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- Croy, Ilona, et al.
(författare)
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Interpersonal stroking touch is targeted to C tactile afferent activation
- 2016
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Ingår i: Behavioural Brain Research. - : Elsevier BV. - 0166-4328 .- 1872-7549. ; 297, s. 37-40
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Tidskriftsartikel (refereegranskat)abstract
- C tactile fibers are a specialized group of fibers innervating the non-glabrous skin that are tuned to light gentle stroking applied with velocities between 1 and 10. cm/s. Those fibers add to the sensation of interpersonal caressing and pleasant touch. It is unclear whether people spontaneously apply touch that is tuned to optimally activate those fibers. This was investigated in three studies. In study one, 45 participants (21.8. ±. 2.3 years, 24 women) were asked to stroke an artificial arm. In study two, 32 participants (28.3. ±. 8.7years, 16 women) were asked to stroke their partner. In study three, 11 parents (29.4. ±. 5.7years, 6 women) were asked to stroke their babies. Stroking velocity was tracked in all conditions. Stroking velocities were significantly slower in the partner touch and baby touch condition than in the artificial arm condition and all of the participants stroking their partner or baby used velocities that can activate C tactile fibers. We conclude that human social stroking is optimized for C tactile stimulation. © 2015 Elsevier B.V.
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| 4. |
- Riva, Federica, et al.
(författare)
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Emotional egocentricity bias across the life-span
- 2016
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Ingår i: Frontiers in Aging Neuroscience. - : Frontiers Media SA. - 1663-4365. ; 8:74
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Tidskriftsartikel (refereegranskat)abstract
- In our daily lives, we often have to quickly estimate the emotions of our conspecifics in order to have successful social interactions. While this estimation process seems quite easy when we are ourselves in a neutral or equivalent emotional state, it has recently been shown that in case of incongruent emotional states between ourselves and the others, our judgments can be biased. This phenomenon, introduced to the literature with the term Emotional Egocentricity Bias (EEB), has been found to occur in young adults and, to a greater extent, in children. However, how the EEB changes across the life-span from adolescence to old age has been largely unexplored. In this study, we recruited 114 participants subdivided in four cohorts (adolescents, young adults, middle-aged adults, older adults) to examine EEB age-related changes. Participants were administered with a recently developed paradigm which, by making use of visuo-tactile stimulation that elicits conflicting feelings in paired participants, allows the valid and reliable exploration of the EEB. Results highlighted a U-shape relation between age and EEB, revealing enhanced emotional egocentricity in adolescents and older adults compared to young and middle-aged adults. These results are in line with the neuroscientific literature which has recently shown that overcoming the EEB is associated with a greater activation of a portion of the parietal lobe, namely the right Supramarginal Gyrus (rSMG). This is an area that reaches full maturation by the end of adolescence and goes through an early decay. Thus, the age-related changes of the EEB could be possibly due to the life-span development of the rSMG. This study is the first one to show the quadratic relation between age and the EEB and set a milestone for further research exploring the neural correlates of the life-span development of the EEB.
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| 5. |
- Sailer, Uta, 1970, et al.
(författare)
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Still Eating Despite Decreased Olfactory Pleasure-The Influence of Odor Liking and Wanting on Food Intake
- 2016
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 41:6, s. 497-504
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Tidskriftsartikel (refereegranskat)abstract
- Typically, the subjective pleasantness of an odor decreases after it has been repeatedly smelled. This study investigates how the pleasantness ("liking") and the wish to be further exposed to the same odor ("wanting") are affected by variety on a longer time scale, and how they relate to actual food intake. Twenty-five participants rated a coconut odor presented 120 times for its liking and wanting before being offered coconut sweets. The amount eaten was assessed. Individual patterns of change were described by fitting 3 different models to the ratings. To study effects of variety on odor evaluation, the ratings were compared with a previous study where coconut was 1 of 3 odors presented in an alternating way. Initially, both liking and wanting the odors were high, but decreased over repetitions in 75% of the subjects. About 40% of all subjects showed an exponential change of ratings, 40% a step-like change, and 20% a linear change. Food intake was not related to the pattern of change in the ratings. Moreover, decreased olfactory pleasure did not seem to affect eating behavior. However, participants who rated the coconut odor higher at the beginning ate twice as many sweets as the others. Odor variety did not affect the experienced pleasure of smelling (liking), but did affect the motivation to experience the same smell again (wanting). This has not been reported for food or touch stimulation and may be specific for the perception of odors.
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| 6. |
- Sailer, Uta, 1970, et al.
