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Function and organization of ascending pathways in the spinal cord. Ascending pathway: A nerve pathway that goes upward from the spinal cord toward the brain carrying sensory information from the body to the brain. Dorsal Column-Medial Lemniscal Pathway Fasciculus gracilis: Functionally carries sensory modalities like light touch, vibration, proprioception. For example these signals can help differentiate two points. This pathway originates from thick myelinated fibres from mechano and proprioreceptors from sacral, lumbal. and up to the sixth thoracic segments. The signals arrive at the nucleus gracilis in the medulla oblongata where they synapse, this is where the tract termiates but the pathway continues in the second order neurons. After decussation they deliver the information to the thalamus ventral posterolateral nucleus(VPL) where they synapse with the third order neurons that carry the signals to the cortex. Fasciculus cuneatus: Functionally carries sensory modalities like light touch, vibration, proprioception. This pathway originates from thick myelinated fibers from mechano and proprioreceptors from the sixth thoracic segment upwards including all cervical segments. The signals arrive at the nucleus cuneatus in the medulla oblongata where they synapse, this is where this tract terminates but the pathway continues in the second order neurons. After decussation they deliver the information to the thalamus(VPL) where they synapse whit the third order neurons that carry the signals to the cortex. Anterolateral System Tractus spinothalamicus: Functions carries the sensation of crude touch, pressure (anterior spinothalamic tract), pain and heat (lateral spinothalamic tract). Its first order neurons that arise from the periphery are thin or non myelinated, they synapse on neurons in the I. IV. and V. lamina of the grey matter in the substantia gelatinosa or in the nucleus proprius at the tip of the dorsal horn. The second order neurons decussate here and goes to the thalamus(VPL) where they synaps with the third order neurons that carry the information to the primary sensory cortex. Spinocerebellar tracts Tractus spinocerebellaris posterior: Carries information of proprioreceptors (muscle spindles and golgi tendon organs) from the ipsilateral trunk and lower limbs, that are important in movement coordination and posture. Originates from the ipsilateral Clarke column and terminates on the cerebellar cortex. Tractus spinocerebellaris anterior: Conveys proprioceptive information that help our brain coordinate and refine movements . Originates from neurons in the V. VI. and VII. lamina of the grey matter. The fibres decussate twice so it terminates on the ipsilateral cerebellar cortex. There are two more tracts that I didn't mention in the slides the cuneocerebellar tract and the rostral spinocerebellar tract these carry the proprioceptive information of the neck, the upper trunk and limbs. The first order neurons ascend in the fasciculus cuneatus and terminate in the accessory cuneate nucleus, Clark homologue at cervical levels. Terminates on the cerebellar cortex without decussation. Sources: http://teachmeanatomy.info/neuro/pathways/ascending-tracts-sensory/ http://braininfo.rprc.washington.edu/ Slides from the previous year Functional Neuroanatomy https://en.wikipedia.org http://www.blackwellpublishing.com/patestas/chapters/10.pdf