Dorsal and Ventral Spinocerebellar Tracts (DSCT, VSCT)
Spinothalamic Tract (STT)
Rubrospinal Tract (RST)
Hypothalamo-Autonomic Tract (HAT)
Pyramidal Tract (PT)
Medial Accessory Olive (MAO)
Note:
The ascending axons in the Cuneate and Gracilis Fasciculi are first order axons which synapse on the the second order neurons of the Cuneate and Gracilis Nuclei which, in turn, send their axons (Internal Arcuate Fibers or IAF) to the Medial Lemniscus.
The Medial Lemnisci at this level are "vertically" oriented adjacent to the midline, but at levels above the inferior olivary nuclei they diverge and come to lie horizontally as they make their way to the Ventral Posterolateral Nucleus of the Thalamus (VPL).
Fibers emanating from the Spinal Trigeminal Nucleus cross and ascend in the most dorsal part of the contralateral Medial Lemniscus as the Ventral Trigeminothalamic Tract and terminate in the Ventral Posteromedial Nucleus of the Thalamus (VPM).
Immediately dorsal to the Medial Lemnisci are two other tracts which, however, are descending rather than ascending.
The Tectospinal Tract (TST) arises in the Superior Colliculus or Tectum and courses immediately dorsal to the Medial Lemniscus; it projects to neck muscle motorneurons in the upper cervical cord.
The Medial Longitudinal Fasciculus (MLF) is the most dorsal midline tract; it arises from many brainstem cell groups and interconnects the Oculomotor Nuclei (III,IV,VI), the Vestibular Nuclei, and the upper cervical spinal cord. The MLF is a vital pathway that serves to coordinate eye and head movements.
