The Mind's Machine - Chapter

neuron

Also called nerve cell. The basic unit of the nervous system, each composed of receptive extensions called dendrites, an integrating cell body, a conducting axon, and a transmitting axon terminal.

glial cells

also called glia. nondeuronal brain cells that provide structural, nutritional, and other types of support to the brain

synapse

the cellular location at which information is transmitted from a neuron to another cell

input zone

the part of a neuron that receives information from other neurons or from specialized sensory structures

dendrite

an extension of the cell body that receives information from other neurons

integration zone

the part of a neuron that initiates neural electrical activity

cell body

also called soma. the region of a neuron that is defined by the presence of the cell nucleus

conduction zone

the part of a neuron - typically the axon - over which the action potential is actively propogated

axon

also called nerve fiber. a single extension from the nerve cell that carries action potentials from the cell body toward the axon terminals

output zone

the part of a neuron at which the cell sends information to another cell

axon terminal

also called synaptic bouton. the end of an axon or axon collateral which forms a synapse with a neuron or other target cell

motoneuron

also called motor neuron. a neuron that transmits neural messages to muscles (or glands)

sensory neuron

a nerve cell that is directly affected by changes in the environment, such as light odor or touch

interneuron

a nerve cell that is neither a sensory neuron nor a motoneuron; receives input from and send output to other neurons

multipolar neuron

a nerve cell that has many dendrites and a single axon

bipolar neuron

a nerve cell that has a single dendrite at one end and a single axon at the other end.

unipolar neuron

also called monopolar neuron. a nerve cell with a single branch that leaves the cell body and then extends in two directions one end is the input zone and the other end is the output zone

presynaptic

located on the "transmitting" side of a synapse

postsynaptic

referring to the region of a synapse that receives and responds to a neurotransmitter

presynaptic membrane

the specialized membrane on the axon terminal of a nerve cell that transmits information by releasing neurotransmitters

postsynaptic membrane

the specialized membrane on the surface of a neuron that receives information by responding to neurotransmitters from a presynaptic neuron

synaptic cleft

the space between the presynaptic and postsynaptic neurons at a synapse

pyramidal cells

They are the main excitatory neurons in the cerebral cortex, and are also found in the hippocampus and amygdala

synaptic vesicle

a small, spherical structure that contains molecules of neurotransmitter

neurotransmitter

also called synaptic transmitter, chemical transmitter, or simply transmitter. the chemical released from the presynaptic axon terminal that serves as the basis of communication between neurons

neurotransmitter receptor

also called simply receptor. a specialized protein, often embedded in the cell membrane, that selectively senses and reacts to molecules of a corresponding neurotransmitter or hormone

neuroplasticity

also called neural plasticity. the ability of the nervous system to change in response to experience or the environment

axon hillock

the cone-shaped area on the cell body from which the axon originates

innervate

innervate

axon collateral

a branch of an axon

axonal transport

the transportation of materials from the neuronal cell body toward the axon terminals, and from the axon terminals back toward the cell body

oligodendrocyte

a type of glial cell that forms myelin in the central nervous system

Schwann cell

a type of glial cell that forms myelin in the peripheral nervous system

myelin

the fatty insulation around an axon, formed by glial cells. This sheath boosts the speed at which nerve impulses are conducted.

node of Ranvier

a gap between successive segments of the myelin sheath where the axon membrane is exposed

astrocyte

a star-shaped glial cell with numerous processes (extensions) that run in all directions

microglial cells

also called microglia. extremely small motile glial cells that remove cellular debris from injured or dead cells

edema

the swelling of tissue in response to injury

gross neuroanatomy

anatomical features of the nervous system that are apparent to the naked eye

central nervous system (CNS)

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

peripheral nervous system

the portion of the nervous system that includes all the nerves and neurons outside the brain and spinal cord

nerve

a collection of axons bundled together outside of the central nervous system

motor nerve

a nerve that transmits information from the central nervous system to the muscles and glands

sensory nerve

convey information from body to CNS

somatic nervous system

a part of the peripheral nervous system that supplies neural connections mostly to the skeletal muscles and sensory systems of the body. It consists of cranial nerves and spinal nerves.

