Psychological Science (Gazzaniga, Chapter 3)


The basic units of the nervous system;cells that receive, integrate, and transmit information in the nervous system. They operate through electrical impulses, communicate with other neurons through chemical signals, and form neural networks.

neural networks

Circuits formed between neurons

central nervous system (CNS)

The brain and the spinal cord.

peripheral nervous system (PNS)

All nerve cells in the body that are not part of the central nervous system.The peripheral nervous system includes the somatic and autonomic nervous systems.

sensory neurons

One of the three types of neurons;these neurons detect information from the physical world and pass that information to the brain.

somatosensory neurons

The sensory nerves that provide information from the skin and muscles

motor neurons

One of the three types of neurons; these neurons direct muscles to contract or relax, thereby producing movement.


One of the three types of neurons; these neurons communicate within local or short-distance circuits.


Automatic motor responses


Branchlike extensions of the neuron that detect information from other neurons.

cell body

The site in the neuron where information from thousands of other neurons is collected and integrated; also known as the soma


A long narrow outgrowth of a neuron by which information is transmitted to other neurons.


A bundle of axons that carry information between the brain and other specific locations in the body

terminal buttons

At the ends of axons, small nodules that release chemical signals from the neuron into the synapse.


The gap between the axon of a "sending" neuron and the dendrites of a "receiving" neuron; the site at which chemical communication occurs between neurons.


A fatty barrier that doesn't dissolve in the watery environment inside and outside the neuron; covers the neuron

ion channels

Allow ions to pass in and out of the cell when the neuron transmit signals down the axon

resting membrane potential

The electrical charge of a neuron when it is not active.


When the neuron has more negative ions inside than outside

sodium-potassium pumps

Increases potassium and decreases sodium inside the neuron; maintains the resting membrane potential

action potential

The electrical signal that passes along the axon and subsequently causes the release of chemicals from the terminal buttons.

excitatory signals

Depolarize the cell membrane (decrease the negative charge inside the cell)

inhibitory signals

Hyperpolarize the cell (increase the negative charge the cell)

myelin sheath

A fatty material, made up of glial cells, that insulates some axons to allow for faster movement of electrical impulses along the axon.

nodes of Ranvier

Small gaps of exposed axon, between the segments of myelin sheath, where action potentials take place.

all-or-none principle

The principle that when a neuron fires, it fires with the same potency each time; a neuron either fires or not�it cannot partially fire, although the frequency of firing can vary.


Chemical substances that transmit signals from one neuron to another.


In neurons, specialized protein molecules on the postsynaptic membrane; neurotransmitters bind to these molecules after passing across the synapse.


The process whereby a neurotransmitter is taken back into the presynaptic terminal buttons, thereby stopping its activity.

enzyme deactivation

An enzyme that destroys the neurotransmitter in the synapse


The process where autoreceptors that monitor the neurotransmitter release and signals the presynaptic neuron to stop releasing when there is an excess


Drugs and toxins that enhance the actions of the neurotransmitters (activating or increasing; block reuptake)


Drugs and toxins that inhibit the actions of neurotransmitters (decrease, destroy, or block binding)

acetylcholine (ACh)

The neurotransmitter responsible for motor control at the junction between nerves and muscles; it is also involved in mental processes such as learning, memory, sleeping, and dreaming.


A monoamine neurotransmitter responsible for bursts of energy after an event that is exciting or


A monoamine neurotransmitter involved in states of arousal and attention.


A monoamine neurotransmitter important for a wide range of psychological activity, including
emotional states, impulse control, and dreaming.


A monoamine neurotransmitter involved in motivation, reward, and motor control over voluntary movement.

deep brain stimulation

Procedure that involves surgically implanting electrodes deep within the brain and using mild electric stimulation is the regions affected by the disorder


Gamma-aminobutyric acid; the primary inhibitory transmitter in the nervous system.


The primary excitatory transmitter in the nervous system.


