| 1. |
- Ackerley, Rochelle, et al.
(författare)
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Investigating the Putative Impact of Odors Purported to Have Beneficial Effects on Sleep: Neural and Perceptual Processes
- 2020
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Ingår i: Chemosensory Perception. - : Springer Science and Business Media LLC. - 1936-5802 .- 1936-5810. ; 13, s. 93-105
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Olfaction has an important role in physiological and affective processes, as well as the potential to have profound effects on activities such as sleep and learning. We investigated two commercially manufactured odors (“Deep Sleep” and “Oriental,” from This Works) purported to promote sleep, compared with control odor, where we aimed to explore whether neural and behavioral differences existed after odor inhalation. Methods: In a neuroimaging study, 30 healthy participants were exposed to the odors via an olfactometer during functional magnetic resonance imaging (fMRI). In a further behavioral study using 12 chronic insomniacs, we investigated whether the commercial odors showed effects on sleep during a double-blind, randomized home evaluation. Results: In the neuroimaging, the odors were related to activation of olfactory-relevant areas, such as the orbitofrontal cortex, and we found positive connectivity between the piriform cortex and the hippocampus, amygdala, insula, and middle cingulate cortex. Deep Sleep specifically activated the superior temporal gyrus, whereas Oriental activated the caudate. Further, these commercial odors showed some beneficial impact on sleep. Conclusions: The perceptual and neural impacts of the commercial odors showed that olfactory stimulation can potentially aid sleep and modify affective processes in a number of ways. Implications: The present work opens up opportunities for further investigations into how different odors may lead to specific behavioral and physiological modifications, such as their impact on sleep and well-being, which may provide non-pharmacological alternative approaches.
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| 2. |
- Bendas, Johanna, et al.
(författare)
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C-Tactile Mediated Erotic Touch Perception Relates to Sexual Desire and Performance in a Gender-Specific Way
- 2017
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Ingår i: Journal of Sexual Medicine. - : WILEY. - 1743-6095 .- 1743-6109. ; 14:5, s. 645-653
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Tidskriftsartikel (refereegranskat)abstract
- Background: Unmyelinated low-threshold mechanoreceptors-the so-called C-tactile (CT) afferents-play a crucial role in the perception and conduction of caressing and pleasant touch sensations and significantly contribute to the concept of erotic touch perception. Aim: To investigate the relations between sexual desire and sexual performance and the perception of touch mediated by CT afferents. Methods: Seventy healthy participants (28 men, 42 women; mean age+/-SD = 24.84+/-4.08 years, range = 18-36 years) underwent standardized and highly controlled stroking stimulation that varied in the amount of CT fiber stimulation by changing stroking velocity (CT optimal = 1, 3 and 10 cm/s; CT suboptimal = 0.1, 0.3, and 30 cm/s). Participants rated the perceived pleasantness, eroticism, and intensity of the applied tactile stimulation on a visual analog scale, completed the Sexual Desire Inventory, and answered questions about sexual performance. Outcomes: Ratings of perceived eroticism of touch were related to self-report levels of sexual desire and sexual performance. Results: Pleasantness and eroticism ratings showed similar dependence on stroking velocity that aligned with the activity of CT afferents. Erotic touch perception was related to sexual desire and sexual performance in a gender-specific way. In women, differences in eroticism ratings between CT optimal and suboptimal velocities correlated positively with desire for sexual interaction. In contrast, in men, this difference correlated to a decreased frequency and longer duration of partnered sexual activities. Clinical Implications: The present results lay the foundation for future research assessing these relations in patients with specific impairments of sexual functioning (eg, hypoactive sexual desire disorder). Strengths and Limitations: The strength of the study is the combination of standardized neurophysiologic methods and behavioral data. A clear limitation of the study design is the exclusion of exact data on the female menstrual cycle and the recruitment of an inhomogeneous sample concerning sexual orientation. Conclusion: The present results provide further evidence that unmyelinated CT afferents play a role in the complex mechanism of erotic touch perception. The ability to differentiate between CT optimal and suboptimal stimuli relates to sexual desire and performance in a gender-specific way. Copyright (C) 2017, International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.
