51
|
D'Angelo M, Zanor MI, Sance M, Cortina PR, Boggio SB, Asprelli P, Carrari F, Santiago AN, Asís R, Peralta IE, Valle EM. Contrasting metabolic profiles of tasty Andean varieties of tomato fruit in comparison with commercial ones. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2018; 98:4128-4134. [PMID: 29393974 DOI: 10.1002/jsfa.8930] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 12/29/2017] [Accepted: 01/28/2018] [Indexed: 05/22/2023]
Abstract
BACKGROUND The fruits of most commercial tomato cultivars (Solanum lycopersicum L.) are deficient in flavour. In contrast, traditional 'criollo' tomato varieties are appreciated for fruit of excellent organoleptic quality. Small farmers from the Andean valleys in Argentina have maintained their own tomato varieties, which were selected mainly for flavour. This work aims to correlate the chemical composition of the fruit with the sensory attributes of eight heirloom tomato varieties. The long-term goal is to identify potential candidate genes capable of altering the chemicals involved in flavour. RESULTS A sensory analysis was conducted and the metabolomics of fruit were determined. The data revealed that defined tomato aroma and sourness correlated with citrate and several volatile organic compounds (VOC), such as α-terpineol, p-menth-1-en-9-al, linalool and 3,6-dimethyl-2,3,3a,4,5,7a-hexahydrobenzofuran (DMHEX), a novel volatile recently identified in tomato. Two sensory attributes - sweetness and a not-acidic taste - correlated with the characteristic tomato taste, and also with fructose, glucose, and two VOCs, benzaldehyde, and 2-methyl-2-octen-4-one. CONCLUSIONS These data provide new evidence of the complex chemical combination that induced the flavour and aroma of the good-tasting 'criollo' tomato fruit. That is, the compounds that correlated with defined tomato aroma and acidic taste did not correlate with sweetness, or with characteristic tomato taste. © 2018 Society of Chemical Industry.
Collapse
Affiliation(s)
- Matilde D'Angelo
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET-UNR), Rosario, Argentina
| | - María I Zanor
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET-UNR), Rosario, Argentina
| | - María Sance
- Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Pablo R Cortina
- Instituto de Investigación en Físico-Química de Córdoba (INFIQC-CONICET), Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Silvana B Boggio
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET-UNR), Rosario, Argentina
| | - Pablo Asprelli
- Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Fernando Carrari
- Instituto de Biotecnología, Instituto Nacional de Tecnología Agropecuaria (IB-INTA), and CONICET, Hurlingham, Argentina
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, São Paulo, Brazil
| | - Ana N Santiago
- Instituto de Investigación en Físico-Química de Córdoba (INFIQC-CONICET), Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Ramón Asís
- Facultad de Ciencias Químicas - CIBICI, Universidad Nacional de Córdoba - CONICET, Córdoba, Argentina
| | - Iris E Peralta
- Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Mendoza, Argentina
- IADIZA CCT-CONICET, Mendoza, Argentina
| | - Estela M Valle
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET-UNR), Rosario, Argentina
| |
Collapse
|
52
|
Barwich AS. How to be rational about empirical success in ongoing science: The case of the quantum nose and its critics. STUDIES IN HISTORY AND PHILOSOPHY OF SCIENCE 2018; 69:40-51. [PMID: 29857800 DOI: 10.1016/j.shpsa.2018.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Revised: 12/21/2017] [Accepted: 02/20/2018] [Indexed: 06/08/2023]
Abstract
Empirical success is a central criterion for scientific decision-making. Yet its understanding in philosophical studies of science deserves renewed attention: Should philosophers think differently about the advancement of science when they deal with the uncertainty of outcome in ongoing research in comparison with historical episodes? This paper argues that normative appeals to empirical success in the evaluation of competing scientific explanations can result in unreliable conclusions, especially when we are looking at the changeability of direction in unsettled investigations. The challenges we encounter arise from the inherent dynamics of disciplinary and experimental objectives in research practice. In this paper we discuss how these dynamics inform the evaluation of empirical success by analyzing three of its requirements: data accommodation, instrumental reliability, and predictive power. We conclude that the assessment of empirical success in developing inquiry is set against the background of a model's interactive success and prospective value in an experimental context. Our argument is exemplified by the analysis of an apparent controversy surrounding the model of a quantum nose in research on olfaction. Notably, the public narrative of this controversy rests on a distorted perspective on measures of empirical success.
Collapse
Affiliation(s)
- Ann-Sophie Barwich
- Columbia University, Presidential Scholar in Society and Neuroscience, Department of the Biological Sciences, Department of Philosophy, The Center for Science and Society, Fayerweather 511, 1180 Amsterdam Ave., New York, NY, 10027, USA.
| |
Collapse
|
53
|
Armelin-Correa LM, Malnic B. Combining In Vivo and In Vitro Approaches To Identify Human Odorant Receptors Responsive to Food Odorants. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:2214-2218. [PMID: 28054485 DOI: 10.1021/acs.jafc.6b04998] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Olfactory perception plays an important role in food flavor. Humans have around 400 odorant receptors (ORs), which can be activated by an enormous number of odorants in a combinatorial fashion. To date, only a few odorant receptors have been linked to their respective odorants, due to the difficulties in expressing these receptor proteins in heterologous cell systems. In vivo approaches allow for the analysis of odorant-receptor interactions in their native environment and have the advantage that the complete OR repertoire is simultaneously tested. Once mouse odorant-receptor pairs are defined, one can search for the corresponding human orthologues, which can be validated against the odorants in heterologous cells. Thus, the combination of in vivo and in vitro methods should contribute to the identification of human ORs that recognize odorants of interest, such as key food odorants.
Collapse
Affiliation(s)
- Lucia M Armelin-Correa
- Department of Biological Sciences, Diadema Campus , Federal University of São Paulo , São Paulo , Brazil
| | - Bettina Malnic
- Department of Biochemistry , University of São Paulo , São Paulo , Brazil
| |
Collapse
|
54
|
Abstract
It is commonly believed that humans have a poor sense of smell compared to other mammalian species. However, this idea derives not from empirical studies of human olfaction but from a famous 19th-century anatomist's hypothesis that the evolution of human free will required a reduction in the proportional size of the brain's olfactory bulb. The human olfactory bulb is actually quite large in absolute terms and contains a similar number of neurons to that of other mammals. Moreover, humans have excellent olfactory abilities. We can detect and discriminate an extraordinary range of odors, we are more sensitive than rodents and dogs for some odors, we are capable of tracking odor trails, and our behavioral and affective states are influenced by our sense of smell.
Collapse
Affiliation(s)
- John P McGann
- Behavioral and Systems Neuroscience, Psychology Department, Rutgers University, 152 Frelinghuysen Road, Piscataway, NJ 08854, USA.
| |
Collapse
|
55
|
Up the nose of the beholder? Aesthetic perception in olfaction as a decision-making process. NEW IDEAS IN PSYCHOLOGY 2017. [DOI: 10.1016/j.newideapsych.2017.03.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
56
|
de Groot JHB, Semin GR, Smeets MAM. On the Communicative Function of Body Odors. PERSPECTIVES ON PSYCHOLOGICAL SCIENCE 2017; 12:306-324. [PMID: 28346117 DOI: 10.1177/1745691616676599] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Humans use multiple senses to navigate the social world, and the sense of smell is arguably the most underestimated one. An intriguing aspect of the sense of smell is its social communicative function. Research has shown that human odors convey information about a range of states (e.g., emotions, sickness) and traits (e.g., individuality, gender). Yet, what underlies the communicability of these states and traits via smell? We fill this explanatory gap with a framework that highlights the dynamic and flexible aspects of human olfactory communication. In particular, we explain how chemical profiles, associative learning (i.e., the systematic co-occurrence of chemical profiles with state- or trait-related information), and top-down contextual influences could interact to shape human odor perception. Our model not only helps to integrate past research on human olfactory communication but it also opens new avenues for future research on this fascinating, yet to date poorly understood, field.
