Wikipedia

Somatosensory system

(Redirected fromTouch)
"Touch" redirects here. For other uses, seeTouch (disambiguation).

Thesomatosensory system,orsomatic sensory systemis a subset of thesensory nervous system.It has two subdivisions, one for the detection ofmechanosensoryinformation related to touch, and the other for thenociceptiondetection 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]

Touch is a crucial means of receiving information. This photo shows tactile markings identifying stairs for visually impaired people.

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 thespecial sensesofsight,smell,taste,hearingandbalance.[3]

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

The sense of touch in perceiving the environment uses specialsensory receptorsin theskincalledcutaneous receptors.They includemechanoreceptorssuch astactile corpusclesthat relay information about pressure and vibration; nociceptors, and thermoreceptors for temperature perception.[5]

Stimulation of the receptors activateperipheral sensory neuronsthat convey signals to thespinal cordthat may drive a responsivereflex,and may also be conveyed to the brain for conscious perception. Somatosensory information from the face and head enter the brain viacranial nervessuch as thetrigeminal 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 thesomatosensory cortexrepresent nearby locations on the skin or in the body, creating a map orsensory homunculus.

Touch communication

edit

Tactile signing

edit

Tactile signingis a common means of communication used by people withdeafblindness.It is based on a sign language or another system of manual communication.

Emotion communication

edit

Humans can communicate specific emotions through touch alone including anger, fear, disgust, love, gratitude, and sympathy via touch at much-better-than-chance levels.[6]

Overview

edit
This diagram linearly (unless otherwise mentioned) tracks the projections of all known structures that allow for touch to their relevant endpoints in the human brain.

Sensory receptors

edit

The two different types ofmechanoreceptorin the skin are termedlow-threshold mechanoreceptors,andhigh threshold mechanoreceptors. The four mechanoreceptors inglabrous skinare low-threshold that respond to harmless stimuli. They are innervated by four different afferent fibers. High-threshold mechanoreceptors, respond toharmful stimuli.[7]

Merkel cellnerve endings are found in the basalepidermisandhair follicles;they react to low vibrations (5–15Hz) and deep static touch such as shapes and edges. Due to having a small receptive field (extremely detailed information), they are used in areas like fingertips the most; they are not covered (shelled) and thus respond to pressures over long periods.

Tactile corpusclesreact to moderate vibration (10–50 Hz) and light touch. They are located in thedermal papillae;due to their reactivity, they are primarily located in fingertips and lips. They respond in quickaction potentials,unlike Merkel nerve endings. They are responsible for the ability to read Braille and feel gentle stimuli.

Pacinian corpusclesdetermine gross touch and distinguish rough and soft substances. They react in quick action potentials, especially to vibrations around 250 Hz (even up to centimeters away). They are the most sensitive to vibrations and have large receptor fields. Pacinian corpuscles react only to sudden stimuli so pressures like clothes that are always compressing their shape are quickly ignored. They have also been implicated in detecting the location of touch sensations on handheld tools.[8]

Bulbous corpusclesreact slowly and respond to sustained skin stretch. They are responsible for the feeling of object slippage and play a major role in thekinestheticsense and control of finger position and movement. Merkel and bulbous cells - slow-response - aremyelinated;the rest - fast-response - are not. All of these receptors are activated upon pressures that distort their shape causing an action potential.[9][10][11][12]

Somatosensory cortex

edit
See also:Haptic perception
Gray's Anatomy,figure 759: the sensory tract, showing the pathway (blue) up the spinal cord, through the somatosensory thalamus, to S1 (Brodmann areas 3, 1, and 2), S2, and BA7
Gray's Anatomy,figure 717: detail showing path adjacent to theinsular cortex(marked insula in this figure), adjacent to S1, S2, and BA7

Thepostcentral gyrusis in theparietal lobeand its cortex is theprimary somatosensory cortex(Brodmann areas3, 2 and 1) collectively referred to as S1.

