White matter refers to areas of the central nervous system (CNS) that are mainly made up of myelinated axons, also called tracts. ... White matter is named for its relatively light appearance resulting from the lipid content of myelin.

What are white matter pathways?

The white matter of the brain consists of myelinated bundles of nerve fibers, known as fascicles or fiber tracts. These fibers form a complex three-dimensional architecture within the hemispheres and the brainstem (Fig. 1).

What are white fiber tracts?

White matter nerve fibers connect the cerebrum with the spinal cord and other areas of the brain. There are three main types of white matter nerve fiber tracts: commissural fibers, association fibers, and projection fibers. Commissural fibers connect corresponding regions of the left and right hemispheres of the brain.

Are tracts white or gray matter?

White matter areas of the brain mainly consist of myelinated axons, which are long relays that extend out from the soma, and which are whiteish in color due to the relatively high lipid fat content of the myelin protein that sheathes them, These form connections between brain cells, and white matter is typically ...

Are spinal tracts in white matter?

Spinal white matter consists of nerve fibers entering from dorsal roots; nerve fibers exiting to ventral roots; and millions of longitudinally oriented fibers organized into spinal tracts (some tracts are called fasciculi).

WHITE MATTER TRACTS OF THE BRAIN (1/3) - COMMISSURAL TRACTS

What are the white matter tracts of the spinal cord?

Spinal Cord Tracts

The white matter of the spinal cord is divided into the paired posterior (dorsal), lateral, and anterior (ventral) columns. These columns are sometimes called funiculi (or funiculus when singular) and are made up of axons that are traveling up (ascending) or down (descending) the spinal cord.

What is white matter in the spinal cord?

The white matter of your brain and spinal cord is composed of bundles of axons. These axons are coated with myelin, a mixture of proteins and lipids, that helps conduct nerve signals and protect the axons. White matter's job is to conduct, process, and send nerve signals up and down the spinal cord.

What is white matter and gray matter?

The white matter refers to those parts of the brain and spinal cord that are responsible for communication between the various gray matter regions and between the gray matter and the rest of the body. In essence, the gray matter is where the processing is done and the white matter is the channels of communication.

What composes the gray and white matter?

The white matter of the brain is made up primarily of axon tracts, the long, spindly appendages of some brain cells. ... In contrast, gray matter is mostly neuron cell bodies and non-neuron brain cells called glial cells. These glial cells provide nutrients and energy to neurons.

What is GREY white matter differentiation?

Grey-white differentiation refers to the appearance of the interface between cerebral and cerebellar white matter and grey matter on brain CT and MRI. The term is most often used when trying to differentiate cytotoxic from vasogenic edema.

What is the white matter of the cerebellum called?

Nuclei: The cerebellum consists of an outer layer of highly convoluted gray matter (cerebellar cortex) surrounding a highly branched body of white matter known as the arbor vitae (Latin for “tree of life”), which in turn surrounds the 3 pairs of deep cerebellar nuclei embedded in the central cerebellar white matter ( ...

Is the optic tract white matter?

The white matter tracts are broadly classified into 3 groups according to their connectivity (Table 1): 1. ... Other tracts and fibers, which can be seen in DTI maps, include the optic pathway, fornix, and many fibers within the cerebellum and brainstem.

What does white matter do in the brain?

In the most general sense, the gray matter of the brain facilitates information processing, and the white matter facilitates information transfer; both are critical for efficient operation of the neural networks responsible for a specific mental domain.

What are the three types of tracts found in cerebral white matter?

There are three main kinds of white matter tracts: projection, commissural, and association. The largest white matter structure of the brain is the corpus collosum, a form of commissural tract that connects the right and left hemispheres.

What is commissural tract?

Commissural fibers of the brain, also known as commissural tracts of the brain or commissures are a type of white matter tract that cross the midline, connecting the same cortical area in opposite hemispheres (right-left hemispheric connections ³).

What are commissural pathways?

Commissural pathways are interhemispheric fibers interconnecting the cortical areas of both hemispheres in homo (similar anatomic regions) or heterotopic (different anatomic regions) in fashion. Projection pathways arise either in the cortex and terminate in the subcortical centers, or vice versa.

Why is white matter white quizlet?

Why is white matter white? The white matter of the CNS appears white because the majority of the nerve fibers in these regions are myelinated.

How are gray matter and white matter arranged in the CNS?

White matter is found buried in the inner layer of the brain's cortex, while the grey matter is mainly located on the surface of the brain. The spinal cord is arranged in the opposite way, with grey matter found deep inside its core and the insulating white matter wrapped around the outside.

Is the corpus callosum white matter?

The corpus callosum is the largest white matter structure in the brain, consisting of 200-250 million contralateral axonal projections and the major commissural pathway connecting the hemispheres of the human brain.

What is the function of white matter quizlet?

White matter in brain is known as the cerebral white matter. The white matter deep to the cortical gray matter is responsible for communication between cerebral areas and between the cerebral cortex and lower CNS.

Where is white matter in the spinal cord?

White matter in the spinal cord is sometimes called superficial tissue because it is located in the outer regions of the brain and spinal cord. Gray matter is situated closer to the center of the central nervous system.

Why is white matter on the outside of the spinal cord?

The white matter is white because of the fatty substance ( myelin ) that surrounds the nerve fibers. Myelin acts as an electrical insulation. It allows the messages to pass quickly from place to place.

What is white matter called in the PNS?

Myelin, the lipid that forms a thin layer, known as the myelin sheath, around the axons providing electrical insulation is white in color, giving rise to the name white matter.

What cells make up white matter?

The white matter contains the glial cells responsible for the production of myelin (the oligodendrocytes) and the astrocytes (1).

What is white matter in MRI?

White matter hyperintensities (WMHs) are lesions in the brain that show up as areas of increased brightness when visualised by T2-weighted magnetic resonance imaging (MRI). WMH's are also referred to as Leukoaraiosis and are often found in CT or MRI's of older patients.