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| 3. |
- Blomkvist, Anna, 1987-
(författare)
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Intimate relationships and olfaction : Body odors, adult attachment, and romance
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Odors influence several aspects of life, such as thoughts, memories, decisions, and emotions. Numerous studies have shown that human behavior can be affected by odors in different contexts. One such context is social relationships, in which body odors play a role. For example, previous studies have shown that close family members can identify each other’s body odors and prefer these compared to the body odors of non-family members. However, further research is needed to establish how body odors and olfactory functioning affect interpersonal behaviors and intimate relationships. In this thesis, I have conducted three studies highlighting the interplay between intimate relationships and olfaction. The overall purpose of this thesis was to investigate if and how olfaction is related to behaviors in intimate relationships.Study I tested if a romantic partner’s body odors have stress-altering effects and whether such effects differ depending on individual differences in romantic attachment security. As the practice of smelling a partner’s worn garment has been reported as a self-treatment against stress, my colleagues and I carried out an experiment to determine whether exposure to a partner’s body odor attenuates adult individuals’ subjective discomfort and psychophysiological responses. To induce discomfort and stress responses, participants were exposed to weak electric shocks while smelling their partner’s body odor (experimental condition) and three control odors (control conditions). The results showed that partner body odor had an attenuating effect on subjective discomfort during stress. Additionally, highly attachment-secure participants exhibited attenuated skin conductance specifically when exposed to their partner’s body odor. Thus, study I concluded that partner body odor is a scent of security, especially for relatively attachment-secure adults.Next, to determine whether olfaction is linked to sexual outcomes in intimate relationships, study II explored associations between self-reported olfactory functioning, on the one hand, and infidelity and sexual well-being, on the other, using a survey design. Our exploratory analyses found that self-reported olfactory function predicted sexual well-being positively and infidelity negatively, while controlling for other relevant socio-demographic variables. These results are discussed from a relationship science perspective, in which one’s intimate partner signifies sexual bonding in addition to caregiving and attachment. Thus, study II suggests that a partner’s body odor might be a scent of monogamy.Study III summarized the literature on populations with an impaired or total absence of a sense of smell. The interplay between olfaction and intimate relationship variables was examined by reviewing research reports and empirical studies concerning individuals with an impaired sense of smell. My colleague and I provided an overview of how olfactory impairment can impact three types of close social relationships: family relationships, friendships, and romantic relationships. For romantic relationships, which are the main focus of this thesis, three categories were defined in which olfactory impairment can impact close social relationships: eating, social support, and sexuality. Thus, study III concludes that olfactory ability is related to various romantic, intimate relationship behaviors.In sum, all three studies reported findings highlighting that olfaction (body odors and olfactory functioning) is related to intimate relationships. The results from the three studies are discussed via theoretical frameworks concerning the sense of smell, romantic relationships, and attachment. The thesis concludes that olfactory functioning and the experience of body odors are meaningful for intimate relationships and, as such, also for various behaviors in these relationships.
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| 4. |
- Cavazzana, Annachiara, et al.
(författare)
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Sensory-specific impairment among older people : An investigation using both sensory thresholds and subjective measures across the five senses
- 2018
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- Age-related sensory impairment is a slow and gradual progress, which affects multiple modalities. Two contradictory hypotheses exist about the age-related decline of sensory thresholds. The common factor theory assumes one underlying factor-which accounts for the loss of several sensory modalities simultaneously-and the specific factor theory predicts that the sensory decline is uncorrelated between different modalities. In this study, we aimed to explore whether (i) there is a common factor of sensory thresholds in older people, (ii) older people assume that sensory decline in one modality also affects other modalities, (iii) there is a relation between sensory threshold and the subjective assessment of sensory function. This was accomplished by collecting both threshold measures and self-reported ratings for smell, hearing, taste, vision, and touch function in a group of 104 older people (mean age: 67.2 years; SD: 9.85; range: 50-100 years). Results indicated that there was no common factor of sensory thresholds, hence an impairment in one modality did not necessarily imply a shortfall in other modalities. In contrast, our results suggested one or two common factor(s) for the participants' ratings. Participants who reported a diminished function in one sense tended to generalize this rating to the other senses as well. The correspondence between subjective ratings and sensory thresholds was relatively good for vision and audition, although no correlations were observed for the other domains. These findings have implications for clinicians, suggesting that subjective measures should be combined with sensory threshold measurements when evaluating sensory dysfunction. Also, these data convey a positive message for older people and their physicians by showing that loss in one sensory modality does not necessarily generalize to losses across all sensory modalities.
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| 5. |
- Chen, Ben, et al.
