Spinotalamisk

Spinotalamisk, commonly known as the spinothalamic tract, is an ascending somatosensory pathway that transmits pain, temperature, and crude touch from the body to the thalamus and cerebral cortex. It consists of two main components: the lateral spinothalamic tract, which carries pain and temperature, and the anterior (ventral) spinothalamic tract, which carries crude touch and pressure.

Neurons originate in the dorsal horn of the spinal cord, particularly in the substantia gelatinosa and nucleus proprius. Fibers cross to the opposite side within a few spinal segments at the level of entry via the anterior white commissure and then ascend in the contralateral anterolateral funiculus toward the brain. The primary relay in the thalamus is the ventral posterior lateral nucleus (VPL); some fibers project to intralaminar thalamic nuclei before reaching the cortex. From the thalamus, third-order neurons project to the primary somatosensory cortex (postcentral gyrus) via the posterior limb of the internal capsule and the corona radiata.

Functionally, the spinothalamic tract provides perceptual aspects of somatic sensation, with pain and temperature as core modalities and crude touch contributing to non-discriminative tactile perception. The pathway is widely involved in mediating the affective and adaptive responses to noxious and thermal stimuli.

Clinical relevance: lesions can produce contralateral loss of pain and temperature beginning a few segments below the lesion, with potential impairment of crude touch depending on the extent. The tract can be affected by spinal cord injury, stroke, or compressive lesions.