Functional role of unmyelinated tactile afferents in human hairy skin: sympathetic response and perceptual localization

Olausson, Håkan; Cole, Jonathan; Rylander, Karin; McGlone, Francis; Lamarre, Y.; Wallin, B. Gunnar; Krämer, Heidrun H.; Wessberg, Johan; Elam, Mikael; Bushnell, M. Catherine; Vallbo, Å. B.

doi:10.1007/s00221-007-1175-x

Cited by 150 publications

(118 citation statements)

References 26 publications

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“…Well, as described by Olausson and colleagues in the January 2008 issue of Experimental Brain Research, activation of C-tactile afferents evokes a sympathetic skin response (i.e. sweat release)-consistent with the idea that these low-threshold unmyelinated afferents are involved in the affective aspects of touch [11].…”

Section: That Touchy Feelingsupporting

confidence: 54%

Developments in autonomic research: a review of the latest literature

Macefield

2009

Clin Auton Res

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Small-diameter afferents do not just subserve pain and temperature sensibilities, important for protection of the body though they are: there is a system of lowthreshold unmyelinated afferents that respond to light stroking (C-tactile afferents) and they are believed to subserve the affective components of touch. Patients with large-fibre sensory neuropathies exhibit skin sympathetic responses to stroking, and report the stimuli as feeling pleasant. Moreover, the posterior insula is activated. Patients with small-diameter sensory neuropathies, specifically those with congenital insensitivity to pain, suffer from cumulative injuries that can lead to joint degeneration. There is evidence that the nociceptive (and sympathetic) axons die because nerve growth factor is not being produced by the target tissues; patients with congenital insensitivity to pain have mutations in the NTRK1 gene, the gene responsible for producing the TrkA receptor, but there is also evidence for mutations in the SCN9A gene, which codes for a specific subunit of the voltage-gated sodium channel. Specific mutations, leading to clusters of cases of congenital insensitivity to pain, have been found in several geographical locations, with several genetic mutations having been documented. Interestingly, even patients with congenital insensitivity to pain, despite having never experienced pain, can still empathise with the pain in others-we do not need to feel pain in order to empathise, but we do need to feel pain in order to ensure that our body looks after itself.

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Section: That Touchy Feelingsupporting

confidence: 54%

Developments in autonomic research: a review of the latest literature

Macefield

2009

Clin Auton Res

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“…Such stimulation of the skin invariably coactivates thick, myelinated fibers, preventing the selective study of CT afferents in healthy subjects. CT system physiology has, nevertheless, been successfully explored in a patient (GL) with neuronopathy syndrome (Sterman et al, 1980), who lacks large myelinated afferents but whose C fibers are intact (Olausson et al, 2002(Olausson et al, , 2008a. Despite asserting no touch sensation below the level of the nose in daily life, GL can, under focused concentration, detect the soft stroking of a brush and reports a vague pleasant sensation in response to the stimuli.…”

Section: Introductionmentioning

confidence: 99%

Somatotopic Organization of Gentle Touch Processing in the Posterior Insular Cortex

Björnsdotter¹,

Löken²,

Olausson³

et al. 2009

J. Neurosci.

237

151

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A network of thin (C and A␦) afferents relays various signals related to the physiological condition of the body, including sensations of gentle touch, pain, and temperature changes. Such afferents project to the insular cortex, where a somatotopic organization of responses to noxious and cooling stimuli was recently observed. To explore the possibility of a corresponding body-map topography in relation to gentle touch mediated through C tactile (CT) fibers, we applied soft brush stimuli to the right forearm and thigh of a patient (GL) lacking A␤ afferents, and six healthy subjects during functional magnetic resonance imaging (fMRI). For improved fMRI analysis, we used a highly sensitive multivariate voxel clustering approach. A somatotopic organization of the left (contralateral) posterior insular cortex was consistently demonstrated in all subjects, including GL, with forearm projecting anterior to thigh stimulation. Also, despite denying any sense of touch in daily life, GL correctly localized 97% of the stimuli to the forearm or thigh in a forced-choice paradigm. The consistency in activation patterns across GL and the healthy subjects suggests that the identified organization reflects the central projection of CT fibers. Moreover, substantial similarities of the presently observed insular activation with that described for noxious and cooling stimuli solidify the hypothesized sensory-affective role of the CT system in the maintenance of physical well-being as part of a thin-afferent homeostatic network.

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“…The C-tactile system is difficult to study in relation to brain processing, mainly since it cannot be activated selectively -any mechanical stimulation of the skin invariably co-activates thick, myelinated fibers in healthy subjects. C-tactile physiology has, nevertheless, been successfully explored in a patient (GL) with neuronopathy syndrome Sterman et al (1980), who lacks large myelinated Aβ afferents but whose C fibers are intact Olausson, Cole, Rylander, McGlone, Lamarre, Wallin, Krämer, Wessberg, Elam, Bushnell & Vallbo (2008); Olausson et al (2002). Due to the lack of Aβ fibers, GL has no sensation of touch.…”

Section: Example: Somatotopic Organization Of the Insular Cortex Due mentioning

confidence: 99%

“…At the age of 31, GL suffered permanent loss specifically of thick myelinated afferents (the so called Aβ fibers), leaving unmyelinated and small-diameter myelinated afferents intact Forget & Lamarre (1995). She can detect temperature and pain normally Olausson, Cole, Rylander, McGlone, Lamarre, Wallin, Krämer, Wessberg, Elam, Bushnell & Vallbo (2008); Olausson et al (2002), but denies any ability to sense touch below the level of the nose Forget & Lamarre (1995). In a forced choice task she could, however, perceive light touch, and she failed to detect vibratory stimuli (which poorly excite C-tactile afferents; Olausson, Cole, Rylander, McGlone, Lamarre, Wallin, Krämer, Wessberg, Elam, Bushnell & Vallbo (2008)).…”

Section: Data Acquisitionmentioning

confidence: 99%

“…She can detect temperature and pain normally Olausson, Cole, Rylander, McGlone, Lamarre, Wallin, Krämer, Wessberg, Elam, Bushnell & Vallbo (2008); Olausson et al (2002), but denies any ability to sense touch below the level of the nose Forget & Lamarre (1995). In a forced choice task she could, however, perceive light touch, and she failed to detect vibratory stimuli (which poorly excite C-tactile afferents; Olausson, Cole, Rylander, McGlone, Lamarre, Wallin, Krämer, Wessberg, Elam, Bushnell & Vallbo (2008)). Moreover, in a four-alternative forced choice procedure, she identified 72% of soft brush stimuli to the correct extremity (at chance level of 25%).…”

Section: Data Acquisitionmentioning

confidence: 99%

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