(författare)
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Symptoms of Depression in Patients with Chemosensory Disorders
- 2021
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Ingår i: Journal for Oto-Rhino-Laryngology. - : S. Karger. - 0301-1569 .- 1423-0275. ; 83:3, s. 135-143
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Patients with chemosensory dysfunction frequently report symptoms of depression. The current study aims to clarify whether the type (smell dysfunction, taste dysfunction, and mixed smell and taste dysfunction), severity, duration, or cause of dysfunction have differential impacts on the symptoms of depression. Methods: 899 patients with chemosensory disorders and 62 controls were included. Following a structured interview and an otorhinolaryngological examination, subjects underwent olfactory tests (Sniffin' Sticks), gustatory tests (taste sprays) and an assessment of depressive symptoms (Beck Depression Inventory). Information on the cause and duration of disorders was also collected. Results: Patients with combined olfactory/gustatory dysfunction had higher depression scores than patients with smell dysfunction only and controls, and no significant difference was found between the smell dysfunction and controls. Anosmia patients, but not hyposmia patients, exhibited higher depression scores than controls. Among various causes of chemosensory disorders, patients from the posttraumatic group had higher depression scores than patients with other causes of chemosensory dysfunction (sinonasal, idiopathic, or postinfectious). Multiple linear regression analyses suggested that reduced olfactory function was associated with enhanced depression scores in the olfactory disorders group (B = -0.326, t = -2.294, and p = 0.02) and in all patients with chemosensory disorders (B = -0.374, t = -2.550, p = 0.017). Discussion/Conclusion: Simultaneously decreased input of olfaction and gustation seems to have an additive effect on the exacerbation of emotional dysfunction. Early intervention should be considered for depression symptoms in patients with mixed olfactory/gustatory dysfunction in clinical practice.
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| 6. |
- Conroy-Beam, Daniel, et al.
(författare)
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Assortative mating and the evolution of desirability covariation
- 2019
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Ingår i: Evolution and human behavior. - : Elsevier. - 1090-5138 .- 1879-0607. ; 40:5, s. 479-491
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Tidskriftsartikel (refereegranskat)abstract
- Mate choice lies dose to differential reproduction, the engine of evolution. Patterns of mate choice consequently have power to direct the course of evolution. Here we provide evidence suggesting one pattern of human mate choice-the tendency for mates to be similar in overall desirability-caused the evolution of a structure of correlations that we call the d factor. We use agent-based models to demonstrate that assortative mating causes the evolution of a positive manifold of desirability, d, such that an individual who is desirable as a mate along any one dimension tends to be desirable across all other dimensions. Further, we use a large cross-cultural sample with n = 14,478 from 45 countries around the world to show that this d-factor emerges in human samples, is a cross-cultural universal, and is patterned in a way consistent with an evolutionary history of assortative mating. Our results suggest that assortative mating can explain the evolution of a broad structure of human trait covariation.
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| 7. |
- Conroy-Beam, Daniel, et al.
(författare)
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Contrasting Computational Models of Mate Preference Integration Across 45 Countries
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Humans express a wide array of ideal mate preferences. Around the world, people desire romantic partners who are intelligent, healthy, kind, physically attractive, wealthy, and more. In order for these ideal preferences to guide the choice of actual romantic partners, human mating psychology must possess a means to integrate information across these many preference dimensions into summaries of the overall mate value of their potential mates. Here we explore the computational design of this mate preference integration process using a large sample of n = 14,487 people from 45 countries around the world. We combine this large cross-cultural sample with agent-based models to compare eight hypothesized models of human mating markets. Across cultures, people higher in mate value appear to experience greater power of choice on the mating market in that they set higher ideal standards, better fulfill their preferences in choice, and pair with higher mate value partners. Furthermore, we find that this cross-culturally universal pattern of mate choice is most consistent with a Euclidean model of mate preference integration.
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| 8. |
- Croy, Ilona, et al.
(författare)
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Affective touch awareness in mental health and disease relates to autistic traits - An explorative neurophysiological investigation
- 2016
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Ingår i: Psychiatry Research. - : ELSEVIER IRELAND LTD. - 0165-1781 .- 1872-7123. ; 245, s. 491-496
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Tidskriftsartikel (refereegranskat)abstract
- Affective touch is important for social interaction within families and groups and there is evidence that unmyelinated C tactile fibers are involved in this process. Individuals with autism spectrum disorders show alterations in the perception and processing of affective touch. sThus, we hypothesized that affective touch awareness based on C tactile fiber activation is impaired in individuals with high levels of autistic trait. The pleasantness perception of optimal and suboptimal C tactile stimuli was tested in an explorative study in 70 patients recruited from an outpatient psychotherapy clinic and 69 healthy comparison subjects. All participants completed questionnaires about autistic traits, depressive symptomatology, childhood maltreatment, and about the daily amount of touch. Relative to comparison subjects, patients reported engaging in touch less frequently in daily life and rated touch less pleasant. Reduced valence ratings of touch were explained by childhood maltreatment but not by any particular disorder or depression severity. Among all tested variables, the affective touch awareness correlated with autistic traits only - in patients as well as in comparison subjects. Taken together, individuals with mental health issues have a lower baseline of expression and reception of affective touch. Autistic traits and childhood maltreatment modulate the experience of affective touch. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
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| 9. |
- Croy, Ilona, et al.
