Editing Spinothalamic tract (section)

===Lateral spinothalamic tract===
The '''lateral spinothalamic tract''' (or '''lateral spinothalamic fasciculus'''), is a bundle of [[afferent nerve fiber]]s ascending through the white matter of the [[spinal cord]], in the spinothalamic tract, carrying sensory information to the [[human brain|brain]]. It carries pain, and temperature sensory information ([[protopathic sensation]]) to the [[thalamus]]. It is composed primarily of fast-conducting, sparsely [[myelinated]] [[A delta fiber]]s and slow-conducting, unmyelinated [[Group C nerve fiber|C fibers]]. These are secondary sensory neurons which have already [[synapse]]d with the primary [[sensory neuron]]s of the [[peripheral nervous system]] in the [[posterior horn of spinal cord|posterior horn of the spinal cord]] (one of the three [[grey column]]s).

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.<ref>{{cite journal |last1=Willis |first1=William D. |last2=Zhang |first2=Xijing |last3=Honda |first3=Christopher N. |last4=Giesler |first4=Glenn J. |title=A critical review of the role of the proposed VMpo nucleus in pain |journal=The Journal of Pain |date=1 April 2002 |volume=3 |issue=2 |pages=79–94 |doi=10.1054/jpai.2002.122949 |pmid=14622792 |url=https://www.sciencedirect.com/science/article/pii/S1526590002798428 |issn=1526-5900}}</ref> In macaque monkeys, neurons from the posterior part of the ventral medial nucleus terminate at the posterior half of the superior limiting sulcus that bounds the dorsal insular cortext.<ref>{{cite journal |last1=Craig |first1=A.D. (Bud) |title=Topographically Organized Projection to Posterior Insular Cortex from the Posterior Portion of the Ventral Medial Nucleus (VMpo) in the Long-tailed Macaque Monkey |journal=The Journal of Comparative Neurology |date=1 January 2014 |volume=522 |issue=1 |pages=36–63 |doi=10.1002/cne.23425 |pmid=23853108 |pmc=4145874 |issn=0021-9967}}</ref>

Together with the anterior spinothalamic tract, the lateral spinothalamic tract is sometimes termed the ''secondary sensory fasciculus'' or ''spinal lemniscus''.

====Anatomy====
The neurons of the lateral spinothalamic tract originate in the [[spinal column|spinal]] [[dorsal root ganglion|dorsal root ganglia]].  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]].  Here, the processes ascend approximately two levels before synapsing on second-order neurons.  These secondary neurons are situated in the posterior horn, specifically in the [[Rexed laminae]] regions I, IV, V and VI.  Region II is primarily composed of [[Golgi II]] [[interneuron]]s, which are primarily for the modulation of pain, and largely project to secondary neurons in regions I and V.  Secondary neurons from regions I and V decussate across the [[anterior white commissure]] and ascend in the (now contralateral) lateral spinothalamic tract. 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]].  The third order neurons in the thalamus will then project through the [[internal capsule]] and [[corona radiata]] to various regions of the [[cerebral cortex|cortex]], primarily the [[primary somatosensory cortex]] ([[Brodmann area]]s 3, 1, and 2).