There are 2 pathways that together form the anterolateral system - the lateral spinothalamic tract which carries the modalities of pain and temperature, and the anterior spinothalamic tract which carries the modality of crude touch and other sensations not known for accurate localization (itch, tickle, sexual).
The incoming fibers of both pathways are thinly myelinated or unmyelinated. They enter on the lateral aspect of the dorsal horn of the spinal cord and have one or more synapses with neurons in the dorsal horn, either at the level of entry or within a few segments of the entry level. The axon of the projecting neuron then crosses in the ventral white commissure of the spinal cord and ascends.
The tract continues throughout the spinal cord, with newer fibers added on medially. It continues through the brainstem, giving off many collaterals including those to the reticular formation. Some of the fibers terminate in the thalamus and some of these are relayed to the cerebral cortex.
Functionally, this pathway carries information slowly, with low degree of retention of information and disperses its messages to many other parts of the nervous system.