(författare)
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COVID-19 and Social Distancing : A Cross-Cultural Study of Interpersonal Distance Preferences and Touch Behaviors Before and During the Pandemic
- 2024
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Ingår i: Cross-Cultural Research. - 1069-3971 .- 1552-3578. ; 58:1, s. 41-69
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Tidskriftsartikel (refereegranskat)abstract
- The COVID-19 pandemic has led to the introduction of unprecedented safety measures, one of them being physical distancing recommendations. Here, we assessed whether the pandemic has led to long-term effects on two important physical distancing aspects, namely interpersonal distance preferences and interpersonal touch behaviors. We analyzed nearly 14,000 individual cases from two large, cross-cultural surveys – the first conducted 2 years prior to the pandemic and the second during a relatively stable period of a decreased infection rate in May-June 2021. Preferred interpersonal distances increased by 54% globally during the COVID-19 pandemic. This increase was observable across all types of relationships, all countries, and was more pronounced in individuals with higher self-reported vulnerability to diseases. Unexpectedly, participants reported a higher incidence of interpersonal touch behaviors during than before the pandemic. We discuss our results in the context of prosocial and self-protection motivations that potentially promote different social behaviors.
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| 10. |
- Croy, Ilona, et al.
(författare)
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Effects of train noise and vibration on human heart rate during sleep –an experimental study
- 2013
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Ingår i: BMJ Open. - : BMJ. - 2044-6055. ; 3:5
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Tidskriftsartikel (refereegranskat)abstract
- Objectives Transportation of goods on railways is increasing and the majority of the increased numbers of freight trains run during the night. Transportation noise has adverse effects on sleep structure, affects the heart rate (HR) during sleep and may be linked to cardiovascular disease. Freight trains also generate vibration and little is known regarding the impact of vibration on human sleep. A laboratory study was conducted to examine how a realistic nocturnal railway traffic scenario influences HR during sleep. Design Case–control. Setting Healthy participants. Participants 24 healthy volunteers (11 men, 13 women, 19–28years) spent six consecutive nights in the sleep laboratory. Interventions All participants slept during one habituation night, one control and four experimental nights in which train noise and vibration were reproduced. In the experimental nights, 20 or 36 trains with low-vibration or high-vibration characteristics were presented. Primary and secondary outcome measures Polysomnographical data and ECG were recorded. Results The train exposure led to a significant change of HR within 1min of exposure onset (p=0.002), characterised by an initial and a delayed increase of HR. The high-vibration condition provoked an average increase of at least 3bpm per train in 79% of the participants. Cardiac responses were in general higher in the high-vibration condition than in the low-vibration condition (p=0.006). No significant effect of noise sensitivity and gender was revealed, although there was a tendency for men to exhibit stronger HR acceleration than women. Conclusions Freight trains provoke HR accelerations during sleep, and the vibration characteristics of the trains are of special importance. In the long term, this may affect cardiovascular functioning of persons living close to railways.
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| 11. |
- Croy, Ilona, et al.
(författare)
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Gentle touch perception: From early childhood to adolescence
- 2019
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Ingår i: Developmental Cognitive Neuroscience. - : Elsevier BV. - 1878-9293 .- 1878-9307. ; 35, s. 81-86
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Tidskriftsartikel (refereegranskat)abstract
- Affective touch plays an important role in children's social interaction and is involved in shaping the development of the social brain. The positive affective component of touch is thought to be conveyed via a group of unmyelinated, low-threshold mechanoreceptive afferents, known as C-tactile fibers that are optimally activated by gentle, slow, stroking touch. Touch targeting these C-tactile fibers has been shown to decrease the heart rate in infants. The current study investigated the relationship between age and psychophysical ratings in response to affective touch. A total of n = 43 participants (early childhood: aged 5-8 years, 9 girls, 12 boys; late childhood: aged 9-12 years, 12 girls, 10 boys) were presented with C-tactile optimal and sub-optimal stroking velocities and rated touch pleasantness on an affective pictorial scale. For both age groups, we found that children preferred C-tactile-targeted stimulation. A comparison with previously published data showed that the children's preference for C-tactile-targeted stimulation was similar to those obtained in adolescents and adults. We speculate that the effect of C-tactile-targeted touch, which is linked with pleasantness, shapes the children's preference for C-tactile over non-C-tactile-targeted stimulation, and that C-tactile afferent stimulation is important for social development.
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| 12. |
- Croy, Ilona, et al.