Collapse
Affiliation(s)
- Jasper H B de Groot
- 1 Faculty of Social and Behavioral Sciences, Utrecht University, The Netherlands
| | - Gün R Semin
- 1 Faculty of Social and Behavioral Sciences, Utrecht University, The Netherlands.,2 William James Center for Research, Instituto Universitário de Ciências Psicológicas, Sociais e da Vida, Portugal
| | - Monique A M Smeets
- 1 Faculty of Social and Behavioral Sciences, Utrecht University, The Netherlands
| |
Collapse
|
57
|
Gardner B, Dieriks BV, Cameron S, Mendis LHS, Turner C, Faull RLM, Curtis MA. Metal concentrations and distributions in the human olfactory bulb in Parkinson's disease. Sci Rep 2017; 7:10454. [PMID: 28874699 PMCID: PMC5585381 DOI: 10.1038/s41598-017-10659-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 08/14/2017] [Indexed: 01/10/2023] Open
Abstract
In Parkinson's disease (PD), the olfactory bulb is typically the first region in the body to accumulate alpha-synuclein aggregates. This pathology is linked to decreased olfactory ability, which becomes apparent before any motor symptoms occur, and may be due to a local metal imbalance. Metal concentrations were investigated in post-mortem olfactory bulbs and tracts from 17 human subjects. Iron (p < 0.05) and sodium (p < 0.01) concentrations were elevated in the PD olfactory bulb. Combining laser ablation inductively coupled plasma mass spectrometry and immunohistochemistry, iron and copper were evident at very low levels in regions of alpha-synuclein aggregation. Zinc was high in these regions, and free zinc was detected in Lewy bodies, mitochondria, and lipofuscin of cells in the anterior olfactory nucleus. Increased iron and sodium in the human PD olfactory bulb may relate to the loss of olfactory function. In contrast, colocalization of free zinc and alpha-synuclein in the anterior olfactory nucleus implicate zinc in PD pathogenesis.
Collapse
Affiliation(s)
- Bronwen Gardner
- Centre for Brain Research and Department of Anatomy with Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Birger V Dieriks
- Centre for Brain Research and Department of Anatomy with Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Steve Cameron
- Waikato Mass Spectrometry Facility, University of Waikato, Hamilton, New Zealand
| | - Lakshini H S Mendis
- Centre for Brain Research and Department of Anatomy with Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Clinton Turner
- Centre for Brain Research and Department of Anatomy with Medical Imaging, University of Auckland, Auckland, New Zealand
- Department of Anatomical Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand
| | - Richard L M Faull
- Centre for Brain Research and Department of Anatomy with Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research and Department of Anatomy with Medical Imaging, University of Auckland, Auckland, New Zealand.
| |
Collapse
|
58
|
Abstract
Olfaction is often viewed as difficult, yet the empirical evidence suggests a different picture. A closer look shows people around the world differ in their ability to detect, discriminate, and name odors. This gives rise to the question of what influences our ability to smell. Instead of focusing on olfactory deficiencies, this review presents a positive perspective by focusing on factors that make someone a better smeller. We consider three driving forces in improving olfactory ability: one’s biological makeup, one’s experience, and the environment. For each factor, we consider aspects proposed to improve odor perception and critically examine the evidence; as well as introducing lesser discussed areas. In terms of biology, there are cases of neurodiversity, such as olfactory synesthesia, that serve to enhance olfactory ability. Our lifetime experience, be it typical development or unique training experience, can also modify the trajectory of olfaction. Finally, our odor environment, in terms of ambient odor or culinary traditions, can influence odor perception too. Rather than highlighting the weaknesses of olfaction, we emphasize routes to harnessing our olfactory potential.
Collapse
Affiliation(s)
- Asifa Majid
- Centre for Language Studies, Radboud University, Nijmegen, The Netherlands; Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Laura Speed
- Centre for Language Studies, Radboud University, Nijmegen, The Netherlands
| | - Ilja Croijmans
- Centre for Language Studies, Radboud University, Nijmegen, The Netherlands; International Max Planck Research School for Language Sciences, Nijmegen, The Netherlands
| | - Artin Arshamian
- Centre for Language Studies, Radboud University, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands; Division of Psychology, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
59
|
Kawamura S, Melin AD. Evolution of Genes for Color Vision and the Chemical Senses in Primates. EVOLUTION OF THE HUMAN GENOME I 2017. [DOI: 10.1007/978-4-431-56603-8_10] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
|
60
|
Uytingco CR, Puche AC, Munger SD. Using Intrinsic Flavoprotein and NAD(P)H Imaging to Map Functional Circuitry in the Main Olfactory Bulb. PLoS One 2016; 11:e0165342. [PMID: 27902689 PMCID: PMC5130181 DOI: 10.1371/journal.pone.0165342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/10/2016] [Indexed: 12/02/2022] Open
Abstract
Neurons exhibit strong coupling of electrochemical and metabolic activity. Increases in intrinsic fluorescence from either oxidized flavoproteins or reduced nicotinamide adenine dinucleotide (phosphate) [NAD(P)H] in the mitochondria have been used as an indicator of neuronal activity for the functional mapping of neural circuits. However, this technique has not been used to investigate the flow of olfactory information within the circuitry of the main olfactory bulb (MOB). We found that intrinsic flavoprotein fluorescence signals induced by electrical stimulation of single glomeruli displayed biphasic responses within both the glomerular (GL) and external plexiform layers (EPL) of the MOB. Pharmacological blockers of mitochondrial activity, voltage-gated Na+ channels, or ionotropic glutamate receptors abolished stimulus-dependent flavoprotein responses. Blockade of GABAA receptors enhanced the amplitude and spatiotemporal spread of the flavoprotein signals, indicating an important role for inhibitory neurotransmission in shaping the spread of neural activity in the MOB. Stimulus-dependent spread of fluorescence across the GL and EPL displayed a spatial distribution consistent with that of individual glomerular microcircuits mapped by neuroanatomic tract tracing. These findings demonstrated the feasibility of intrinsic fluorescence imaging in the olfactory systems and provided a new tool to examine the functional circuitry of the MOB.
Collapse
Affiliation(s)
- Cedric R Uytingco
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America.,Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Adam C Puche
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America.,Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Steven D Munger
- Center for Smell and Taste, University of Florida, Gainesville, Florida, United States of America.,Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States of America.,Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Florida, Gainesville, Florida, United States of America
| |
Collapse
|
61
|
Abstract
Olfaction enables most mammalian species to detect and discriminate vast numbers of chemical structures called odorants and pheromones. The perception of such chemical compounds is mediated via two major olfactory systems, the main olfactory system and the vomeronasal system, as well as minor systems, such as the septal organ and the Grueneberg ganglion. Distinct differences exist not only among species but also among individuals in terms of their olfactory sensitivity; however, little is known about the mechanisms that determine these differences. In research on the olfactory sensitivity of mammals, scientists thus depend in most cases on behavioral testing. In this article, we reviewed scientific studies performed on various mammalian species using different methodologies and target chemical substances. Human and non-human primates as well as rodents and dogs are the most frequently studied species. Olfactory threshold studies on other species do not exist with the exception of domestic pigs. Olfactory testing performed on seals, elephants, and bats focused more on discriminative abilities than on sensitivity. An overview of olfactory sensitivity studies as well as olfactory detection ability in most studied mammalian species is presented here, focusing on comparable olfactory detection thresholds. The basics of olfactory perception and olfactory sensitivity factors are also described.
