Olfactory Landscape Research Articles

Conservation and selective pressures shaping baleen whale olfactory receptor genes supports their use of olfaction in the marine environment.

The relative importance of various sensory modalities can shift in response to evolutionary transitions, resulting in changes to underlying gene families encoding their reception systems. The rapid birth-and-death process underlying the evolution of the large olfactory receptor (OR) gene family has accelerated genomic-level change for the sense of smell in particular. The transition from the land to sea in marine mammals is an attractive model for understanding the influence of habitat shifts on sensory systems, with the retained OR repertoire of baleen whales contrasting with its loss in toothed whales. In this study, we examine to what extent the transition from a terrestrial to a marine environment has influenced the evolution of baleen whale OR repertoires. We developed Gene Mining Pipeline (GMPipe) (https://github.com/AprilJauhal/GMPipe), which can accurately identify large numbers of candidate OR genes. GMPipe identified 707 OR sequences from eight baleen whale species. These repertoires exhibited distinct family count distributions compared to terrestrial mammals, including signs of relative expansion in families OR10, OR11 and OR13. While many receptors have been lost or show signs of random drift in baleen whales, others exhibit signs of evolving under purifying or positive selection. Over 85% of OR genes could be sorted into orthologous groups of sequences containing at least four homologous sequences. Many of these groups, particularly from family OR10, presented signs of relative expansion and purifying selective pressure. Overall, our results suggest that the relatively small size of baleen whale OR repertoires result from specialisation to novel olfactory landscapes, as opposed to random drift.

Study on the Olfactory Landscape of the Shichahai Area in Beijing

Study on the Olfactory Landscape of the Shichahai Area in Beijing

Plant Configuration and Landscape Construction in Blind Gardens

In daily life, landscape design often takes able-bodied people as considerations, while ignoring the blind people who lack vision. According to the blind people's psychological needs and the need for space and landscape, based on taking into account the safety of the blind people and the integrity of the landscape structure, The blind garden plant configuration and landscape construction are carried out based on the principles of sex and accessibility. The content of landscape design includes the design of olfactory landscape, tactile landscape, visual landscape, and auditory landscape; barrier-free design mainly relies on barrier-free design of terrain, road design and public facilities; In order to arouse society's attention to the blind and improve urban gardens. The design theory enables the blind to have a space suitable for their own leisure and entertainment activities, enriching their daily lives, and discusses the design principles and plant configurations of the blind garden construction, hoping to provide some reference for the construction of blind landscapes.

Indo-Islamicate Perfumes in Early Modern India: Textualisation, Transmissions and Assimilations

This article brings to focus the material life of early modern perfumes in the Indian subcontinent. It offers a ‘documentary archaeology’ by foregrounding texts that recorded perfumes in their stage of production and preparation. By studying this corpus, it presents perfumes as a locale where craft, technology and labour interacted with each other in blending scientific knowledge with the natural landscape. With a focus on textualised perfume recipes, listed aromatic ingredients and distillation methods, it examines the various shifts, transitions, cross-cultural material borrowings and finally the assimilations that occurred in the olfactory landscape of an Indo-Islamicate political empire, especially during the Mughal rule in India. A rich perfume-repository, where divergences and acculturations took place could be best understood by identifying the various methods and processes in which material practices and literary traditions were shaping each other. In understanding this, it goes beyond the ephemerality of perfumes and argues in favour of a craft that was labour-intensive, skill-based, technologically innovative and culturally adaptive. Finally, it explores the diversification of its forms, significance of receptacles and amplification of its production, both in texts and in practice, to highlight the pervasive materiality of Indo-Islamicate perfumes in early modern India.

Recruitment of grid-like responses in human entorhinal and piriform cortices by odor landmark-based navigation

Olfactory navigation is universal across the animal kingdom. Humans, however, have rarely been considered in this context. Here, we combined olfactometry techniques, virtual reality (VR) software, and neuroimaging methods to investigate whether humans can navigate an olfactory landscape by learning the spatial relationships among discrete odor cues and integrating this knowledge into a spatial map. Our data show that over time, participants improved their performance on the odor navigation task by taking more direct paths toward targets and completing more trials within a given time period. This suggests that humans can successfully navigate a complex odorous environment, reinforcing the notion of human olfactory navigation. fMRI data collected during the olfactory navigation task revealed the emergence of grid-like responses in entorhinal and piriform cortices that were attuned to the same grid orientation. This result implies the existence of a specialized olfactory grid network tasked with guiding spatial navigation based on odor landmarks.