(författare)
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Habituation effects of pleasant and unpleasant odors
- 2013
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Ingår i: International Journal of Psychophysiology. - : Elsevier BV. - 0167-8760. ; 88:1, s. 104-108
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The hedonic value of odors is reflected in chemosensory evoked potentials with more salient unpleasant odors being processed differently from pleasant odors. However, it is not known if this effect is stable over time. It was examined if chemosensory evoked potentials towards pleasant and unpleasant odors change with repeated presentation. Methods: 42 participants received two pleasant (Peach and PEA) and one unpleasant (H2S) intensity matched odors in a block design. Intensity and pleasantness were rated after each presentation. Subjective ratings, as well as N1 and P2 of the first stimulus of each block were compared with the two following stimuli of each block. Results: Early and late components of the chemosensory evoked potentials had shorter latencies in response to the unpleasant H2S compared to PEA and Peach. Pleasantness ratings for H2S increased with repeated presentation but were far below neutral even for the third stimulus in a row. In line with this, for H2S only, the P2 amplitude diminished with repeated presentation. Conclusion: We assume that unpleasant stimuli catch more attention first hand. However, repeated presentation leads to reduced emotional salience of unpleasant stimuli only, which is mirrored in a decrease of neuronal activation.
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| 13. |
- Croy, Ilona, et al.
(författare)
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Human olfactory lateralization requires trigeminal activation
- 2014
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Ingår i: Neuroimage. - : Elsevier BV. - 1053-8119. ; 98, s. 289-295
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Tidskriftsartikel (refereegranskat)abstract
- Rats are able to lateralize odors. This ability involves specialized neurons in the orbitofrontal cortex which are able to process the left, right and bilateral presentation of stimuli. However, it is not clear whether this function is preserved in humans. Humans are in general not able to differentiate whether a selective olfactory stimulant has been applied to the left or right nostril; however exceptions have been reported. Following a screening of 152 individuals with an olfactory lateralization test, we identified 19 who could lateralize odors above chance level. 15 of these lateralizers" underwent olfactory fMRI scanning in a block design and were compared to 15 controls matched for age and sex distribution. As a result both groups showed comparable activation of olfactory eloquent brain areas. However, subjects with lateralization ability had a significantly enhanced activation of cerebral trigeminal processing areas (somatosensory cortex, intraparietal sulcus). In contrast to controls, lateralizers furthermore exhibited no suppression in the area of the trigeminal principal sensory nucleus. An exploratory study with an olfactory change detection paradigm furthermore showed that lateralizers oriented faster towards changes in the olfactory environment. Taken together, our study suggests that the trigeminal system is activated to a higher degree by the odorous stimuli in the group of lateralizers". We conclude that humans are not able to lateralize odors based on the olfactory input alone, but vary in the degree to which the trigeminal system is recruited. (C) 2014 Elsevier Inc All rights reserved.
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| 14. |
- 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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| 15. |
- Croy, Ilona, et al.
(författare)
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Olfaction as a marker for depression in humans
- 2014
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Ingår i: Journal of Affective Disorders. - : Elsevier BV. - 0165-0327 .- 1573-2517. ; 160, s. 80-86
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Tidskriftsartikel (refereegranskat)abstract
- Background: Animal studies show a strong link between the loss of olfactory function and depressive behavior. We analyzed, whether olfactory function is a marker for depression in humans. If so, reduced olfactory function can be expected in depression that improves to level of normality after successful antidepressive treatment. Methods: Twenty-seven female in-patients with depression were compared to 28 healthy age-matched women at the beginning and at the end of antidepressive therapy or at two visits, respectively. Olfactory function was assessed comprehensively including threshold, discrimination and identification testing, chemosensory event related potentials and olfactory functional magnetic resonance imaging. Results: At the beginning of psychotherapy the patients exhibited reduced olfactory discrimination, prolonged latencies of the event-related potential and reduced activation in secondary olfactory structures (thalamus, insula, and left middle orbitofrontal). After therapy, patients improved significantly in all of the parameters and consequently the differences between control group and patients vanished. Limitations and conclusion: We conclude that olfaction is a marker for depression. However, the results are limited to a relatively selective sample of depressed women. © 2014.
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| 16. |
- Croy, Ilona, et al.
(författare)
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Olfactory disorders and quality of life-an updated review
- 2014
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 39:3, s. 185-194
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Tidskriftsartikel (refereegranskat)abstract
- Olfactory disorders are common and affect about one-fifth of the general population. The main causes of olfactory loss are post viral upper respiratory infection, nasal/sinus disease, and head trauma and are therefore very frequent among patients in ear, nose, and throat clinics. We have systematically reviewed the impact of quantitative, qualitative, and congenital olfactory disorders on daily life domains as well as on general quality of life and depression. From the extensive body of literature, it can be concluded that loss of the sense of smell leads to disturbances in important areas, mainly in food enjoyment, detecting harmful food and smoke, and to some extent in social situations and working life. Most patients seem to deal well and manage those restrictions. However, a smaller proportion has considerable problems and expresses a noticeable reduction in general quality of life and enhanced depression. The impact of coping strategies is discussed. © The Author 2014.
