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Sample records for adult olfactory system

  1. Adult Neurogenesis and the Olfactory System

    PubMed Central

    Whitman, Mary C.; Greer, Charles A.

    2009-01-01

    Though initially described in the early 1960s, it is only within the past decade that the concept of continuing adult neurogenesis has gained widespread acceptance. Neuroblasts from the subventricular zone (SVZ) migrate along the rostral migratory stream (RMS) into the olfactory bulb, where they differentiate into interneurons. Neuroblasts from the subgranular zone (SGZ) of the hippocampal formation show relatively little migratory behavior, and differentiate into dentate gyrus granule cells. In sharp contrast to embryonic and perinatal development, these newly differentiated neurons must integrate into a fully functional circuit, without disrupting ongoing performance. Here, after a brief historical overview and introduction to olfactory circuitry, we review recent advances in the biology of neural stem cells, mechanisms of migration in the RMS and olfactory bulb, differentiation and survival of new neurons, and finally mechanisms of synaptic integration. Our primary focus is on the olfactory system, but we also contrast the events occurring there with those in the hippocampal formation. Although both SVZ and SGZ neurogenesis are involved in some types of learning, their full functional significance remains unclear. Since both systems offer models of integration of new neuroblasts, there is immense interest in using neural stem cells to replace neurons lost in injury or disease. Though many questions remain unanswered, new insights appear daily about adult neurogenesis, regulatory mechanisms, and the fates of the progeny. We discuss here some of the central features of these advances, as well as speculate on future research directions. PMID:19615423

  2. Adult Olfactory Bulb Neurogenesis.

    PubMed

    Lledo, Pierre-Marie; Valley, Matt

    2016-01-01

    Most organisms use their olfactory system to detect and analyze chemical cues from the external world to guide essential behaviors. From worms to vertebrates, chemicals are detected by odorant receptors expressed by olfactory sensory neurons, which in vertebrates send an axon to the primary processing center called the olfactory bulb (OB). Within the OB, sensory neurons form excitatory synapses with projection neurons and with inhibitory interneurons. Thus, because of complex synaptic interactions, the output of a given projection neuron is determined not only by the sensory input, but also by the activity of local inhibitory interneurons that are regenerated throughout life in the process of adult neurogenesis. Herein, we discuss how it is optimized and why. PMID:27235474

  3. Expression of the NMDA receptor subunit GluN3A (NR3A) in the olfactory system and its regulatory role on olfaction in the adult mouse.

    PubMed

    Lee, Jin Hwan; Wei, Ling; Deveau, Todd C; Gu, Xiaohuan; Yu, Shan Ping

    2016-07-01

    Glutamate is an excitatory neurotransmitter in the olfactory system and its N-methyl-D-aspartate-(NMDA) receptor subunits [GluN1 (NR1), GluN2A (NR2A), and GluN2B (NR2B)] are expressed at synapses in the olfactory bulb and olfactory epithelium. Thus, glutamatergic neurons and NMDA receptors play key roles in olfaction. GluN3A (NR3A) is a unique inhibitory subunit in the NMDA receptor complex; however, the expression and functional role of GluN3A in the olfactory bulb and epithelium remain unclear. The present study examined the expression patterns of GluN3A in the olfactory bulb and epithelium and explored its functional role in the olfactory system. Immunohistochemical and Western blot analyses revealed that GluN3A is abundantly expressed in different cellular layers of the olfactory bulb and epithelium of the adult wild type (WT) mice. In littermate GluN3A knockout (GluN3A(-/-); KO) mice, the expression of olfactory marker protein normally found in mature olfactory sensory neurons was significantly reduced in the olfactory bulb and epithelium. A butyl alcohol stimulus increased immediate-early gene c-Fos expression in the olfactory system of WT mice, while this response was absent in GluN3A KO mice. The level of phosphorylated Ca(2+)/calmodulin-dependent kinase II was significantly lower in GluN3A KO mice compared to WT mice. In buried food finding test, GluN3A mice took significantly longer time to find food compared to WT mice. Consistently, impaired odor distinguishing ability was seen in GluN3A KO mice. These findings suggest that GluN3A, expressed in the adult olfactory system, plays a significant regulatory role in olfactory development and functional activity. PMID:26334321

  4. Reversible Deafferentation of the Adult Zebrafish Olfactory Bulb Affects Glomerular Distribution and Olfactory-Mediated Behavior

    PubMed Central

    Paskin, Taylor R.; Byrd-Jacobs, Christine A.

    2012-01-01

    The olfactory system is a useful model for studying central nervous system recovery from damage due to its neuroplasticity. We recently developed a novel method of deafferentation by repeated exposure of Triton X-100 to the olfactory organ of adult zebrafish. This long-term, reversible method of deafferentation allows both degeneration and regeneration to be observed in the olfactory bulb. The aim of the present study is to examine olfactory bulb innervation, glomerular patterns, and olfactory-mediated behavior with repeated Triton X-100 treatment and the potential for recovery following cessation of treatment. Olfactory bulbs of control, chronic-treated, and recovery animals were examined for the presence or absence of glomeruli that have been identified in the zebrafish glomerular map. Following chronic treatment, the number of glomeruli was dramatically reduced; however, partial innervation remained in the lateral region of the bulb. When animals were given time to recover, complete glomerular distribution returned. A behavioral assay was developed to determine if innervation remaining correlated with behavior of the fish. Chronic-treated fish did not respond to odorants involved with social behavior but continued to react to odorants that mediate feeding behavior. Following recovery, responses to odorants involved with social behavior returned. The morphological and behavioral effects of chronic Triton X-100 treatment in the olfactory system suggest there may be differential susceptibility or resistance to external damage in a subset of sensory neurons. The results of this study demonstrate the remarkable regenerative ability of the olfactory system following extensive and long-term injury. PMID:22963994

  5. Reversible deafferentation of the adult zebrafish olfactory bulb affects glomerular distribution and olfactory-mediated behavior.

    PubMed

    Paskin, Taylor R; Byrd-Jacobs, Christine A

    2012-12-01

    The olfactory system is a useful model for studying central nervous system recovery from damage due to its neuroplasticity. We recently developed a novel method of deafferentation by repeated exposure of Triton X-100 to the olfactory organ of adult zebrafish. This long-term, reversible method of deafferentation allows both degeneration and regeneration to be observed in the olfactory bulb. The aim of the present study is to examine olfactory bulb innervation, glomerular patterns, and olfactory-mediated behavior with repeated Triton X-100 treatment and the potential for recovery following cessation of treatment. Olfactory bulbs of control, chronic-treated, and recovery animals were examined for the presence or absence of glomeruli that have been identified in the zebrafish glomerular map. Following chronic treatment, the number of glomeruli was dramatically reduced; however, partial innervation remained in the lateral region of the bulb. When animals were given time to recover, complete glomerular distribution returned. A behavioral assay was developed to determine if innervation remaining correlated with behavior of the fish. Chronic-treated fish did not respond to odorants involved with social behavior but continued to react to odorants that mediate feeding behavior. Following recovery, responses to odorants involved with social behavior returned. The morphological and behavioral effects of chronic Triton X-100 treatment in the olfactory system suggest there may be differential susceptibility or resistance to external damage in a subset of sensory neurons. The results of this study demonstrate the remarkable regenerative ability of the olfactory system following extensive and long-term injury. PMID:22963994

