Spinocerebellar tract

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Brain: Spinocerebellar tract
Spinal cord tracts - English.svg
Spinocerebellar tracts are labeled in blue at right.
Latin Tractus spinocerebellaris
Gray's p.761
NeuroNames ancil-2137625602

The spinocerebellar tract is a set of axonal fibers originating in the spinal cord and terminating in the ipsilateral cerebellum. This tract conveys information to the cerebellum about limb and joint position (proprioception).

Origins of proprioceptive information[edit]

Proprioceptive information is obtained by Golgi tendon organs and muscle spindles.

All of these neurons are "first order" or "primary", are sensory (and thus have their cell bodies in the dorsal root ganglion) and pass through Rexed laminae layers I-VI of the dorsal horn, to form synapses with "second order" or "secondary" neurons in the layer just beneath the dorsal horn (layer VII)

Subdivisions of the tract[edit]

The tract is divided into:[1][dubious ]

Division Peripheral Process of First Order the Neuron Region of Innervation
dorsal (posterior) spinocerebellar tract from muscle spindle (primarily) and golgi tendon organs Ipsilateral Caudal Aspect of the body and legs
ventral (anterior) spinocerebellar tract from golgi tendon organs Ipsilateral Caudal Aspect of the body and legs
cuneocerebellar tract from muscle spindle (primarily) and golgi tendon organs Ipsilateral arm
rostral spinocerebellar tract from golgi tendon organs Ipsilateral arm

Pathway for dorsal and spinocuneocerebellar tracts[edit]

The sensory neurons synapse in an area known as Clarke's nucleus or "Clarke's column".

This is a column of relay neuron cell bodies within the medial gray matter within the spinal cord in layer VII (just beneath the dorsal horn), specifically between T1-L3. These neurons then send axons up the spinal cord, and project ipsilaterally to medial zones of the cerebellum through the inferior cerebellar peduncle.

Below L3, relevant neurons pass into the fasciculus gracilis (usually associated with the dorsal column-medial lemniscal system) until L3 where they synapse with Clarke's nucleus (leading to considerable caudal enlargement).

The neurons in the accessory cuneate nucleus have axons leading to the ipsilateral cerebellum via the inferior cerebellar peduncle.

Pathway for ventral and rostral spinocerebellar tracts[edit]

Some neurons of the ventral spinocerebellar tract instead form synapses with neurons in layer VII of L4-S3. Most of these fibers cross over to the contralateral lateral funiculus via the anterior white commissure and proceed up the spinal cord to synapse with neurons in the superior cerebellar peduncle. The fibers then often cross over again within the cerebellum to end on the ipsilateral side. For this reason the tract is sometimes termed the "double-crosser."

The Rostral Tract synapses at the dorsal horn lamina (intermediate gray zone) of the spinal cord and ascends ipsilaterally to the cerebellum through the inferior cerebellar peduncle.

References[edit]

  1. ^ Siegel, Allan, and Hreday N. Sapru. Essential Neuroscience. 2nd. Lippincott, 2011. 146-149.

External links[edit]