(författare)
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Temporal dynamics of brain activation during 40 minutes of pleasant touch
- 2016
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Ingår i: Neuroimage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 139, s. 360-367
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Touch is important for individuals' subjective well-being, is typically rewarding, and is one of few sensory stimuli which are experienced as pleasant for a rather long time. This study tracked brain activation during slow stroking stimulation of the arm that was applied continuously for 40 min - a much longer time than what previous studies have investigated. Methods: 25 subjects were stroked for 40 min with a soft brush while they were scanned with functional Magnetic Resonance Imaging, and rated the perceived pleasantness of the brush stroking. Two resting baselines were included. Whole brain-based analyses investigated the neural response to long-lasting stroking. Results: Stroking was perceived as pleasant throughout scanning and activated areas that were previously found to be involved in the processing of pleasant touch. Activation in primary somatosensory cortex (S1) and S2, subdivision OP1, decreased over time, whereas activation in orbito-frontal gyrus (OFC) and putamen strongly increased until reaching a plateau after approximately 20 min. Similarly, functional connectivity of posterior insula with middle cingulate and striatal regions increased over time. Discussion: Long-lasting stroking was processed in similar areas as shorter-lasting stroking. The decreased activation in somatosensory cortices over time may represent stimulus habituation, whereas increased activation in OFC and putamen may relate to the stimulation's subjective reward value. This involvement of reward-related brain circuits can facilitate maintenance of long-lasting social touch interactions. (C) 2016 The Authors. Published by Elsevier Inc.
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| 9. |
- Triscoli, Chantal, et al.
(författare)
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Depression predicts interpersonal problems partially through the attitude towards social touch
- 2019
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Ingår i: Journal of Affective Disorders. - : Elsevier BV. - 0165-0327. ; 246, s. 234-240
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: : Depression is associated with difficulties in interpersonal relationships, of which communication is an integral part. Communication can not only be effected by verbal means, but also non-verbally by touch. Against this background, the aim of the present study was to investigate the relationship between depression, interpersonal problems and the attitude towards social touch. Methods: : 147 individuals (115 females; 21-71 years old) seeking treatment in a clinic for outpatient psychotherapy took part in the survey. Three questionnaires evaluating the level of depression (Beck Depression Questionnaire), the degree of interpersonal problems (Inventory of Interpersonal Problems) and the attitude towards social touch (Social Touch Questionnaire, were administered. Results: : Highly depressed individuals had a more negative attitude towards social touch than non-to lowly depressed individuals. Highly depressed individuals particularly reported to dislike physical touch by not well-known people, but not by close ones. Highly depressed individuals also reported more interpersonal problems, with the level of depression predicting the degree of interpersonal problems. This relationship was partially mediated by the attitude towards social touch in general and, to a greater extent, by the dislike of physical touch by people not well-known in particular. Discussion: : Given the role of social touch in the relationship between depression and interpersonal problems, the attitude towards touch may be taken into consideration in the therapy of depressed patients. We assume that a more positive attitude towards social touch can influence the ability to create and maintain interpersonal relationships.
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| 10. |
- Triscoli, Chantal, et al.
(författare)
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Heart rate variability is enhanced by long-lasting gentle touch
- 2017
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Ingår i: International Convention of Psychological Science (ICPS). Vienna, Austria: 23-25 march.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The affective dimension of touch, as coded by the C tactile afferents, plays an important role in the maintenance of the physical and social well-being of the individual. The present study investigates whether long-lasting pleasant touch performed at the velocity which elicits the highest CT firing frequency has a positive effect on autonomic responses and stress hormones. In a between-subjects design, 40 participants received either 40 minutes of brush stroking or vibration on the forearm, and rated the perceived pleasantness and intensity of the tactile stimulation in regular intervals. Salivary cortisol and alpha amylase levels, as well as measures of reward responsiveness, tactile sensitivity and interoceptive awareness were collected prior and after the tactile stimulation. Heart rate was registered throughout the whole experimental session. The pleasantness ratings decreased over continuous stimulation for both groups, with the brush stroking being perceived as more pleasant than vibration. The heart rate variability index “SDNN” increased over time for touch only, whereas it remained stable for vibration. Salivary cortisol levels decreased over time regardless the type of the tactile stimulation. These results indicate that prolonged pleasant touch at the CT optimized stroking velocity has a beneficial effect on the autonomic system, as shown by the increased SDNN, which is associated with wellbeing. The decrease in salivary cortisol levels for both touch and vibration suggests that several kinds of tactile stimulation may reduce stress. The above findings highlight the importance of long-lasting social touch interactions for improving the physiological state of the individual.
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