What is white matter microstructure?
The integrity of white matter microstructure in the corpus callosum (CC)—the largest white matter structure in the human brain that connects the right and left hemispheres—appears to predict performance on a variety of different tasks.
What is white brain matter?
White matter is found in the deeper tissues of the brain (subcortical). It contains nerve fibers (axons), which are extensions of nerve cells (neurons). Many of these nerve fibers are surrounded by a type of sheath or covering called myelin. Myelin gives the white matter its color.
What are white matter tracts?
White matter refers to areas of the central nervous system (CNS) that are mainly made up of myelinated axons, also called tracts. However, the tissue of the freshly cut brain appears pinkish-white to the naked eye because myelin is composed largely of lipid tissue veined with capillaries.
Can MRI measure white matter?
The clinical role of MRI has considerably increased recently for the diagnosis of MS, monitoring of disease progression, and response to therapy. Typically on MRI, white matter MS lesions are ovoid in appearance and are located in the periventricular white matter, brainstem, and cerebellum.
What is fractional anisotropy in brain?
BACKGROUND AND PURPOSE: Fractional anisotropy (FA) is a useful measure of connectivity in the brain that can be derived from the diffusion tensor imaging (DTI) dataset. Relationships between a range of cognitive measures and FA were explored using regional and voxel-based analysis.
What does diffusion tensor imaging measure?
Diffusion Tensor Imaging (DTI) is a technique that detects how water travels along the white matter tracts in the brain (Fig. 2). White-matter tracts connect different parts of the brain and must be protected during surgery.
What parts of the brain are white matter?
White matter is a vast, intertwining system of neural connections that join all four lobes of the brain (frontal, temporal, parietal, and occipital), and the brain’s emotion center in the limbic system, into the complex brain maps being worked out by neuroscientists.
What are the three types of 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.
Can white matter lesions in the brain be nothing?
White matter lesions observed on brain MRI are usually characteristic and occur in specific areas including the corpus callosum and pons. “However, in many cases, the white matter lesions as isolated observations are nonspecific” and could be due to MS or another cause, explained Drs Lange and Melisaratos.
What is the meaning of anisotropy?
Anisotropy, in physics, the quality of exhibiting properties with different values when measured along axes in different directions. Anisotropy is most easily observed in single crystals of solid elements or compounds, in which atoms, ions, or molecules are arranged in regular lattices.
Is white matter anisotropic?
Because diffusion of water in spinal cord white matter is more anisotropic than gray matter, anisotropy indices are often useful for identifying spinal gray and white matter.
Why is white matter important to the brain?
Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distribution of action potentials, acting as a relay and coordinating communication between different brain regions. White matter is named for its relatively light appearance resulting from the lipid content of myelin.
What kind of imaging is used to study white matter?
The study of white matter has been advanced with the neuroimaging technique called diffusion tensor imaging where magnetic resonance imaging (MRI) brain scanners are used. As of 2007, more than 700 publications have been published on the subject.
What causes the loss of white matter in the body?
Clinical significance. White matter injuries (“axonal shearing”) may be reversible, while gray matter regeneration is less likely. Other changes that commonly occur with age include the development of leukoaraiosis, which is a rarefaction of the white matter that can be caused by a variety of conditions, including loss of myelin, axonal loss,…
What makes grey matter darker than white matter?
Grey matter. The substantia nigra is a third colored component found in the brain that appears darker due to higher levels of melanin in dopaminergic neurons than its nearby areas. Note that white matter can sometimes appear darker than grey matter on a microscope slide because of the type of stain used.
