2.9 Summary of Concepts

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.

key terms

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