Gentle touch perception across the lifespan.

Pleasant, affective touch provides various health benefits, including stress and depression relief. There is a dichotomy between mechanoreceptive afferents that predominantly signal discriminative (myelinated A-beta) and affective (unmyelinated C-tactile) aspects of touch. It is well documented that discriminative abilities of touch decline with age. However, a thorough investigation of how the pleasant aspects of touch develop with age has not been previously attempted. Here, we investigated the relationship between age and psychophysical ratings in response to gentle stroking touch. One hundred twenty participants (60 males, 60 females) ages 13-82 years were presented with C-tactile optimal and suboptimal stroking velocities, and rated pleasantness and intensity. Moreover, to examine the specificity of age effects on touch perception, we used olfactory stimuli as a cross-sensory comparison. For all ages, we found that C-tactile optimal stimuli were rated significantly more pleasant than C-tactile suboptimal stimuli. Although, both touch and olfactory intensity ratings were negatively correlated with age, a positive correlation between pleasantness ratings of touch (but not olfactory stimuli) and age was found. We conclude that the affective, but not the discriminative, aspects of touch are enhanced with increasing age. The increase of pleasantness of all touch stimuli in late adulthood is discussed in relation to cognitive modulations.

[1]  M. Inzlicht,et al.  Sex differences in response to physical and social factors involved in human mate selection The importance of smell for women , 2002 .

[2]  I. Croy,et al.  Individual significance of olfaction: development of a questionnaire , 2009, European Archives of Oto-Rhino-Laryngology.

[3]  Gerd Kobal,et al.  Screening of Olfactory Function with a Four-Minute Odor Identification Test: Reliability, Normative Data, and Investigations in Patients with Olfactory Loss , 2001, The Annals of otology, rhinology, and laryngology.

[4]  Johan Wessberg,et al.  A system of unmyelinated afferents for innocuous mechanoreception in the human skin , 1993, Brain Research.

[5]  U. Sailer,et al.  CT-optimized skin stroking delivered by hand or robot is comparable , 2013, Front. Behav. Neurosci..

[6]  H. Olausson,et al.  Touch perceptions across skin sites: differences between sensitivity, direction discrimination and pleasantness , 2014, Front. Behav. Neurosci..

[7]  G. Essick,et al.  Psychophysical assessment of the affective components of non-painful touch. , 1999, Neuroreport.

[8]  J. Wessberg,et al.  Placebo improves pleasure and pain through opposite modulation of sensory processing , 2013, Proceedings of the National Academy of Sciences.

[9]  Johan N Lundström,et al.  Central Processing of the Chemical Senses: an Overview. , 2011, ACS chemical neuroscience.

[10]  J. Wessberg,et al.  The neurophysiology of unmyelinated tactile afferents , 2010, Neuroscience & Biobehavioral Reviews.

[11]  Whei-Min Lin,et al.  Effects of aging on human skin innervation , 2004, Neuroreport.

[12]  C. Spence,et al.  The science of interpersonal touch: An overview , 2010, Neuroscience & Biobehavioral Reviews.

[13]  J. Wessberg,et al.  Unmyelinated afferents constitute a second system coding tactile stimuli of the human hairy skin. , 1999, Journal of neurophysiology.

[14]  E. Friedmann,et al.  The effect of touch on nutritional intake of chronic organic brain syndrome patients. , 1986, Journal of gerontology.

[15]  Ulrike Ehlert,et al.  Effects of different kinds of couple interaction on cortisol and heart rate responses to stress in women , 2007, Psychoneuroendocrinology.

[16]  Francis McGlone,et al.  Tactile Experience Does Not Ameliorate Age-Related Reductions in Sensory Function , 2014, Experimental aging research.

[17]  R. Johansson,et al.  Properties of cutaneous mechanoreceptors in the human hand related to touch sensation. , 1984, Human neurobiology.

[18]  Jean-Louis Thonnard,et al.  Rasch-Built Measure of Pleasant Touch through Active Fingertip Exploration , 2012, Front. Neurorobot..

[19]  J. Wessberg,et al.  Human C-Tactile Afferents Are Tuned to the Temperature of a Skin-Stroking Caress , 2014, The Journal of Neuroscience.

[20]  Myra A. Fernandes,et al.  Emotional Expressivity in Older and Younger Adults' Descriptions of Personal Memories , 2012, Experimental aging research.

[21]  D. Benos,et al.  Guidelines for reporting statistics in journals published by the American Physiological Society. , 2004, Advances in physiology education.

[22]  J C Stevens,et al.  Spatial acuity of the body surface over the life span. , 1996, Somatosensory & motor research.

[23]  T. Field Touch Therapy Effects on Development , 1998 .

[24]  Clemens Kirschbaum,et al.  Sex-Specific Effects of Social Support on Cortisol and Subjective Responses to Acute Psychological Stress , 1995, Psychosomatic medicine.

[25]  Y. Lamarre,et al.  Unmyelinated tactile afferents signal touch and project to insular cortex , 2002, Nature Neuroscience.