  6. Wiring stability of the adult Drosophila olfactory circuit after lesion.

    PubMed

    Berdnik, Daniela; Chihara, Takahiro; Couto, Africa; Luo, Liqun

    2006-03-29

    Neuronal wiring plasticity in response to experience or injury has been reported in many parts of the adult nervous system. For instance, visual or somatosensory cortical maps can reorganize significantly in response to peripheral lesions, yet a certain degree of stability is essential for neuronal circuits to perform their dedicated functions. Previous studies on lesion-induced neuronal reorganization have primarily focused on systems that use continuous neural maps. Here, we assess wiring plasticity in a discrete neural map represented by the adult Drosophila olfactory circuit. Using conditional expression of toxins, we genetically ablated specific classes of neurons and examined the consequences on their synaptic partners or neighboring classes in the adult antennal lobe. We find no alteration of connection specificity between olfactory receptor neurons (ORNs) and their postsynaptic targets, the projection neurons (PNs). Ablating an ORN class maintains PN dendrites within their glomerular borders, and ORN axons normally innervating an adjacent target do not expand. Likewise, ablating PN classes does not alter their partner ORN axon connectivity. Interestingly, an increase in the contralateral ORN axon terminal density occurs in response to the removal of competing ipsilateral ORNs. Therefore, plasticity in this circuit can occur but is confined within a glomerulus, thereby retaining the wiring specificity of ORNs and PNs. We conclude that, although adult olfactory neurons can undergo plastic changes in response to the loss of competition, the olfactory circuit overall is extremely stable in preserving segregated information channels in this discrete map. PMID:16571743

  7. Follistatin-like 5 is expressed in restricted areas of the adult mouse brain: Implications for its function in the olfactory system.

    PubMed

    Masuda, Tomoyuki; Sakuma, Chie; Nagaoka, Atsuko; Yamagishi, Toshiyuki; Ueda, Shuichi; Nagase, Takahiro; Yaginuma, Hiroyuki

    2014-02-01

    Follistatin-like 5 (Fstl5), a member of the follistatin family of genes, encodes a secretory glycoprotein. Previous studies revealed that other members of this family including Fstl1 and Fstl3 play an essential role in development, homeostasis, and congenital disorders. However, the in vivo function of Fstl5 is poorly understood. To gain insight into the function of Fstl5 in the mouse central nervous system, we examined the Fstl5 expression pattern in the adult mouse brain. The results of in situ hybridization analysis showed a highly restricted pattern of Fstl5, namely, with localization in the olfactory system, hippocampal CA3 area and granular cell layer of the cerebellum. Restricted expression in the olfactory system suggests a possible role for Fstl5 in maintaining odor perception. PMID:24588779

  8. Aberrant Adult Neurogenesis in the Subventricular Zone-Rostral Migratory Stream-Olfactory Bulb System Following Subchronic Manganese Exposure.

    PubMed

    Fu, Sherleen; Jiang, Wendy; Gao, Xiang; Zeng, Andrew; Cholger, Daniel; Cannon, Jason; Chen, Jinhui; Zheng, Wei

    2016-04-01

    Adult neurogenesis occurs in brain subventricular zone (SVZ). Our recent data reveal an elevated proliferation of BrdU(+) cells in SVZ following subchronic manganese (Mn) exposure in rats. This study was designed to distinguish Mn effect on the critical stage of adult neurogenesis, ie, proliferation, migration, survival and differentiation from the SVZ via the rostral migratory stream to the olfactory bulb (OB). Adult rats received a single ip-dose of BrdU at the end of 4-week Mn exposure to label proliferating cells. Immunostaining and cell-counting showed a 48% increase of BrdU(+) cells in Mn-exposed SVZ than in controls (P< .05). These BrdU(+) cells were identified as a mixed population of mainly GFAP(+) type-B neural stem cells, Nestin(+) type-C transit progenitor cells, DCX(+) migratory neuroblasts and Iba1(+) microglial cells. Another group of adult rats received 3 daily ip-injections of BrdU followed by subchronic Mn exposure. By 4-week post BrdU labeling, most of the surviving BrdU(+) cells in the OB were differentiated into NeuN(+) matured neurons. However, survival rates of BrdU/NeuN/DAPI triple-labeled cells in OB were 33% and 64% in Mn-exposed and control animals, respectively (P< .01). Infusion of Cu directly into the lateral ventricle significantly decreased the cell proliferation in the SVZ. Taken together, these results suggest that Mn exposure initially enhances the cell proliferation in adult SVZ. In the OB, however, Mn exposure significantly reduces the surviving adult-born cells and markedly inhibits their differentiation into mature neurons, resulting in an overall decreased adult neurogenesis in the OB. PMID:26794142

  9. A lifetime of neurogenesis in the olfactory system.

    PubMed

    Brann, Jessica H; Firestein, Stuart J

    2014-01-01

    Neurogenesis continues well beyond embryonic and early postnatal ages in three areas of the nervous system. The subgranular zone supplies new neurons to the dentate gyrus of the hippocampus. The subventricular zone supplies new interneurons to the olfactory bulb, and the olfactory neuroepithelia generate new excitatory sensory neurons that send their axons to the olfactory bulb. The latter two areas are of particular interest as they contribute new neurons to both ends of a first-level circuit governing olfactory perception. The vomeronasal organ and the main olfactory epithelium comprise the primary peripheral olfactory epithelia. These anatomically distinct areas share common features, as each exhibits extensive neurogenesis well beyond the juvenile phase of development. Here we will discuss the effect of age on the structural and functional significance of neurogenesis in the vomeronasal and olfactory epithelia, from juvenile to advanced adult ages, in several common model systems. We will next discuss how age affects the regenerative capacity of these neural stem cells in response to injury. Finally, we will consider the integration of newborn neurons into an existing circuit as it is modified by the age of the animal. PMID:25018692

  10. From chemical neuroanatomy to an understanding of the olfactory system

    PubMed Central

    Oboti, L.; Peretto, P.; De Marchis, S.; Fasolo, A.

    2011-01-01

    The olfactory system of mammals is the appropriate model for studying several aspects of neuronal physiology spanning from the developmental stage to neural network remodelling in the adult brain. Both the morphological and physiological understanding of this system were strongly supported by classical histochemistry. It is emblematic the case of the Olfactory Marker Protein (OMP) staining, the first, powerful marker for fully differentiated olfactory receptor neurons and a key tool to investigate the dynamic relations between peripheral sensory epithelia and central relay regions given its presence within olfactory fibers reaching the olfactory bulb (OB). Similarly, the use of thymidine analogues was able to show neurogenesis in an adult mammalian brain far before modern virus labelling and lipophilic tracers based methods. Nowadays, a wealth of new histochemical techniques combining cell and molecular biology approaches is available, giving stance to move from the analysis of the chemically identified circuitries to functional research. The study of adult neurogenesis is indeed one of the best explanatory examples of this statement. After defining the cell types involved and the basic physiology of this phenomenon in the OB plasticity, we can now analyze the role of neurogenesis in well testable behaviours related to socio-chemical communication in rodents. PMID:22297441

