From the ventral posterolateral nucleus in the thalamus, sensory information is relayed upward to the somatosensory cortex of the postcentral gyrus.

Pseudounipolar neurons in the dorsal root ganglion have axons that lead from the skin into the dorsal spinal cord where they ascend or descend one or two vertebral levels via Lissauer's tract and then synapse with secondary neurons in either the substantia gelatinosa of Rolando or the nucleus proprius.

The fibers of the anterior spinothalamic tract conduct information about pressure and crude touch (protopathic).

High-resolution RNA sequencing finds the anterior spinothalamic tract has five distinct types of neurons.

There is evidence to suggest the existence of a projection from lamina I and deeper layers of the dorsal horn to the ventrobasal complex and other thalamic nuclei, eventually passing pain and temperature information to the SI and SII somatosensory cortices.

They project peripheral processes to the tissues in the form of free nerve endings which are sensitive to molecules indicative of cell damage.

The central processes enter the spinal cord in an area at the back of the posterior horn known as the posterolateral tract.

These secondary neurons are situated in the posterior horn, specifically in the Rexed laminae regions I, IV, V and VI.

These fibers will ascend through the brainstem, including the medulla oblongata, pons and midbrain, as the spinal lemniscus until synapsing in the ventroposteriorlateral (VPL) nucleus of the thalamus.

[citation needed] There are two sub-systems identified: The anterolateral system (ALS) is an ascending bundle of fibers in the spinal cord, carried in three main pathways or tracts.

This article incorporates text in the public domain from page 760 of the 20th edition of Gray's Anatomy (1918) 2° (Spinomesencephalic tract → Superior colliculus of Midbrain tectum)