What are C-tactile afferents and how do they relate to “affective touch”?

Abraira, 2017, The cellular and synaptic architecture of the mechanosensory dorsal horn, Cell, 168, 295, 10.1016/j.cell.2016.12.010 Ackerley, 2014, Human C-Tactile afferents are tuned to the temperature of a skin-stroking caress, J. Neurosci., 34, 2879, 10.1523/JNEUROSCI.2847-13.2014 Ackerley, 2014, Quantifying the sensory and emotional perception of touch: differences between glabrous and hairy skin, Front. Behav. Neurosci., 8 Ackerley, 2018, Differential effects of radiant and mechanically applied thermal stimuli on human C-tactile afferent firing patterns, J. Neurophysiol., 120, 1885, 10.1152/jn.00940.2017 Adrian, 1926, The impulses produced by sensory nerve endings, J. Physiol., 61, 465, 10.1113/jphysiol.1926.sp002308 Ainsworth, 1979, Attachment as Related to Mother-Infant Interaction. In, Vol. 9, 1 de Araujo, 2005, Cognitive modulation of olfactory processing, Neuron, 46, 671, 10.1016/j.neuron.2005.04.021 Araújo, 2022, Decreased self-reported receiving of social touch and social support predict loneliness in healthy adults, Psicol. Reflex. e Crit., 35 Auvray, 2010, The sensory-discriminative and affective-motivational aspects of pain, Neurosci. Biobehav. Rev., 34, 214, 10.1016/j.neubiorev.2008.07.008 Barrett, 2017, The theory of constructed emotion: an active inference account of interoception and categorization, Soc. Cogn. Affect. Neurosci., 12, 1 Brauer, 2016, Frequency of maternal touch predicts resting activity and connectivity of the developing social brain, Cereb. Cortex, 26, 3544, 10.1093/cercor/bhw137 Bytomski, 2020, Maternal stroking is a fine-tuned mechanism relating to C-tactile afferent activation: an exploratory study, Psychol. Neurosci., 13, 149, 10.1037/pne0000184 Case, 2021, Pleasant deep pressure: expanding the social touch hypothesis, Neuroscience, 464, 3, 10.1016/j.neuroscience.2020.07.050 Champagne, 2008, Maternal care and hippocampal plasticity: evidence for experience-dependent structural plasticity altered synaptic functioning, and differential responsiveness to glucocorticoids and stress, J. Neurosci., 28, 6037, 10.1523/JNEUROSCI.0526-08.2008 Croy, 2016, Interpersonal stroking touch is targeted to C tactile afferent activation, Behav. Brain Res., 297, 37, 10.1016/j.bbr.2015.09.038 Croy, 2021, Individual variability of pleasantness ratings to stroking touch over different velocities, Neuroscience, 464, 33, 10.1016/j.neuroscience.2020.03.030 Croy, 2022, The role of C-tactile nerve fibers in human social development, Curr. Opin. Behav. Sci., 43, 20, 10.1016/j.cobeha.2021.06.010 Debrot, 2021, Is touch in romantic relationships universally beneficial for psychological well-being? the role of attachment avoidance, Personal. Soc. Psychol. Bull., 47, 1495, 10.1177/0146167220977709 Della Longa, 2019, Tune to touch: affective touch enhances learning of face identity in 4-month-old infants, Dev. Cogn. Neurosci., 35, 42, 10.1016/j.dcn.2017.11.002 Edin, 2001, Cutaneous afferents provide information about knee joint movements in humans, J. Physiol., 531, 289, 10.1111/j.1469-7793.2001.0289j.x Feldman, 2002, Comparison of skin-to-skin (kangaroo) and traditional care: parenting outcomes and preterm infant development, Pediatrics, 110, 16, 10.1542/peds.110.1.16 Fidanza, 2021, A better touch: c-tactile fibers related activity is associated to pain reduction during temporal summation of second pain, J. Pain., 22, 567, 10.1016/j.jpain.2021.01.001 