PSYC 1F90 Chapter 2 Definitions

Central nervous system (CNS)

The brain and spinal cord.

Spinal cord

A column of nerves that transmits information between the brain and the peripheral nervous system.

Spinal nerves

Major nerves that carry sensory and motor messages in and out of the spinal cord.

Peripheral nervous system (PNS)

The parts of the nervous system outside the brain and spinal cord.

Neuron

A cell in the nervous system that transmits information.

Nerve

A bundle of neuron axons.

Cranial nerves

Major nerves that leave the brain without passing through the spinal cord.

Somatic nervous system (SNS)

A network linking the spinal cord with the body and sense organs.

Autonomic nervous system (ANS)

The collection of axons that carry information to and from internal organs and glands.

Sympathetic nervous system (sympathetic branch)

The division of the autonomic nervous system that coordinates arousal.

Parasympathetic nervous system (parasympathetic branch)

The division of the autonomic nervous system that quiets the body and conserves energy.

Dendrites

Neuron fibers that receive incoming messages.

Cell body

The part of the neuron or other cell that contains the nucleus of the cell.

Axon

A fiber that carries information away from the cell body of a neuron.

Axon terminals

Bulb-shaped structures at the ends of axons that form synapses with the dendrites and cell bodies of other neurons.

Resting potential

The electrical charge of an inactive neuron.

Threshold

In neurons, the point at which a nerve impulse is triggered.

Action potential

A brief change in a neuron's electrical charge.

Myelin sheath

Insulating material that covers some axons.

Ion channels

Tiny openings through the axon membrane.

Negative after-potential

A drop in electrical charge below the resting potential.

Synapse

A microscopic space over which messages pass between two neurons.

Synaptic transmission

The chemical process that carries information from one neuron to another.

Neurotransmitter

A chemical that moves information from one nervous-system cell to another.

Receptor site

An area on the surface of neurons and other cells that is sensitive to neurotransmitters or hormones.

Neuropeptides

Brain chemicals, such as enkephalins and endorphins, that regulate the activity of neurons.

Neuroplasticity

The capacity of the brain to change in response to experience.

Neurogenesis

The production of new brain cells.

Computed tomographic (CT) scan

A computer-enhanced X-ray image of the brain or body.

Magnetic resonance imaging (MRI)

An imaging technique that results in a three-dimensional image of the brain or body, based on its response to a magnetic field.

Localization of function

The research strategy of linking specific structures in the brain to specific psychological or behavioral functions.

Electrical stimulation of the brain (ESB)

Direct electrical stimulation and activation of brain tissue.

Electrode

Any device (such as a wire, needle, or metal plate) used to stimulate or destroy nerve tissue electrically or to record its activity.

Ablation

In biopsychology, the surgical removal of tissue from the surface of the brain.

Deep lesioning

Removal of tissue within the brain by the use of an electrode.

Electroencephalograph (EEG)

A device that records electrical activity in the brain.

Positron emission tomography (PET)

A high-resolution imaging technique that captures brain activity by attaching radioactive particles to glucose molecules.

Functional MRI (fMRI)

An MRI technique that records activity levels in various areas of the brain.

Cerebral cortex

The thin, wrinkled outer covering of the brain in which high-level processes take place.

Corticalization

An increase in the relative size of the cerebral cortex.

Cerebral hemispheres

The left and right sides of the cerebral cortex; interconnected by the corpus callosum.

Lateralization

Differences between the two sides of the body, especially differences in the abilities of the brain hemispheres.

Split-brain operation

A surgical procedure that involves cutting the corpus callosum.

Handedness

A preference for the right or left hand in most activities.

Dominant hemisphere

A term usually applied to the side of a person's brain that produces language.

Lobes of the cerebral cortex

Areas on the left and right cortex bordered by major fissures or defined by their functions.

Frontal lobes

Areas of the cortex associated with movement, the sense of self, and higher mental functions.

Prefrontal area (prefrontal cortex)

The very front of the frontal lobes; involved in the sense of self, executive functions, and planning.

Executive functions

The higher-level mental processes that allow us to regulate and coordinate our own thought processes.

Association areas (association cortex)

All areas of the cerebral cortex that are not primarily sensory or motor in function.

Aphasia

A speech disturbance resulting from brain damage.

Broca's area

A language area related to grammar and pronunciation.

Primary motor area (primary motor cortex)

A brain area associated with the control of movement.

Mirror neurons

Neurons that become active when a motor action is carried out and when another organism is observed performing the same action.

Motor neuron

A cell in the nervous system that transmits commands from the brain to the muscles.

Autism spectrum disorder

A lifetime disorder whose primary features are impaired communication and social interaction.

Parietal lobes

Areas of the cortex in which body sensations register.

Primary somatosensory area (primary somatosensory cortex)

A receiving area for body sensations.

Temporal lobes

Areas of the cortex that include the sites where hearing registers.

Primary auditory area (primary auditory cortex)

The part of the temporal lobe that first receives input from the ears.

Wernicke's area

A temporal lobe brain area related to language comprehension.

Occipital lobes

Cortical areas at the back of the brain that play a role in visual processing.

Primary visual area (primary visual cortex)

The part of the occipital lobe that first receives input from the eyes.

Visual agnosia

An inability to identify seen objects.

Facial agnosia

An inability to perceive familiar faces.

Subcortex

A term referring to all brain structures below the cerebral cortex.

Hindbrain

A primitive part of the brain that comprises the medulla, pons, and cerebellum.

Medulla

The structure that connects the brain with the spinal cord and controls vital life functions.

Pons

An area of the hindbrain that acts as a bridge between the medulla and other structures.

Reticular formation (RF)

A collection of cells and fibers in the medulla and pons involved in arousal and attention.

Cerebellum

The structure in the hindbrain involved in controlling coordination and balance.

Midbrain

A structure that connects the hindbrain with the forebrain.

Forebrain

A brain structure, including the limbic system, thalamus, hypothalamus, and cortex, that governs higher-order mental processes.

Thalamus

A brain structure that relays sensory information to the cerebral cortex.

Hypothalamus

A small area of the brain that regulates emotional behaviors and basic biological needs.

Limbic system

A set of brain structures that play important roles in regulating emotion and memory.

Amygdala

A part of the limbic system associated with the rapid processing of emotions; especially fear.

Hippocampus

Part of the limbic system associated with storing memories.