BA3receives the densest projections from thethalamus.BA3a is involved with the sense of relative position of neighboring body parts and amount of effort being used during movement. BA3b is responsible for distributing somatosensory information, it projects texture information to BA1 and shape and size information to BA2.

Region S2 (secondary somatosensory cortex) divides into Area S2 and parietal ventral area. Area S2 is involved with specific touch perception and is thus integrally linked with the amygdala and hippocampus to encode and reinforce memories.

Parietal ventral area is the somatosensory relay to the premotor cortex and somatosensory memory hub, BA5.

BA5is the topographically organized somato memory field and association area.

BA1processes texture info while BA2 processes size and shape information.

Area S2 processes light touch, pain, visceral sensation, and tactile attention.

S1 processes the remaining info (crude touch, pain, temperature).[13][14][15]

BA7integrates visual and proprioceptive info to locate objects in space.[16][17]

Theinsular cortex(insula) plays a role in the sense of bodily-ownership, bodily self-awareness, and perception. Insula also plays a role in conveying info about sensual touch, pain, temperature, itch, and local oxygen status. Insula is a highly connected relay and thus is involved in numerous functions.

Structure

edit

The somatosensory system is spread through all major parts of thevertebratebody. It consists both ofsensory receptorsandsensory neuronsin the periphery (skin, muscle and organs for example), to deeper neurons within thecentral nervous system.[3]

General somatosensory pathway

edit
Further information:Dorsal column–medial lemniscus pathway

All afferent touch/vibration information ascends the spinal cord via thedorsal column-medial lemniscus pathwayvia gracilis (T7 and below) or cuneatus (T6 and above). Cuneatus sends signals to the cochlear nucleus indirectly via spinal grey matter, this info is used in determining if a perceived sound is just villi noise/irritation. All fibers cross (left becomes right) in the medulla.

A somatosensory pathway will typically have three neurons:[18]first-order, second-order, and third-order.[19]

  1. Thefirst-order neuronis a type ofpseudounipolar neuronand always has itscell bodyin thedorsal root ganglionof thespinal nervewith a peripheralaxoninnervating touchmechanoreceptorsand a central axon synapsing on the second-order neuron. If the somatosensory pathway is in parts of the head or neck not covered by the cervical nerves, the first-order neuron will be thetrigeminal nerve gangliaor the ganglia of other sensorycranial nerves).
  2. Thesecond-order neuronhas itscell bodyeither in the spinal cord or in the brainstem. This neuron's ascendingaxonswill cross (decussate) to the opposite side either in thespinal cordor in thebrainstem.
  3. In the case of touch and certain types of pain, thethird-order neuronhas itscell bodyin theventral posterior nucleusof the thalamus and ends in thepostcentral gyrusof theparietal lobein theprimary somatosensory cortex(or S1).

Photoreceptors, similar to those found in theretinaof theeye,detect potentially damagingultraviolet radiation(ultraviolet Aspecifically), inducing increased production ofmelaninbymelanocytes.[20]Thus tanning potentially offers the skin rapid protection from DNA damage and sunburn caused byultraviolet radiation(DNA damage caused byultraviolet B). However, whether this offers protection is debatable, because the amount of melanin released by this process is modest in comparison to the amounts released in response to DNA damage caused byultraviolet Bradiation.[20]

Tactile feedback

edit
Touch can result in many different physiological reactions such as laughing at beingtickled.

The tactile feedback fromproprioceptionis derived from the proprioceptors in the skin, muscles, and joints.[21]

Balance

edit

The receptor for the sense of balance resides in thevestibular systemin the ear (for the three-dimensional orientation of the head, and by inference, the rest of the body). Balance is also mediated by the kinesthetic reflex fed byproprioception(which senses the relative location of the rest of the body to the head).[22]In addition, proprioception estimates the location of objects which are sensed by thevisual system(which provides confirmation of the place of those objects relative to the body), as input to the mechanical reflexes of the body.

Fine touch and crude touch

edit
See also:Two-point discrimination
Thecortical homunculus,a map of somatosensory areas of the brain, was devised byWilder Penfield.

