fNIRS neuroimaging in olfactory research: A systematic literature review

There are a number of key features which make olfaction difficult to study; subjective processes of odor detection, discrimination and identification, and individualistic odor hedonic perception and associated odor memories. In this systematic review we explore the role functional near-infrared spectroscopy (fNIRS) has played in understanding olfactory perception in humans. fNIRS is an optical neuroimaging technique able to measure changes in brain hemodynamics and oxygenation related to neural electrical activity. Adhering to PRISMA guidelines, results of this search found that generally the majority of studies involving healthy adult subjects observed increased activity in response to odors. Other population types were also observed, such as infants, individuals with autism, attention deficit hyperactivity disorder (ADHD), post-traumatic stress disorder (PTSD), mild cognitive impairment (MCI) and dysosmia. fNIRS coverage heavily favored the prefrontal cortex, temporal and parietal regions. This review finds that odor induced cortical activation is dependent on multiple factors, such as odorant type, gender and population type. This review also finds that there is room for improvement in areas such as participant diversity, use of wearable fNIRS systems, physiological monitoring and multi-distance channels

State of the art and major clinical outcomes of the use of essential oils in the performance of athletes: a systematic review

Introduction: Essential oils (EOs) has been around for years and studies show that they are useful in treating various diseases and improving health. According to the United States OEs Handbook, OEs are a vital part of complementary and alternative medicine and the positive findings of OEs are now becoming a trend in sports performance research for athletes. Objective: It was to list the main scientific findings of clinical studies on the effectiveness of essential oils in improving the health and sports performance of athletes. Methods: A total of 195 articles were found involving clinical studies of the influence of essential oils on human health. After this process, 42 articles were included and 32 were discussed in this study. The present study was prepared following the systematic review guidelines – PRISMA. Results and Conclusion: Essential oils have been used in medicine for decades and have been proven to eliminate toxins from the body. They are also shown to improve the body's ability to absorb essential vitamins and nutrients. In this sense, the application of these oils not only helps to prevent and heal sports injuries but also to stimulate and relax the mind and body, leading to higher levels of fitness. Because of these inherent properties of EOs, there is growing interest in using them to tone the body and mind in a variety of ways, such as musculoskeletal preparation, injury prevention, and improving mood and performance to achieve a higher success rate in sports. sports and fitness, as well as post-exertion recovery. They can be used as an aid to make recovery faster, reducing the effect of fatigue and raising the energy level of the mind and body

Forefront users\u2019 experience evaluation by employing together virtual reality and electroencephalography: A case study on cognitive effects of scents

Scents have the ability to affect peoples\u2019 mental states and task performance with to different extents. It has been widely demonstrated that the lemon scent, included in most all-purpose cleaners, elicits stimulation and activation, while the lavender scent elicits relaxation and sedative effects. The present study aimed at investigating and fostering a novel approach to evaluate users\u2019 experience with respect to scents\u2019 effects through the joint employment of Virtual Reality and users\u2019 neurophysiological monitoring, in particular Electroencephalography. In particular, this study, involving 42 participants, aimed to compare the effects of lemon and lavender scents on the deployment of cognitive resources during a daily life experience consisting in a train journey carried out in virtual reality. Our findings showed a significant higher request of cognitive resources during the processing of an informative message for subjects exposed to the lavender scent with respect to the lemon exposure. No differences were found between lemon and lavender conditions on the self\u2010reported items of pleasantness and involvement; as this study demonstrated, the employment of the lavender scent preserves the quality of the customer experience to the same extent as the more widely used lemon scent

A longitudinal study of cortical EEG to olfactory stimulation : involving inter- and intra- subjective responses

This thesis forms the largest and most systematic study of the topographical EEG response to odour. The evolutionary history of the olfactory sense is briefly presented and its relevance to humans in the present day is considered. This thesis examines the information processing that occurs in this sensory system. The type of processing that the olfactory system utilises at each anatomical stage is discussed. The character of olfactory information that may reach neocortical levels in humans is considered in the light of the technology available to detect such information. The neurogenesis of the EEG is considered, together with questions concerning its postulated functional significance. The empirical work carried out uses the most advanced methodology for this type of study. The large number of odourants and subjects, combined with the longitudinal element, make this the most ambitious study of this nature undertaken. The issues surrounding the analysis and interpretation of EEG data arc fully discussed and the impact of Chaos theory is considered. Five major analysis techniques were used on the data collected, but largely negative findings arc reported. The reasons for the failure of this experimental paradigm are discussed and improvements arc suggested for future work. The major contribution of this thesis lies in its exploration of the assumptions of the EEG response to odour. The thesis notes the lack of a conceptual framework that has hindered progress in the area of the "odour" EEG. Recent developments in neural network theory and Chaos theory are highlighted as possible alternative approaches to the modelling and understanding of the olfactory system