Collapse
|
62
|
Cinema audiences reproducibly vary the chemical composition of air during films, by broadcasting scene specific emissions on breath. Sci Rep 2016; 6:25464. [PMID: 27160439 PMCID: PMC4862009 DOI: 10.1038/srep25464] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 04/18/2016] [Indexed: 11/08/2022] Open
Abstract
Human beings continuously emit chemicals into the air by breath and through the skin. In order to determine whether these emissions vary predictably in response to audiovisual stimuli, we have continuously monitored carbon dioxide and over one hundred volatile organic compounds in a cinema. It was found that many airborne chemicals in cinema air varied distinctively and reproducibly with time for a particular film, even in different screenings to different audiences. Application of scene labels and advanced data mining methods revealed that specific film events, namely “suspense” or “comedy” caused audiences to change their emission of specific chemicals. These event-type synchronous, broadcasted human chemosignals open the possibility for objective and non-invasive assessment of a human group response to stimuli by continuous measurement of chemicals in air. Such methods can be applied to research fields such as psychology and biology, and be valuable to industries such as film making and advertising.
Collapse
|
63
|
Abstract
Insights into risk factors for olfactory decline are needed, because knowledge about its origin is limited. This impairment has important implications for human health. Several epidemiologic studies of olfaction provide insight into the prevalence of olfactory disorders. Here, we review the major population studies carried out on this topic to date. Our purpose is to characterize knowledge about olfactory disorders from human studies. We also describe the existing methods for measuring the sense of smell in population studies, present recent insights into the epidemiology of smell disorders, and discuss the risk factors identified to date. Synthesis of these data shows that olfactory dysfunction increases as people age and is worse in men. Further study of olfaction is warranted for gaining better information on the etiologies affecting its impairment, research that will have a large public health impact.
Collapse
Affiliation(s)
- Jingpu Yang
- Department of Otolaryngology-Head and Neck Surgery, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun, Jilin Province, 130041, China
| | - Jayant M Pinto
- Section of Otolaryngology-Head and Neck Surgery, Department of Surgery, The University of Chicago Medicine and Biological Sciences, 5841 South Maryland Avenue, MC1035, Chicago, IL 60637
| |
Collapse
|
64
|
Rowe TB, Shepherd GM. Role of ortho-retronasal olfaction in mammalian cortical evolution. J Comp Neurol 2016; 524:471-95. [PMID: 25975561 PMCID: PMC4898483 DOI: 10.1002/cne.23802] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 03/16/2015] [Accepted: 04/29/2015] [Indexed: 02/02/2023]
Abstract
Fossils of mammals and their extinct relatives among cynodonts give evidence of correlated transformations affecting olfaction as well as mastication, head movement, and ventilation, and suggest evolutionary coupling of these seemingly separate anatomical regions into a larger integrated system of ortho-retronasal olfaction. Evidence from paleontology and physiology suggests that ortho-retronasal olfaction played a critical role at three stages of mammalian cortical evolution: early mammalian brain development was driven in part by ortho-retronasal olfaction; the bauplan for neocortex had higher-level association functions derived from olfactory cortex; and human cortical evolution was enhanced by ortho-retronasal smell.
Collapse
Affiliation(s)
- Timothy B. Rowe
- Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, 78712 USA
| | - Gordon M. Shepherd
- Department of Neurobiology, Yale University School of Medicine, New Haven, CT, 06510 USA
| |
Collapse
|
65
|
Affiliation(s)
- Anne Tromelin
- CNRS; UMR6265 Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
- INRA; UMR1324 Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
- Université de Bourgogne; UMR Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
| |
Collapse
|
66
|
Barwich AS. What is so special about smell? Olfaction as a model system in neurobiology. Postgrad Med J 2015; 92:27-33. [PMID: 26534994 DOI: 10.1136/postgradmedj-2015-133249] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 10/05/2015] [Indexed: 11/04/2022]
Abstract
Neurobiology studies mechanisms of cell signalling. A key question is how cells recognise specific signals. In this context, olfaction has become an important experimental system over the past 25 years. The olfactory system responds to an array of structurally diverse stimuli. The discovery of the olfactory receptors (ORs), recognising these stimuli, established the olfactory pathway as part of a greater group of signalling mechanisms mediated by G-protein-coupled receptors (GPCRs). GPCRs are the largest protein family in the mammalian genome and involved in numerous fundamental physiological processes. The OR family exhibits two characteristics that make them an excellent model system to understand GPCRs: its size and the structural diversity of its members. Research on the OR binding site investigates what amino acid sequences determine the receptor-binding capacity. This promises a better understanding of how the basic genetic makeup of GPCRs relates to their diversification in ligand-binding capacities.
Collapse
|
67
|
A new dopaminergic nigro-olfactory projection. Acta Neuropathol 2015; 130:333-48. [PMID: 26072303 DOI: 10.1007/s00401-015-1451-y] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 06/05/2015] [Accepted: 06/08/2015] [Indexed: 10/23/2022]
Abstract
Parkinson disease (PD) is a neurodegenerative disorder characterized by massive loss of midbrain dopaminergic neurons. Whereas onset of motor impairments reflects a rather advanced stage of the disorder, hyposmia often marks the beginning of the disease. Little is known about the role of the nigro-striatal system in olfaction under physiological conditions and the anatomical basis of hyposmia in PD. Yet, the early occurrence of olfactory dysfunction implies that pathogens such as environmental toxins could incite the disease via the olfactory system. In the present study, we demonstrate a dopaminergic innervation from neurons in the substantia nigra to the olfactory bulb by axonal tracing studies. Injection of two dopaminergic neurotoxins-1-methyl-4-phenylpyridinium and 6-hydroxydopamine-into the olfactory bulb induced a decrease in the number of dopaminergic neurons in the substantia nigra. In turn, ablation of the nigral projection led to impaired olfactory perception. Hyposmia following dopaminergic deafferentation was reversed by treatment with the D1/D2/D3 dopamine receptor agonist rotigotine. Hence, we demonstrate for the first time the existence of a direct dopaminergic projection into the olfactory bulb and identify its origin in the substantia nigra in rats. These observations may provide a neuroanatomical basis for invasion of environmental toxins into the basal ganglia and for hyposmia as frequent symptom in PD.
Collapse
|
68
|
Valenta K, Brown KA, Rafaliarison RR, Styler SA, Jackson D, Lehman SM, Chapman CA, Melin AD. Sensory integration during foraging: the importance of fruit hardness, colour, and odour to brown lemurs. Behav Ecol Sociobiol 2015. [DOI: 10.1007/s00265-015-1998-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
69
|
|
70
|
Chatelain P, Veithen A, Wilkin F, Philippeau M. Deorphanization and characterization of human olfactory receptors in heterologous cells. Chem Biodivers 2015; 11:1764-81. [PMID: 25408322 DOI: 10.1002/cbdv.201400083] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Indexed: 11/07/2022]
Abstract
Olfaction plays an indispensable role in human and animals in self and environmental recognition, as well as intra- and interspecific communication. Following the discovery of a family of olfactory receptors (ORs) by Buck and Axel in 1991, it has been established that the sense of smell begins with the molecular recognition of a chemical odorant by one or more ORs expressed in the olfactory sensory neurons. Therefore, characterization of the molecular interactions between odorant molecules and ORs is a key step in the elucidation of the general properties of the olfactory system and in the development of applications, i.e., design of new odorants, search for blockers, etc. The process putted in place at ChemCom to improve the expression of ORs at the cytoplasmic membrane of the HEK293 cell and assays enabling large-scale deorphanization, and to characterize the interaction between chemical odorants and ORs is described. The family of human ORs includes ca. 400 putatively functional ORs which are GPCRs (G protein-coupled receptors); to date over 100 human ORs have been deorphanized.
