Individual Body Odors Research Articles

Discrimination Between Individual Body Odors Is Unaffected by Perfume.

Body odor conveys personal information and is important in social evaluations and bonding. As most body odor research uses samples devoid of exogenous fragrances, we asked whether fragrances interact with body odor to change social olfactory information. We investigated whether (a) aversive conditioning could induce learned responses to individual body odors, (b) the addition of perfume worn by the odor donor alters this effect, and (c) this conditioned response affects the interpretation of visual information. Participants underwent classical (electric shock) conditioning with perfumed or unperfumed body odors as stimuli. During acquisition phase, we monitored galvanic skin response. After conditioning, participants rated the emotions of neutral faces in the presence of both conditioned and control odors. Increased galvanic skin response activity when smelling the conditioned odor on unshocked trials ( p = .041) suggested successful conditioning. We found no differences in conditioning success between perfumed and unperfumed body odors, suggesting that perfume does not mask individual differences. Participants perceived neutral faces as more surprised when smelling the conditioned odor ( p = .001), suggesting that olfactory stimuli may modify social perception in other modalities. Sharing emotional experiences with another individual, necessarily in the presence of their body odor, may affect future interactions with and assessments of that person.

The role of the Major Histocompatibility Complex in the Immunobiology of Self-Aromas

The authors present a review of the immunobiological mechanism of olfaction considering current and relevant information about the odors released by vertebrate organisms, and its association with the immune system. Many theories concerning to the type and the quality of the molecular structures of odors or aromas have been proposed, but the most important are the steric theory of odor and the vibration theory of odor. Several techniques based on brain activities have been studied in association with sensorial processes, and they were particularly important to evaluate the physiologycal effects of odors. Molecules of the Major Histocompatibility Complex (MHC) have been identified in individual body odors (odortype), and volatile compounds of the MHC were easily detected in the urine of mice. The major relevant studies related to the Olfactory Receptors (ORs) and the MHC were conducted in mice models, and these studies demonstrated that the odortype has an important role in the partner choice, as well as in the relationship between mothers and their offsprings. A sensorial gas apparatus called “eletronic nose” has been used as an instrument capable of detecting molecules of the MHC in the odortypes. In conclusion, the diversity of self-aromas or odortypes seems to be generated in the context of the MHC, and consequently varies according to the genetic background of the individual. In spite of several controversies among scientists concerning to the immunobiology of the aromas, mostly in human beings, we could hypothesize that similar types of odors could influence the human choice. Future studies are necessary to clarify and confirm these findings in human beings.

The volatilome \u2013 investigation of volatile organic metabolites (VOM) as potential tumor markers in patients with head and neck squamous cell carcinoma (HNSCC)

BackgroundDifferent organisms such as bacteria, molds and humans produce and release a relative unknown class of metabolites which are responsible for the individual olfactory pattern. These volatile organic metabolites (VOM) represent a kind of biosignature that reflects the sum of all multifactorial influences, including genetics, environmental factors, nutritional and disease status. As a result of pathological processes the individual body odor can be influenced by newly produced or altered compositions of the VOM. Until now, human VOM have been detected in various body media, such as on the skin, in the exhaled air as well as in body fluids such as saliva, mother’s milk, sweat, blood and urine.MethodsIn this retrospective case-control study urinary VOM of 53 therapy-naive patients with head and neck squamous cell carcinoma (HNSCC) and 82 healthy controls were semi-quantified by headspace solid-phase micro extraction (SPME) gas chromatography (GC) mass spectrometry (MS). At first, the procedure was optimized in respect to the extraction parameters. By using Student’s t-test significant differences in the VOM pattern with the corresponding p-values were obtained. For multivariate metabolite pattern recognition the hierarchical cluster analysis by Ward was applied, followed by the supervised partial least squares-discriminant analysis (PLS-DA).ResultsIn total 81 VOMs could identified in the urine samples of all study participants, of which 25 were significantly increased and of which were 10 significantly reduced in HNSCC-patients compared to the controls. In addition, the multivariate statistics confirmed that on the basis of the renal excreted pattern of the volatile metabolites a high discrimination can be carried out between patients with a tumor in the head and neck region and controls. The substance group of the saturated, unbranched aldehydes makes a substantial contribution in this context.ConclusionsThe systematic pattern analysis of urinary VOMs appears to have potential clinical application as a diagnostic tool for cancer, especially HNSCC.

