Somatosensory system

The somatosensory system, or somatic sensory system is a subset of the sensory nervous system. It has two subdivisions, one for the detection of mechanosensory information related to touch, and the other for the nociception detection of pain and temperature.^[1] The main functions of the somatosensory system are the perception of external stimuli, the perception of internal stimuli, and the regulation of body position and balance (proprioception).^[2]

Mechanosensory information includes that of light touch, vibration, pressure and tension in the skin. Much of this information belongs to the sense of touch which is a general somatic sense in contrast to the special senses of sight, smell, taste, hearing and balance.^[3]

Nociceptory information is that received from pain and temperature that is deemed as harmful (noxious). Thermoreceptors relay temperature information in normal circumstances.^[1] Nociceptors are specialised receptors for signals of pain.^[4]

The sense of touch in perceiving the environment uses special sensory receptors in the skin called cutaneous receptors. They include mechanoreceptors such as tactile corpuscles that relay information about pressure and vibration; nociceptors, and thermoreceptors for temperature perception.^[5]

Stimulation of the receptors activate peripheral sensory neurons that convey signals to the spinal cord that may drive a responsive reflex, and may also be conveyed to the brain for conscious perception. Somatosensory information from the face and head enter the brain via cranial nerves such as the trigeminal nerve.

The neural pathways that go to the brain are structured such that information about the location of the physical stimulus is preserved. In this way, neighboring neurons in the somatosensory cortex represent nearby locations on the skin or in the body, creating a map or sensory homunculus.

^ ^a ^b Purves, Dale; Augustine, George J.; Fitzpatrick, David; Katz, Lawrence C.; LaMantia, Anthony-Samuel; McNamara, James O.; Williams, S. Mark (2001). "The Somatic Sensory System". Neuroscience. 2nd edition. Sinauer Associates.
^ Wang, L; Ma, L; Yang, J; Wu, J (2021). "Human Somatosensory Processing and Artificial Somatosensation". Cyborg and bionic systems (Washington, D.C.). 2021: 9843259. doi:10.34133/2021/9843259. PMID 36285142.
^ Saladin, Kenneth S. (2011). Human anatomy (3rd ed.). New York: McGraw-Hill. p. 420. ISBN 9780071222075.
^ Saladin, Kenneth S. (2011). Human anatomy (3rd ed.). New York: McGraw-Hill. p. 464. ISBN 9780071222075.
^ Sherman, Carl (August 12, 2019). "The Senses: The Somatosensory system". Dana Foundation. New York.

[Purves-1] Purves, Dale; Augustine, George J.; Fitzpatrick, David; Katz, Lawrence C.; LaMantia, Anthony-Samuel; McNamara, James O.; Williams, S. Mark (2001). "The Somatic Sensory System". Neuroscience. 2nd edition. Sinauer Associates.

[Wang-2] Wang, L; Ma, L; Yang, J; Wu, J (2021). "Human Somatosensory Processing and Artificial Somatosensation". Cyborg and bionic systems (Washington, D.C.). 2021: 9843259. doi:10.34133/2021/9843259. PMID 36285142.

[Saladin1-3] Saladin, Kenneth S. (2011). Human anatomy (3rd ed.). New York: McGraw-Hill. p. 420. ISBN 9780071222075.

[Saladin2-4] Saladin, Kenneth S. (2011). Human anatomy (3rd ed.). New York: McGraw-Hill. p. 464. ISBN 9780071222075.

[5] Sherman, Carl (August 12, 2019). "The Senses: The Somatosensory system". Dana Foundation. New York.

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