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Metabolites Feb 2020Chemical communication is common among animals. In humans, the chemical basis of social communication has remained a black box, despite psychological and neural research...
Chemical communication is common among animals. In humans, the chemical basis of social communication has remained a black box, despite psychological and neural research showing distinctive physiological, behavioral, and neural consequences of body odors emitted during emotional states like fear and happiness. We used a multidisciplinary approach to examine whether molecular cues could be associated with an emotional state in the emitter. Our research revealed that the volatile molecules transmitting different emotions to perceivers also have objectively different chemical properties. Chemical analysis of underarm sweat collected from the same donors in fearful, happy, and emotionally neutral states was conducted using untargeted two-dimensional (GC×GC) coupled with time of flight (ToF) MS-based profiling. Based on the multivariate statistical analyses, we find that the pattern of chemical volatiles (N = 1655 peaks) associated with fearful state is clearly different from that associated with (pleasant) neutral state. Happy sweat is also significantly different from the other states, chemically, but shows a bipolar pattern of overlap with fearful as well as neutral state. Candidate chemical classes associated with emotional and neutral sweat have been identified, specifically, linear aldehydes, ketones, esters, and cyclic molecules (5 rings). This research constitutes a first step toward identifying the chemical fingerprints of emotion.
PubMed: 32121157
DOI: 10.3390/metabo10030084 -
Frontiers in Neurorobotics 2014This study reports an examination of the internal clock model, according to which subjective time duration is influenced by attention and arousal state. In a time...
This study reports an examination of the internal clock model, according to which subjective time duration is influenced by attention and arousal state. In a time production task, we examine the hypothesis that an arousing odor and an upright body posture affect perceived duration. The experimental task was performed while participants were exposed to an odor and either sitting upright (arousing condition) or lying down in a relaxing chair (relaxing condition). They were allocated to one of three experimental odor conditions: rosemary (arousing condition), peppermint (relaxing condition), and no odor (control condition). The predicted effects of the odors were not borne out by the results. Self-reported arousal (SRA) and pleasure (PL) states were measured before, during (after each body posture condition) and postexperimentally. Heart rate (HR) and skin conductance were measured before and during the experiment. As expected, odor had an effect on perceived duration. When participants were exposed to rosemary odor, they produced significantly shorter time intervals than in the no odor condition. This effect, however, could not be explained by increased arousal. There was no effect of body posture on perceived duration, even though body posture did induce arousal. The results do not support the proposed arousal mechanism of the internal clock model.
PubMed: 24567718
DOI: 10.3389/fnbot.2014.00006 -
PLoS Genetics Feb 2022The olfactory system combines input from multiple receptor types to represent odor information, but there are few explicit examples relating olfactory receptor (OR)...
The olfactory system combines input from multiple receptor types to represent odor information, but there are few explicit examples relating olfactory receptor (OR) activity patterns to odor perception. To uncover these relationships, we performed genome-wide scans on odor-perception phenotypes for ten odors in 1000 Han Chinese and validated results for six of these odors in an ethnically diverse population (n = 364). In both populations, consistent with previous studies, we replicated three previously reported associations (β-ionone/OR5A1, androstenone/OR7D4, cis-3-hexen-1-ol/OR2J3 LD-band), but not for odors containing aldehydes, suggesting that olfactory phenotype/genotype studies are robust across populations. Two novel associations between an OR and odor perception contribute to our understanding of olfactory coding. First, we found a SNP in OR51B2 that associated with trans-3-methyl-2-hexenoic acid, a key component of human underarm odor. Second, we found two linked SNPs associated with the musk Galaxolide in a novel musk receptor, OR4D6, which is also the first human OR shown to drive specific anosmia to a musk compound. We noticed that SNPs detected for odor intensity were enriched with amino acid substitutions, implying functional changes of odor receptors. Furthermore, we also found that the derived alleles of the SNPs tend to be associated with reduced odor intensity, supporting the hypothesis that the primate olfactory gene repertoire has degenerated over time. This study provides information about coding for human body odor, and gives us insight into broader mechanisms of olfactory coding, such as how differential OR activation can converge on a similar percept.
Topics: Adolescent; Adult; Female; Humans; Male; Middle Aged; Young Adult; Asian People; Benzopyrans; Body Odor; Caproates; Olfactory Perception; Polymorphism, Single Nucleotide; Receptors, Odorant; Reproducibility of Results; Smell
PubMed: 35113854
DOI: 10.1371/journal.pgen.1009564 -
Scientific Reports Mar 2021Olfactory learning and conditioning in the fruit fly is typically modelled by correlation-based associative synaptic plasticity. It was shown that the conditioning of an...