Effect of fragrance use on discrimination of individual body odor.

Previous research suggests that artificial fragrances may be chosen to complement or enhance an individual’s body odor, rather than simply masking it, and that this may create an odor blend with an emergent quality that is perceptually distinguishable from body odor or fragrance alone. From this, it can be predicted that a new emergent odor might be more easily identified than an individual’s body odor in isolation. We used a triangle test paradigm to assess whether fragrance affects people’s ability to distinguish between individual odors. Six male and six female donors provided axillary odor samples in three conditions (without fragrance, wearing their own fragrance, and wearing an assigned fragrance). In total, 296 female and 131 male participants selected the odd one from three odor samples (two from one donor, one from another; both of the same sex). We found that participants could discriminate between the odors at above chance levels in all three odor conditions. Olfactory identification ability (measured using Sniffin’ Sticks) positively predicted discrimination performance, and sex differences in performance were also observed, with female raters being correct more often than men. Success rates were also higher for odors of male donors. Additionally, while performance was above chance in all conditions, individual odor discrimination varied across the three conditions. Discrimination rate was significantly higher in the “no fragrance” condition than either of the fragranced conditions. Importantly, however, discrimination rate was also significantly higher in the “own fragrance” condition than the “assigned fragrance” condition, suggesting that naturally occurring variance in body odor is more preserved when blended with fragrances that people choose for themselves, compared with other fragrances. Our data are consistent with the idea that fragrance choices are influenced by fragrance interactions with an individual’s own body odor.

The Pharmacogenetics of Body Odor: As Easy as ABCC?

ABCC11 genotype affects apocrine secretory cell function and determines individual body odor phenotype. Rodriguez et al. have applied genetic epidemiology using predetermined phenotype data to demonstrate an association between a single-nucleotide polymorphism (rs17822931) and the human behavior of deodorant application. Individuals with the ABCC11 genotype predicting a nonodorous phenotype report a significantly lower frequency of deodorant use.

Do Trained Dogs Discriminate Individual Body Odors of Women Better than Those of Men?*

Scent identification lineups using dogs are a potentially valuable forensic tool, but have been dismissed by some critics because of cases where a false identification was shown to have occurred. It is not known, however, why dogs appear to make more false indications to the odors of some persons than of others. In this study, human genders were compared as to the degree their individual odors are distinguishable or "attractive" to dogs. Six dogs were trained to smell an individual's hand odor sample and then find the matching hand odor sample in a lineup of five odors. Using one-gender lineups and two-gender lineups with different gender ratios, it was found that dogs trained for the study identified individual women's hand odors more accurately than those of men. It is hypothesized that this is either because of differences in chemical compounds making discrimination of women's odors easier, or because of greater "odor attractiveness" of women's scents to dogs.

The Possible Role of the Uropygial Gland on Mate Choice in Domestic Chicken

In avian mating systems, male domestic fowls are polygamous and mate with a number of selected members of the opposite sex. The factors that influence mating preference are considered to be visual cues. However, several studies have indicated that chemosensory cues also affect socio-sexual behavior, including mate choice and individual recognition. The female uropygial gland appears to provide odor for mate choice, as uropygial gland secretions are specific to individual body odor. Chicken olfactory bulbs possess efferent projections to the nucleus taeniae that are involved in copulatory behavior. From various reports, it appears that the uropygial gland has the potential to act as the source of social odor cues that dictate mate choice. In this review, evidence for the possible role of the uropygial gland on mate choice in domestic chickens is presented. However, it remains unclear whether a relationship exists between the uropygial gland and major histocompatibility complex-dependent mate choice.