  11. From chemical neuroanatomy to an understanding of the olfactory system.

    PubMed

    Oboti, L; Peretto, P; Marchis, S De; Fasolo, A

    2011-01-01

    The olfactory system is the appropriate model for studying several aspects of neuronal physiology spanning from the developmental stage to neural network remodelling in the adult brain. Both the morphological and physiological understanding of this system were strongly supported by classical histochemistry. It is emblematic the case of the Olfactory Marker Protein (OMP) staining, the first, powerful marker for fully differentiated olfactory receptor neurons and a key tool to investigate the dynamic relations between peripheral sensory epithelia and central relay regions given its presence within olfactory fibers reaching the olfactory bulb (OB). Similarly, the use of thymidine analogues was able to show neurogenesis in an adult mammalian brain far before modern virus labelling and lipophilic tracers based methods. Nowadays, a wealth of new histochemical techniques combining cell and molecular biology approaches is available, giving stance to move from the analysis of the chemically identified circuitries to functional research. The study of adult neurogenesis is indeed one of the best explanatory examples of this statement. After defining the cell types involved and the basic physiology of this phenomenon in the OB plasticity, we can now analyze the role of neurogenesis in well testable behaviours related to socio-chemical communication in rodents. PMID:22297441

  12. Unraveling Cajal's view of the olfactory system

    PubMed Central

    Figueres-Oñate, María; Gutiérrez, Yolanda; López-Mascaraque, Laura

    2014-01-01

    The olfactory system has a highly regular organization of interconnected synaptic circuits from the periphery. It is therefore an excellent model for understanding general principles about how the brain processes information. Cajal revealed the basic cell types and their interconnections at the end of the XIX century. Since his original descriptions, the observation and analysis of the olfactory system and its components represents a major topic in neuroscience studies, providing important insights into the neural mechanisms. In this review, we will highlight the importance of Cajal contributions and his legacy to the actual knowledge of the olfactory system. PMID:25071462

  13. [Odor sensing system and olfactory display].

    PubMed

    Nakamoto, Takamichi

    2014-01-01

    In this review, an odor sensing system and an olfactory display are introduced into people in pharmacy. An odor sensing system consists of an array of sensors with partially overlapping specificities and pattern recognition technique. One of examples of odor sensing systems is a halitosis sensor which quantifies the mixture composition of three volatile sulfide compounds. A halitosis sensor was realized using a preconcentrator to raise sensitivity and an electrochemical sensor array to suppress the influence of humidity. Partial least squares (PLS) method was used to quantify the mixture composition. The experiment reveals that the sufficient accuracy was obtained. Moreover, the olfactory display, which present scents to human noses, is explained. A multi-component olfactory display enables the presentation of a variety of smells. The two types of multi-component olfactory display are described. The first one uses many solenoid valves with high speed switching. The valve ON frequency determines the concentration of the corresponding odor component. The latter one consists of miniaturized liquid pumps and a surface acoustic wave (SAW) atomizer. It enables the wearable olfactory display without smell persistence. Finally, the application of the olfactory display is demonstrated. Virtual ice cream shop with scents was made as a content of interactive art. People can enjoy harmony among vision, audition and olfaction. In conclusion, both odor sensing system and olfactory display can contribute to the field of human health care. PMID:24584010

  14. Id2 IS REQUIRED FOR SPECIFICATION OF DOPAMINERGIC NEURONS DURING ADULT OLFACTORY NEUROGENESIS

    PubMed Central

    Havrda, Matthew C.; Harris, Brent T.; Mantani, Akio; Ward, Nora M.; Paolella, Brenton R.; Cuzon, Verginia C.; Yeh, Hermes H.; Israel, Mark A.

    2009-01-01

    Understanding the biology of adult neural stem cells has important implications for nervous system development and may contribute to our understanding of neurodegenerative disorders and their treatment. We have characterized the process of olfactory neurogenesis in adult mice lacking Inhibitor of DNA Binding 2 (Id2). We found a diminished olfactory bulb containing reduced numbers of granular and periglomerular neurons with a distinct paucity of dopaminergic periglomerular neurons. While no deficiency of the stem cell compartment was detectable, migrating neuroblasts in Id2−/− mutant mice prematurely undergo astroglial differentiation within a disorganized rostral migratory stream. Further, when evaluated in vitro loss of Id2 results in decreased proliferation of neural progenitors and decreased expression of the Hes1 and Mash1 transcription factors, known mediators of neuronal differentiation. These data support a novel role for sustained Id2 expression in migrating neural progenitors mediating olfactory dopaminergic neuronal differentiation in adult animals. PMID:19109490

  15. Early Olfactory Environment Influences Social Behaviour in Adult Octodon degus

    PubMed Central

    Márquez, Natalia; Martínez-Harms, Jaime; Vásquez, Rodrigo A.; Mpodozis, Jorge

    2015-01-01

    We evaluated the extent to which manipulation of early olfactory environment can influence social behaviours in the South American Hystricognath rodent Octodon degus. The early olfactory environment of newborn degus was manipulated by scenting all litter members with eucalyptol during the first month of life. The social behaviour of sexually mature animals (5–7 months old) towards conspecifics was then assessed using a y-maze to compare the response of control (naïve) and treated animals to two different olfactory configurations (experiment 1): (i) a non-familiarized conspecific impregnated with eucalyptol (eucalyptol arm) presented against (ii) a non-familiarized unscented conspecific (control arm). In addition, in dyadic encounters, we assessed the behaviour of control and eucalyptol treated animals towards a non-familiarized conspecific scented with eucalyptol (experiment 2). We found that control subjects explored and spent significantly less time in the eucalyptol arm, indicating neophobic behaviours towards the artificially scented conspecific. Treated subjects explored and spent similar time in both arms of the maze, showing the same interest for both olfactory stimuli presented. During dyadic encounters in experiment 2, an interaction effect between early experience and sex was observed. Control males escaped and avoided their scented partner more frequently than eucalyptol treated male subjects and than females. Both groups did not differ in the exploration of their scented partners, suggesting that avoidance within agonistic context does not relate to neophobic behaviours. Our results suggest that the exposure to eucalyptol during early ontogeny decreases evasive behaviours within an agonistic context as a result of olfactory learning. Altogether, these results indicate that olfactory cues learned in early ontogeny can influence olfactory-guided behaviours in adult degus. PMID:25671542

  16. Adult neurogenesis restores dopaminergic neuronal loss in the olfactory bulb.

    PubMed

    Lazarini, Françoise; Gabellec, Marie-Madeleine; Moigneu, Carine; de Chaumont, Fabrice; Olivo-Marin, Jean-Christophe; Lledo, Pierre-Marie

    2014-10-22

    Subventricular zone (SVZ) neurogenesis continuously provides new GABA- and dopamine (DA)-containing interneurons for the olfactory bulb (OB) in most adult mammals. DAergic interneurons are located in the glomerular layer (GL) where they participate in the processing of sensory inputs. To examine whether adult neurogenesis might contribute to regeneration after circuit injury in mice, we induce DAergic neuronal loss by injecting 6-hydroxydopamine (6-OHDA) in the dorsal GL or in the right substantia nigra pars compacta. We found that a 6-OHDA treatment of the OB produces olfactory deficits and local inflammation and partially decreases the number of neurons expressing the enzyme tyrosine hydroxylase (TH) near the injected site. Blockade of inflammation by minocycline treatment immediately after the 6-OHDA administration rescued neither TH(+) interneuron number nor the olfactory deficits, suggesting that the olfactory impairments are most likely linked to TH(+) cell death and not to microglial activation. TH(+) interneuron number was restored 1 month later. This rescue resulted at least in part from enhanced recruitment of immature neurons targeting the lesioned GL area. Seven days after 6-OHDA lesion in the OB, we found that the integration of lentivirus-labeled adult-born neurons was biased: newly formed neurons were preferentially incorporated into glomerular circuits of the lesioned area. Behavioral rehabilitation occurs 2 months after lesion. This study establishes a new model into which loss of DAergic cells could be compensated by recruiting newly formed neurons. We propose that adult neurogenesis not only replenishes the population of DAergic bulbar neurons but that it also restores olfactory sensory processing. PMID:25339754

  17. Expression of polysialyltransferases (STX and PST) in adult rat olfactory bulb after an olfactory associative discrimination task.