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| 17. |
- Croy, Ilona, et al.
(författare)
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Olfactory modulation of affective touch processing - A neurophysiological investigation
- 2016
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Ingår i: Neuroimage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 135, s. 135-141
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Tidskriftsartikel (refereegranskat)abstract
- Touch can be highly emotional, and depending on the environment, it can be perceived as pleasant and comforting or disgusting and dangerous. Here, we studied the impact of context on the processing of tactile stimuli using a functional magnetic resonance imaging (fMRI) paradigm. This was achieved by embedding tactile stimulation in a variable olfactory environment. Twenty people were scanned with BOLD fMRI while receiving the following stimulus blocks: Slow stroking Touch, Civette odor (feces like), Rose odor, Touch + Civette, and Touch + Rose. Ratings of pleasantness and intensity of tactile stimuli and ratings of disgust and intensity of olfactory stimuli were collected. The impact of the olfactory context on the processing of touch was studied using covariance analyses. Coupling between olfactory processing and somatosensory processing areas was assessed with psychophysiological interaction analysis (PPI). A subjectively disgusting olfactory environment significantly reduced the perceived pleasantness of touch. The touch fMRI activation in the secondary somatosensory cortex, operculum 1 (OP1), was positively correlated with the disgust towards the odors. Decreased pleasantness of touch was related to decreased posterior insula activity. PPI analysis revealed a significant interaction between the OP1, posterior insula, and regions processing the disgust of odors (orbitofrontal cortex and amygdala). We conclude that the disgust evaluation of the olfactory environment moderates neural reactivity in somatosensory regions by upregulation of the OP1 and downregulation of the posterior insula. This adaptive regulation of affective touch processing may facilitate adaptive reaction to a potentially harmful stimulus.
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| 18. |
- Croy, Ilona, et al.
(författare)
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Optimal questions for sleep in epidemiological studies: Comparisons of subjective and objective measures in laboratory and field studies
- 2017
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Ingår i: Behavioural Sleep Medicine. - : Informa UK Limited. - 1540-2002 .- 1540-2010. ; 15:6, s. 466-482
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Tidskriftsartikel (refereegranskat)abstract
- Epidemiological studies on sleep often use questionnaires, and measurement of validity provides necessary guidance in selection of valid single sleep questions. Twenty-five items assessing different aspects of sleep, including overall sleep quality, specific sleep parameters, nocturnal restoration, and exposure-related questions, were tested. This involved coherence with objective polysomnographic (PSG) laboratory measurements of sleep in 47 participants and application of selected items under field conditions in over 3,000 participants. Items on overall sleep quality correlated significantly with PSG data. For specific sleep parameter questions, tiredness in the morning, time to fall asleep, difficulties to sleep and estimated number of awakenings were correlated to PSG data. Questions asking specifically about the effect of potential sleep disturbances correlated poorly with PSG data, but showed highest effects between environmental exposure (noise and vibration) and control nights in the laboratory and highest correlation with the dose of exposure in the field. In conclusion, healthy participants seem to be able to access their sleep reliably; and sleep questions asking about specific sleep parameters can be recommended for the assessment of sleep.
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| 19. |
- Croy, Ilona, et al.
(författare)
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Reduced Olfactory Bulb Volume in Adults with a History of Childhood Maltreatment
- 2013
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 38:8, s. 679-684
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Tidskriftsartikel (refereegranskat)abstract
- The human olfactory bulb (OB) is the first relay station of the olfactory pathway and may have the potential for postnatal neurogenesis in early childhood. In animals, chronic stress affects the OB and olfactory functioning. For humans, it has been shown that major depressive disorder is accompanied by reduced OB volume and reduced olfactory function. However, it is not clear if major stress in childhood development also affects olfactory functioning and OB volume in humans. OB volume was measured and olfactory function was tested in 17 depressive patients with and 10 without a history of severe childhood maltreatment (CM). CM patients exhibited a significantly reduced olfactory threshold and identification ability. The OB volume of the CM patients was significantly reduced to 80% of the non-CM patients. In conclusion, postnatal neurogenesis might be by reduced in CM, which may affect olfactory function of the brain in later life. Alternatively, a reduced OB volume may enhance psychological vulnerability in the presence of adverse childhood conditions although other areas not analyzed in this study may also be involved.
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| 20. |
- Croy, Ilona, et al.
