Association fibers are
axon
An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action p ...
s that connect
cortical areas within the same
cerebral hemisphere
The vertebrate cerebrum (brain) is formed by two cerebral hemispheres that are separated by a groove, the longitudinal fissure. The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres ...
.
In human neuroanatomy,
axon
An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action p ...
s (nerve fibers) within the brain, can be categorized on the basis of their course and connections as association fibers,
projection fibers
The projection fibers consist of efferent and afferent fibers uniting the cortex with the lower parts of the brain and with the spinal cord. In human neuroanatomy, bundles of axons (nerve fibers) called tracts, within the brain, can be cate ...
, and
commissural fibers.
The association fibers unite different parts of the same
cerebral hemisphere
The vertebrate cerebrum (brain) is formed by two cerebral hemispheres that are separated by a groove, the longitudinal fissure. The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres ...
, and are of two kinds: (1) short association fibers that connect adjacent gyri; (2) long association fibers that make connections between more distant parts.
Short association fibers
Many of the short association fibers (also called arcuate or "U"-fibers) lie immediately beneath the gray substance of the cortex of the hemispheres, and connect together adjacent
gyri
In neuroanatomy, a gyrus (pl. gyri) is a ridge on the cerebral cortex. It is generally surrounded by one or more sulci (depressions or furrows; sg. ''sulcus''). Gyri and sulci create the folded appearance of the brain in humans and other m ...
.
Some pass from one wall of the sulcus to the other.
Long association fibers
The long association fibers connect the more widely separated gyri and are grouped into bundles.
They include the following:
Diffusion tensor imaging is a non-invasive method to study the course of association fibers.
See also
*
Interneuron
*
Tractography
In neuroscience, tractography is a 3D modeling technique used to visually represent nerve tracts using data collected by diffusion MRI. It uses special techniques of magnetic resonance imaging (MRI) and computer-based diffusion MRI. The results a ...
References
External links
*
*
{{Authority control
Cerebral white matter