Red junglefowl have individual body odors

Olfaction may play an important role in regulating bird behavior, and has been suggested to be involved in feather-pecking. We investigated possible differences in the body odors of red junglefowl females by using an automated olfactometer which assessed the ability of trained mice to discriminate between the odors of uropygial gland secretions (the main carrier of potential individual odors in chickens) of six feather-pecked and six non-pecked birds. All mice were clearly able to discriminate between all individual red junglefowl odors, showing that each bird has an individual body odor. We analyzed whether it was more difficult to discriminate between the odors of two feather-pecked, or two non-pecked birds, than it was to discriminate between the odors of two randomly selected birds. This was not the case, suggesting that feather-pecked birds did not share a common odor signature. Analyses using gas chromatography and mass spectrometry showed that the composition of aliphatic carboxylic acids in uropygial gland secretions differed consistently between individuals. However, chemical composition did not vary according to feather-pecking status. We conclude that red junglefowl have individual body odors which appear to be largely based on differences in the relative abundance of aliphatic carboxylic acids, but there is no evidence of systematic differences between the body odors of pecked and non-pecked birds.

Towards a neuroscience of love: olfaction, attention and a model of neurohypophysial hormone action

The significance of odor in mediating affective state in humans has become increasingly recognized in recent years (Weber and Heuberger, 2008). In particular, human body odor or its constituent compounds influence general mood (e.g., Chen and Haviland-Jones, 1999), attentional state (Jacob et al., 2001) or proclivity toward other individuals, such as in a mate searching context (Saxton et al., 2008). Such effects are usually sex-specific, and women in particular appear more sensitive to, and cognizant of, olfactory cues (e.g., Havlicek et al., 2008). In a recent paper, Lundstrom and Jones-Gotman (2009) used women's odor perception of male body odor as a novel approach for investigating the neurobiological basis of romantic love. Their idea was that the extent to which women could identify the body odor of partners compared with those of other men might shed light on the mechanisms underlying directed attention toward partners when in love. They tested the ability of 20 coupled women to recognize individual body odor using a three-alternative forced-choice paradigm. Women were asked to identify their partner's axillary odor, or that of a male friend, from among three odors where the other two odors were of unfamiliar men. Separately, the women completed a psychometric instrument, the Passionate Love Scale, which estimates the degree to which they are in love with their partner. Women who scored highly on this scale were found to have lower success in identifying their male friends, but in contrast, there was no similar correlation for odor recognition of partners. There was also no similar correlation between their passionate love score and identification of female friends, indicating a sex-specific effect. Lundstrom and Jones-Gotman argue that this specific reduction in recognition of opposite-sex friends supports the deflection theory for the psychological mechanism of romantic love. The deflection theory proposes that love is accompanied by a decrease in attention toward opposite-sex individuals, in contrast with an alternative idea which postulates intensified attention toward the romantic partner (although, as they acknowledge, these need not be mutually exclusive). Furthermore, they suggest a testable mechanism for this effect through antagonistic effects of the neurohypophysial hormones oxytocin and vasopressin, whereby elevated oxytocin levels, promoted by romantic love and attachment, causes a reduction in levels of bound vasopressin and an associated fall in attention toward individuals of the opposite sex. The race is now on to test this intriguing hypothesis, and to examine whether the effect holds for male responses to female stimuli. Research in this area will also benefit from using tasks that measure verbalized hedonic perception or subliminal hedonic “decisions” manifested in affective change, in addition to those addressing cognitive processes such as verbal labeling and levels of olfactory recognition. Humans do indeed recognize their own odors, or those of partners, relatives and friends at levels higher than chance (Lenochova and Havlicek, 2008). However, level of performance is significantly lower compared to recognition based on visual appearance or voice: one can imagine how different our world would be if we misidentified our partner as often as one-half to two-thirds of the time (Hold and Schleidt, 1977). Use of hedonic rating scales, measurement of chemosensory event-related potentials (CSERPs) or functional neuroimaging would be illuminating; all these approaches have previously been successfully employed in tests of perception of bodily odors. For example, hedonic ratings (e.g., Roberts et al., 2008; Wedekind et al., 1995) and CSERPs (Krauel et al., 1998; Pause et al., 2006) have been used to explore relationships between genetic dissimilarity in potential mates in perception of axillary odors, while functional imaging has been used to investigate effects of 16-androstenes, constituents of axillary odor (e.g., Gulyas et al., 2004). Through the use of such techniques, olfactory processing may hold the key to understanding the neuroscientific basis of love.