[26]  L. Carstensen The Influence of a Sense of Time on Human Development , 2006, Science.

[27]  Kenneth O. Johnson,et al.  The roles and functions of cutaneous mechanoreceptors , 2001, Current Opinion in Neurobiology.

[28]  R. Omdal,et al.  The effect of age and gender on epidermal nerve fiber density , 2004, Neurology.

[29]  M Nordin,et al.  Low‐threshold mechanoreceptive and nociceptive units with unmyelinated (C) fibres in the human supraorbital nerve. , 1990, The Journal of physiology.

[30]  K. Berridge,et al.  Affective neuroscience of pleasure: reward in humans and animals , 2008, Psychopharmacology.

[31]  W. Roth,et al.  Social anxiety and response to touch: incongruence between self-evaluative and physiological reactions , 2001, Biological Psychology.

[32]  H. Olausson,et al.  Reduced Pleasant Touch Appraisal in the Presence of a Disgusting Odor , 2014, PloS one.

[33]  A. Craig How do you feel? Interoception: the sense of the physiological condition of the body , 2002, Nature Reviews Neuroscience.

[34]  E. Rolls The affective and cognitive processing of touch, oral texture, and temperature in the brain , 2010, Neuroscience & Biobehavioral Reviews.

[35]  J. Fisher,et al.  Multidimensional reaction to therapeutic touch in a hospital setting. , 1979, Journal of personality and social psychology.

[36]  A. Beck,et al.  Psychometric properties of the Beck Depression Inventory: Twenty-five years of evaluation , 1988 .

[37]  J. Wessberg,et al.  Pleasantness of touch in human glabrous and hairy skin: Order effects on affective ratings , 2011, Brain Research.

[38]  J. Wessberg,et al.  Functional role of unmyelinated tactile afferents in human hairy skin: sympathetic response and perceptual localization , 2007, Experimental Brain Research.

[39]  G. Essick,et al.  Quantitative assessment of pleasant touch , 2010, Neuroscience & Biobehavioral Reviews.

[40]  E T Rolls,et al.  Representations of pleasant and painful touch in the human orbitofrontal and cingulate cortices. , 2003, Cerebral cortex.

[41]  N. Christenfeld,et al.  Gender, social support, and cardiovascular responses to stress. , 1999, Psychosomatic medicine.

[42]  G. Essick,et al.  Touching and feeling: differences in pleasant touch processing between glabrous and hairy skin in humans , 2012, The European journal of neuroscience.

[43]  J. Wessberg,et al.  Discriminative and Affective Touch: Sensing and Feeling , 2014, Neuron.

[44]  H. Ohsawa,et al.  Effects of aging on numbers, sizes and conduction velocities of myelinated and unmyelinated fibers of the pelvic nerve in rats. , 1998, Journal of the autonomic nervous system.

[45]  T. Hummel,et al.  Is the age-related loss in olfactory sensitivity similar for light and heavy molecules? , 2014, Chemical senses.

[46]  M. Paré,et al.  Differential hypertrophy and atrophy among all types of cutaneous innervation in the glabrous skin of the monkey hand during aging and naturally occurring type 2 diabetes , 2007, The Journal of comparative neurology.

[47]  Malin Björnsdotter,et al.  Development of brain mechanisms for processing affective touch , 2014, Front. Behav. Neurosci..

[48]  A. Mackay-Sim,et al.  Normative data for the “Sniffin’ Sticks” including tests of odor identification, odor discrimination, and olfactory thresholds: an upgrade based on a group of more than 3,000 subjects , 2007, European Archives of Oto-Rhino-Laryngology.

[49]  J. Wessberg,et al.  Coding of pleasant touch by unmyelinated afferents in humans , 2009, Nature Neuroscience.

[50]  A. Prehn-Kristensen,et al.  Induction of Empathy by the Smell of Anxiety , 2009, PloS one.

[51]  O. Svensson,et al.  A novel NGFB point mutation: a phenotype study of heterozygous patients , 2008, Journal of Neurology, Neurosurgery, and Psychiatry.

[52]  T. Field Touch for Socioemotional and Physical Well-Being: A Review. , 2010 .

[53]  A. Craig,et al.  How do you feel — now? The anterior insula and human awareness , 2009, Nature Reviews Neuroscience.

[54]  U. Sailer,et al.  Liking and wanting pleasant odors: different effects of repetitive exposure in men and women , 2014, Front. Psychol..

[55]  J. Amoore,et al.  Olfactory Threshold, in Relation to Age, Sex or Smoking , 1968 .

[56]  D. Ceballos,et al.  Morphometric and ultrastructural changes with ageing in mouse peripheral nerve , 1999, Journal of anatomy.

[57]  Martin P. Paulus,et al.  The effect of age on neural processing of pleasant soft touch stimuli , 2014, Front. Behav. Neurosci..

[58]  Johan Wessberg,et al.  Reduced C-afferent fibre density affects perceived pleasantness and empathy for touch. , 2011, Brain : a journal of neurology.