Field, 2003 Francis, 1999, The representation of pleasant touch in the brain and its relationship with taste and olfactory areas, Neuroreport, 10, 453, 10.1097/00001756-199902250-00003 Fu, 2018, Touch-induced face conditioning is mediated by genetic variation in opioid but not oxytocin receptors, Sci. Rep., 8, 9004, 10.1038/s41598-018-27199-2 Glimcher, 2011, Understanding dopamine and reinforcement learning: the dopamine reward prediction error hypothesis, Proc. Natl. Acad. Sci., 108, 15647, 10.1073/pnas.1014269108 Guest, 2011, The development and validation of sensory and emotional scales of touch perception, Atten. Percept. Psychophys., 73, 531, 10.3758/s13414-010-0037-y Gursul, 2018, Stroking modulates noxious-evoked brain activity in human infants, Curr. Biol. CB, 28, R1380, 10.1016/j.cub.2018.11.014 Harlow, 1958, The nature of love, Am. Psychol., 13, 673, 10.1037/h0047884 Hasenack, 2023, Longing for touch and quality of life during the COVID-19 pandemic, Int. J. Environ. Res. Public Health, 20(5) Hofbauer, 2001, Cortical representation of the sensory dimension of pain, J. Neurophysiol., 86, 402, 10.1152/jn.2001.86.1.402 Huzard, 2022, The impact of C-tactile low-threshold mechanoreceptors on affective touch and social interactions in mice, Sci. Adv., 8, 10.1126/sciadv.abo7566 Jakubiak, 2022, Affectionate touch in satisfying and dissatisfying romantic relationships, J. Soc. Pers. Relatsh., 10.1177/02654075221077280 Jakubiak, 2017, Affectionate touch to promote relational, psychological, and physical well-being in adulthood: a theoretical model and review of the research, Personal. Soc. Psychol. Rev., 21, 228, 10.1177/1088868316650307 Johansson, 1988, Mechanoreceptor activity from the human face and oral mucosa, Exp. Brain Res., 72, 204, 10.1007/BF00248518 Kaiser, 2015, Brain mechanisms for processing affective (and Nonaffective) touch are atypical in autism, Cereb. Cortex, 26, 2705, 10.1093/cercor/bhv125 Krahé, 2018, Sensitivity to CT-optimal affective touch depends on adult attachment style, Sci. Rep., 8, 1, 10.1038/s41598-018-32865-6 Kulkarni, 2005, Attention to pain localization and unpleasantness discriminates the functions of the medial and lateral pain systems, Eur. J. Neurosci., 21, 3133, 10.1111/j.1460-9568.2005.04098.x L.K. Case N. Madian M. McCall M. Bradson J. Liljencrantz B. Goldstein V. Alasha M. Zimmerman Aβ-CT Affect. Touch. Touch. Pleas. Rat. gentle stroking Deep Press. Exhib. Depend. A-Fiber 2022 doi: 10.1101/2022.12.06.518627. Lawson, 1997, Relationship of substance P to afferent characteristics of dorsal root ganglion neurones in guinea-pig, J. Physiol., 505, 177, 10.1111/j.1469-7793.1997.00177.x Liu, 2022, Molecular and neural basis of pleasant touch sensation in mice, Science, 376, 483, 10.1126/science.abn2479 Lo, 2021, 3D hand-motion tracking and bottom-up classification sheds light on the physical properties of gentle stroking, Neuroscience, 464, 90, 10.1016/j.neuroscience.2020.09.037 Löffler, 2022, Pleasant touch perception in borderline personality disorder and its relationship with disturbed body representation, Bord. Personal. Disord. Emot. Dysregulation, 9, 3, 10.1186/s40479-021-00176-4 Löken, 2009, Coding of pleasant touch by unmyelinated afferents in humans, Nat. Neurosci., 12, 547, 10.1038/nn.2312 Löken, 2011, Pleasantness of touch in human glabrous and hairy skin: order effects on affective ratings, Brain Res., 1417, 9, 10.1016/j.brainres.2011.08.011 Löken, 2022, A topographical and physiological