    PubMed

    Mione, J; Manrique, C; Duhoo, Y; Roman, F S; Guiraudie-Capraz, G

    2016-04-01

    Neuronal plasticity and neurogenesis occur in the adult hippocampus and in other brain structures such as the olfactory bulb and often involve the neural cell adhesion molecule NCAM. During an olfactory associative discrimination learning task, NCAM polysialylation triggers neuronal plasticity in the adult hippocampus. The PST enzyme likely modulates this polysialylation, but not STX, a second sialyltransferase. How the two polysialyltransferases are involved in the adult olfactory bulb remains unknown. We addressed this question by investigating the effect of olfactory associative learning on plasticity and neurogenesis. After a hippocampo-dependent olfactory associative task learning, we measured the expression of both PST and STX polysialyltransferases in the olfactory bulbs of adult rats using quantitative PCR. In parallel, immunohistochemistry was used to evaluate both NCAM polysialylation level and newly-born cells, with or without learning. After learning, no changes were observed neither in the expression level of PST and NCAM polysialylation, nor in STX gene expression level and newly-born cells number in the olfactory bulb. PMID:26844880

  18. Interactions with the young down-regulate adult olfactory neurogenesis and enhance the maturation of olfactory neuroblasts in sheep mothers

    PubMed Central

    Brus, Maïna; Meurisse, Maryse; Keller, Matthieu; Lévy, Frédéric

    2014-01-01

    New neurons are continuously added in the dentate gyrus (DG) and the olfactory bulb of mammalian brain. While numerous environmental factors controlling survival of newborn neurons have been extensively studied, regulation by social interactions is less documented. We addressed this question by investigating the influence of parturition and interactions with the young on neurogenesis in sheep mothers. Using Bromodeoxyuridine, a marker of cell division, in combination with markers of neuronal maturation, the percentage of neuroblasts and new mature neurons in the olfactory bulb and the DG was compared between groups of parturient ewes which could interact or not with their lamb, and virgins. In addition, a morphological analysis was performed by measuring the dendritic arbor of neuroblasts in both structures. We showed that the postpartum period was associated with a decrease in olfactory and hippocampal adult neurogenesis. In the olfactory bulb, the suppressive effect on neuroblasts was dependent on interactions with the young whereas in the DG the decrease in new mature neurons was associated with parturition. In addition, dendritic length and number of nodes of neuroblasts were significantly enhanced by interactions with the lamb in the olfactory bulb but not in the DG. Because interactions with the young involved learning of the olfactory signature of the lamb, we hypothesize that this learning is associated with a down-regulation in olfactory neurogenesis and an enhancement of olfactory neuroblast maturation. Our assumption is that fewer new neurons decrease cell competition in the olfactory bulb and enhance maturation of those new neurons selected to participate in the learning of the young odor. PMID:24600367

  19. Interneurons in the human olfactory system in Alzheimer's disease.

    PubMed

    Saiz-Sanchez, Daniel; Flores-Cuadrado, Alicia; Ubeda-Bañon, Isabel; de la Rosa-Prieto, Carlos; Martinez-Marcos, Alino

    2016-02-01

    The principal olfactory structures display Alzheimer's disease (AD) related pathology at early stages of the disease. Consequently, olfactory deficits are among the earliest symptoms. Reliable olfactory tests for accurate clinical diagnosis are rarely made. In addition, neuropathological analysis postmortem of olfactory structures is often not made. Therefore, the relationship between the clinical features and the underlying pathology is poorly defined. Traditionally, research into Alzheimer's disease has focused on the degeneration of cortical temporal projection neurons and cholinergic neurons. Recent evidence has demonstrated the neurodegeneration of interneuron populations in AD. This review provides an updated overview of the pathological involvement of interneuron populations in the human olfactory system in Alzheimer's disease. PMID:26616239

  20. Electrophysiological Measurements from a Moth Olfactory System

    PubMed Central

    Syed, Zainulabeuddin; Leal, Walter S.

    2011-01-01

    Insect olfactory systems provide unique opportunities for recording odorant-induced responses in the forms of electroantennograms (EAG) and single sensillum recordings (SSR), which are summed responses from all odorant receptor neurons (ORNs) located on the antenna and from those housed in individual sensilla, respectively. These approaches have been exploited for getting a better understanding of insect chemical communication. The identified stimuli can then be used as either attractants or repellents in management strategies for insect pests. PMID:21490575

  1. Identification and functional analysis of olfactory receptor family reveal unusual characteristics of the olfactory system in the migratory locust.

    PubMed

    Wang, Zhifeng; Yang, Pengcheng; Chen, Dafeng; Jiang, Feng; Li, Yan; Wang, Xianhui; Kang, Le

    2015-11-01

    Locusts represent the excellent model of insect olfaction because the animals are equipped with an unusual olfactory system and display remarkable density-dependent olfactory plasticity. However, information regarding receptor molecules involved in the olfactory perception of locusts is very limited. On the basis of genome sequence and antennal transcriptome of the migratory locust, we conduct the identification and functional analysis of two olfactory receptor families: odorant receptors (ORs) and ionotropic receptors (IRs). In the migratory locust, there is an expansion of OR family (142 ORs) while distinctly lower number of IR genes (32 IRs) compared to the repertoires of other insects. The number of the locust OR genes is much less than that of glomeruli in antennal lobe, challenging the general principle of the "one glomerulus-one receptor" observed in other insects. Most OR genes are found in tandem arrays, forming two large lineage-specific subfamilies in the phylogenetic tree. The "divergent IR" subfamily displays a significant contraction, and most of the IRs belong to the "antennal IR" subfamily in the locust. Most ORs/IRs have olfactory-specific expression while some broadly- or internal-expressed members are also found. Differing from holometabolous insects, the migratory locust contains very similar expression profiles of ORs/IRs between nymph and adult stages. RNA interference and behavioral assays indicate that an OR-based signaling pathway, not IR-based, mediates the attraction of locusts to aggregation pheromones. These discoveries provide insights into the unusual olfactory system of locusts and enhance our understanding of the evolution of insect olfaction. PMID:26265180

  2. Sex hormone binding globulin in the rat olfactory system.

    PubMed

    Ploss, V; Gebhart, V M; Dölz, W; Jirikowski, G F

    2014-05-01

    Ovarian steroids are known to act on the olfactory system. Their mode of action, however, is mostly unclear to date since nuclear receptors are lacking in sensory neurons. Here we used immunocytochemistry and RT-PCR to study expression and distribution of sex hormone binding globulin (SHBG) in the rat olfactory system. Single sensory cells in the olfactory mucosa and their projections in the olfactory bulb showed specific SHBG immunostaining as determined by double immunofluorescence with olfactory marker protein OMP. Larger groups of SHBG stained sensory cells occurred in the vomeronasal organ (VNO). A portion of the olfactory glomeruli in the accessory olfactory bulb showed large networks of SHBG positive nerve fibres. Some of the mitral cells showed SHBG immune fluorescence. RT-PCR revealed SHBG encoding mRNA in the olfactory mucosa, in the VNO and in the olfactory bulbs indicating intrinsic expression of the binding globulin. The VNO and its related projections within the limbic system are known to be sensitive to gonadal steroid hormones. We conclude that SHBG may be of functional importance for rapid effects of olfactory steroids on limbic functions including the control of reproductive behaviours through pheromones. PMID:24681170

  3. Olfactory Detection Thresholds and Adaptation in Adults with Autism Spectrum Condition

    ERIC Educational Resources Information Center

    Tavassoli, T.; Baron-Cohen, S.