Fine touch (or discriminative touch) is a sensory modality that allows a subject to sense and localize touch. The form of touch where localization is not possible is known as crude touch. Thedorsal column–medial lemniscus pathwayis the pathway responsible for the sending of fine touch information to thecerebral cortexof the brain.

Crude touch (non-discriminating) is a sensory modality that allows the subject to sense that something has touched them, without being able to localize where they were touched (contrasting "fine touch" ). Its fibres are carried in thespinothalamic tract,unlike the fine touch, which is carried in the dorsal column. [23] As fine touch normally works in parallel to crude touch, a person will be able to localize touch until fibres carrying fine touch (in the dorsal column–medial lemniscus pathway) have been disrupted. Then the subject will feel the touch, but be unable to identify where they were touched.

Neural processing of social touch

edit

The somatosensory cortex encodes incoming sensory information from receptors all over the body. Affective touch is a type of sensory information that elicits an emotional reaction and is usually social in nature, such as a physical human touch. This type of information is actually coded differently than other sensory information. Intensity of affective touch is still encoded in the primary somatosensory cortex and is processed in a similar way to emotions invoked by sight and sound, as exemplified by the increase of adrenaline caused by the social touch of a loved one, as opposed to the physical inability to touch someone you do not love.

Meanwhile, the feeling of pleasantness associated with affective touch activates the anterior cingulate cortex more than the primary somatosensory cortex.Functional magnetic resonance imaging(fMRI) data shows that increased blood-oxygen-level contrast (BOLD) signal in the anterior cingulate cortex as well as the prefrontal cortex is highly correlated with pleasantness scores of an affective touch. Inhibitorytranscranial magnetic stimulation(TMS) of the primary somatosensory cortex inhibits the perception of affective touch intensity, but not affective touch pleasantness. Therefore, the S1 is not directly involved in processing socially affective touch pleasantness, but still plays a role in discriminating touch location and intensity.[23]

Tactile interaction is important amongst some animals. Usually, tactile contact between two animals occurs through stroking, licking, or grooming. These behaviours are essential for the individual's social healthcare, as in the hypothalamus they induce the release of oxytocin, a hormone that decreases stress and anxiety and increases social bonding between animals.[24][clarification needed]

More precisely, the consistency of oxytocin neuron activation in rats stroked by humans has been observed, especially in the caudal paraventricular nucleus.[25]It was found that this affiliative relationship induced by tactile contact is common no matter the relationship between the two individuals (mother-infant, male-female, human-animal). It has also been discovered that the level of oxytocin release through this behaviour correlates with the time course of social interaction as longer stroking induced a greater release of the hormone.[26]

The importance of somatosensory stimulation in social animals such as primates has also been observed. Grooming is part of the social interaction primates exert on their conspecifics. This interaction is required between individuals to maintain the affiliative relationship within the group, avoid internal conflict and increase group bonding.[27]However, such social interaction requires the recognition of every member in the group. As such, it has been observed that the size of the neocortex is positively correlated with the size of the group, reflecting a limit to the number of recognizable members amongst which grooming can occur.[27]Furthermore, the time course of grooming is related to vulnerability due to predation to which animals are exposed to whilst performing such social interaction. The relationship between tactile interaction, stress reduction and social bonding depends on the evaluation of risks that occur during conducting such behaviours in the wild life, and further research is required to unveil the connection between tactile caring and fitness level.

Studies show a correlation between touching a soft or hard object and how a person thinks or even makes decisions.[28]Further, between the firmness of a touch and the evoking of gender stereotyping.[29]

Tactile memories as part ofhaptic memory,are organizedsomatotopically,following the organization of the somatosensory cortex.