Olfactory learning and conditioning in the fruit fly is typically modelled by correlation-based associative synaptic plasticity. It was shown that the conditioning of an odor-evoked response by a shock depends on the connections from Kenyon cells (KC) to mushroom body output neurons (MBONs). Although on the behavioral level conditioning is recognized to be predictive, it remains unclear how MBONs form predictions of aversive or appetitive values (valences) of odors on the circuit level. We present behavioral experiments that are not well explained by associative plasticity between conditioned and unconditioned stimuli, and we suggest two alternative models for how predictions can be formed. In error-driven predictive plasticity, dopaminergic neurons (DANs) represent the error between the predictive odor value and the shock strength. In target-driven predictive plasticity, the DANs represent the target for the predictive MBON activity. Predictive plasticity in KC-to-MBON synapses can also explain trace-conditioning, the valence-dependent sign switch in plasticity, and the observed novelty-familiarity representation. The model offers a framework to dissect MBON circuits and interpret DAN activity during olfactory learning.
Topics: Animals; Avoidance Learning; Dopaminergic Neurons; Drosophila; Models, Biological; Mushroom Bodies; Neuronal Plasticity; Smell; Stochastic Processes; Synapses
PubMed: 33762640
DOI: 10.1038/s41598-021-85841-y -
Communications Chemistry Mar 2024Body odors change during development, and this change influences the interpersonal communication between parents and their children. The molecular basis for this...
Body odors change during development, and this change influences the interpersonal communication between parents and their children. The molecular basis for this chemical communication has not been elucidated yet. Here, we show by combining instrumental and sensory analyses that the qualitative odorant composition of body odor samples is similar in infants (0-3 years) and post-pubertal children (14-18 years). The post-pubertal samples are characterized by higher odor dilution factors for carboxylic acids and by the presence of 5α-androst-16-en-3-one and 5α-androst-16-en-3α-ol. In addition to the olfaction-guided approach, the compounds 6-methylhept-5-en-2-one (6MHO), geranyl acetone (GA) and squalene (SQ) were quantified. Both age groups have similar concentrations of 6MHO and GA, whereas post-pubertal children tend to have higher concentration of SQ. In conclusion, sexual maturation coincides with changes to body odor chemical composition. Whether those changes explain differences in parental olfactory perception needs to be determined in future studies with model odors.
PubMed: 38514840
DOI: 10.1038/s42004-024-01131-4 -
Human Brain Mapping May 2020Odors can increase memory performance when presented as context during both encoding and retrieval phases. Since information from different sensory modalities is...
Odors can increase memory performance when presented as context during both encoding and retrieval phases. Since information from different sensory modalities is integrated into a unified conceptual knowledge, we hypothesize that the social information from body odors and faces would be integrated during encoding. The integration of such social information would enhance retrieval more so than when the encoding occurs in the context of common odors. To examine this hypothesis and to further explore the underlying neural correlates of this behavior, we have conducted a functional magnetic resonance imaging study in which participants performed an encoding-retrieval memory task for faces during the presentation of common odor, body odor or clean air. At the behavioral level, results show that participants were less biased and faster in recognizing faces when presented in concomitance with the body odor compared to the common odor. At the neural level, the encoding of faces in the body odor condition, compared to common odor and clean air conditions, showed greater activation in areas related to associative memory (dorsolateral prefrontal cortex), odor perception and multisensory integration (orbitofrontal cortex). These results suggest that face and body odor information were integrated and as a result, participants were faster in recognizing previously presented material.
Topics: Adolescent; Adult; Affect; Association Learning; Face; Female; Human Body; Humans; Magnetic Resonance Imaging; Male; Memory, Episodic; Mental Recall; Odorants; Olfactory Perception; Prefrontal Cortex; Psychomotor Performance; Recognition, Psychology; Young Adult
PubMed: 31904899
DOI: 10.1002/hbm.24920 -
PloS One 2021Human sweat odor serves as social communication signal for a person's traits and emotional states. This study explored whether body odors can also communicate...
Human sweat odor serves as social communication signal for a person's traits and emotional states. This study explored whether body odors can also communicate information about one's self-esteem, and the role of applied fragrance in this relationship. Female participants were asked to rate self-esteem and attractiveness of different male contestants of a dating show, while being exposed to male participant's body odors differing in self-esteem. High self-esteem sweat was rated more pleasant and less intense than low self-esteem sweat. However, there was no difference in perceived self-esteem and attractiveness of male contestants in videos, hence explicit differences in body odor did not transfer to judgments of related person characteristics. When the body odor was fragranced using a fragranced body spray, male contestants were rated as having higher self-esteem and being more attractive. The finding that body odors from male participants differing in self-esteem are rated differently and can be discriminated suggests self-esteem has distinct perceivable olfactory features, but the remaining findings imply that only fragrance affect the psychological impression someone makes. These findings are discussed in the context of the role of body odor and fragrance in human perception and social communication.