A Novel Approach to Visualizing Olfactory Landscapes

This article focuses on the exploration and mapping of olfactory landscapes. For this purpose, a brief introduction to the social and cultural significance of odors in the 'Western world', especially in the sciences and philosophy, is first given and the visuality paradigm of these societies is highlighted. Subsequently, olfactory landscapes are integrated into a basic social constructivist-phenomenological concept to create a theoretical basis for the discussion of these special landscapes. This is accompanied by a brief discussion of current approaches to smellscape survey and the particular mapping approach of Kate McLean (in comparison with the here used approach), which forms the basis for the mapping and presentation presented here. This presented approach was developed and tested in a master's thesis on the smellscape of Christmas and Christmas markets. An extended signature system and the detailed procedure for a smellwalk are presented.

Smellscape of a Pompeian neighborhood

AbstractSmelling and other sensations that are often considered solely physiological phenomena are in fact deeply influenced by culture and history, and without understanding the ancient sensory landscape, our knowledge of the past inevitably remains limited. This paper explores the olfactory nuisances in one Pompeian city block (IX,3) and its immediate neighbors. I examine the area's stenches by tracing and mapping the sources of smells, focusing on those that in previous scholarship have been considered to render ancient towns foul smelling. The analysis contests the views of malodorous Roman urban space presented in previous studies and suggests that the smellscape of urban Pompeii was not a constant reek but milder and manageable. However, the analysis also reveals that social hierarchies and power relations played a part in Pompeian odor control, and the olfactory landscape was not the same for all inhabitants.

The Olfactory Landscape Concept: A Key Source of Past, Present, and Future Information Driving Animal Movement and Decision-making.

Odor is everywhere, emitted across the landscape from predators, prey, decaying carcasses, conspecifics, vegetation, surface water, and smoke. Many animals exploit odor to find food, avoid threats, and attract or judge potential mates. Here, we focus on odor in terrestrial ecosystems to introduce the concept of an olfactory landscape: real-time dynamic olfactory contours reflecting the patchy distribution of resources and risks, providing a key source of information used by many animals in their movement and decision-making. Incorporating the olfactory landscape into current frameworks of movement ecology and animal behavior will provide a mechanistic link to help answer significant questions about where, why, and when many animals move, and how they do so efficiently in both space and time. By understanding how animals use the olfactory landscape to make crucial decisions affecting their fitness, we can then manipulate the landscape to modify ecological interactions and, ultimately, ecosystem consequences of these interactions.

Unique neural coding of crucial versus irrelevant plant odors in a hawkmoth.

The sense of smell is pivotal for nocturnal moths to locate feeding and oviposition sites. However, these crucial resources are often rare and their bouquets are intermingled with volatiles emanating from surrounding 'background' plants. Here, we asked if the olfactory system of female hawkmoths, Manduca sexta, could differentiate between crucial and background cues. To answer this question, we collected nocturnal headspaces of numerous plants in a natural habitat of M. sexta. We analyzed the chemical composition of these headspaces and used them as stimuli in physiological experiments at the antenna and in the brain. The intense odors of floral nectar sources evoked strong responses in virgin and mated female moths, most likely enabling the localization of profitable flowers at a distance. Bouquets of larval host plants and most background plants, in contrast, were subtle, thus potentially complicating host identification. However, despite being subtle, antennal responses and brain activation patterns evoked by the smell of larval host plants were clearly different from those evoked by other plants. Interestingly, this difference was even more pronounced in the antennal lobe of mated females, revealing a status-dependent tuning of their olfactory system towards oviposition sites. Our study suggests that female moths possess unique neural coding strategies to find not only conspicuous floral cues but also inconspicuous bouquets of larval host plants within a complex olfactory landscape.