    2012-01-01

    Sensory issues have been widely reported in Autism Spectrum Conditions (ASC). Since olfaction is one of the least investigated senses in ASC, the current studies explore olfactory detection thresholds and adaptation to olfactory stimuli in adults with ASC. 80 participants took part, 38 (18 females, 20 males) with ASC and 42 control participants…

  4. Mitral cells in the olfactory bulb of adult zebrafish (Danio rerio): morphology and distribution.

    PubMed

    Fuller, Cynthia L; Yettaw, Holly K; Byrd, Christine A

    2006-11-10

    The mitral cell is the primary output neuron and central relay in the olfactory bulb of vertebrates. The morphology of these cells has been studied extensively in mammalian systems and to a lesser degree in teleosts. This study uses retrograde tract tracing and other techniques to characterize the morphology and distribution of mitral cells in the olfactory bulb of adult zebrafish, Danio rerio. These output neurons, located primarily in the glomerular layer and superficial internal cell layer, had variable-shaped somata that ranged in size from 4-18 microm in diameter and 31-96 microm2 in cross-sectional area. The mitral cells exhibited two main types of morphologies with regard to their dendrites: the unidendritic morphology was a single primary dendrite with one or more tufts, but multidendritic cells with several dendritic projections also were seen. The axons of these cells projected to either the medial or the lateral olfactory tract and, in general, the location of the cell on the medial or lateral side of the bulb was indicative of the tract to which it would project. Further, this study shows that the majority of zebrafish mitral cells likely innervate a single glomerulus rather than multiple glomeruli. This information is contrary to the multiple innervation pattern suggested for all teleost mitral cells. Our findings suggest that mitral cells in zebrafish may be more similar to mammalian mitral cells than previously believed, despite variation in size and structure. This information provides a revised anatomical framework for olfactory processing studies in this key model system. PMID:16977629

  5. Development of the olfactory system in a wallaby (Macropus eugenii).

    PubMed

    Ashwell, K W S; Marotte, L R; Cheng, Gang

    2008-01-01

    We used carbocyanine dye tracing techniques in conjunction with hematoxylin and eosin staining, immunohistochemistry for GAP-43, and tritiated thymidine autoradiography to examine the development of the olfactory pathways in early pouch young tammar wallabies (Macropus eugenii). The overarching aim was to test the hypothesis that the olfactory system of newborn tammars is sufficiently mature at birth to contribute to the guidance of the pouch young to the nipple. Although GAP-43 immunoreactive fibers emerge from the olfactory epithelium and enter the olfactory bulb at birth, all other components of the olfactory pathway in newborn tammars are very immature at birth, postnatal day (P0). In particular, maturation of the vomeronasal organ and its projections to the accessory olfactory bulb appears to be delayed until P5 and the olfactory bulb is poorly differentiated until P12, with glomerular formation delayed until P25. The lateral olfactory tract is also very immature at birth with pioneer axons having penetrated only the most rostral portion of the piriform lobe. Interestingly, there were some early (P0) projections from the olfactory epithelium to the medial septal region and lamina terminalis (by the terminal nerve) and to olfactory tubercle and basal forebrain. The former of these is presumably serving the transfer of LHRH(+) neurons to the forebrain, as seen in eutherians, but neither of these very early pathways is sufficiently robust or connected to the more caudal neuraxis to play a role in nipple finding. Tritiated thymidine autoradiography confirmed that most piriform cortex pyramidal neurons are generated in the first week of life and are unlikely to be able to contribute to circuitry guiding the climb to the pouch. Our findings lead us to reject the hypothesis that olfactory projections contribute to guidance of the newborn tammar to the pouch and nipple. It appears far more likely that the trigeminal pathways play a significant role in this behavior

  6. Fault tolerant architecture for artificial olfactory system

    NASA Astrophysics Data System (ADS)

    Lotfivand, Nasser; Nizar Hamidon, Mohd; Abdolzadeh, Vida

    2015-05-01

    In this paper, to cover and mask the faults that occur in the sensing unit of an artificial olfactory system, a novel architecture is offered. The proposed architecture is able to tolerate failures in the sensors of the array and the faults that occur are masked. The proposed architecture for extracting the correct results from the output of the sensors can provide the quality of service for generated data from the sensor array. The results of various evaluations and analysis proved that the proposed architecture has acceptable performance in comparison with the classic form of the sensor array in gas identification. According to the results, achieving a high odor discrimination based on the suggested architecture is possible.

  7. Exposure to Zinc Sulfate Results in Differential Effects on Olfactory Sensory Neuron Subtypes in Adult Zebrafish.

    PubMed

    Hentig, James T; Byrd-Jacobs, Christine A

    2016-01-01

    Zinc sulfate is a known olfactory toxicant, although its specific effects on the olfactory epithelium of zebrafish are unknown. Olfactory organs of adult zebrafish were exposed to zinc sulfate and, after 2, 3, 5, 7, 10 or 14 days, fish were processed for histological, immunohistochemical, ultrastructural, and behavioral analyses. Severe morphological disruption of the olfactory organ was observed two days following zinc sulfate exposure, including fusion of lamellae, epithelial inflammation, and significant loss of anti-calretinin labeling. Scanning electron microscopy revealed the apical surface of the sensory region was absent of ciliated structures, but microvilli were still present. Behavioral analysis showed significant loss of the ability to perceive bile salts and some fish also had no response to amino acids. Over the next several days, olfactory organ morphology, epithelial structure, and anti-calretinin labeling returned to control-like conditions, although the ability to perceive bile salts remained lost until day 14. Thus, exposure to zinc sulfate results in rapid degeneration of the olfactory organ, followed by restoration of morphology and function within two weeks. Zinc sulfate appears to have a greater effect on ciliated olfactory sensory neurons than on microvillous olfactory sensory neurons, suggesting differential effects on sensory neuron subtypes. PMID:27589738

  8. Face detection for interactive tabletop viewscreen system using olfactory display

    NASA Astrophysics Data System (ADS)

    Sakamoto, Kunio; Kanazawa, Fumihiro

    2009-10-01

    An olfactory display is a device that delivers smells to the nose. It provides us with special effects, for example to emit smell as if you were there or to give a trigger for reminding us of memories. The authors have developed a tabletop display system connected with the olfactory display. For delivering a flavor to user's nose, the system needs to recognition and measure positions of user's face and nose. In this paper, the authors describe an olfactory display which enables to detect the nose position for an effective delivery.

