalamus
thyroid gland
Wernicke’s area
1. __________ are the specialized cells found in the nervous system that are the building blocks of the central nervous system and the peripheral nervous system.
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c. Neurons
2. When positive ions at the axon hillock raise the internal cell voltage of the first segment of the axon from its resting voltage to its threshold potential, the neuron becomes activated. This spike in electrical energy causes __________ to occur.
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a. an action potential
3. A colleague of yours tells you that she has been diagnosed with multiple sclerosis. Luckily, the disease was diagnosed early and she is getting state-of-the-art treatment. So far, it does not appear that she has experienced problems with the __________ covering the axons in her nervous system.
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a. myelin sheath
4. A neuroscientist studying the brain and the spinal cord would describe her general area of interest as the:
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a. central nervous system.
5. A serious diving accident can result in damage to the __________, which is responsible for receiving information from the body and sending it to the brain, and for sending information from the brain throughout the body.
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b. spinal cord
6. While sitting at your desk, you hear the tone signaling an incoming e-mail. That sound is received by your auditory system and information is sent via sensory neurons to your brain. Here, we can see how the __________ provides a communication link between the central nervous system and the rest of the body.
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d. peripheral nervous system
7. After facing a frightening situation in a war zone, Brandon’s parasympathetic nervous system is in charge of the:
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d. “rest-and-digest” process.
8. Lately, your friend has been prone to mood swings and aggressive behavior. The doctor has pinpointed a problem in his __________, which is a communication system that uses __________ to convey messages via hormones.
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b. endocrine system; glands
9. Which of the following statements is correct regarding the function of the right hemisphere in comparison to the left hemisphere?
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b. The right hemisphere is more competent handling visual tasks.
10. Although Gall’s phrenology has been discredited as a true brain “science,” Gall’s major contribution to the field of psychology is the idea that:
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a. locations in the brain are responsible for certain activities.
11. Broca’s area is involved in speech production, and is __________ critical for language comprehension.
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d. Wernicke’s area
12. The __________ is located in the midbrain and is responsible for levels of arousal and your ability to selectively attend to important stimuli.
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d. reticular formation
13. Describe the differences between the agonists and antagonists and develop an analogy to help you remember these differences.
Answers will vary. Agonists boost normal neurotransmitter activity and antagonists dampen normal neurotransmitter activity. An agonist is somewhat like a substance you add to your car engine to increase its efficiency. An antagonist might be compared to a character in a novel who prevents a heroine from doing her job.
14. The “knee-jerk” reaction that occurs when a doctor taps your knee with a rubber hammer provides a good example of a reflex arc. Describe this involuntary reaction and then draw your own diagram to show the reflex arc associated with it.
Diagrams will vary; see Figure 2.3. A reflex is an uncontrollable reaction that often protects us from bodily harm. For example, we automatically pull away when we touch a hot surface. Sensory neurons are activated and carry information from the environment to interneurons in the spinal cord, which activates motor neurons. The motor neurons excite the muscle and initiate the motion of pulling away.
15. Describe two major differences between neurotransmitters and hormones and how they influence behavior.
Neurotransmitters are chemical messengers produced by neurons that enable communication between neurons. Hormones are chemical messengers produced by the endocrine system and released into the bloodstream. The effects of the neurotransmitters are almost instantaneous, whereas those of hormones are usually delayed and longer lasting. Both influence thoughts, emotions, and behaviors. Neurotransmitters and hormones can work together, for example directing the fight-or-flight response to stress.
16. The research conducted by Sperry and Gazzaniga examined the effects of surgeries that severed the corpus callosum. Describe what these split-brain experiments tell us about the lateralization of the hemispheres of the brain and how they communicate.
Sperry and Gazzaniga’s research demonstrated that the hemispheres of the human brain, while strikingly similar in appearance, specialize in different functions. The left hemisphere excels in language processing, and the right hemisphere excels at visuospatial tasks. The corpus callosum normally allows the two hemispheres to share and integrate information.
17. We described a handful of tools scientists use to study the brain. Compare their functions and weaknesses.
The EEG detects electrical impulses in the brain. The CT uses X-rays to create many cross-sectional images of the brain. The MRI uses pulses of radio waves to produce more detailed cross-sectional images than those of a CT scan, but both MRI and CT are used to study the structure of the brain. The PET uses radioactivity to track glucose consumption and construct a map of brain activity. The fMRI also captures changes in brain activity, but instead of tracking glucose consumption, it reveals patterns of blood flow in the brain, which is a good indicator of how much oxygen is being used. All of these tools have strengths and limitations (see Table 2.1).
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