Individual variation

edit

A variety of studies have measured and investigated the causes for differences between individuals in the sense of fine touch. One well-studied area is passive tactile spatial acuity, the ability to resolve the fine spatial details of an object pressed against the stationary skin. A variety of methods have been used to measure passive tactile spatial acuity, perhaps the most rigorous being the grating orientation task.[30]In this task subjects identify the orientation of a grooved surface presented in two different orientations,[31]which can be applied manually or with automated equipment.[32]Many studies have shown a decline in passive tactile spatial acuity with age;[33][34][35]the reasons for this decline are unknown, but may include loss of tactile receptors during normal aging. Remarkably, index finger passive tactile spatial acuity is better among adults with smaller index fingertips;[36]this effect of finger size has been shown to underlie the better passive tactile spatial acuity of women, on average, compared to men.[36]The density oftactile corpuscles,a type of mechanoreceptor that detects low-frequency vibrations, is greater in smaller fingers;[37]the same may hold forMerkel cells,which detect the static indentations important for fine spatial acuity.[36]Among children of the same age, those with smaller fingers also tend to have better tactile acuity.[38]Many studies have shown that passive tactile spatial acuity is enhanced among blind individuals compared to sighted individuals of the same age,[35][39][40][41][42]possibly because ofcross modal plasticityin the cerebral cortex of blind individuals. Perhaps also due to cortical plasticity, individuals who have been blind since birth reportedly consolidate tactile information more rapidly than sighted people.[43]

Clinical significance

edit
Main article:Somatosensory disorder

A somatosensory deficiency may be caused by aperipheral neuropathyinvolving peripheral nerves of the somatosensory system. This may present asnumbnessorparesthesia.

Society and culture

edit
Main articles:Haptic technologyandHaptic communication

Haptic technologycan provide touch sensation in virtual and real environments.[44]In the field ofspeech therapy,tactile feedback can be used to treatspeech disorders.[citation needed]

Affectionate touch is present in everyday life and can take multiple forms. These actions, however, seem to carry specific functions even though the evolutionary benefit from such a wide range of behaviours is not entirely understood. Researchers investigated the expression patterns and characteristics of 8 different affectionate touch actions - embracing, holding, kissing, leaning, petting, squeezing, stroking, and tickling - in a self-report study.[45]It was found that the affectionate touch has distinct target areas on the body, different associated affect, comfort-value, and expression frequency based on the type of touch action that is performed.

Besides the rather obvious sensory consequences of touch, it can also affect higher-level aspects of cognition such as social judgements and decision-making. This effect might arise due to a physical-to-mental scaffolding process in early development, whereby sensorimotor experiences are linked to the emergence of conceptual knowledge.[46]Such links might be maintained throughout life, and so touching an object may cue the physical sensation to its related conceptual processing. Indeed, it was found that different physical properties - weight, texture, and hardness - of a touched object can influence social judgement and decision-making.[47]For example, participants described a passage of a social interaction to be harsher when they touched a hard wooden block instead of a soft blanket prior to the task. Building on these findings, the ability of touch to have an unconscious influence on such higher-order thoughts may provide a novel tool for marketing and communication strategies.

