Ascending pathways

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Anatomical system	Anatomical tracts	Functional components
anterolateral (ALS)	spinothalamic spinoreticular spinomesencephalic spinotectal spinohypothalamic	pain,temperature, nondiscriminative touch, pressure, some proprioceptive sensation
dorsal column-medial lemniscal	fasciculus gracilis fasciculus cuneatus	discriminative (fine) touch, vibratory sense, position sense
somatosensory to the cerebellum	anterior spinocerebellar posterior spinocerebellar rostral spinocerebellar  cuneocerebellar	primarily proprioceptive information (also some pain and pressure)

Anterolateral system

The ALS transmits nociceptive, thermal,and nondiscriminatory touch information to higher brain centers,generally by a sequence of three neurons and interneurons

1) First order neuron (pseudounipolar neuron) 
                cell body is located in a dorsal root ganglion
                 transmits sensory information from peripheral structures to the dorsal (posterior) horn of the spinal cord

2) Second order neuron
                   celll body is located within the dorsal horn of the spinal cord 
                   whose axon decusates and ascends
                                        >in the direct pathway of the ALS  (spinothalamic tract) to synapse in the contralateral thalamus and sending some                                                collaterals to the reticular fromation 
                                        > in the indirect patway of the ALS (spinoreticular tract) to synapse in the reticular formation and sending some                                                         collaterals to the thalamus
                                         > as spinomesencephalic, spinotectal or spino hypothalamic fibers to synapse in several brainstem nuclei

3) third order neuron 
                      cell body is located at the thalamus, and whose axon ascends ipsilaterally to terminate in the somatosensory cortex

 

http://www.blackwellpublishing.com/patestas/chapters/10.pdf