  9. Notch2 is required for maintaining sustentacular cell function in the adult mouse main olfactory epithelium

    PubMed Central

    Rodriguez, Steve; Sickles, Heather M.; DeLeonardis, Chris; Alcaraz, Ana; Gridley, Thomas; Lin, David M.

    2008-01-01

    Notch receptors are expressed in neurons and glia in the adult nervous system, but why this expression persists is not well-understood. Here we examine the role of the Notch pathway in the postnatal mouse main olfactory system, and show evidence consistent with a model where Notch2 is required for maintaining sustentacular cell function. In the absence of Notch2, the laminar nature of these glial-like cells is disrupted. Hes1, Hey1, and Six1, which are downstream effectors of the Notch pathway, are down-regulated, and cytochrome P450 and Glutathione S-transferase (GST) expression by sustentacular cells is reduced. Functional levels of GST activity are also reduced. These disruptions are associated with increased olfactory sensory neuron degeneration. Surprisingly, expression of Notch3 is also down-regulated. This suggests the existence of a feedback loop where expression of Notch3 is initially independent of Notch2, but requires Notch2 for maintained expression. While the Notch pathway has previously been shown to be important for promoting gliogenesis during development, this is the first demonstration that the persistent expression of Notch receptors is required for maintaining glial function in adult. PMID:18155189

  10. Expression of corticosteroid binding globulin in the rat olfactory system.

    PubMed

    Dölz, Wilfried; Eitner, Annett; Caldwell, Jack D; Jirikowski, Gustav F

    2013-05-01

    Glucocorticoids are known to act on the olfactory system although their mode of action is still unclear since nuclear glucocorticoid receptors are mostly absent in the olfactory mucosa. In this study we used immunocytochemistry, in situ hybridization, and RT-PCR to study the expression and distribution of corticosteroid binding globulin (CBG) in the rat olfactory system. Mucosal goblet cells could be immunostained for CBG. Nasal secretion contained measurable amounts of CBG suggesting that CBG is liberated. CBG immunoreactivity was localized in many of the basal cells of the olfactory mucosa, while mature sensory cells contained CBG only in processes as determined by double immunostaining with the olfactory marker protein OMP. This staining was most pronounced in the vomeronasal organ (VNO). The appearance of CBG in the non-sensory and sensory parts of the VNO and in nerve terminals in the accessory bulb indicated axonal transport. Portions of the periglomerular cells, the mitral cells and the tufted cells were also CBG positive. CBG encoding transcripts were confirmed by RT-PCR in homogenates of the olfactory mucosa and VNO. Olfactory CBG may be significant for uptake, accumulation and transport of glucocorticoids, including aerosolic cortisol. PMID:23141917

  11. Olfactory Enrichment Influences Adult Neurogenesis Modulating GAD67 and Plasticity-Related Molecules Expression in Newborn Cells of the Olfactory Bulb

    PubMed Central

    Peretto, Paolo; Fasolo, Aldo; De Marchis, Silvia

    2009-01-01

    The olfactory bulb (OB) is a highly plastic region of the adult mammalian brain characterized by continuous integration of inhibitory interneurons of the granule (GC) and periglomerular cell (PGC) types. Adult-generated OB interneurons are selected to survive in an experience-dependent way but the mechanisms that mediate the effects of experience on OB neurogenesis are unknown. Here we focus on the new-generated PGC population which is composed by multiple subtypes. Using paradigms of olfactory enrichment and/or deprivation combined to BrdU injections and quantitative confocal immunohistochemical analyses, we studied the effects of olfactory experience on adult-generated PGCs at different survival time and compared PGC to GC modulation. We show that olfactory enrichment similarly influences PGCs and GCs, increasing survival of newborn cells and transiently modulating GAD67 and plasticity-related molecules expression. However, PGC maturation appears to be delayed compared to GCs, reflecting a different temporal dynamic of adult generated olfactory interneuron integration. Moreover, olfactory enrichment or deprivation do not selectively modulate the survival of specific PGC phenotypes, supporting the idea that the integration rate of distinct PGC subtypes is independent from olfactory experience. PMID:19626121

  12. Adiponectin enhances the responsiveness of the olfactory system.

    PubMed

    Loch, Diana; Heidel, Christian; Breer, Heinz; Strotmann, Jörg

    2013-01-01

    The peptide hormone adiponectin is secreted by adipose tissue and the circulating concentration is reversely correlated with body fat mass; it is considered as starvation signal. The observation that mature sensory neurons of the main olfactory epithelium express the adiponectin receptor 1 has led to the concept that adiponectin may affect the responsiveness of the olfactory system. In fact, electroolfactogram recordings from olfactory epithelium incubated with exogenous adiponectin resulted in large amplitudes upon odor stimulation. To determine whether the responsiveness of the olfactory sensory neurons was enhanced, we have monitored the odorant-induced expression of the immediate early gene Egr1. It was found that in an olfactory epithelium incubated with nasally applied adiponectin the number of Egr1 positive cells was significantly higher compared to controls, suggesting that adiponectin rendered the olfactory neurons more responsive to an odorant stimulus. To analyze whether the augmented responsiveness of sensory neurons was strong enough to elicit a higher neuronal activity in the olfactory bulb, the number of activated periglomerular cells of a distinct glomerulus was determined by monitoring the stimulus-induced expression of c-fos. The studies were performed using the transgenic mOR256-17-IRES-tauGFP mice which allowed to visualize the corresponding glomerulus and to stimulate with a known ligand. The data indicate that upon exposure to 2,3-hexanedione in adiponectin-treated mice the number of activated periglomerular neurons was significantly increased compared to controls. The results of this study indicate that adiponectin increases the responsiveness of the olfactory system, probably due to a higher responsiveness of olfactory sensory neurons. PMID:24130737

  13. Adiponectin Enhances the Responsiveness of the Olfactory System

    PubMed Central

    Loch, Diana; Heidel, Christian; Breer, Heinz; Strotmann, Jörg

    2013-01-01

    The peptide hormone adiponectin is secreted by adipose tissue and the circulating concentration is reversely correlated with body fat mass; it is considered as starvation signal. The observation that mature sensory neurons of the main olfactory epithelium express the adiponectin receptor 1 has led to the concept that adiponectin may affect the responsiveness of the olfactory system. In fact, electroolfactogram recordings from olfactory epithelium incubated with exogenous adiponectin resulted in large amplitudes upon odor stimulation. To determine whether the responsiveness of the olfactory sensory neurons was enhanced, we have monitored the odorant-induced expression of the immediate early gene Egr1. It was found that in an olfactory epithelium incubated with nasally applied adiponectin the number of Egr1 positive cells was significantly higher compared to controls, suggesting that adiponectin rendered the olfactory neurons more responsive to an odorant stimulus. To analyze whether the augmented responsiveness of sensory neurons was strong enough to elicit a higher neuronal activity in the olfactory bulb, the number of activated periglomerular cells of a distinct glomerulus was determined by monitoring the stimulus-induced expression of c-fos. The studies were performed using the transgenic mOR256-17-IRES-tauGFP mice which allowed to visualize the corresponding glomerulus and to stimulate with a known ligand. The data indicate that upon exposure to 2,3-hexanedione in adiponectin-treated mice the number of activated periglomerular neurons was significantly increased compared to controls. The results of this study indicate that adiponectin increases the responsiveness of the olfactory system, probably due to a higher responsiveness of olfactory sensory neurons. PMID:24130737

  14. Olfactory instruction for fear: neural system analysis

    PubMed Central

    Canteras, Newton S.; Pavesi, Eloisa; Carobrez, Antonio P.