Smells, well-being and the built environment

In this Research Topic, we aimed to collect a range of contributions to understand the emotional and wellbeing responses resulting from smells in different public spaces (museums, highstreets, heritage buildings, food districts, neighborhoods, squares, etc.) to inform future spatial design and management. The articles in this Research Topic are presented according to three types of contributions: reviews and conceptual analyses, empirical research in fieldwork, in laboratory studies and technological applications. Reviews and Conceptual Analyses Xiao et al. reviewed smellscape research studies conducted in the past 10 years to identify the challenges and related areas of future research, namely smell archives and databases, social justice within odor control and management, and research into advanced building materials. Spence reviewed the changing role of smells in the built environment from negative associations with sanitation to meaningful personal and cultural associations with memories and experiences which led to an evaluation of different approaches in examining the impact of smells on people's mood or wellbeing and the challenges of researching smells in the multi-sensory environment. Moving from the sick building sydrome to sick transport sydrome, Spence further reviewed the smells in transport environments as aesthetic and functional, and suggests challenges for future transportation to produce a more tangible vision to integrate smells in the design process to achieve the right balance of olfactory stimulation. Looking backwards to scented past, Bembibre and Strlič make the case for the need of knowledge exchange and interdisciplinary interpretation of findings in the field of olfactory heritage, providing an overview of methodological and museal studies as well as challenges associated with historical scent reconstruction. Empirical Research - Fieldwork Pálsdóttir et al. carried out a field study with participants suffering from stress-related mental disorders and explored how they would describe their smellscape perception of a garden in the context of a nature-based rehabilitation intervention. In a different field study, de Groot investigated whether ambient scents could affect customers' subjective experience and spending behavior in an experiment with customers of a second-hand clothing store. The author concluded that for that to happen, the smellscape should have a meaningful link to the physical context. Masaoka et al. present the results of a study conducted to examine whether continuous odor stimuli associated with autobiographical memories could activate olfactory areas in the brain of older adults and assess whether this odor stimulation could have a protective effect against age-related cognitive decline. Empirical Research - Laboratory Studies and Technological Applications Masaoka et al. investigated the potential protective effect from age-related cognitive decline of continuous odor stimuli associated with autobiographical memories and whether those could activate the above olfactory areas in older adults. Jiang et al. used blood pressure, pulse rate, EEG, POMS, and SD data to examine the odor-visual effects of the Primula forbesii Franch compared with the non-fragrant Primula malacoides Franch on the physiological and psychological state of Chinese female college students in the indoor environment. Courrèges et al. examined the correlations between odor and texture in users' perceptions of cosmetic creams cross-culturally, in laboratory conditions, using questionnaires, minimizing the impacts of branded messages from the packing and retail spaces. Amores et al. discussed the design and technical implementation of Essence- a smartphone-controlled wearable device that monitors users' EEG and real-time sleep staging algorithm to release scents to interact with users- in home-based sleep environments. The articles included in this Research Topic represent a nice balance between the theoretical reviews, empirical studies and laboratory research, showing the vibrance and dynamic in this research field as well as new technological developments such as extended reality, emotional sensors (i.e. EEG, GSR) and odor monitoring devices. New insights are drawn into the theoretical frameworks to understand relationships between smells, wellbeing and emotions, behaviors and physiological aspects; methodological approaches to measure smell triggered emotions, experiences, and quality of life; practical explorations on the process and challenges of using smells to influence user experiences in the built environment

Forefront users’ experience evaluation by employing together virtual reality and electroencephalography: a case study on cognitive effects of scents

Scents have the ability to affect peoples’ mental states and task performance with to different extents. It has been widely demonstrated that the lemon scent, included in most all-purpose cleaners, elicits stimulation and activation, while the lavender scent elicits relaxation and sedative effects. The present study aimed at investigating and fostering a novel approach to evaluate users’ experience with respect to scents’ effects through the joint employment of Virtual Reality and users’ neurophysiological monitoring, in particular Electroencephalography. In particular, this study, involving 42 participants, aimed to compare the effects of lemon and lavender scents on the deployment of cognitive resources during a daily life experience consisting in a train journey carried out in virtual reality. Our findings showed a significant higher request of cognitive resources during the processing of an informative message for subjects exposed to the lavender scent with respect to the lemon exposure. No differences were found between lemon and lavender conditions on the self-reported items of pleasantness and involvement; as this study demonstrated, the employment of the lavender scent preserves the quality of the customer experience to the same extent as the more widely used lemon scent