Neurotransmitters involved in natural pain
reduction and reward; short for endogenous morphins


Carefully feeling the skull to describe the personality of the individual

Broca's area

A small portion of the left frontal region of the brain, crucial for the production of language.

psychophysiological assessment

Measurements of bodily systems


A data collection method that measures electrical activity in the brain

electroencephalograph (EEG)

A device that measures electrical activity in the brain.

event-related potential (ERP)

Examines brain activity and its changes in response to a specific stimulus by conducting many trials with a single individual and averaging across the trials

brain imaging

Measure changes in the rate or speed of the flow of blood to different regions of the brain

positron emission tomography (PET)

A method of brain imaging that assesses metabolic activity by using a radioactive substance injected into the bloodstream.

magnetic resonance imaging (MRI)

A method of brain imaging that uses a powerful magnetic field to produce high-quality images of the brain.

functional magnetic resonance imaging (fMRI)

An imaging technique used to examine changes in the activity of the working human brain by measuring changes in the blood's oxygen levels.

transcranial magnetic stimulation (TMS)

The use of strong magnets to briefly interrupt normal brain activity as a way to study brain regions.

brain stem

An extension of the spinal cord; it houses structures that control functions associated with survival, such as heart rate, breathing, swallowing, vomiting, urination, and orgasm.


A large, convoluted protuberance at the back of the brain stem; it is essential for coordinated movement and balance.


Above the brain steam and the cerebellum and consists of the cerebral hemisphere

limbic system

Serves as the border between the evolutionarily older parts of the brain and the evolutionarily newer part


The gateway to the brain; it receives almost all incoming sensory information before that information reaches the cortex.


A brain structure that is involved in the regulation of bodily functions, including body temperature, body rhythms, blood pressure, and blood glucose levels; it also influences our basic motivated behaviors.


A brain structure that is associated with the formation of memories.


A brain structure that serves a vital role in learning to associate things with emotional responses and in processing emotional information.

basal ganglia

A system of subcortical structures that are important for the planning and production of movement.

nucleus accumbens

Structure in the basal ganglia; important for experiencing reward and motivating behavior

cerebral cortex

The outer layer of brain tissue, which forms the convoluted surface of the brain; the site of all thoughts, perceptions, and complex behaviors.

corpus callosum

A massive bridge of millions of axons that connects the hemispheres and allows information to flow between them.

occipital lobes

Regions of the cerebral cortex�at the back of the brain�important for vision

parietal lobes

Regions of the cerebral cortex�in front of the occipital lobes and behind the frontal lobes�important for the sense of touch and for attention to the environment.

temporal lobes

Regions of the cerebral cortex�below the parietal lobes and in front of the occipital lobe� important for processing auditory information,
for memory, and for object and face perception.

frontal lobes

Regions of the cerebral cortex�at the front of the brain�important for movement and higher-level psychological processes associated with the prefrontal cortex.

prefrontal cortex

The frontmost portion of the frontal lobes, especially prominent in humans; important for attention, working memory, decision making, appropriate social behavior, and personality

split brain

A condition that occurs when the corpus callosum is surgically cut and the two hemispheres of the brain do not receive information directly from each other.

somatic nervous system (SNS)

A component of the peripheral nervous system; it transmits sensory signals and motor signals between the central nervous system and the skin, muscles, and joints.

autonomic nervous system (ANS)

A component of the peripheral nervous system; it transmits sensory signals and motor signals between the central nervous system and the body's glands and internal organs.

sympathetic division

A division of the autonomic nervous system; it prepares the body for action.

parasympathetic division

A division of the autonomic nervous system; it returns the body to its resting state.

endocrine system

A communication system that uses hormones to influence thoughts, behaviors, and actions.


Chemical substances, released from endocrine glands, that travel through the bloodstream to targeted tissues; the tissues are subsequently
influenced by the hormones.


The main endocrine glands involved in sexual behavior: in males, the testes; in females, the ovaries.

pituitary gland

A gland located at the base of the hypothalamus; it sends hormonal signals to other endocrine glands, controlling their release of hormones


A property of the brain that allows it to change as a result of experience or injury

gene expression

Whether a particular gene is turned on or off.


Structures within the cell body that are made up of DNA, segments of which comprise individual genes.


The units of heredity that help determine the characteristics of an organism.

dominant gene

A gene that is expressed in the offspring whenever it is present.

recessive gene

A gene that is expressed only when it is matched with a similar gene from the other parent.


The genetic constitution of an organism, determined at the moment of conception.


Observable physical characteristics, which result from both genetic and environmental influences.

monozygotic twins

Also called identical twins; twin siblings that result from one zygote splitting in two and therefore share the same genes.

dizygotic twins

Also called fraternal twins; twin siblings that result from two separately fertilized eggs and therefore are no more similar genetically than nontwin siblings.


A statistical estimate of the extent to which variation in a trait within a population is due to genetics.