Psycology 100 Chapter 3 terms

Action Potential

A transient all-or-nothing electrical current that is conducted down the axon when the

membrane potential reaches the threshold of excitation.

Axon

Part of the neuron that extends off the soma, splitting several times to connect with other

neurons; main output of the neuron.

Brain Stem

The “trunk” of the brain comprised of the medulla, pons, midbrain, and diencephalon

Broca’s Area

An area in the frontal lobe of the left hemisphere. Implicated in language production.

Central Nervous System

The portion of the nervous system that includes the brain and spinal cord.

Cerebellum

The distinctive structure at the back of the brain, Latin for “small brain.”

Cerebrum

Usually refers to the cerebral cortex and associated white matter, but in some texts includes

the subcortical structures.

Contralateral

Literally “opposite side”; used to refer to the fact that the two hemispheres of the brain process

sensory information and motor commands for the opposite side of the body (e.g., the left

hemisphere controls the right side of the body).

Corpus Callosum

The thick bundle of nerve cells that connect the two hemispheres of the brain and allow them

to communicate.

Dendrites

Part of a neuron that extends away from the cell body and is the main input to the neuron.

Diffuse Optical Imaging (DOI)

A neuroimaging technique that infers brain activity by measuring changes in light as it is

passed through the skull and surface of the brain.

Electroencephalography (EEG)

A neuroimaging technique that measures electrical brain activity via multiple electrodes on

the scalp.

Frontal Lobe

The front most (anterior) part of the cerebrum; anterior to the central sulcus and responsible

for motor output and planning, language, judgment, and decision-making.

Functional Magnetic Resonance Imaging (fMRI)

Functional magnetic resonance imaging (fMRI): A neuroimaging technique that infers brain

activity by measuring changes in oxygen levels in the blood.

Limbic System

Includes the subcortical structures of the amygdala and hippocampal formation as well as

some cortical structures; responsible for aversion and gratification.

Myelin

Fatty tissue, that insulates the axons of the neurons; myelin is necessary for normal conduction

of electrical impulses among neurons.

Nervous System

The body’s network for electrochemical communication. This system includes all the nerves

cells in the body.

Neurons

Individual brain cells

Neurotransmitters

Chemical substance released by the presynaptic terminal button that acts on the postsynaptic

cell.

Occipital Lobe

The back most (posterior) part of the cerebrum; involved in vision.

Parietal Lobe

The part of the cerebrum between the frontal and occipital lobes; involved in bodily sensations,

visual attention, and integrating the senses.

Peripheral Nervous System

All of the nerve cells that connect the central nervous system to all the other parts of the body.

Positron Emission Tomography (PET)

A neuroimaging technique that measures brain activity by detecting the presence of a

radioactive substance in the brain that is initially injected into the bloodstream and then pulled

in by active brain tissue.

Soma

Cell body of a neuron that contains the nucleus and genetic information, and directs protein synthesis

Spatial Resolution

A term that refers to how small the elements of an image are; high spatial resolution means

the device or technique can resolve very small elements; in neuroscience it describes how

small of a structure in the brain can be imaged.

Split-brain Patient

A patient who has had most or all of his or her corpus callosum severed.

Synapses

unction between the presynaptic terminal button of one neuron and the dendrite, axon, or

soma of another postsynaptic neuron.

Synaptic Gap

Also known as the synaptic cleft; the small space between the presynaptic terminal button

and the postsynaptic dendritic spine, axon, or soma.

Temporal Lobe

he part of the cerebrum in front of (anterior to) the occipital lobe and below the lateral fissure;

involved in vision, auditory processing, memory, and integrating vision and audition.

Temporal Resolution

A term that refers to how small a unit of time can be measured; high temporal resolution

means capable of resolving very small units of time; in neuroscience it describes how precisely

in time a process can be measured in the brain.

Action potential

A transient all-or-nothing electrical current that is conducted down the axon when the

membrane potential reaches the threshold of excitation.

Axon

Part of the neuron that extends off the soma, splitting several times to connect with other

neurons; main output of the neuron.

Dendrite

Part of a neuron that extends away from the cell body and is the main input to the neuron.

Electrostatic pressure

The force on two ions with similar charge to repel each other; the force of two ions with

opposite charge to attract to one another.

Excitatory postsynaptic potentials

A depolarizing postsynaptic current that causes the membrane potential to become more

positive and move towards the threshold of excitation.

Inhibitory postsynaptic potentials

A hyperpolarizing postsynaptic current that causes the membrane potential to become more

negative and move away from the threshold of excitation.

Ion channels

Proteins that span the cell membrane, forming channels that specific ions can flow through

between the intracellular and extracellular space.

Ionotropic receptor

Ion channel that opens to allow ions to permeate the cell membrane under specific conditions,such as the presence of a neurotransmitter or a specific membrane potential.

Resting membrane potential

The voltage inside the cell relative to the voltage outside the cell while the cell is a rest

(approximately -70 mV).

Sodium-potassium pump

An ion channel that uses the neuron’s energy (adenosine triphosphate, ATP) to pump three

Na+ ions outside the cell in exchange for bringing two K+ ions inside the cell.

Threshold of excitation

Specific membrane potential that the neuron must reach to initiate an action potential.