    2015-01-01

    Different types of predator odors engage elements of the hypothalamic predator-responsive circuit, which has been largely investigated in studies using cat odor exposure. Studies using cat odor have led to detailed mapping of the neural sites involved in innate and contextual fear responses. Here, we reviewed three lines of work examining the dynamics of the neural systems that organize innate and learned fear responses to cat odor. In the first section, we explored the neural systems involved in innate fear responses and in the acquisition and expression of fear conditioning to cat odor, with a particular emphasis on the role of the dorsal premammillary nucleus (PMd) and the dorsolateral periaqueductal gray (PAGdl), which are key sites that influence innate fear and contextual conditioning. In the second section, we reviewed how chemical stimulation of the PMd and PAGdl may serve as a useful unconditioned stimulus in an olfactory fear conditioning paradigm; these experiments provide an interesting perspective for the understanding of learned fear to predator odor. Finally, in the third section, we explored the fact that neutral odors that acquire an aversive valence in a shock-paired conditioning paradigm may mimic predator odor and mobilize elements of the hypothalamic predator-responsive circuit. PMID:26300721

  15. Role of Nrf2 antioxidant defense in mitigating cadmium-induced oxidative stress in the olfactory system of zebrafish

    SciTech Connect

    Wang, Lu; Gallagher, Evan P.

    2013-01-15

    Exposure to trace metals can disrupt olfactory function in fish leading to a loss of behaviors critical to survival. Cadmium (Cd) is an olfactory toxicant that elicits cellular oxidative stress as a mechanism of toxicity while also inducing protective cellular antioxidant genes via activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway. However, the molecular mechanisms of Cd-induced olfactory injury have not been characterized. In the present study, we investigated the role of the Nrf2-mediated antioxidant defense pathway in protecting against Cd-induced olfactory injury in zebrafish. A dose-dependent induction of Nrf2-regulated antioxidant genes associated with cellular responses to oxidative stress was observed in the olfactory system of adult zebrafish following 24 h Cd exposure. Zebrafish larvae exposed to Cd for 3 h showed increased glutathione S-transferase pi (gst pi), glutamate–cysteine ligase catalytic subunit (gclc), heme oxygenase 1 (hmox1) and peroxiredoxin 1 (prdx1) mRNA levels indicative of Nrf2 activation, and which were blocked by morpholino-mediated Nrf2 knockdown. The inhibition of antioxidant gene induction in Cd-exposed Nrf2 morphants was associated with disruption of olfactory driven behaviors, increased cell death and loss of olfactory sensory neurons (OSNs). Nrf2 morphants also exhibited a downregulation of OSN-specific genes after Cd exposure. Pre-incubation of embryos with sulforaphane (SFN) partially protected against Cd-induced olfactory tissue damage. Collectively, our results indicate that oxidative stress is an important mechanism of Cd-mediated injury in the zebrafish olfactory system. Moreover, the Nrf2 pathway plays a protective role against cellular oxidative damage and is important in maintaining zebrafish olfactory function. -- Highlights: ► Oxidative stress is an important mechanism of Cd-mediated olfactory injury. ► Cd induces antioxidant gene expression in the zebrafish olfactory system. ► The

  16. Dietary intakes of fats, fish and nuts and olfactory impairment in older adults.

    PubMed

    Gopinath, Bamini; Sue, Carolyn M; Flood, Victoria M; Burlutsky, George; Mitchell, Paul

    2015-07-01

    It is unclear whether lifestyle modifications, such as dietary changes, should be advocated to prevent olfactory dysfunction. We investigated the association between dietary intakes of fats (saturated, mono-unsaturated and polyunsaturated fats, and cholesterol) and related food groups (nuts, fish, butter, margarine) with olfactory impairment. There were 1331 and 667 participants (older than 60 years) at baseline and 5-year follow-up, respectively, with complete olfaction and dietary data. Dietary data were collected using a validated semi-quantitative FFQ. Olfaction was measured using the San Diego Odor Identification Test. In a cross-sectional analysis of baseline data, those in the highest v. lowest quartile of n-6 PUFA intake had reduced odds of having any olfactory impairment, multivariable-adjusted OR 0.66 (95% CI 0.44, 0.97), P for trend = 0.06. Participants in the highest v. lowest quartile of margarine consumption had a 65% reduced odds of having moderate/severe olfactory impairment (P for trend = 0.02). Participants in the highest quartile compared to the lowest quartile (reference) of nut consumption had a 46% (P for trend = 0.01) and 58% (P for trend = 0.001) reduced odds of having any or mild olfactory impairment, respectively. Older adults in the highest v. lowest quartile of fish consumption had 35% (P for trend = 0.03) and 50% (P for trend = 0.01) reduced likelihood of having any or mild olfactory impairment, respectively. In longitudinal analyses, a marginally significant association was observed between nut consumption and incidence of any olfactory impairment, highest v. lowest quartile of nut consumption: OR 0.61 (95% CI 0.37, 1.00). Older adults with the highest consumption of nuts and fish had reduced odds of olfactory impairment, independent of potential confounding variables. PMID:26079067

  17. Dog and mouse: toward a balanced view of the mammalian olfactory system.

    PubMed

    Barrios, Arthur W; Sánchez-Quinteiro, Pablo; Salazar, Ignacio

    2014-01-01

    Although the most intensively studied mammalian olfactory system is that of the mouse, in which olfactory chemical cues of one kind or another are detected in four different nasal areas [the main olfactory epithelium (MOE), the septal organ (SO), Grüneberg's ganglion, and the sensory epithelium of the vomeronasal organ (VNO)], the extraordinarily sensitive olfactory system of the dog is also an important model that is increasingly used, for example in genomic studies of species evolution. Here we describe the topography and extent of the main olfactory and vomeronasal sensory epithelia of the dog, and we report finding no structures equivalent to the Grüneberg ganglion and SO of the mouse. Since we examined adults, newborns, and fetuses we conclude that these latter structures are absent in dogs, possibly as the result of regression or involution. The absence of a vomeronasal component based on VR2 receptors suggests that the VNO may be undergoing a similar involutionary process. PMID:25309347

  18. Olfactory System Involvement in Natural Scrapie Disease ▿

    PubMed Central

    Corona, Cristiano; Porcario, Chiara; Martucci, Francesca; Iulini, Barbara; Manea, Barbara; Gallo, Marina; Palmitessa, Claudia; Maurella, Cristiana; Mazza, Maria; Pezzolato, Marzia; Acutis, Pierluigi; Casalone, Cristina