exploration of C-tactile afferents and their response to menthol and histamine, J. Neurophysiol., 127, 463, 10.1152/jn.00310.2021 Luong, 2017, The individual preferred velocity of stroking touch as a stable measurement, Physiol. Behav., 177, 129, 10.1016/j.physbeh.2017.04.022 Manzotti, 2019, Dynamic touch reduces physiological arousal in preterm infants: a role for c-tactile afferents, Dev. Cogn. Neurosci., 39, 10.1016/j.dcn.2019.100703 Marshall, 2019, Spinal signalling of C-fiber mediated pleasant touch in humans, ELife, 8, 10.7554/eLife.51642 McGlone, 2007, Discriminative touch and emotional touch, Can. J. Exp. Psychol. Rev. Can. De. Psychol. Expérimentale, 61, 173, 10.1037/cjep2007019 McGlone, 2012, Touching and feeling: differences in pleasant touch processing between glabrous and hairy skin in humans, Eur. J. Neurosci., 35, 1782, 10.1111/j.1460-9568.2012.08092.x McGlone, 2014, Discriminative and affective touch: sensing and feeling, Neuron, 82, 737, 10.1016/j.neuron.2014.05.001 McGurk, 1976, Hearing lips and seeing voices, Nature, 264, 746, 10.1038/264746a0 Middleton, 2022, Nav1.7 is required for normal C-low threshold mechanoreceptor function in humans and mice, Brain, 145, 3637, 10.1093/brain/awab482 Moors, 2013, Appraisal theories of emotion: state of the art and future development, Emot. Rev., 5, 119, 10.1177/1754073912468165 Morrison, 2016, Keep calm and cuddle on: social touch as a stress buffer, Adapt. Hum. Behav. Physiol., 2, 344, 10.1007/s40750-016-0052-x Morrison, 2022, Affective and discriminative touch: a reappraisal, Curr. Opin. Behav. Sci., 43, 145, 10.1016/j.cobeha.2021.09.007 Morrison, 2010, The skin as a social organ, Exp. Brain Res., 204, 305, 10.1007/s00221-009-2007-y Nordin, 1990, Low-threshold mechanoreceptive and nociceptive units with unmyelinated (C) fibres in the human supraorbital nerve, J. Physiol., 426, 229, 10.1113/jphysiol.1990.sp018135 Novembre, 2021, Hedonic responses to touch are modulated by the perceived attractiveness of the caresser, Neuroscience, 464, 79, 10.1016/j.neuroscience.2020.10.007 Olausson, 2010, The neurophysiology of unmyelinated tactile afferents, Neurosci. Biobehav. Rev., 34, 185, 10.1016/j.neubiorev.2008.09.011 Püschel, 2022, Gentle as a mother’s touch: C-tactile touch promotes autonomic regulation in preterm infants, Physiol. Behav., 257, 10.1016/j.physbeh.2022.113991 Rainville, 1997, Pain affect encoded in human anterior cingulate but not somatosensory cortex, Science, 277, 968, 10.1126/science.277.5328.968 Reece, 2016, Maternal touch predicts social orienting in young children, Cogn. Dev., 39, 128, 10.1016/j.cogdev.2016.05.001 Rouhani, 2021, Signed and unsigned reward prediction errors dynamically enhance learning and memory, ELife, 10, 10.7554/eLife.61077 Sailer, 2020, Pleasantness only, Exp. Psychol., 67, 224, 10.1027/1618-3169/a000492 Schaefer, 2022, Sensory processing sensitivity and somatosensory brain activation when feeling touch, Sci. Rep., 12, 10.1038/s41598-022-15497-9 Schirmer, 2014 Schirmer, 2023, Stroking trajectory shapes velocity effects on pleasantness and other touch percepts, J. Exp. Psychol.: Hum. Percept. Perform., 49, 71 Schirmer, 2017, The right touch: Stroking of CT-innervated skin promotes vocal emotion processing, Cogn. Affect. Behav. Neurosci., 17, 1129, 10.3758/s13415-017-0537-5 Schirmer, 2022, Editorial overview: affective touch: neurobiology and function, Curr. Opin. Behav. Sci., 45 Schirmer, 2022, Gentle stroking elicits somatosensory