See also

edit

References

edit
  1. ^abPurves, 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.
  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.PMC9494715.PMID36285142.
  3. ^abSaladin, Kenneth S. (2011).Human anatomy(3rd ed.). New York: McGraw-Hill. p. 420.ISBN9780071222075.
  4. ^Saladin, Kenneth S. (2011).Human anatomy(3rd ed.). New York: McGraw-Hill. p. 464.ISBN9780071222075.
  5. ^Sherman, Carl (August 12, 2019)."The Senses: The Somatosensory system".Dana Foundation.New York.
  6. ^Hertenstein, Matthew J.; Keltner, Dacher; App, Betsy; Bulleit, Brittany A.; Jaskolka, Ariane R. (August 2006)."Touch communicates distinct emotions".Emotion.6(3): 528–533.doi:10.1037/1528-3542.6.3.528.ISSN1528-3542.PMID16938094.
  7. ^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.PMC9494715.PMID36285142.
  8. ^Sima, Richard (23 December 2019)."The Brain Senses Touch beyond the Body".Scientific American.Retrieved16 February2020.
  9. ^Paré, Michel; Behets, Catherine; Cornu, Olivier (2003-02-10)."Paucity of presumptive ruffini corpuscles in the index finger pad of humans".Journal of Comparative Neurology.456(3): 260–266.doi:10.1002/cne.10519.ISSN0021-9967.PMID12528190.S2CID13396416.
  10. ^Scheibert J, Leurent S, Prevost A, Debrégeas G (March 2009). "The role of fingerprints in the coding of tactile information probed with a biomimetic sensor".Science.323(5920): 1503–6.arXiv:0911.4885.Bibcode:2009Sci...323.1503S.doi:10.1126/science.1166467.PMID19179493.S2CID14459552.
  11. ^Biswas A, Manivannan M, Srinivasan MA (2015)."Vibrotactile sensitivity threshold: nonlinear stochastic mechanotransduction model of the Pacinian Corpuscle".IEEE Transactions on Haptics.8(1): 102–13.doi:10.1109/TOH.2014.2369422.PMID25398183.S2CID15326972.
  12. ^Paré, Michel; Elde, Robert; Mazurkiewicz, Joseph E.; Smith, Allan M.; Rice, Frank L. (2001-09-15)."The Meissner Corpuscle Revised: A Multiafferented Mechanoreceptor with Nociceptor Immunochemical Properties".The Journal of Neuroscience.21(18): 7236–7246.doi:10.1523/JNEUROSCI.21-18-07236.2001.ISSN0270-6474.PMC6763005.PMID11549734.
  13. ^Hashim IH, Kumamoto S, Takemura K, Maeno T, Okuda S, Mori Y (November 2017)."Tactile Evaluation Feedback System for Multi-Layered Structure Inspired by Human Tactile Perception Mechanism".Sensors.17(11): 2601.Bibcode:2017Senso..17.2601H.doi:10.3390/s17112601.PMC5712818.PMID29137128.
  14. ^Buccino G, Binkofski F, Fink GR, Fadiga L, Fogassi L, Gallese V, Seitz RJ, Zilles K, Rizzolatti G, Freund HJ (January 2001). "Action observation activates premotor and parietal areas in a somatotopic manner: an fMRI study".The European Journal of Neuroscience.13(2): 400–4.doi:10.1111/j.1460-9568.2001.01385.x.PMID11168545.S2CID107700.
  15. ^Seelke AM, Padberg JJ, Disbrow E, Purnell SM, Recanzone G, Krubitzer L (August 2012)."Topographic Maps within Brodmann's Area 5 of macaque monkeys".Cerebral Cortex.22(8): 1834–50.doi:10.1093/cercor/bhr257.PMC3388892.PMID21955920.
  16. ^Geyer S, Schleicher A, Zilles K (July 1999). "Areas 3a, 3b, and 1 of Human Primary Somatosensory Cortex".NeuroImage.10(1): 63–83.doi:10.1006/nimg.1999.0440.PMID10385582.S2CID22498933.
  17. ^Disbrow E (June 2002). "Thalamocortical connections of the parietal ventral area (PV) and the second somatosensory area (S2) in macaque monkeys".Thalamus & Related Systems.1(4): 289–302.doi:10.1016/S1472-9288(02)00003-1.
