Anterior spinocerebellar tract

The anterior spinocerebellar tract is an example of an ascending sensory tract. It serves to transmit unconscious proprioceptive information from the muscle spindles, golgi tendon organs and joint receptors, to the cerebellum. The information about the movements of the muscles and joints and the associated tension in the tendons is computed by the cerebellum to coordinate muscle movements and maintain posture and gait.

The axons of first order neurons arise from the dorsal root ganglion and enter the posterior gray horn of spinal cord via the posterior nerve rootlets. These synapse with the cell bodies of second order sensory neurons in the nucleus dorsalis (or Clarke’s column). The nucleus is situated in the lateral intermediate substance in the base of posterior horn (lamina VII). It is important to know that since the nucleus dorsalis resides in the C8–L3 spinal segments only, hence axons entering spinal cord via upper cervical or lower lumber and sacral spinal nerves must descend or ascend a few segments to be able to synapse with the nucleus dorsalis.

The axons of second order sensory neurons–originating from the nucleus dorsalis–ascend in the anterolateral part of the lateral funiculus (or lateral white column), as the anterior spinocerebellar tract. Majority of anterior spinocerebellar tract fibers cross in the spinal cord and ascend in the contralateral lateral funiculus, while a few ascend uncrossed in the ipsilateral lateral funiculus.

The tract reaches the medulla oblongata and pons, where it passes through the superior cerebellar peduncle to terminate in the cerebellar cortex of the same side. Those majority fibers which crossed, also return back to the cerebellum of the same side by traversing through the brainstem.

A lesion in lateral spinal cord, that effects the spinocerebellar tracts, can lead to problems with coordinating the muscle movements, manifesting as nystagmus, dysmetria, dysdiadochokinesia and gait imbalance, all on the same side of the lesion.