Seeing smell: the structural underpinnings of insect olfaction

In a landmark paper, del Mármol et al. describe cryo-electron microscopy (cryo-EM) structures of an insect olfactory receptor (OR) ion channel, detailing the mechanism by which odorants can directly gate ion flow and providing insights into how this incredibly diverse family of receptors have evolved to support insects navigating complex olfactory landscapes.

Effects of Multi-Component Backgrounds of Volatile Plant Compounds on Moth Pheromone Perception.

Simple SummaryIt is well acknowledged that some of the volatile plant compounds (VPC) naturally present in insect natural habitats alter the perception of their own pheromone when presented individually as a background to pheromone. However, the effects of mixing VPCs as they appear to insects in natural olfactory landscapes are poorly understood. We measured the activity of brain neurons and neurons that detect a sex pheromone component in a moth antenna, while exposed to simple or composite backgrounds of VPCs representative of the odorant variety encountered by this moth. Maps of activities were built using calcium imaging to visualize which brain areas were most affected by VPCs. In the antenna, we observed differences in VPC capacity to elicit firing response that cannot be explained by differences in stimulus intensities because we adjusted concentrations according to volatility. The neuronal network, which reformats the input from antenna neurons in the brain, did not improve pheromone salience. We postulate that moth olfactory system evolved to increase sensitivity and encode fast changes of concentration at some cost for signal extraction. Comparing blends to single compounds indicated that a blend shows the activity of its most active component, VPC salience seems more important than background complexity.The volatile plant compounds (VPC) alter pheromone perception by insects but mixture effects inside insect olfactory landscapes are poorly understood. We measured the activity of receptor neurons tuned to Z7-12Ac (Z7-ORN), a pheromone component, in the antenna and central neurons in male Agrotis ipsilon while exposed to simple or composite backgrounds of a panel of VPCs representative of the odorant variety encountered by a moth. Maps of activities were built using calcium imaging to visualize which areas in antennal lobes (AL) were affected by VPCs. We compared the VPC activity and their impact as backgrounds at antenna and AL levels, individually or in blends. At periphery, VPCs showed differences in their capacity to elicit Z7-ORN firing response that cannot be explained by differences in stimulus intensities because we adjusted concentrations according to vapor pressures. The AL neuronal network, which reformats the ORN input, did not improve pheromone salience. We postulate that the AL network evolved to increase sensitivity and to encode for fast changes of pheromone at some cost for signal extraction. Comparing blends to single compounds indicated that a blend shows the activity of its most active component. VPC salience seems to be more important than background complexity.

The smell of time in Ana Margarida de Carvalho’s Não se pode morar nos olhos de um gato: an outline of the human condition

This article analyses the olfactory landscapes represented in the novel Não se pode morar nos olhos de um gato (You can’t live in a cat’s eyes) by Ana Margarida de Carvalho (2016) reflecting upon the way in which the various smells described ‘presentify’ the multiple memories of the characters, emphasising their human dimension in a confinement scenario predisposed to completely dehumanising them. Using the theoretical contributions of Drobnick (2006a, 2006b), Reinarz (2014) and Byung-Chul Han (2015) among others, we examine how the smellscapes contribute to the construction of the characters’ identitary memory giving the narrative temporal cohesion.

New Residential Districts Ordering: from Language of Smells Description to the Space Sensory Order

The article analyzes the sensory aspects of urban life in one of the districts in the outskirts of Moscow. Revising the concepts of sensory ordering of space, I analyze the ways how urban dwellers in this district order the space by smell perception. I define three components of sensory ordering: i) the language of sensory experience, ii) ascription of meanings to space and smells localization, iii) actions aimed at supporting the desirable olfactory landscape. The process of creating this language and negotiations about the desirable olfactory landscape are based on adopting the special terms and visualizing the smells. This language allows to interact with the various agents on different levels of power, to transform and control the space. The production of meanings, based on smells, influences the district identity. Both positive and negative smell perception produce the value of the district, while the negative smells acts differently and devalues the other city territories. Citizens actions support the sensory normativity: through sensory patrolling (different ways of detecting the smells) and microordering (creating the cleanliness and freshness within neighborhoods). These ways of ordering sensory experience and creating olfactory landscape help to explain the interaction between district dwellers, the principles of how their agency is formed, and the principles of being responsible for the space.