  18. ^Saladin KS. Anatomy and Physiology 3rd edd. 2004. McGraw-Hill, New York.
  19. ^"Second Order Neuron".Encyclopedia of Pain.Springer. 2013. p. 3448.doi:10.1007/978-3-642-28753-4_201964.ISBN978-3-642-28752-7.Retrieved2 December2022.
  20. ^abZukerman, Wendy."Skin 'sees' the light to protect against sunshine".newscientist.com.New Scientist.Retrieved2015-01-22.
  21. ^Proske U, Gandevia SC (October 2012). "The proprioceptive senses: their roles in signaling body shape, body position and movement, and muscle force".Physiological Reviews.92(4): 1651–97.doi:10.1152/physrev.00048.2011.PMID23073629.S2CID1512089.
  22. ^Proske U, Gandevia SC (September 2009)."The kinaesthetic senses".The Journal of Physiology.587(Pt 17): 4139–46.doi:10.1113/jphysiol.2009.175372.PMC2754351.PMID19581378.
  23. ^abCase LK, Laubacher CM, Olausson H, Wang B, Spagnolo PA, Bushnell MC (May 2016)."Encoding of Touch Intensity But Not Pleasantness in Human Primary Somatosensory Cortex".The Journal of Neuroscience.36(21): 5850–60.doi:10.1523/JNEUROSCI.1130-15.2016.PMC4879201.PMID27225773.
  24. ^Knobloch, H. Sophie; Grinevich, Valery (2014)."Evolution of oxytocin pathways in the brain of vertebrates".Frontiers in Behavioral Neuroscience.8:31.doi:10.3389/fnbeh.2014.00031.ISSN1662-5153.PMC3924577.PMID24592219.
  25. ^Okabe, Shota; Takayanagi, Yuki; Yoshida, Masahide; Onaka, Tatsushi (2020-06-04)."Gentle stroking stimuli induce affiliative responsiveness to humans in male rats".Scientific Reports.10(1): 9135.Bibcode:2020NatSR..10.9135O.doi:10.1038/s41598-020-66078-7.ISSN2045-2322.PMC7272613.PMID32499488.
  26. ^Tang, Yan; Benusiglio, Diego; Lefevre, Arthur; Hilfiger, Louis; Althammer, Ferdinand; Bludau, Anna; Hagiwara, Daisuke; Baudon, Angel; Darbon, Pascal; Schimmer, Jonas; Kirchner, Matthew K.; Roy, Ranjan K.; Wang, Shiyi; Eliava, Marina; Wagner, Shlomo (September 2020)."Social touch promotes interfemale communication via activation of parvocellular oxytocin neurons"(PDF).Nature Neuroscience.23(9): 1125–1137.doi:10.1038/s41593-020-0674-y.ISSN1546-1726.PMID32719563.S2CID220810651.
  27. ^abLehmann, J.; Korstjens, A. H.; Dunbar, R. I. M. (2007-12-01)."Group size, grooming and social cohesion in primates".Animal Behaviour.74(6): 1617–1629.doi:10.1016/j.anbehav.2006.10.025.ISSN0003-3472.S2CID14866172.
  28. ^"Just a Touch Can Influence Thoughts and Decisions".Live Science.24 June 2010.
  29. ^"Firmness of Touch May Evoke Gender Stereotyping".Live Science.12 January 2011.
  30. ^Van Boven, R. W.; Johnson, K. O. (1 December 1994). "The limit of tactile spatial resolution in humans: Grating orientation discrimination at the lip, tongue, and finger".Neurology.44(12): 2361–6.doi:10.1212/WNL.44.12.2361.PMID7991127.S2CID32255147.
  31. ^Craig JC (1999). "Grating orientation as a measure of tactile spatial acuity".Somatosensory & Motor Research.16(3): 197–206.doi:10.1080/08990229970456.PMID10527368.
  32. ^Goldreich D, Wong M, Peters RM, Kanics IM (June 2009)."A Tactile Automated Passive-Finger Stimulator (TAPS)".Journal of Visualized Experiments(28).doi:10.3791/1374.PMC2726582.PMID19578327.
  33. ^Stevens JC, Alvarez-Reeves M, Dipietro L, Mack GW, Green BG (2003). "Decline of tactile acuity in aging: a study of body site, blood flow, and lifetime habits of smoking and physical activity".Somatosensory & Motor Research.20(3–4): 271–9.doi:10.1080/08990220310001622997.PMID14675966.S2CID19729552.