Collapse
|
71
|
Yang B, Ren B, Xiang Z, Yang J, Yao H, Garber PA, Li M. Major histocompatibility complex and mate choice in the polygynous primate: the Sichuan snub-nosed monkey (Rhinopithecus roxellana). Integr Zool 2015; 9:598-612. [PMID: 24382257 DOI: 10.1111/1749-4877.12084] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The highly polymorphic genes within the major histocompatibility complex (MHC) not only play a major role in immunity resistance, but also seem to provide hints for mate choice in some animal populations. In the present study we investigated MHC-related mate choice in a small natural population (group size 40-55 individuals) of a polygynous primate, the Sichuan snub-nosed monkey (Rhinopithecus roxellana). We found that there was no evidence either for MHC-disassortative mating, or for females to mate with males based on MHC heterozygosity or specific alleles. Nevertheless, of the 11 alleles identified, we found that the frequencies of 2 alleles, Rhro-DRB2 (P < 0.01) and Rhro-DRB5 (P < 0.05) were higher in offspring than in their parents. These findings suggest that MHC-DRB in this population of R. roxellana is unlikely to be associated with mating preferences. Limited female opportunities for mate choice are likely due, in part, to the harem breeding structure present in R. roxellana, and the relatively small number of resident adult males in our study band (N = 4-6). In addition, we suggest that differences in the frequency of particular alleles across generations may be linked to parasite resistance in a fluctuating environment; however, confirmation of this finding requires further study.
Collapse
Affiliation(s)
- Banghe Yang
- Key Lab of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; Graduate School of the University of Chinese Academy of Sciences, Beijing, China
| | | | | | | | | | | | | |
Collapse
|
72
|
Jacobs LF, Arter J, Cook A, Sulloway FJ. Olfactory Orientation and Navigation in Humans. PLoS One 2015; 10:e0129387. [PMID: 26083337 PMCID: PMC4470656 DOI: 10.1371/journal.pone.0129387] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 05/07/2015] [Indexed: 11/18/2022] Open
Abstract
Although predicted by theory, there is no direct evidence that an animal can define an arbitrary location in space as a coordinate location on an odor grid. Here we show that humans can do so. Using a spatial match-to-sample procedure, humans were led to a random location within a room diffused with two odors. After brief sampling and spatial disorientation, they had to return to this location. Over three conditions, participants had access to different sensory stimuli: olfactory only, visual only, and a final control condition with no olfactory, visual, or auditory stimuli. Humans located the target with higher accuracy in the olfaction-only condition than in the control condition and showed higher accuracy than chance. Thus a mechanism long proposed for the homing pigeon, the ability to define a location on a map constructed from chemical stimuli, may also be a navigational mechanism used by humans.
Collapse
Affiliation(s)
- Lucia F. Jacobs
- Department of Psychology, University of California, Berkeley, California, United States of America
- * E-mail:
| | - Jennifer Arter
- Department of Psychology, University of California, Berkeley, California, United States of America
| | - Amy Cook
- Department of Psychology, University of California, Berkeley, California, United States of America
| | - Frank J. Sulloway
- Department of Psychology, University of California, Berkeley, California, United States of America
| |
Collapse
|
73
|
Wyatt TD. The search for human pheromones: the lost decades and the necessity of returning to first principles. Proc Biol Sci 2015; 282:20142994. [PMID: 25740891 PMCID: PMC4375873 DOI: 10.1098/rspb.2014.2994] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/02/2015] [Indexed: 12/22/2022] Open
Abstract
As humans are mammals, it is possible, perhaps even probable, that we have pheromones. However, there is no robust bioassay-led evidence for the widely published claims that four steroid molecules are human pheromones: androstenone, androstenol, androstadienone and estratetraenol. In the absence of sound reasons to test the molecules, positive results in studies need to be treated with scepticism as these are highly likely to be false positives. Common problems include small sample sizes, an overestimate of effect size (as no effect can be expected), positive publication bias and lack of replication. Instead, if we are to find human pheromones, we need to treat ourselves as if we were a newly discovered mammal, and use the rigorous methods already proven successful in pheromone research on other species. Establishing a pheromone relies on demonstration of an odour-mediated behavioural or physiological response, identification and synthesis of the bioactive molecule(s), followed by bioassay confirmation of activity. Likely sources include our sebaceous glands. Comparison of secretions from adult and pre-pubertal humans may highlight potential molecules involved in sexual behaviour. One of the most promising human pheromone leads is a nipple secretion from the areola glands produced by all lactating mothers, which stimulates suckling by any baby not just their own.
Collapse
Affiliation(s)
- Tristram D Wyatt
- Department of Zoology, University of Oxford, Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
| |
Collapse
|
74
|
Sorokowska A, Sorokowski P, Frackowiak T. Determinants of human olfactory performance: a cross-cultural study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 506-507:196-200. [PMID: 25460952 DOI: 10.1016/j.scitotenv.2014.11.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 11/04/2014] [Accepted: 11/06/2014] [Indexed: 05/09/2023]
Abstract
Olfaction allows us to detect subtle changes in our environment, but sensitivity of the sense of smell varies among individuals. Although a significant number of research papers discuss the relationship between olfactory abilities and environmental factors, most studies have been conducted on Western populations or in developed Asian societies. The potential environmental and cultural determinants of olfactory acuity warrant further exploration. In the current study, we compared previously published data on olfaction in an industrialized, modern society (i.e., Europeans) and an indigenous society living in unpolluted, natural environmental conditions (i.e., Tsimane'), with novel data on the olfactory acuity of inhabitants of the Cook Islands. Like the European population (and contrary to the Tsimane'), the Cook Islands people form a modern society, and like the Tsimane' population (and contrary to the Europeans), they live in an unpolluted region. Thus, these comparisons enabled us to independently assess the importance of both air pollution and changes in lifestyle for olfactory abilities in modern societies. Our results indicate that people from the Cook Islands had significantly higher olfactory acuity (i.e., lower thresholds of odor detection) than did Europeans and Tsimane' people. Interestingly, the olfactory sensitivity of Europeans was significantly lower than the olfactory sensitivity of the remaining two groups. Our data suggest that air pollution is an important factor in the deterioration of the sense of smell. However, it is also possible that factors such as agricultural and/or cooking practices, alcohol consumption, and access to medical service may also influence olfactory acuity.
Collapse
Affiliation(s)
- Agnieszka Sorokowska
- Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany; Institute of Psychology, University of Wroclaw, Wroclaw, Poland.
| | | | | |
Collapse
|
75
|
Drea CM. D'scent of man: a comparative survey of primate chemosignaling in relation to sex. Horm Behav 2015; 68:117-33. [PMID: 25118943 DOI: 10.1016/j.yhbeh.2014.08.001] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/29/2014] [Accepted: 08/01/2014] [Indexed: 11/24/2022]
Abstract
This article is part of a Special Issue (Chemosignals and Reproduction). As highly visual animals, primates, in general, and Old World species (including humans), in particular, are not immediately recognized for reliance in their daily interactions on olfactory communication. Nevertheless, views on primate olfactory acuity and the pervasiveness of their scent signaling are changing, with increased appreciation for the important role of body odors in primate social and sexual behavior. All major taxonomic groups, from lemurs to humans, are endowed with scent-producing organs, and either deposit or exude a wealth of volatile compounds, many of which are known semiochemicals. This review takes a comparative perspective to illustrate the reproductive context of primate signaling, the relevant information content of their signals, the sexually differentiated investigative responses generated, and the behavioral or physiological consequences of message transmission to both signaler and receiver. Throughout, humans are placed alongside their relatives to illustrate the evolutionary continuum in the sexual selection of primate chemosignals. This ever-growing body of evidence points to a critical role of scent in guiding the social behavior and reproductive function throughout the primate order.
