Lateral spinothalamic tract

The lateral spinothalamic tract (or lateral spinothalamic fasciculus), which is a part of the anterolateral system, is a bundle of sensory axons ascending through the white matter of the spinal cord, carrying sensory information to the brain. It carries pain and temperature sensory information (protopathic sensation) to the thalamus. It is composed primarily of fast-conducting, sparsely myelinated A delta fibers and slow-conducting, unmyelinated C fibers. These are secondary sensory neurons which have already synapsed with the primary sensory neurons of the peripheral nervous system in the posterior horn of the spinal cord (one of the three grey columns).