  34. ^Manning H, Tremblay F (2006)."Age differences in tactile pattern recognition at the fingertip".Somatosensory & Motor Research.23(3–4): 147–55.doi:10.1080/08990220601093460.PMID17178550.S2CID24407285.
  35. ^abGoldreich D, Kanics IM (April 2003)."Tactile acuity is enhanced in blindness".The Journal of Neuroscience.23(8): 3439–45.doi:10.1523/jneurosci.23-08-03439.2003.PMC6742312.PMID12716952.
  36. ^abcPeters RM, Hackeman E, Goldreich D (December 2009)."Diminutive digits discern delicate details: fingertip size and the sex difference in tactile spatial acuity".The Journal of Neuroscience.29(50): 15756–61.doi:10.1523/JNEUROSCI.3684-09.2009.PMC3849661.PMID20016091.
  37. ^Dillon YK, Haynes J, Henneberg M (November 2001)."The relationship of the number of Meissner's corpuscles to dermatoglyphic characters and finger size".Journal of Anatomy.199(Pt 5): 577–84.doi:10.1046/j.1469-7580.2001.19950577.x.PMC1468368.PMID11760888.
  38. ^Peters RM, Goldreich D (2013)."Tactile spatial acuity in childhood: effects of age and fingertip size".PLOS ONE.8(12): e84650.Bibcode:2013PLoSO...884650P.doi:10.1371/journal.pone.0084650.PMC3891499.PMID24454612.
  39. ^Stevens, Joseph C.; Foulke, Emerson; Patterson, Matthew Q. (1996). "Tactile acuity, aging, and braille reading in long-term blindness".Journal of Experimental Psychology: Applied.2(2): 91–106.doi:10.1037/1076-898X.2.2.91.
  40. ^Van Boven RW, Hamilton RH, Kauffman T, Keenan JP, Pascual-Leone A (June 2000). "Tactile spatial resolution in blind braille readers".Neurology.54(12): 2230–6.doi:10.1212/wnl.54.12.2230.PMID10881245.S2CID12053536.
  41. ^Goldreich D, Kanics IM (November 2006)."Performance of blind and sighted humans on a tactile grating detection task".Perception & Psychophysics.68(8): 1363–71.doi:10.3758/bf03193735.PMID17378422.
  42. ^Wong M, Gnanakumaran V, Goldreich D (May 2011)."Tactile spatial acuity enhancement in blindness: evidence for experience-dependent mechanisms".The Journal of Neuroscience.31(19): 7028–37.doi:10.1523/JNEUROSCI.6461-10.2011.PMC6703211.PMID21562264.
  43. ^Bhattacharjee A, Ye AJ, Lisak JA, Vargas MG, Goldreich D (October 2010)."Vibrotactile masking experiments reveal accelerated somatosensory processing in congenitally blind braille readers".The Journal of Neuroscience.30(43): 14288–98.doi:10.1523/JNEUROSCI.1447-10.2010.PMC3449316.PMID20980584.
  44. ^Gabriel Robles-De-La-Torre."International Society for Haptics: Haptic technology, an animated explanation".Isfh.org. Archived fromthe originalon 2010-03-07.Retrieved2010-02-26.
  45. ^Schirmer, Annett; Chiu, Man Hey; Croy, Ilona (September 2021)."More than one kind: Different sensory signatures and functions divide affectionate touch".Emotion.21(6): 1268–1280.doi:10.1037/emo0000966.ISSN1931-1516.PMID34435843.
  46. ^Williams, Lawrence E.; Huang, Julie Y.; Bargh, John A. (2009-12-01)."The Scaffolded Mind: Higher mental processes are grounded in early experience of the physical world".European Journal of Social Psychology.39(7): 1257–1267.doi:10.1002/ejsp.665.ISSN0046-2772.PMC2799930.PMID20046813.
  47. ^Ackerman, Joshua M.; Nocera, Christopher C.; Bargh, John A. (2010-06-25)."Incidental haptic sensations influence social judgments and decisions".Science.328(5986): 1712–1715.Bibcode:2010Sci...328.1712A.doi:10.1126/science.1189993.ISSN1095-9203.PMC3005631.PMID20576894.

Further reading

edit
edit
Retrieved from "https://en.wikipedia.org/w/index.php?title=Somatosensory_system&oldid=1249117707"