Proprioreception

Proprioreception is the sense of position and movement.

Receptors

 

There are three types of mechanoreceptors in muscles and joints:

Stretch-sensitive receptors in the skin, including Ruffini endings and Merkel discs, also signal postural information.

 

 

 

Afferent Nerve Fibres

Somatotopic information is retained as nerves enter the spinal cord through dorsal roots.

  diameter velocity myelinated  
Ia 12-20 70-120 yes muscle spindle stretch - proprioreception
Ib 12-20 70-120 yes golgi tendon organs (contraction)
II (Aβ) 6-12 30-70 yes Meissner corpuscles, Merkel cells
III (Aδ) 1-5 5-30 yes free nerve endings: sharp pain, cold, hair receptors
IV (C) 1 0.5-2 no free nerve endings: dull pain, warmth, itch

 

 

 

 

 

 

 

Ia fibres participate in spinal reflexes

 

 

Spinal Pathways

 

 

Spinocerebellar Tracts

There are many ways for sensory information to reach the cerebellum, both directly and through brainstem relays.

 

The posterior spinocerebellar tract carries information from muscle spindles and Golgi tendon organs, synapsing on the thoracic nucleus at the base of the dorsal horn. It ascend ipsilaterally and travels through the inferior cerebellar peduncle to reach the cerebellar vermis and adjoining areas. It primarily carries proprioreceptive information about the lower limbs. The cuneocerebellar tract travels alongside the PSCT and carries information about the arm.

 

The anterior spinocerebellar tract carries information from proprioreceptors, cutaneous receptors, spinal interneurons, and descending tract fibres. This integration allows it to carry complex information related to attempted movements. The ASCT crosses in the spinal cord and ascends to the superior pons, entering the cerebellum through the superior peduncle. It then recrosses the midline, ending in the ipsilateral vermis and adjoining areas.

 

The dorsal column and medial lemniscus also carry proprioreceptive information.

 

 

 

Central Processing and Perception