White matter tracts

White matter tracts in the brain, also known as white matter fibers, are classified into three categories: projection fibers, association fibers and commissural fibers.

Projection tracts

Tracts connecting the cortex with other areas in the CNS, e.g. deep nuclei, brainstem, cerebellum or spine; may be efferent (motor) or afferent tracts (sensory). White matter tracts that can be identified by fiber tracking include:

Association tracts

Tracts connecting different areas in the same hemisphere, also known as intrahemispheric tracts (cortex-cortex connections 4).There are two types of association fibers: long-range and U-fibers (short-range) 4DTI tractography can identify the following long-range tracts:

  • arcuate fasciculus (Broca's-Geschwind's-Wernicke's areas connections 5). It contains long-range and short-range fibers that connect the frontal, parietal and temporal lobes 6;  
  • superior and inferior fronto-occipital fasciculi;
  • cingulum (Limbic System Fibers) 4;
  • uncinate fasciculus;
  • superior and inferior longitudinal fasciculi.
Commissural tracts

Tracts connecting the same cortical area in opposite hemispheres (right-left hemispheric connections 4):

See also

Anatomy: Brain
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Article information

rID: 22721
Section: Anatomy
Synonyms or Alternate Spellings:
  • White matter bundles
  • White matter fibers
  • white matter fibres

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Cases and figures

  • Figure 1: association fibers
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