(författare)
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Reduced Pleasant Touch Appraisal in the Presence of a Disgusting Odor
- 2014
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Odors are powerful emotional stimuli influencing mood, attention and behavior. Here we examined if odors change the perception of pleasant touch. In line with the warning function of the olfactory system, we proposed that especially unpleasant odors will reduce touch pleasantness, presumably through a disgust-related mechanism. Methods: Forty-five healthy participants (mean age 23.3 +/- 3years SD, 24 females) were presented to slow (3 cm/s) and fast (30 cm/s) brush stroking delivered by a robot to the forearm. Touch pleasantness under the influence of an unpleasant odor (Civette, smelling like feces) and an intensity matched pleasant odor (Rose) was compared to an odorless control condition. In a pilot study with 30 participants (mean age 25.9 +/-6 years, 21 females), the odors were matched according to their intensity, and we studied the influence of disgust sensitivity on the perception of 4 different odor qualities. Results: The unpleasant odor decreased touch pleasantness for both stroking velocities compared to the odorless control (p<0.005) whereas the rose odor did not change touch pleasantness significantly. Disgust sensitivity was correlated with the modulation of touch pleasantness. The pilot study revealed a significant correlation between disgust sensitivity and the perception of the unpleasant odor qualities (r = -0.56; p = 0.007), but not with any of the other odors. Conclusion: Unpleasant odors are powerful in modulating touch pleasantness, and disgust might be a moderating variable.
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| 21. |
- Croy, Ilona, et al.
(författare)
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Test-Retest Reliability and Validity of the Sniffin' TOM Odor Memory Test
- 2015
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 40:3, s. 173-179
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Tidskriftsartikel (refereegranskat)abstract
- Few attempts have been made to develop an olfactory test that captures episodic retention of olfactory information. Assessment of episodic odor memory is of particular interest in aging and in the cognitively impaired as both episodic memory deficits and olfactory loss have been targeted as reliable hallmarks of cognitive decline and impending dementia. Here, 96 healthy participants (18-92 years) and an additional 19 older people with mild cognitive impairment were tested (73-82 years). Participants were presented with 8 common odors with intentional encoding instructions that were followed by a yes-no recognition test. After recognition completion, participants were asked to identify all odors by means of free or cued identification. A retest of the odor memory test (Sniffin' TOM = test of odor memory) took place 17 days later. The results revealed satisfactory test-retest reliability (0.70) of odor recognition memory. Both recognition and identification performance were negatively affected by age and more pronounced among the cognitively impaired. In conclusion, the present work presents a reliable, valid, and simple test of episodic odor recognition memory that may be used in clinical groups where both episodic memory deficits and olfactory loss are prevalent preclinically such as Alzheimer's disease.
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| 22. |
- Han, Pengfei, et al.
(författare)
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Neural processing of odor-associated words : an fMRI study in patients with acquired olfactory loss
- 2020
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Ingår i: Brain Imaging and Behavior. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 14, s. 1164-1174
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Tidskriftsartikel (refereegranskat)abstract
- Perception of olfactory information is mediated by both bottom-up (from molecules to perception) and top-down (e.g. cross-modal associative learning) processes. Acquired olfactory loss is a frequent disorder which is typically due to alterations in the bottom-up pathway. However, it is unclear how the top-down modulation of olfactory processing is affected by olfactory impairment. Our study aimed to investigate the top-down olfactory processing in patients with acquired olfactory loss and participants with normal olfaction. Using functional MRI, brain responses from 14 patients and 16 healthy controls were assessed during a task of expectation and reading of words with strong olfactory associations (OW) (e.g. “Rose”) and control words with little to no olfactory associations (CW) (e.g. “Door”). The expectation but not reading of the OW was associated with stronger neural activation in the angular gyrus and the inferior frontal gyrus extending to insula in the group of patients. During OW reading, the brain activation in the left OFC and right putamen was negatively correlated with odor identification score in patient and control groups, respectively. In addition, the duration of olfactory loss among patients was positively associated with activation in the left putamen during OW expectation. Taken together, these findings suggest an enhanced top-down olfactory modulation in patients with olfactory loss.
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| 23. |
- Javaheripour, Nooshin, et al.