Collapse
Affiliation(s)
- Christine M Drea
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708-0383, USA; Department of Biology, Duke University, Durham, NC 27708-0383, USA.
| |
Collapse
|
76
|
Persuy MA, Sanz G, Tromelin A, Thomas-Danguin T, Gibrat JF, Pajot-Augy E. Mammalian olfactory receptors: molecular mechanisms of odorant detection, 3D-modeling, and structure-activity relationships. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 130:1-36. [PMID: 25623335 DOI: 10.1016/bs.pmbts.2014.11.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This chapter describes the main characteristics of olfactory receptor (OR) genes of vertebrates, including generation of this large multigenic family and pseudogenization. OR genes are compared in relation to evolution and among species. OR gene structure and selection of a given gene for expression in an olfactory sensory neuron (OSN) are tackled. The specificities of OR proteins, their expression, and their function are presented. The expression of OR proteins in locations other than the nasal cavity is regulated by different mechanisms, and ORs display various additional functions. A conventional olfactory signal transduction cascade is observed in OSNs, but individual ORs can also mediate different signaling pathways, through the involvement of other molecular partners and depending on the odorant ligand encountered. ORs are engaged in constitutive dimers. Ligand binding induces conformational changes in the ORs that regulate their level of activity depending on odorant dose. When present, odorant binding proteins induce an allosteric modulation of OR activity. Since no 3D structure of an OR has been yet resolved, modeling has to be performed using the closest G-protein-coupled receptor 3D structures available, to facilitate virtual ligand screening using the models. The study of odorant binding modes and affinities may infer best-bet OR ligands, to be subsequently checked experimentally. The relationship between spatial and steric features of odorants and their activity in terms of perceived odor quality are also fields of research that development of computing tools may enhance.
Collapse
Affiliation(s)
- Marie-Annick Persuy
- INRA UR 1197 NeuroBiologie de l'Olfaction, Domaine de Vilvert, Jouy-en-Josas, France
| | - Guenhaël Sanz
- INRA UR 1197 NeuroBiologie de l'Olfaction, Domaine de Vilvert, Jouy-en-Josas, France
| | - Anne Tromelin
- INRA UMR 1129 Flaveur, Vision et Comportement du Consommateur, Dijon, France
| | | | - Jean-François Gibrat
- INRA UR1077 Mathématique Informatique et Génome, Domaine de Vilvert, Jouy-en-Josas, France
| | - Edith Pajot-Augy
- INRA UR 1197 NeuroBiologie de l'Olfaction, Domaine de Vilvert, Jouy-en-Josas, France.
| |
Collapse
|
77
|
Endevelt-Shapira Y, Shushan S, Roth Y, Sobel N. Disinhibition of olfaction: human olfactory performance improves following low levels of alcohol. Behav Brain Res 2014; 272:66-74. [PMID: 24973535 DOI: 10.1016/j.bbr.2014.06.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 05/07/2014] [Accepted: 06/09/2014] [Indexed: 10/25/2022]
Abstract
We hypothesize that true human olfactory abilities are obscured by cortical inhibition. Alcohol reduces inhibition. We therefore tested the hypothesis that olfactory abilities will improve following alcohol consumption. We measured olfaction in 85 subjects, 45 in a between-subjects design, and 40 in a repeated-measures within-subjects design before and after consumption of alcoholic or non-alcoholic beverages. Subjects were also assessed using neurocognitive measures of inhibition. Following alcohol consumption, blood alcohol levels ranged from 0.005% to 0.11%. Across subjects, before any consumption of alcohol, we found that individuals who were less inhibited had lower (better) olfactory detection thresholds (r=0.68, p<0.005). Moreover, after alcohol consumption, subjects with low alcohol levels could make olfactory discriminations that subjects with 0% alcohol could not make (chance=33%, alcohol=51.3±22.7%, control=34.7±31.6%, t(43)=2.03, p<0.05). Within subjects, we found correlations between levels of alcohol and olfactory detection (r=0.63, p<0.005) and discrimination (r=-0.50, p<0.05), such that performance was improved at low levels of alcohol (significantly better than baseline for detection) and deteriorated at higher levels of alcohol. Finally, levels of alcohol-induced improved olfactory discrimination were correlated with levels of alcohol-induced cognitive disinhibition (r=0.48, p<0.05). Although we cannot rule out alternative non-inhibitory alcohol-induced routes of influence, we conclude that improved olfaction at low levels of alcohol supports the notion of an inhibitory mechanism obscuring true olfactory abilities.
Collapse
Affiliation(s)
| | - Sagit Shushan
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel; Department of Otolaryngology-Head and Neck Surgery, Edith Wolfson Medical Center, Holon 58100, Israel
| | - Yehudah Roth
- Department of Otolaryngology-Head and Neck Surgery, Edith Wolfson Medical Center, Holon 58100, Israel
| | - Noam Sobel
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| |
Collapse
|
78
|
A computational microscope focused on the sense of smell. Biochimie 2014; 107 Pt A:3-10. [PMID: 24952349 DOI: 10.1016/j.biochi.2014.06.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 06/07/2014] [Indexed: 11/24/2022]
Abstract
In this article, we review studies of the protagonists of the perception of smell focusing on Odorant-Binding Proteins and Olfactory Receptors. We notably put forward studies performed by means of molecular modeling, generally combined with experimental data. Those works clearly emphasize that computational approaches are now a force to reckon with. In the future, they will certainly be more and more used, notably in the framework of a computational microscope meant to observe how the laws of physics govern the biomolecular systems originating our sense of smell.
Collapse
|
79
|
Ruddigkeit L, Awale M, Reymond JL. Expanding the fragrance chemical space for virtual screening. J Cheminform 2014; 6:27. [PMID: 24876890 PMCID: PMC4037718 DOI: 10.1186/1758-2946-6-27] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 05/12/2014] [Indexed: 12/30/2022] Open
Abstract
The properties of fragrance molecules in the public databases SuperScent and Flavornet were analyzed to define a “fragrance-like” (FL) property range (Heavy Atom Count ≤ 21, only C, H, O, S, (O + S) ≤ 3, Hydrogen Bond Donor ≤ 1) and the corresponding chemical space including FL molecules from PubChem (NIH repository of molecules), ChEMBL (bioactive molecules), ZINC (drug-like molecules), and GDB-13 (all possible organic molecules up to 13 atoms of C, N, O, S, Cl). The FL subsets of these databases were classified by MQN (Molecular Quantum Numbers, a set of 42 integer value descriptors of molecular structure) and formatted for fast MQN-similarity searching and interactive exploration of color-coded principal component maps in form of the FL-mapplet and FL-browser applications freely available at http://www.gdb.unibe.ch. MQN-similarity is shown to efficiently recover 15 different fragrance molecule families from the different FL subsets, demonstrating the relevance of the MQN-based tool to explore the fragrance chemical space.
Collapse
Affiliation(s)
- Lars Ruddigkeit
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Mahendra Awale
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Jean-Louis Reymond
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| |
Collapse
|
80
|
Wnuk E, Majid A. Revisiting the limits of language: The odor lexicon of Maniq. Cognition 2014; 131:125-38. [DOI: 10.1016/j.cognition.2013.12.008] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 11/29/2013] [Accepted: 12/19/2013] [Indexed: 11/28/2022]
|
81
|
A Sense So Rare: Measuring Olfactory Experiences and Making a Case for a Process Perspective on Sensory Perception. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s13752-014-0165-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
82
|
Abstract
Ample evidence suggests that social chemosignaling plays a significant role in human behavior. Processing of odors and chemosignals depends on sniffing. Given this, we hypothesized that humans may have evolved an automatic mechanism driving sniffs in response to conspecific sniffing. To test this, we measured sniffing behavior of human subjects watching the movie Perfume, which contains many olfactory sniffing events. Despite the total absence of odor, observers sniffed when characters in the movie sniffed. Moreover, this effect was most pronounced in scenes where subjects heard the sniff but did not see the sniffed-at object. We liken this response to the orienting towards conspecific gaze in vision and argue that its robustness further highlights the significance of olfactory information processing in human behavior.