Coding of odour and space in the hemimetabolous insect Periplaneta americana.

The general architecture of the olfactory system is highly conserved from insects to humans, but neuroanatomical and physiological differences can be observed across species. The American cockroach, inhabiting dark shelters with a rather stable olfactory landscape, is equipped with long antennae used for sampling the surrounding air-space for orientation and navigation. The antennae's exceptional length provides a wide spatial working range for odour detection; however, it is still largely unknown whether and how this is also used for mapping the structure of the olfactory environment. By selectively labelling antennal lobe projection neurons with a calcium-sensitive dye, we investigated the logic of olfactory coding in this hemimetabolous insect. We show that odour responses are stimulus specific and concentration dependent, and that structurally related odorants evoke physiologically similar responses. By using spatially confined stimuli, we show that proximal stimulations induce stronger and faster responses than distal ones. Spatially confined stimuli of the female pheromone periplanoneB activate a subregion of the male macroglomerulus. Thus, we report that the combinatorial logic of odour coding deduced from holometabolous insects applies also to this hemimetabolous species. Furthermore, a fast decrease in sensitivity along the antenna, not supported by a proportionate decrease in sensillar density, suggests a neural architecture that strongly emphasizes neuronal inputs from the proximal portion of the antenna.

Avian and rodent responses to the olfactory landscape in a Mediterranean cavity community

Animals rely on cues informing about future predation risk when selecting habitats to breed in. Olfactory information may play a fundamental role in the assessment of predation threats, because predators produce characteristic body odours, but the role of odours in habitat selection has seldom been considered. Here, we test whether fear of predation induced by odour cues may affect the settlement pattern of a Mediterranean cavity-dependent community of rodents and non-excavator hole-nesting birds. To test this hypothesis, we experimentally manipulated the perception of predation risk on a scale of patch by applying either odours of a carnivore predator (risky odour treatment), lemon essence (non-risky odour treatment) and a control non-odorous treatment and studied bird and rodent settlement patterns. Nest-box occupation probability differed across treatments so that species in the community settled in more numbers in control than in non-risky and than in risky odour-treated nest boxes. Concerning settlement patterns, control nest boxes were occupied more rapidly than nest boxes with odour information. Birds and rodents settled earlier in control than in risky odour-treated nest boxes, but their settlement pattern did not significantly vary between risky odour and non-risky odour-treated nest boxes. Our findings demonstrate that olfactory cues may be used to assess habitat quality by settling species in this community, but we cannot pinpoint the exact mechanism that has given rise to the pattern of preference by nest boxes.

Grid-like Neural Representations Support Olfactory Navigation of a Two-Dimensional Odor Space

Searching for food, friends, and mates often begins with an airborne scent. Importantly, odor concentration rises with physical proximity to an odorous source, suggesting a framework for orienting within olfactory landscapes to optimize behavior. Here, we created a two-dimensional odor space composed purely of odor stimuli to model how a navigator encounters smells in a natural environment. We show that human subjects can learn to navigate in olfactory space and form predictions of to-be-encountered smells. During navigation, fMRI responses in entorhinal cortex and ventromedial prefrontal cortex take the form of grid-like representations with hexagonal periodicity and entorhinal grid strength scaled with behavioral performance across subjects. The identification of olfactory grid-like codes with 6-fold symmetry highlights a unique neural mechanism by which odor information can be assembled into spatially navigable cognitive maps, optimizing orientation, and path finding toward an odor source.