(författare)
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Altered resting-state functional connectome in major depressive disorder : a mega-analysis from the PsyMRI consortium
- 2021
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Ingår i: Translational Psychiatry. - : Springer Nature. - 2158-3188. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Major depressive disorder (MDD) is associated with abnormal neural circuitry. It can be measured by assessing functional connectivity (FC) at resting-state functional MRI, that may help identifying neural markers of MDD and provide further efficient diagnosis and monitor treatment outcomes. The main aim of the present study is to investigate, in an unbiased way, functional alterations in patients with MDD using a large multi-center dataset from the PsyMRI consortium including 1546 participants from 19 centers (). After applying strict exclusion criteria, the final sample consisted of 606 MDD patients (age: 35.8 +/- 11.9 y.o.; females: 60.7%) and 476 healthy participants (age: 33.3 +/- 11.0 y.o.; females: 56.7%). We found significant relative hypoconnectivity within somatosensory motor (SMN), salience (SN) networks and between SMN, SN, dorsal attention (DAN), and visual (VN) networks in MDD patients. No significant differences were detected within the default mode (DMN) and frontoparietal networks (FPN). In addition, alterations in network organization were observed in terms of significantly lower network segregation of SMN in MDD patients. Although medicated patients showed significantly lower FC within DMN, FPN, and SN than unmedicated patients, there were no differences between medicated and unmedicated groups in terms of network organization in SMN. We conclude that the network organization of cortical networks, involved in processing of sensory information, might be a more stable neuroimaging marker for MDD than previously assumed alterations in higher-order neural networks like DMN and FPN.
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| 24. |
- Jönsson, Emma H., et al.
(författare)
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Unmyelinated Tactile Cutaneous Nerves Signal Erotic Sensations
- 2015
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Ingår i: Journal of Sexual Medicine. - : Oxford University Press (OUP). - 1743-6095 .- 1743-6109. ; 12:6, s. 1338-1345
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionIntrapersonal touch is a powerful tool for communicating emotions and can among many things evoke feelings of eroticism and sexual arousal. The peripheral neural mechanisms of erotic touch signaling have been less studied. C tactile afferents (unmyelinated low-threshold mechanoreceptors), known to underpin pleasant aspects of touch processing, have been posited to play an important role. MethodIn two studies, we investigated the relationship between C tactile activation and the perception of erotic and pleasant touch, using tactile brushing stimulation. In total, 66 healthy subjects (37 women, age range 19-51 years) were examined. In study 1 (n=20), five different stroking velocities were applied to the forearm and the inner thigh. The participants answered questions about partnership, mood, and touch. In study 2 (n=46), the same five stroking velocities were applied to the forearm. The participants answered questions about partnership, touch, and sexuality. ResultsBoth touch eroticism and pleasantness were rated significantly higher for C tactile optimal velocities compared with suboptimal velocities. No difference was found between the ratings of the thigh and the forearm. The velocity-dependent rating curves of pleasantness, intensity, and eroticism differed from each other. Pleasantness was best explained by a quadratic fit, intensity by a linear fit, and eroticism by both. A linear transformation of pleasantness and intensity predicted the observed eroticism ratings reliably. Eroticism ratings were negatively correlated with length of relationship. ConclusionTouch was rated most erotic when perceived as pleasant and weak. In human hairy skin, perception of pleasantness is correlated with the firing rate of C tactile afferents, and perception of intensity is correlated with the firing rate of A afferents. Accordingly, eroticism may be perceived most readily for touch stimuli that induce high activity in C tactile fibers and low activity in A fibers. Jonsson EH, Backlund Wasling H, Wagnbeck V, Dimitriadis M, Georgiadis JR, Olausson H, and Croy I. Unmyelinated tactile cutaneous nerves signal erotic sensations. J Sex Med 2015;12:1338-1345.
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| 25. |
- Luong, Amanda, et al.
(författare)
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The individual preferred velocity of stroking touch as a stable measurement
- 2017
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Ingår i: Physiology and Behavior. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0031-9384 .- 1873-507X. ; 177, s. 129-134
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Tidskriftsartikel (refereegranskat)abstract
- Affective touch is of fundamental importance in human social interactions and there is an increasing interest in using touch as a probe for general affective perception. To this end, we developed a test of preferred velocity (ToP-V) of touch and tested whether the individually preferred stroking velocity is a stable and valid measurement. In study one, thirty healthy participants (18-30 years, 17 women) were examined with the ToP-V. Therefore, pairs of different slow stroking stimuli were presented by the Rotary Tactile Stimulator a robotic device - on the forearm and the participants chose the velocity they preferred in a forced choice paradigm. A retest was conducted after about 12 days. In study two, twenty-two healthy participants (20-43 years, 11 women) were tested with a shorter version of the ToP-V on the forearm and also on the palm. Moreover, they rated the pleasantness and the intensity of the stroking stimulations on both body sites. Results suggest that humans possess an individual and stable preferred velocity of stroking touch (test-retest reliability r = 0.86) which can be tested in a standardized procedure. A shortened 5 min version of the ToP-V also exhibited reasonable test characteristics (split half reliability: r = 0.7; test-retest reliability r = 0.77). The ToP-V correlated well with the pleasantness ratings when tested on the forearm (r = 0.65), but not when tested on the palm (r = 0.22), indicating that the ToP-V targets a C-tactile nerve fiber specific perception. Hence, the ToP-V can be used for reliably probing affective touch perception.
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