autonomic nervous system

a part of the peripheral nervous system that provides the main neural connections to glands and to smooth muscles of internal organs

cranial nerve

a nerve that is connected directly to the brain

spinal nerve

a nerve that emerges from the spinal cord

cervical

referring to the topmost eight segments of the spinal cord, in the neck region

thoracic

referring to the 12 spinal segments below the cervical (neck) portion of the spinal cord, corresponding to the chest

lumbar

referring to the 5 spinal segments that make up the upper part of the lower back

sacral

referring to the five spinal segments that make up the lower part of the lower back

coccygeal

referring to the lowest spinal vertebra (the coccyx, also known as the tailbone)

sympathetic nervous system

the part of the autonomic nervous system that acts as the "fight or flight" system, generally activating the body for action

parasympathetic nervous system

the part of the autonomic nervous system that generally prepares the body to relax and recuperate

cerebral hemisphere

one of the two halves - right and left - of the forebrain

cerebral cortex

also called simply cortex. the outer covering of the cerebral hemispheres, which consists largely of nerve cell bodies and their branches

gyrus

a ridged or raised portion of a convoluted brain surface

sulcus

a crevice or valley of a convoluted brain surface

frontal lobe

the most anterior portion of the cerebral cortex

parietal lobe

the large region of cortex lying between the frontal and occipital lobes in each cerebral hemisphere

temporal lobe

the large lateral region of cortex in each cerebral hemisphere. it is continuous with the parietal lobe posteriorly and separated from the frontal lobe by the Sylvian fissure

occipital lobe

a large region of cortex that covers much of the posterior part of each cerebral hemisphere

Sylvian fissure

also called lateral sulcus. a deep fissure that demarcates the temporal lobe

central sulcus

a fissure that divides the frontal lobe from the parietal lobe

corpus callosum

the main band of axons that connects the two cerebral hemispheres

postcentral gyrus

the strip of parietal cortex, just behind the central sulcus, that receives somatosensory information from the entire body

precentral gyrus

the strip of frontal cortex, just in front of the central sulcus, that is crucial for motor control

gray matter

areas of the brain that are dominated by cell bodies and are devoid of myelin. Gray matter mostly receives and processes information

white matter

a light-colored layer of tissue, consisting mostly of myelin-sheathed axons, that lies underneath the gray matter of the cortex. white matter mostly transmits information

neural tube

an embryonic structure with subdivisions that correspond to the future forebrain, midbrain, and hindbrain

forebrain

the frontal division of the neural tube, containing the cerebral hemispheres, the thalamus and hypothalamus

midbrain

the tectum, the tegmentum, and the cerebral peduncles. The midbrain is crucial for eye movement, visual and auditory processing, and motor control.

hindbrain

the rear division of the brain which in the mature vertebrate contains the cerebellum, pons and medulla

telencephalon

the anterior part of the fetal forebrain, which will become the cerebral hemispheres in the adult brain

diencephalon

tha posterior part of the fetal forebrain which will become the thalamus and hypothalamus in the adult brain

brainstem

the region of the brain that consists of the midbrain the pons and medulla

nucleus

here, a collection of neuronal cell bodies within the CNS

tract

a bundle of axons found within the CNS

pons

Plays a key role in regulating breathing, relaying signals between different parts of the brain, and is involved in sleep and arousal. It also contains nuclei that are important for facial sensations and motor control.

medulla

This structure is located in the brainstem and plays a crucial role in autonomic functions, including reflex actions like swallowing and coughing. It also serves as a pathway for signals between the brain and spinal cord.

cerebellum

This structure is located at the back of the brain, beneath the occipital lobes. It plays a crucial role in processing sensory information related to movement and helps to regulate voluntary motor movements. It also contributes to motor learning and the timing of movements.

Meninges

the three protective membranes--dura mater, pia mater, and arachnoid--that surround the brain and spinal cord

cerebellum

a structure located at the back of the brain, dorsal to the pons, that is involved in the central regulation of movement, and in some forms of learning

Cortical Column

one of the vertical columns that constitute the basic organization of the cerebral cortex

Basal Ganglia

a group of forebrain nuclei, including the caudate nucleus, globus pallidus, and putamen, found deep within the cerebral hemispheres

Caudate Nucleus

one of the basal ganglia; it has a long extension or tail

Putamen

one of the basal ganglia

Globus Pallidus

one of the basal ganglia

Limbic System

a loosely define, widespread group of brain nuclei that innervate each other and form a network

Amygdala

a group of nuclei in the medial anterior part of the temporal lobe

Hippocampus

a medial temporal lobe structure that is important for learning and memory

Fornix

a fiber tract that extends from the hippocampus to the mammillary body

Reticular Formation

an extensive region of the brainstem, extending from the medulla through the thalamus, that is involved in sleep and arousal

Periaqueductal Gray

A midbrain region involved in pain perception

Cingulate Gyrus

a strip of cortex, found in the frontal and parietal midline, that is part of the limbic system and is implicated in many cognitive functions

Olfactory Bulb

an anterior projection of the brain that terminates in the upper nasal passages and, through small openings in the skull, provides receptors for smell

Thalamus

the brain regions that surround the third ventricle

Hypothalamus

Part of the diencephalon, lying ventral to the thalamus

Tectum

the dorsal portion of the midbrain consisting of the inferior and superior colliculi