Topics: Adolescent; Adult; Body Odor; Communication; Emotions; Female; Healthy Volunteers; Humans; Interpersonal Relations; Judgment; Male; Odorants; Olfactory Perception; Perfume; Self Concept; Self Report; Smell; Sweat; Young Adult
PubMed: 34780484
DOI: 10.1371/journal.pone.0258773 -
Medicina (Kaunas, Lithuania) Jun 2021(1) Background: Halitosis is a frequent condition that affects a large part of the population. It is considered a "social stigma", as it can determine a number of... (Review)
Review
(1) Background: Halitosis is a frequent condition that affects a large part of the population. It is considered a "social stigma", as it can determine a number of psychological and relationship consequences that affect people's lives. The purpose of this review is to examine the role of psychological factors in the condition of self-perceived halitosis in adolescent subjects and adulthood. (2) Type of studies reviewed: We conducted, by the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analyses) guidelines, systematic research of the literature on PubMed and Scholar. The key terms used were halitosis, halitosis self-perception, psychological factors, breath odor and two terms related to socio-relational consequences ("Halitosis and Social Relationship" OR "Social Issue of Halitosis"). Initial research identified 3008 articles. As a result of the inclusion and exclusion criteria, the number of publications was reduced to 38. (3) Results: According to the literature examined, halitosis is a condition that is rarely self-perceived. In general, women have a greater ability to recognize it than men. Several factors can affect the perception of the dental condition, such as socioeconomic status, emotional state and body image. (4) Conclusion and practical implication: Self-perceived halitosis could have a significant impact on the patient's quality of life. Among the most frequent consequences are found anxiety, reduced levels of self-esteem, misinterpretation of other people's attitudes and embarrassment and relational discomfort that often result in social isolation.
Topics: Adolescent; Adult; Female; Halitosis; Humans; Interpersonal Relations; Male; Quality of Life; Self Concept
PubMed: 34204752
DOI: 10.3390/medicina57060614 -
Microbiome Nov 2018Even though human sweat is odorless, bacterial growth and decomposition of specific odor precursors in it is believed to give rise to body odor in humans. While...
BACKGROUND
Even though human sweat is odorless, bacterial growth and decomposition of specific odor precursors in it is believed to give rise to body odor in humans. While mechanisms of odor generation have been widely studied in adults, little is known for teenagers and pre-pubescent children who have distinct sweat composition from immature apocrine and sebaceous glands, but are arguably more susceptible to the social and psychological impact of malodor.
RESULTS
We integrated information from whole microbiome analysis of multiple skin sites (underarm, neck, and head) and multiple time points (1 h and 8 h after bath), analyzing 180 samples in total to perform the largest metagenome-wide association study to date on malodor. Significant positive correlations were observed between odor intensity and the relative abundance of Staphylococcus hominis, Staphylococcus epidermidis, and Cutibacterium avidum, as well as negative correlation with Acinetobacter schindleri and Cutibacterium species. Metabolic pathway analysis highlighted the association of isovaleric and acetic acid production (sour odor) from enriched S. epidermidis (teen underarm) and S. hominis (child neck) enzymes and sulfur production from Staphylococcus species (teen underarm) with odor intensity, in good agreement with observed odor characteristics in pre-pubescent children and teenagers. Experiments with cultures on human and artificial sweat confirmed the ability of S. hominis and S. epidermidis to independently produce malodor with distinct odor characteristics.
CONCLUSIONS
These results showcase the power of skin metagenomics to study host-microbial co-metabolic interactions, identifying distinct pathways for odor generation from sweat in pre-pubescent children and teenagers and highlighting key enzymatic targets for intervention.
Topics: Acetic Acid; Acinetobacter; Adolescent; Axilla; Bacteria; Child; Female; Head; Hemiterpenes; Humans; Male; Metagenomics; Neck; Odorants; Pentanoic Acids; Propionibacteriaceae; Puberty; Sequence Analysis, DNA; Skin; Staphylococcus epidermidis; Staphylococcus hominis; Sulfur; Sweat
PubMed: 30497517
DOI: 10.1186/s40168-018-0588-z -
Frontiers in Psychology 2017Attractiveness plays a central role in human non-verbal communication and has been broadly examined in diverse subfields of contemporary psychology. Researchers have... (Review)
Review
Attractiveness plays a central role in human non-verbal communication and has been broadly examined in diverse subfields of contemporary psychology. Researchers have garnered compelling evidence in support of the evolutionary functions of physical attractiveness and its role in our daily lives, while at the same time, having largely ignored the significant contribution of non-visual modalities and the relationships among them. Acoustic and olfactory cues can, separately or in combination, strongly influence the perceived attractiveness of an individual and therefore attitudes and actions toward that person. Here, we discuss the relative importance of visual, auditory and olfactory traits in judgments of attractiveness, and review neural and behavioral studies that support the highly complex and multimodal nature of person perception. Further, we discuss three alternative evolutionary hypotheses aimed at explaining the function of multiple indices of attractiveness. In this review, we provide several lines of evidence supporting the importance of the voice, body odor, and facial and body appearance in the perception of attractiveness and mate preferences, and therefore the critical need to incorporate cross-modal perception and multisensory integration into future research on human physical attractiveness.
PubMed: 28572777
DOI: 10.3389/fpsyg.2017.00778