ERP that differentiates between hairy and glabrous skin, Soc. Cogn. Affect. Neurosci., 10.1093/scan/nsac012 Schirmer, 2022, Velocity-tuning of somatosensory eeg predicts the pleasantness of gentle caress, NeuroImage Schultz, 2017, Reward prediction error, Curr. Biol., 27, R369, 10.1016/j.cub.2017.02.064 Schulze, 2022, Social touch social isolation and loneliness in borderline personality disorder during the COVID-19 pandemic, Front. Psychiatry, 13, 10.3389/fpsyt.2022.876413 Shea, 1985, Sensory receptors with unmyelinated (C) fibers innervating the skin of the rabbit’s ear, J. Neurophysiol., 54, 491, 10.1152/jn.1985.54.3.491 Simpson, 2019, Social touch alters newborn monkey behavior, Infant. Behav. Dev., 57, 10.1016/j.infbeh.2019.101368 Spitoni, 2020, Disorganized attachment pattern affects the perception of affective touch, Sci. Rep., 10, 10.1038/s41598-020-66606-5 Strauss, 2020, The influence of emotional closeness on interindividual touching, J. Nonverbal Behav., 10.1007/s10919-020-00334-2 Tang, 2020, Social touch promotes interfemale communication via activation of parvocellular oxytocin neurons, Nat. Neurosci., 23, 10.1038/s41593-020-0674-y Torebjörk, 1974, Afferent G units responding to mechanical, thermal and chemical stimuli in human non-glabrous skin, Acta Physiol. Scand., 92, 374, 10.1111/j.1748-1716.1974.tb05755.x Triscoli, 2017, Touch between romantic partners: being stroked is more pleasant than stroking and decelerates heart rate, Physiol. Behav., 177, 169, 10.1016/j.physbeh.2017.05.006 Vallbo, 1967, Impulses recorded with micro-electrodes in human muscle nerves during stimulation of mechanoreceptors and voluntary contractions, Electroencephalogr. Clin. Neurophysiol., 23, 392 Vallbo, 1984, Properties of cutaneous mechanoreceptors in the human hand related to touch sensation, Hum. Neurobiol., 3, 3 Vallbo, 1993, A system of unmyelinated afferents for innocuous mechanoreception in the human skin, Brain Res., 628, 301, 10.1016/0006-8993(93)90968-S Vallbo, 1999, Unmyelinated afferents constitute a second system coding tactile stimuli of the human hairy skin, J. Neurophysiol., 81, 2753, 10.1152/jn.1999.81.6.2753 Vallbo, 2009, Pleasant Touch, 741 Van Puyvelde, 2019, Does touch matter? the impact of stroking versus non-stroking maternal touch on cardio-respiratory processes in mothers and infants, Physiol. Behav., 207, 55, 10.1016/j.physbeh.2019.04.024 Vrontou, 2013, Genetic identification of C fibres that detect massage-like stroking of hairy skin in vivo, Nature, 493, 669, 10.1038/nature11810 Watkins, 2022, Slow touch in non-human species: translational research into the C-tactile (CT) afferent system, Curr. Opin. Behav. Sci., 43, 193, 10.1016/j.cobeha.2021.10.010 Watkins, 2017, Optimal delineation of single C-tactile and C-nociceptive afferents in humans by latency slowing, J. Neurophysiol., 117, 1608, 10.1152/jn.00939.2016 Watkins, 2021, Evidence for sparse C-tactile afferent innervation of glabrous human hand skin, J. Neurophysiol., 125, 232, 10.1152/jn.00587.2020 Wessberg, 2003, Receptive field properties of unmyelinated tactile afferents in the human skin, J. Neurophysiol., 89, 1567, 10.1152/jn.00256.2002 Wijaya, 2020, The human “feel” of touch contributes to its perceived pleasantness, J. Exp. Psychol. Hum. Percept. Perform., 46, 155, 10.1037/xhp0000705 Zotterman, 1939, Touch, pain and tickling: an electro-physiological investigation on cutaneous sensory nerves, J. Physiol., 95, 1, 10.1113/jphysiol.1939.sp003707