The effects of e-store atmosphere on consumers' buying behavior

Consumer behavior in traditional stores is already a vastly studied field of research. In contradiction to consumer behavior in a e-retail environment, which is still lacking a lot of research and has to be studied more. This literature review tries to better understand the dynamics of consumer behavior in a e-retail environment and to give an overall introduction to designing a functional e-retail website. This is done by researching the effects of atmospherics in a traditional store environment and adapting those principles to the e-retail environment. Studies on e-retail environment are also used as much as possible. The findings of this literature review suggest that many theories about traditional store related consumer behavior have been proven, but many of those related to e-retail are just assumptions and more research has to be done. Fortunarely there are some principles that have been also proven in a e-retail environment and it is a good basis to create a functioning web store for a company

The artificially scented ape: Investigating the role of fragrances and body odours in human interactions

It was long believed that humans were unable to utilise the odours of conspecifics to co-ordinate social interactions in ways in which other species appear to be capable. However, a surge in interest in human social olfaction has recently challenged this view. The numerous studies conducted in this area have found that multiple state and trait related cues can be detected in body odour. Furthermore, many studies indicate that women are often more sensitive to these cues, and that sensitivity can be associated with fertility, findings that are consistent with sex differences in reproductive effort and benefits of choosiness in mate-searching. Since previous studies in this area have usually addressed the potential for humans to use olfactory communication in a comparable manner to other mammals, they typically involve collection and assessment of ‘natural’ odour. That is, they explicitly exclude the possibility of ‘contamination’ of odour samples by artificial fragrances. However, humans have used artificial fragrances for millennia, across many different cultures. This raises the question of whether widespread fragrance use may affect or disrupt the detection of this information in modern humans. The first aim of this thesis was to address this question by investigating how fragrance use may mediate the detection of olfactory information in humans. As well as providing further evidence for sex differences in the assessment of olfactory cues, and for the role of olfaction in real world partner choice, the findings herein suggest that fragrance may act differently on different information being assessed, potentially masking accurate assessment of certain traits (such as masculinity), while fragrance choice and preferences may be important in complementing other olfactory information (such as the general distinguishability of an individuals’ odour profile). A second aim of the thesis was to develop a scale in order to more accurately describe the varying perceptual qualities of human body odour – in other words to map human body odours. This work was conducted alongside perfumers in order to benefit from their expertise in olfactory perception and semantic labelling of odours. The development of such a scale could enable improved understanding of the perceptual qualities of human odour, making it possible to link specific perceptual qualities to specific cues (e.g. symmetry, masculinity, sex) or to manipulate odours based on perceptual qualities in experimental settings, and has direct practical implications for fragrance designers and for improving the ability of individuals to choose fragrance products that suit their odour profile. The second section of the thesis focuses on the effects of odours on the individual wearer as well as on perceivers in the environment. One study is presented which investigates the role of malodour reduction compared to the addition of fragrances in perceptions of confidence and attractiveness, finding that both the reduction of malodour and the addition of fragrance appear to be important for confidence as rated by others in the environment. The final study presented in the thesis examines a hitherto un-investigated role of olfaction during human pregnancy. The rationale for the study is based on evidence suggesting that in certain non-human species, which also show bi-parental care of offspring, there may be a role for chemical, or odour based, communication which underpins behavioural and endocrinological changes related to infant care behaviours in males. The study found little evidence to support the presence of analogous olfactory signalling during human pregnancy, though the findings are discussed in light of methodological changes which, if made in future studies, may result in different outcomes. The thesis concludes with a discussion of the importance of continuing to investigate various forms of olfactory communication, as well as improving our understanding of odours through the mapping of their perceptual qualities, and finally further examining the ways in which various fragranced products, which are widely used in society, may affect all of this. Future directions for this area of research are discussed. This line of investigation will, I argue, enable us to finally establish the true role of olfaction in contemporary social environments

Restorative effects of biophilic workplace and nature exposure during working time: A systematic review

The work environment plays a crucial role in the health and performance of employees. The growing interest in workers’ well-being has driven the inclusion of nature in workplaces, despite many employees spending most of their time indoors, away from nature. Studies show that biophilic design in offices can have positive effects and promote workers’ well-being. However, research on the beneficial effects of nature exposure in the workplace is limited and scattered. Thus, the aim of this systematic review was to consolidate current knowledge on the restorative effects of nature exposure on workers during work activities. Different types of exposure, both outdoors and indoors, were considered, with a focus on outcomes related to well-being, motivation, job satisfaction, and work performance. Out of the initially identified 1225 articles, only 16 met the criteria for analysis. Although the analysed studies provided compelling evidence regarding the restorative effects of nature exposure in the workplace, the review also points out gaps and limitations concerning the number of specific studies in this area and the need to adequately assess the sensory dimensions involved in these effects. Conducting more comprehensive and multidimensional investigations into the impacts of nature on the work environment could contribute to guiding more effective design strategies and creating healthier and more productive workplaces for employees.info:eu-repo/semantics/publishedVersio