Ascending spinal tracts - Spinocerebellar tracts

Question 1

What is the difference between the spinocerebellar tracts and the dorsal columns and anterolateral tracts?

Answer 1

1. Dorsal columns and anterolateral tracts transmit conscious sensations (pain, touch, temperature) whereas spinocerebellar tracts transmit unconscious proprioceptive information - help our brain co-ordinate and refine motor movements
2. Spinocerebellar system consists only of first order and second order neurons

Question 2

Where do the spinocerebellar tracts transmit information from and to?

Answer 2

Transmits information derived from muscle spindles, mechanoreceptors (such as Golgi tendon organs) and tactile receptors to the cerebellum for control of posture and coordination of movement

Question 3

Within the spinocerebellar tracts there are 4 individual pathways, what are they?

Answer 3

1. Posterior spinocerebellar tract
2. Cunceocerebellar tract
3. Anterior spinocerebellar tract
4. Rostral spinocerebellar tract

Question 4

What does the posterior (dorsal) spinocerebellar tract do?

Answer 4

Carries proprioceptive information from the lower limbs to the ipsilateral cerebellum

Question 5

What does the cuneocerebellar tract do?

Answer 5

Carries proprioceptive information from the upper limbs to the ipsilateral cerebellum

Question 6

What does the anterior (ventral) spinocerebellar tract do?

Answer 6

Carries proprioceptive information from the lower limbs. The fibres decussate twice and so terminate in the ipsilateral cerebellum

Question 7

What does the rostral spinocerebellar tract do?

Answer 7

Carries proprioceptive information from the upper limbs to the ipsilateral cerebellum

Question 8

Where do fibres of the anterior/ventral spinocerebellar tract originate?

Answer 8

From a prominent group of cells in lamina VII of cord segments T1-L2, known as the thoracic nucleus or Clark’s column. The axons ascend ipsilaterally to enter the cerebellum through the inferior cerebellar peduncle

Question 9

Where do fibres of the posterior/dorsal spinocerebellar tract originate?

Answer 9

From cells at the lumbrosacral cord levels. The fibres decussate, ascend on the contralateral side of the cord and enter the cerebellum via the superior cerebellar peduncle - some axons then recross within the cerebellar white matter

Question 10

What is the upper limb equivalent of the dorsal spinocerebellar tract?

Answer 10

Cuneocerebellar tract

Question 11

Outline the cuneocerebellar tract

Answer 11

In this pathway some primary proprioceptive afferents, originating mostly in the cervical enlargement and ascending ipsilaterally in the fasciculus cuneatus (one of the dorsal columns), terminate in the medulla in the lateral cuneate nucleus (just lateral to the principal cuneate nucleus). From here, second order neurons enter the cerebellum via the inferior cerebellar peduncle

Question 12

What is the upper limb equivalent of the ventral spinocerebellar tract?

Answer 12

Rostral spinocerebellar tract

Question 13

Outline the rostral spinocerebellar tract

Answer 13

Axons arise from cells in the cervical enlargement and ascend ipsilaterally in the lateral funiculus, entering the cerebellum mostly through the inferior cerebellar peduncle

Question 14

Clinical link - outline Friedreich’s ataxia

Answer 14

Inherited degenerative disease, in which the spinocerebellar tracts are particularly disordered, leading to profound incoordination of the arms (intention tremor) and a wide-based, reeling gait (ataxia). The disorder begins in childhood and the patient is wheelchair-bound by 20 years of age