Lateral spinothalamic tract

 

The lateral spinothalamic tract, also known as the lateral spinothalamic fasciculus, is an ascending pathway located anterolaterally within the peripheral white matter of the spinal cord. It is primarily responsible for transmitting pain and temperature as well as coarse touch. 

The anterior spinothalamic tract (discussed separately), in contrast, primarily transmits coarse touch and pressure. 

First-order neurons, whose cell bodies are in the dorsal root ganglion and whose axons extend from peripheral receptors, enter the cord via dorsal nerve roots. 

First-order neurons synapse with second-order neurons whose bodies are located in the ipsilateral substantia gelatinosa of dorsal horn of the spinal cord.

The lateral spinothalamic tract then ascends in the lateral funiculus, just medial to the ventral spinocerebellar tract. Fibers of this tract are somatotopically organized for their entire course.

Upon reaching the brainstem, the lateral and anterior spinothalamic tracts combine to form the spinal lemniscus, which runs lateral to the medial lemniscus

 The spinal lemniscus terminates in the ventral posterior nucleus of the thalamus. Here, it synapses with third-order neurons, which project to the primary somatosensory area on the ipsilateral side of the cerebral cortex.

Lesion : 

Contra-lateral loss of pain & thermal sensibilities below the level of the lesion

Unable to sense pin prick or recognize hot or cold objects