КОНЦЕПТ ЗАПАХУ В ІТАЛІЙСЬКІЙ ПОЕЗІЇ ДРУГОЇ ПОЛОВИНИ ХХ СТОЛІТТЯ

The article focuses on the features of the concept smell and its structure. It also deals with creating a field model of the concept. The concept smell is analyzed on the example of Italian poetry of the second half of the twentieth century. Olfactory phenomena are studied on the material of literary movements of futurism, on the works of the crepusculars, in hermetic, neoavant-garde and postmodernism poetry. Concepts are mental constructions. The research is based on the model of concept elaborated by scientists Z. Popovа and J. Sternin. The concept of smell in Italian poetry has its own nucleus (basic layer), the near and far periphery (interpretive layer), which are responsible for fundamental and optional levels. Nuclear characteristics of the concept are determined by analyzing its vocabulary definitions. The nucleus of the lexical semantic field “odore” is represented by nouns-odorants that reproduce the sensual image, for instance “profumo”, “aroma”, “fragranza”, “olezzo”. The basic layer and interpretive features of the concept can be identified by examining the compatibility of its nominations with attributes and predicates that adds different cognitive classification features. Layer of interpretation is formed by such fixed combinations which reflects certain features of odors, their characteristics, intensity, duration, satisfaction / dissatisfaction etc. The concept of smell was analyzed due to its interpretative features: an olfactory landscape (a peculiar variety of odors that is characteristic for a particular area or work of art), an olfactory scene (a cognitive and mental structure that establishes the relation between the source of odors, the smell itself and the subject, which perceives them), an olfactory object (an object that is distinctively separated and identified among other sensory sensations), an evaluative aspect of the smell (pleasant / unpleasant odor). In our research the schemes of descriptions and verbalization of the olfactory information in poetry have been identified. Olfaction is holistic phenomenon and transforms the world in a Gestalt manner. An odor acquires meaning through learned associations. This is depicted in odor nominations: words are mainly names of sources of odour (lemon, garlic, mint, etc.). Only language as a cultural phenomenon though based on genetically developed algorithms, relates natural objects to neurophysiological actions via standardized semiotic mechanisms. Our perception could be described in loose terms of objectiveness only because we have an agreement in naming. Olfaction forms an integral part of of ingestive behavior, it serves as an acquired signal for danger (e. g. gas, smoke, rotting flesh) and has an important role in social communication and social life in general. The main problems in the terms of odor researches are: lack of theoretical background knowledge, subjective and cultural peculiarities in odor perception, some smells do not have their own names and are called due to their sources. Furthermore, there is the lack of measurements and data of odors and problems of how clearly defined the boundaries of an olfactory stimuli and the concept of odor. We should take the subjects’ linguistic representations as indications of olfactory perception and іts categorization.

The Artistic Structure of Perceptive Space in the Story “A Lear of the Steppes” by I. S. Turgenev

This article scrutinizes I. S. Turgenev’s “A Lear of the Steppes” and the artistic structure of its perceptual space. The story, written in 1870, finds its place between the middle and the last periods of the author’s artistic life and combines realistic, mystic, and fantastic features. The purpose of this work is to show the “ambivalent essence” of the protagonist in a composition of visual, acoustic, and olfactory artistic space. These aspects were studied on olfactory codes and landscape imagery. The novelty of the current research lies in comparing the poetics of spatial images to the point of view of the narrator, whose psychoacoustic experiences became the subject of the author’s self-reflection. The story’s sensory space is multilevel: it is concentrated in the “hero of the steppe”, Kharlov, and in the narrator, and for the latter the steppe is both a friendly and a foreign world. The topic of estrangement of a patchy understanding of the motherland is latent and reveals itself in the personal mode of narration. This article also shows that the narrator’s view dominates the visual space; the narrator describes the protagonist’s portrait in terms that are characteristic of the steppe’s landscape. The acoustic and olfactory spaces are also depicted from the point of view of the narrator. The subjective character of the sensory images serves to emphasize the conflict that lies at the basis of the narrative structure of the story whose main two types of characters turn to be a natural national character and a reflecting character molded under the influence of the European culture.