Collapse
Affiliation(s)
- Anat Arzi
- Department of Neurobiology, Weizmann Institute of Science, 234 Herzl street, Rehovot 76100, Israel.
| | | | | | | |
Collapse
|
83
|
Patel RM, Pinto JM. Olfaction: anatomy, physiology, and disease. Clin Anat 2013; 27:54-60. [PMID: 24272785 DOI: 10.1002/ca.22338] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 10/02/2013] [Indexed: 11/08/2022]
Abstract
The olfactory system is an essential part of human physiology, with a rich evolutionary history. Although humans are less dependent on chemosensory input than are other mammals (Niimura 2009, Hum. Genomics 4:107-118), olfactory function still plays a critical role in health and behavior. The detection of hazards in the environment, generating feelings of pleasure, promoting adequate nutrition, influencing sexuality, and maintenance of mood are described roles of the olfactory system, while other novel functions are being elucidated. A growing body of evidence has implicated a role for olfaction in such diverse physiologic processes as kin recognition and mating (Jacob et al. 2002a, Nat. Genet. 30:175-179; Horth 2007, Genomics 90:159-175; Havlicek and Roberts 2009, Psychoneuroendocrinology 34:497-512), pheromone detection (Jacob et al. 200b, Horm. Behav. 42:274-283; Wyart et al. 2007, J. Neurosci. 27:1261-1265), mother-infant bonding (Doucet et al. 2009, PLoS One 4:e7579), food preferences (Mennella et al. 2001, Pediatrics 107:E88), central nervous system physiology (Welge-Lüssen 2009, B-ENT 5:129-132), and even longevity (Murphy 2009, JAMA 288:2307-2312). The olfactory system, although phylogenetically ancient, has historically received less attention than other special senses, perhaps due to challenges related to its study in humans. In this article, we review the anatomic pathways of olfaction, from peripheral nasal airflow leading to odorant detection, to epithelial recognition of these odorants and related signal transduction, and finally to central processing. Olfactory dysfunction, which can be defined as conductive, sensorineural, or central (typically related to neurodegenerative disorders), is a clinically significant problem, with a high burden on quality of life that is likely to grow in prevalence due to demographic shifts and increased environmental exposures.
Collapse
Affiliation(s)
- Riddhi M Patel
- Department of Surgery, Section of Otolaryngology-Head and Neck Surgery, The University of Chicago, Chicago, Illinois
| | | |
Collapse
|
84
|
Auffarth B. Understanding smell—The olfactory stimulus problem. Neurosci Biobehav Rev 2013; 37:1667-79. [DOI: 10.1016/j.neubiorev.2013.06.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 05/09/2013] [Accepted: 06/13/2013] [Indexed: 01/30/2023]
|
85
|
Heydel JM, Coelho A, Thiebaud N, Legendre A, Bon AML, Faure P, Neiers F, Artur Y, Golebiowski J, Briand L. Odorant-Binding Proteins and Xenobiotic Metabolizing Enzymes: Implications in Olfactory Perireceptor Events. Anat Rec (Hoboken) 2013; 296:1333-45. [DOI: 10.1002/ar.22735] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 02/01/2013] [Accepted: 02/26/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Jean-Marie Heydel
- INRA UMR1324, CNRS UMR6265; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
| | - Alexandra Coelho
- INRA UMR1324, CNRS UMR6265; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
| | - Nicolas Thiebaud
- INRA UMR1324, CNRS UMR6265; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
| | - Arièle Legendre
- INRA UMR1324, CNRS UMR6265; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
| | - Anne-Marie Le Bon
- INRA UMR1324, CNRS UMR6265; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
| | - Philippe Faure
- INRA UMR1324, CNRS UMR6265; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
| | - Fabrice Neiers
- INRA UMR1324, CNRS UMR6265; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
| | - Yves Artur
- INRA UMR1324, CNRS UMR6265; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
| | - Jérôme Golebiowski
- Université de Nice Sophia Antipolis; CNRS UMR7272, Institut de Chimie de Nice; F-06108 Nice Cedex 2 France
| | - Loïc Briand
- INRA UMR1324, CNRS UMR6265; Université de Bourgogne, Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
| |
Collapse
|
86
|
Abellán A, Desfilis E, Medina L. The olfactory amygdala in amniotes: an evo-devo approach. Anat Rec (Hoboken) 2013; 296:1317-32. [PMID: 23904411 DOI: 10.1002/ar.22744] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 06/18/2013] [Indexed: 11/11/2022]
Abstract
In tetrapods, the medial amygdala is a forebrain center that integrates olfactory and/or vomeronasal signals with the endocrine and autonomic systems, playing a key role in different social behaviors. The vomeronasal system has undergone important changes during evolution, which may be behind some interspecies differences in chemosensory-mediated social behavior. These evolutionary changes are associated with variations in vomeronasal-recipient brain structures, including the medial amygdala. Herein, we employed an evolutionary developmental biology approach for trying to understand the function and evolution of the medial amygdala. For that purpose, we reviewed published data on fate mapping in mouse, and the expression of orthologous developmental regulatory genes (Nkx2.1, Lhx6, Shh, Tbr1, Lhx9, Lhx5, Otp, and Pax6) in embryos of mouse, chicken, emydid turtles, and a pipid frog. We also analyzed novel data on Lhx9 and Otp in a lacertid lizard. Based on distinct embryonic origin and genetic profile, at least five neuronal subpopulations exist in the medial amygdala of rodents, expressing either Nkx2.1/Lhx6, Shh, Lhx9, Otp/Lhx5, or Pax6. Each neuronal subpopulation appears involved in different functional pathways. For example, Lhx6 cells are specifically activated by sex pheromones and project to preoptic and hypothalamic centers involved in reproduction. Based on data in nonmammals, at least three of these neuronal subtypes might have been present in the medial amygdala of the amniote common ancestor. During mammalian evolution, the downregulation of Nkx2.1 in the alar hypothalamus may have been a driving force for an increment of the Otp/Lhx5 subpopulation.
Collapse
Affiliation(s)
- Antonio Abellán
- Laboratory of Brain Development and Evolution, Department of Experimental Medicine, Faculty of Medicine, University of Lleida, Institute of Biomedical Research of Lleida, Lleida, Spain
| | | | | |
Collapse
|
87
|
Moessnang C, Pauly K, Kellermann T, Krämer J, Finkelmeyer A, Hummel T, Siegel SJ, Schneider F, Habel U. The scent of salience--is there olfactory-trigeminal conditioning in humans? Neuroimage 2013; 77:93-104. [PMID: 23558094 DOI: 10.1016/j.neuroimage.2013.03.049] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/15/2013] [Accepted: 03/17/2013] [Indexed: 11/18/2022] Open
Abstract
Pavlovian fear conditioning has been thoroughly studied in the visual, auditory and somatosensory domain, but evidence is scarce with regard to the chemosensory modality. Under the assumption that Pavlovian conditioning relies on the supra-modal mechanism of salience attribution, the present study was set out to attest the existence of chemosensory aversive conditioning in humans as a specific instance of salience attribution. fMRI was performed in 29 healthy subjects during a differential aversive conditioning paradigm. Two odors (rose, vanillin) served as conditioned stimuli (CS), one of which (CS+) was intermittently coupled with intranasally administered CO2. On the neural level, a robust differential response to the CS+ emerged in frontal, temporal, occipito-parietal and subcortical brain regions, including the amygdala. These changes were paralleled by the development of a CS+-specific connectivity profile of the anterior midcingulate cortex (aMCC), which is a key structure for processing salience information in order to guide adaptive response selection. Increased coupling could be found between key nodes of the salience network (anterior insula, neo-cerebellum) and sensorimotor areas, representing putative input and output structures of the aMCC for exerting adaptive motor control. In contrast, behavioral and skin conductance responses did not show significant effects of conditioning, which has been attributed to contingency unawareness. These findings imply substantial similarities of conditioning involving chemosensory and other sensory modalities, and suggest that salience attribution and adaptive control represent a general, modality-independent principle underlying Pavlovian conditioning.
