Editing Spinothalamic tract (section)

====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).