Olfaction at depth: cribriform plate size declines with dive depth and duration in aquatic arctoids

It is widely accepted that cetaceans, obligate aquatic mammals with almost no chemosensory input, rely little on olfaction and have lost the adaptive olfactory anatomy and behaviors present in their terrestrial ancestors. There is less agreement, however, on the relative role of a sense of smell in the life of aquatic mammals with residual ties to the land, such as the carnivoran sea otter (Enhydra lutris) and pinnipeds. Field observations of marine carnivorans often stress their keen use of smell for social communication and predator defense during forays onto land. Yet, one critical aspect of the olfactory landscape has been lost to the pinnipeds and otters. In contrast to terrestrial mammals, aquatic carnivorans forage underwater “noseblind” with nares closed and therefore completely without chemical cues. For this reason, we hypothesize that marine carnivorans rely less on the sense of smell than their terrestrial relatives and thus predict that this loss will be manifested in reduced olfactory anatomy. Second, we predict that pinniped species that dive to greater depths and for longer durations will display a greater reduction in olfactory anatomy, as they are further separated from, and likely less reliant on, surface odor cues. To test this, we look to one olfactory skull feature, the cribriform plate (CP), a bone in the posterior nasal cavity that is perforated by passageways for olfactory nerve bundles carrying chemical signals from the periphery to the olfactory bulb of the brain. Because CP size varies with the amount of peripheral olfactory innervation in a mammal's snout, quantifying the CP provides a gauge with which to compare relative olfactory investment across species. Using high-resolution CT scans and 3D imaging software, we performed the first extensive comparative and quantitative study of CP morphology across 28 species of arctoid carnivorans, a clade at the intersection of terrestrial and aquatic life. Overall results show that within this clade, aquatic species have substantially smaller relative CP surface area than terrestrial species. Moreover, within the aquatic arctoid species (pinnipeds and sea otter), we found a significant negative correlation between relative CP size and three variables of diving behavior: mean dive depth, mean dive duration, and maximum dive duration. By contrast, maximum dive depth was not significantly correlated with relative CP size after correcting for phylogenetic effects. Moving forward, we hope to apply our digital methods for quantifying CP morphology to the fossil record to provide insights into the process and rate of evolutionary losses of olfactory anatomy during the transition to an aquatic lifestyle in lineages of arctoids. Support or Funding Information NSF Graduate Research Fellowship Program grant DGE-1144087, Sigma Xi, Department of Ecology and Evolutionary Biology UCLA, UCLA Graduate Division Top: sagittal section of a CT scan of a female elephant seal skull. Individual morphological featured were segmented in Mimics software. Bottom: volumentric rendering of skull and nasal elements. Red: Cribriform plate. Green: olfactory-related ethmoturbinal bones. Blue: respiratory maxilloturbinal bones. Scale bar: 50 mm. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Spatial Receptive Fields for Odor Localization

Animals rely on olfaction to navigate through complex olfactory landscapes, but the mechanisms that allow an animal to encode the spatial structure of an odorous environment remain unclear. To acquire information about the spatial distribution of an odorant, animals may rely on bilateral olfactory organs and compare side differences of odor intensity and timing [1-6] or may perform spatial and temporal signal integration of subsequent samplings [7]. The American cockroach can efficiently locate a source of sex pheromone even after the removal of one antenna, suggesting that bilateral comparison is not a prerequisite for odor localization in this species [8, 9]. Cognate olfactory sensory neurons (OSNs) originating from different locations on the flagellum, but bearing the same olfactory receptor, converge onto the same glomerulus within the antennal lobe, which is thought to result in a loss of spatial information. Here, we identified 12 types ofpheromone-responsive projection neurons (PNs), each with spatially tuned receptive field. The combination of (1) the antennotopic organization of OSNs terminals and (2) the stereotyped compartmentalization of PNs' dendritic arborization within the macroglomerulus (MG), allows encoding the spatial position of the pheromone. Furthermore, each PN type innervates adifferent compartment of the mushroom body, providing the means for encoding spatial olfactory information along the olfactory circuit. Finally, MG PNs exhibit both excitatory and inhibitory spatial receptive fields and modulate their responses based on changes in stimulus geometry. In conclusion, we propose a mechanism for encoding information on the spatial distribution of a pheromone, expanding both our understanding of odor coding and of the strategies insects adopt to localize a sexual mate.