Collapse
Affiliation(s)
- C Moessnang
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Pauwelsstraße 30, Aachen, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
88
|
Romagnani P, Lasagni L, Remuzzi G. Renal progenitors: an evolutionary conserved strategy for kidney regeneration. Nat Rev Nephrol 2013; 9:137-46. [PMID: 23338209 DOI: 10.1038/nrneph.2012.290] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Following kidney injury, repair can result in functional tissue becoming a patch of cells and disorganized extracellular matrix--a scar--or it can recapitulate the original tissue architecture through the process of regeneration. Regeneration can potentially occur in all animal species and humans. Indeed, the repair of portions of the existing nephron after tubular damage, a response that has been designated classically as cellular regeneration, is conserved in all animal species from the ancestral phases of evolution. By contrast, another type of regenerative response--nephron neogenesis--has been described in lower branches of the animal kingdom, but does not occur in adult mammals. Converging evidence suggests that a renal progenitor system is present in the adult kidney across different stages of evolution, with renal progenitors having been identified as the main drivers of kidney regenerative responses in fish, insects, rodents and humans. In this Review, we describe similarities and differences between the renal progenitor systems through evolution, and propose explanations for how progressive kidney adaptation to environmental changes both required and permitted neonephrogenesis to be given up and for cellular regeneration to be retained as the main regenerative strategy. Understanding the mechanisms that drive renal progenitor growth and differentiation represent the key step for modulating this potential for therapeutic purposes.
Collapse
Affiliation(s)
- Paola Romagnani
- Pediatric Nephrology Unit, Meyer Children's Hospital, University of Florence, Viale Pieraccini 24, 50139 Florence, Italy.
| | | | | |
Collapse
|
89
|
Sinding C, Thomas-Danguin T, Chambault A, Béno N, Dosne T, Chabanet C, Schaal B, Coureaud G. Rabbit neonates and human adults perceive a blending 6-component odor mixture in a comparable manner. PLoS One 2013; 8:e53534. [PMID: 23341948 PMCID: PMC3547025 DOI: 10.1371/journal.pone.0053534] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 12/03/2012] [Indexed: 11/18/2022] Open
Abstract
Young and adult mammals are constantly exposed to chemically complex stimuli. The olfactory system allows for a dual processing of relevant information from the environment either as single odorants in mixtures (elemental perception) or as mixtures of odorants as a whole (configural perception). However, it seems that human adults have certain limits in elemental perception of odor mixtures, as suggested by their inability to identify each odorant in mixtures of more than 4 components. Here, we explored some of these limits by evaluating the perception of three 6-odorant mixtures in human adults and newborn rabbits. Using free-sorting tasks in humans, we investigated the configural or elemental perception of these mixtures, or of 5-component sub-mixtures, or of the 6-odorant mixtures with modified odorants' proportion. In rabbit pups, the perception of the same mixtures was evaluated by measuring the orocephalic sucking response to the mixtures or their components after conditioning to one of these stimuli. The results revealed that one mixture, previously shown to carry the specific odor of red cordial in humans, was indeed configurally processed in humans and in rabbits while the two other 6-component mixtures were not. Moreover, in both species, such configural perception was specific not only to the 6 odorants included in the mixture but also to their respective proportion. Interestingly, rabbit neonates also responded to each odorant after conditioning to the red cordial mixture, which demonstrates their ability to perceive elements in addition to configuration in this complex mixture. Taken together, the results provide new insights related to the processing of relatively complex odor mixtures in mammals and the inter-species conservation of certain perceptual mechanisms; the results also revealed some differences in the expression of these capacities between species putatively linked to developmental and ecological constraints.
Collapse
Affiliation(s)
| | | | | | - Noelle Béno
- Centre des Sciences du Goût et de l'Alimentation, Dijon, France
| | - Thibaut Dosne
- Centre des Sciences du Goût et de l'Alimentation, Dijon, France
| | - Claire Chabanet
- Centre des Sciences du Goût et de l'Alimentation, Dijon, France
| | - Benoist Schaal
- Centre des Sciences du Goût et de l'Alimentation, Dijon, France
| | - Gérard Coureaud
- Centre des Sciences du Goût et de l'Alimentation, Dijon, France
- * E-mail: (TTD); (GC)
| |
Collapse
|
90
|
Pierron D, Cortés NG, Letellier T, Grossman LI. Current relaxation of selection on the human genome: tolerance of deleterious mutations on olfactory receptors. Mol Phylogenet Evol 2012; 66:558-64. [PMID: 22906809 DOI: 10.1016/j.ympev.2012.07.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 07/20/2012] [Accepted: 07/27/2012] [Indexed: 01/24/2023]
Abstract
Knowledge and understanding about the selective pressures that have shaped present human genetic diversity have dramatically increased in the last few years in parallel with the availability of large genomic datasets. The release of large datasets composed of millions of SNPs across hundreds of genomes by HAPMAP, the Human Genome Diversity Panel, and other projects has led to considerable effort to detect selection signals across the nuclear genome (Coop et al., 2009; Lopez Herraez et al., 2009; Sabeti et al., 2006, 2007; Voight et al., 2006). Most of the research has focused on positive selection forces although other selective forces, such as negative selection, may have played a substantive role on the shape of our genome. Here we studied the selective strengths acting presently on the genome by making computational predictions of the pathogenicity of nonsynonymous protein mutations and interpreting the distribution of scores in terms of selection. We could show that the genetic diversity for all the major pathways is still constrained by negative selection in all 11 human populations studied. In a single exception, we observed a relaxation of negative selection acting on olfactory receptors. Since a decreased number of functioning olfactory receptors in human compared with other primates had already been shown, this suggests that the role of olfactory receptors for survival and reproductive success has decreased during human evolution. By showing that negative selection is still relaxed, the present results imply that no plateau of minimal function has yet been reached in modern humans and therefore that olfactory capability might still be decreasing. This is a first clue to present human evolution.
Collapse
Affiliation(s)
- Denis Pierron
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | | | | | | |
Collapse
|
91
|
Doty RL. Has human olfaction evolved primarily to provide flavor to foods? Trends Neurosci 2012. [DOI: 10.1016/j.tins.2011.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
92
|
Behaviour and hormonal status in healthy rats on a diet rich in Maillard reaction products with or without solvent extractable aroma compounds. Physiol Behav 2012; 105:693-701. [DOI: 10.1016/j.physbeh.2011.10.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 09/27/2011] [Accepted: 10/04/2011] [Indexed: 02/02/2023]
|
93
|
|
94
|
Bastir M, Rosas A, Gunz P, Peña-Melian A, Manzi G, Harvati K, Kruszynski R, Stringer C, Hublin JJ. Evolution of the base of the brain in highly encephalized human species. Nat Commun 2011; 2:588. [PMID: 22158443 DOI: 10.1038/ncomms1593] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 11/14/2011] [Indexed: 01/14/2023] Open
Abstract
The increase of brain size relative to body size-encephalization-is intimately linked with human evolution. However, two genetically different evolutionary lineages, Neanderthals and modern humans, have produced similarly large-brained human species. Thus, understanding human brain evolution should include research into specific cerebral reorganization, possibly reflected by brain shape changes. Here we exploit developmental integration between the brain and its underlying skeletal base to test hypotheses about brain evolution in Homo. Three-dimensional geometric morphometric analyses of endobasicranial shape reveal previously undocumented details of evolutionary changes in Homo sapiens. Larger olfactory bulbs, relatively wider orbitofrontal cortex, relatively increased and forward projecting temporal lobe poles appear unique to modern humans. Such brain reorganization, beside physical consequences for overall skull shape, might have contributed to the evolution of H. sapiens' learning and social capacities, in which higher olfactory functions and its cognitive, neurological behavioral implications could have been hitherto underestimated factors.