Olfactory Fingerprints for Major Histocompatibility Complex-Determined Body Odors

Recognition of individual body odors is analogous to human face recognition in that it provides information about identity. Individual body odors determined by differences at the major histocompatibility complex (MHC or H-2) have been shown to influence mate choice, pregnancy block, and maternal behavior in mice. Unfortunately, the mechanism and extent of the main olfactory bulb (MOB) and accessory olfactory bulb (AOB) involvement in the discrimination of animals according to H-2-type has remained ambiguous. Here we study the neuronal activation patterns evoked in the MOB in different individuals on exposure to these complex, biologically meaningful sensory stimuli. We demonstrate that body odors from H-2 disparate mice evoke overlapping but distinct maps of neuronal activation in the MOB. The spatial patterns of odor-evoked activity are sufficient to be used like fingerprints to predict H-2 identity using a novel computer algorithm. These results provide functional evidence for discrimination of H-2-determined body odors in the MOB, but do not preclude a role for the AOB. These data further our understanding of the neural strategies used to decode socially relevant odors.

PM processing of titanium-nickel shape memory alloy: S.M.Green et al. (University of Nottingham, Nottingham, UK.) Powder Metall., vol 40, no 1, 1997, 43–47

Pause, B. M., K. Haberkorn, F. Eggert, W. MÜLler-Ruchholtz, H. J. Bestmann and R. Ferstl. Fractionation and bioassay of human odor types. Physiol Behav 61(6) 957–961, 1997.—Human urine samples were fractionated to examine the contribution of volatiles to the individual body odor. The samples were obtained from 4 male donors and fractionated using a vacuum technique. The volatiles from the chemical fractions were analyzed using the CLSA technique and gas chromatography. Thereafter, these fractions were tested in a computer-controlled olfactometer by trained rats. Although the rats were able to discriminate the distillation residue, they could not recognize the urine odor in the distilled fraction. The results of gas chromatography indicate a continuous release of volatile constituents in the distillation residue.

Fractionation and Bioassay of Human Odor Types

Pause, B. M., K. Haberkorn, F. Eggert, W. MÜLler-Ruchholtz, H. J. Bestmann and R. Ferstl. Fractionation and bioassay of human odor types. Physiol Behav 61(6) 957–961, 1997.—Human urine samples were fractionated to examine the contribution of volatiles to the individual body odor. The samples were obtained from 4 male donors and fractionated using a vacuum technique. The volatiles from the chemical fractions were analyzed using the CLSA technique and gas chromatography. Thereafter, these fractions were tested in a computer-controlled olfactometer by trained rats. Although the rats were able to discriminate the distillation residue, they could not recognize the urine odor in the distilled fraction. The results of gas chromatography indicate a continuous release of volatile constituents in the distillation residue.

Soluble MHC class I molecules in human body fluids

Apart from their well-known function of antigen presentation in the form of peptides, major histocompatibility antigens (MHC) have been found to be unique markers of individual body odors in murine experimental models. In the current study we examined the nature and expression of soluble human MHC class I molecules in body fluids. Biochemical analysis of affinity purified serum class I molecules revealed a variety of molecules within the molecular weight region of 45 to 21 kD. SDS-Western blotting of HLA derived from hepatocytes and spleen cells suggested that much of the small molecular mass fraction of sHLA (< 45 kD) found in serum is derived from the liver. sHLA were detected and quantitated in serum, plasma, urine, cerebrospinal fluid, and sweat. No sHLA were detectable in cerebrospinal fluid (n = 20). In addition, sHLA was measured in serum of women during the menstrual cycle. A significant increase in sHLA was observed during the first half of the cycle, suggesting that sexual hormones may increase sHLA concentration. The observed increase was most prominent in women that were HLA-A24.

Responses of female rats to the individual body odors of male rats

Sixteen receptive females were first observed during a 10-min habituation period that consisted of presenting them with two empty cardboard tubes housing the odors from the same male. After the habituation period one tube was removed and replaced with a tube housing the odors from a novel male. During the second 10-min testing period, the females spent a significantly greater amount of time with the novel males’ odor, after both 5 min (p &lt;.02) and 10 min (p &gt;.01) of testing. The females’ response to the novel males’ odor indicated that female rats can use olfactory cues to discriminate between individual male rats.