Collapse
Affiliation(s)
- Markus Bastir
- Paleoanthropology Group, Department of Paleobiology, Museo Nacional de Ciencias Naturales, CSIC. J. G. Abascal 2, 28006 Madrid, Spain.
| | | | | | | | | | | | | | | | | |
Collapse
|
95
|
Kummer K, Klement S, Eggart V, Mayr MJ, Saria A, Zernig G. Conditioned place preference for social interaction in rats: contribution of sensory components. Front Behav Neurosci 2011; 5:80. [PMID: 22232578 PMCID: PMC3246900 DOI: 10.3389/fnbeh.2011.00080] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 11/14/2011] [Indexed: 11/13/2022] Open
Abstract
A main challenge in the therapy of drug dependent individuals is to help them reactivate interest in non-drug-associated activities. We previously developed a rat experimental model based on the conditioned place preference (CPP) paradigm in which only four 15-min episodes of social interaction with a gender- and weight-matched male Sprague Dawley rat (1) reversed CPP from cocaine to social interaction despite continuing cocaine training and (2) prevented the reinstatement of cocaine CPP. In the present study, we investigated which of the sensory modalities of the composite stimulus "social interaction" contributes most to the rats' preference for it. If touch was limited by steel bars spaced at a distance of 2 cm and running across the whole length of a partitioning, CPP was still acquired, albeit to a lesser degree. If both rats were placed on the same side of a partitioning, rats did not develop CPP for social interaction. Thus, decreasing the available area for social interaction from 750 to 375 cm(2) prevented the acquisition of CPP to social interaction despite the fact that animals could touch each other more intensely than through the bars of the partitioning. When touch was fully restricted by a glass screen dividing the conditioning chambers, and the only sensory modalities left were visual and olfactory cues, place preference shifted to place aversion. Overall, our findings indicate that the major rewarding sensory component of the composite stimulus "social interaction" is touch (taction).
Collapse
Affiliation(s)
- Kai Kummer
- Experimental Psychiatry Unit, Center of Psychiatry and Psychotherapy, Innsbruck Medical University Innsbruck, Austria
| | | | | | | | | | | |
Collapse
|
96
|
Midbrain dopamine neurons associated with reward processing innervate the neurogenic subventricular zone. J Neurosci 2011; 31:13078-87. [PMID: 21917791 DOI: 10.1523/jneurosci.1197-11.2011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Coordinated regulation of the adult neurogenic subventricular zone (SVZ) is accomplished by a myriad of intrinsic and extrinsic factors. The neurotransmitter dopamine is one regulatory molecule implicated in SVZ function. Nigrostriatal and ventral tegmental area (VTA) midbrain dopamine neurons innervate regions adjacent to the SVZ, and dopamine synapses are found on SVZ cells. Cell division within the SVZ is decreased in humans with Parkinson's disease and in animal models of Parkinson's disease following exposure to toxins that selectively remove nigrostriatal neurons, suggesting that dopamine is critical for SVZ function and nigrostriatal neurons are the main suppliers of SVZ dopamine. However, when we examined the aphakia mouse, which is deficient in nigrostriatal neurons, we found no detrimental effect to SVZ proliferation or organization. Instead, dopamine innervation of the SVZ tracked to neurons at the ventrolateral boundary of the VTA. This same dopaminergic neuron population also innervated the SVZ of control mice. Characterization of these neurons revealed expression of proteins indicative of VTA neurons. Furthermore, exposure to the neurotoxin MPTP depleted neurons in the ventrolateral VTA and resulted in decreased SVZ proliferation. Together, these results reveal that dopamine signaling in the SVZ originates from a population of midbrain neurons more typically associated with motivational and reward processing.
Collapse
|
97
|
De Smet D, Van Speybroeck L, Verplaetse J. Why humans do not make good vampires. Testing the ability of humans to detect true blood. Ann Hum Biol 2011; 39:1-10. [DOI: 10.3109/03014460.2011.629681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
98
|
Lundström JN, Boesveldt S, Albrecht J. Central Processing of the Chemical Senses: an Overview. ACS Chem Neurosci 2011; 2:5-16. [PMID: 21503268 PMCID: PMC3077578 DOI: 10.1021/cn1000843] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 11/04/2010] [Indexed: 11/28/2022] Open
Abstract
Our knowledge regarding the neural processing of the three chemical senses has been lagging behind that of our other senses considerably. It is only during the last 25 years that significant advances have been made in our understanding of where in the human brain odors, tastants, and trigeminal stimuli are processed. Here we provide an overview of the current knowledge of how the human brain processes chemical stimuli based on findings in neuroimaging studies using positron emission tomography and functional magnetic resonance imaging. Additionally, we provide new insights from recent meta-analyses, based on all published neuroimaging studies of the chemical senses, of where the chemical senses converge in the brain.
Collapse
Affiliation(s)
- Johan N. Lundström
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States
- Department of Psychology, University of Pennsylvania, Pennsylvania, United States
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Sanne Boesveldt
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States
- Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - Jessica Albrecht
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States
| |
Collapse
|
99
|
De Groof G, Gwinner H, Steiger S, Kempenaers B, Van der Linden A. Neural correlates of behavioural olfactory sensitivity changes seasonally in European starlings. PLoS One 2010; 5:e14337. [PMID: 21179464 PMCID: PMC3002280 DOI: 10.1371/journal.pone.0014337] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 11/24/2010] [Indexed: 11/19/2022] Open
Abstract
Background Possibly due to the small size of the olfactory bulb (OB) as compared to rodents, it was generally believed that songbirds lack a well-developed sense of smell. This belief was recently revised by several studies showing that various bird species, including passerines, use olfaction in many respects of life. During courtship and nest building, male European starlings (Sturnus vulgaris) incorporate aromatic herbs that are rich in volatile compounds (e.g., milfoil, Achillea millefolium) into the nests and they use olfactory cues to identify these plants. Interestingly, European starlings show seasonal differences in their ability to respond to odour cues: odour sensitivity peaks during nest-building in the spring, but is almost non-existent during the non-breeding season. Methodology/Principal Findings This study used repeated in vivo Manganese-enhanced MRI to quantify for the first time possible seasonal changes in the anatomy and activity of the OB in starling brains. We demonstrated that the OB of the starling exhibits a functional seasonal plasticity of certain plant odour specificity and that the OB is only able to detect milfoil odour during the breeding season. Volumetric analysis showed that this seasonal change in activity is not linked to a change in OB volume. By subsequently experimentally elevating testosterone (T) in half of the males during the non-breeding season we showed that the OB volume was increased compared to controls. Conclusions/Significance By investigating the neural substrate of seasonal olfactory sensitivity changes we show that the starlings' OB loses its ability during the non-breeding season to detect a natural odour of a plant preferred as green nest material by male starlings. We found that testosterone, applied during the non-breeding season, does not restore the discriminatory ability of the OB but has an influence on its size.
Collapse
Affiliation(s)
- Geert De Groof
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium.
| | | | | | | | | |
Collapse
|
100
|
Setchell JM, Huchard E. The hidden benefits of sex: evidence for MHC-associated mate choice in primate societies. Bioessays 2010; 32:940-8. [PMID: 20827785 DOI: 10.1002/bies.201000066] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Major histocompatibility complex (MHC)-associated mate choice is thought to give offspring a fitness advantage through disease resistance. Primates offer a unique opportunity to understand MHC-associated mate choice within our own zoological order, while their social diversity provides an exceptional setting to examine the genetic determinants and consequences of mate choice in animal societies. Although mate choice is constrained by social context, increasing evidence shows that MHC-dependent mate choice occurs across the order in a variety of socio-sexual systems and favours mates with dissimilar, diverse or specific genotypes non-exclusively. Recent research has also identified phenotypic indicators of MHC quality. Moreover, novel findings rehabilitate the importance of olfactory cues in signalling MHC genes and influencing primate mating decisions. These findings underline the importance to females of selecting a sexual partner of high genetic quality, as well as the generality of the role of MHC genes in sexual selection.
Collapse
Affiliation(s)
- Joanna M Setchell
- Evolutionary Anthropology Research Group, Department of Anthropology, Durham University, Durham, UK.
| | | |
Collapse
|