    2009-01-01

    The olfactory system (OS) is involved in many infectious and neurodegenerative diseases, both human and animal, and it has recently been investigated in regard to transmissible spongiform encephalopathies. Previous assessments of nasal mucosa infection by prions following intracerebral challenge suggested a potential centrifugal spread along the olfactory nerve fibers of the pathological prion protein (PrPSc). Whether the nasal cavity may be a route for centripetal prion infection to the brain has also been experimentally studied. With the present study, we wanted to determine whether prion deposition in the OS occurs also under field conditions and what type of anatomical localization PrPSc might display there. We report here on detection by different techniques of PrPSc in the nasal mucosa and in the OS-related brain areas of sheep affected by natural scrapie. PrPSc was detected in the perineurium of the olfactory nerve bundles in the medial nasal concha and in nasal-associated lymphoid tissue. Olfactory receptor neurons did not show PrPSc immunostaining. PrPSc deposition was found in the brain areas of olfactory fiber projection, chiefly in the olfactory bulb and the olfactory cortex. The prevalent PrPSc deposition patterns were subependymal, perivascular, and submeningeal. This finding, together with the discovery of an intense PrPSc immunostaining in the meningeal layer of the olfactory nerve perineurium, at the border with the subdural space extension surrounding the nerve rootlets, strongly suggests a probable role of cerebrospinal fluid in conveying prion infectivity to the nasal submucosa. PMID:19158242

  19. The impact of adult neurogenesis on olfactory bulb circuits and computations.

    PubMed

    Lepousez, Gabriel; Valley, Matthew T; Lledo, Pierre-Marie

    2013-01-01

    Modern neuroscience has demonstrated how the adult brain has the ability to profoundly remodel its neurons in response to changes in external stimuli or internal states. However, adult brain plasticity, although possible throughout life, remains restricted mostly to subcellular levels rather than affecting the entire cell. New neurons are continuously generated in only a few areas of the adult brain-the olfactory bulb and the dentate gyrus-where they integrate into already functioning circuitry. In these regions, adult neurogenesis adds another dimension of plasticity that either complements or is redundant to the classical molecular and cellular mechanisms of plasticity. This review extracts clues regarding the contribution of adult-born neurons to the different circuits of the olfactory bulb and specifically how new neurons participate in existing computations and enable new computational functions. PMID:23190074

  20. Adult Olfactory Bulb Interneuron Phenotypes Identified by Targeting Embryonic and Postnatal Neural Progenitors

    PubMed Central

    Figueres-Oñate, Maria; López-Mascaraque, Laura

    2016-01-01

    Neurons are generated during embryonic development and in adulthood, although adult neurogenesis is restricted to two main brain regions, the hippocampus and olfactory bulb. The subventricular zone (SVZ) of the lateral ventricles generates neural stem/progenitor cells that continually provide the olfactory bulb (OB) with new granule or periglomerular neurons, cells that arrive from the SVZ via the rostral migratory stream. The continued neurogenesis and the adequate integration of these newly generated interneurons is essential to maintain homeostasis in the olfactory bulb, where the differentiation of these cells into specific neural cell types is strongly influenced by temporal cues. Therefore, identifying the critical features that control the generation of adult OB interneurons at either pre- or post-natal stages is important to understand the dynamic contribution of neural stem cells. Here, we used in utero and neonatal SVZ electroporation along with a transposase-mediated stable integration plasmid, in order to track interneurons and glial lineages in the OB. These plasmids are valuable tools to study the development of OB interneurons from embryonic and post-natal SVZ progenitors. Accordingly, we examined the location and identity of the adult progeny of embryonic and post-natally transfected progenitors by examining neurochemical markers in the adult OB. These data reveal the different cell types in the olfactory bulb that are generated in function of age and different electroporation conditions. PMID:27242400

  1. Adult Olfactory Bulb Interneuron Phenotypes Identified by Targeting Embryonic and Postnatal Neural Progenitors.

    PubMed

    Figueres-Oñate, Maria; López-Mascaraque, Laura

    2016-01-01

    Neurons are generated during embryonic development and in adulthood, although adult neurogenesis is restricted to two main brain regions, the hippocampus and olfactory bulb. The subventricular zone (SVZ) of the lateral ventricles generates neural stem/progenitor cells that continually provide the olfactory bulb (OB) with new granule or periglomerular neurons, cells that arrive from the SVZ via the rostral migratory stream. The continued neurogenesis and the adequate integration of these newly generated interneurons is essential to maintain homeostasis in the olfactory bulb, where the differentiation of these cells into specific neural cell types is strongly influenced by temporal cues. Therefore, identifying the critical features that control the generation of adult OB interneurons at either pre- or post-natal stages is important to understand the dynamic contribution of neural stem cells. Here, we used in utero and neonatal SVZ electroporation along with a transposase-mediated stable integration plasmid, in order to track interneurons and glial lineages in the OB. These plasmids are valuable tools to study the development of OB interneurons from embryonic and post-natal SVZ progenitors. Accordingly, we examined the location and identity of the adult progeny of embryonic and post-natally transfected progenitors by examining neurochemical markers in the adult OB. These data reveal the different cell types in the olfactory bulb that are generated in function of age and different electroporation conditions. PMID:27242400

  2. Selective Viral Transduction of Adult-born Olfactory Neurons for Chronic in vivo Optogenetic Stimulation

    PubMed Central

    Lepousez, Gabriel; Alonso, Mariana; Wagner, Sebastian; Gallarda, Benjamin W.; Lledo, Pierre-Marie

    2011-01-01

    Local interneurons are continuously regenerated in the olfactory bulb of adult rodents1-3. In this process, called adult neurogenesis, neural stem cells in the walls of the lateral ventricle give rise to neuroblasts that migrate for several millimeters along the rostral migratory stream (RMS) to reach and incorporate into the olfactory bulb. To study the different steps and the impact of adult-born neuron integration into preexisting olfactory circuits, it is necessary to selectively label and manipulate the activity of this specific population of neurons. The recent development of optogenetic technologies offers the opportunity to use light to precisely activate this specific cohort of neurons without affecting surrounding neurons4,5. Here, we present a series of procedures to virally express Channelrhodopsin2(ChR2)-YFP in a temporally restricted cohort of neuroblasts in the RMS before they reach the olfactory bulb and become adult-born neurons. In addition, we show how to implant and calibrate a miniature LED for chronic in vivo stimulation of ChR2-expressing neurons. PMID:22231709

  3. Ontogenetic Development of the Derived Olfactory System of the Mantellid Frog Mantidactylus betsileanus.

    PubMed

    Nowack, Christine; Vences, Miguel

    2016-07-01

    The nasal cavity of Mantidactylus betsileanus, a frog of the Madagascar-Comoroan endemic family Mantellidae, is characterized by a unique internal architecture. Unlike the state commonly observed in anurans, the two discernible olfactory subsystems of M. betsileanus (the main olfactory organ and the vomeronasal organ) are anatomically separated from each other, suggesting an enhanced functional differentiation. Here we evaluate the ontogenetic formation of this extraordinary anatomical state based on a histological study of a developmental series of M. betsileanus. The olfactory system of premetamorphic tadpoles, and most of its changes during metamorphosis, resembles that of other anurans. At the end of metamorphosis however, a growing obstruction of the passage between main olfactory organ and vomeronasal organ takes place, leading to the deviant morphological state previously described for adults. The late appearance of this atypical anatomical feature in the course of ontogeny agrees with the phylogenetic hypothesis of the observed obstruction representing a derived state for these frogs. From a functional point of view, the apparent autonomy of the vomeronasal organ is possibly linked to the presence of clade-specific femoral glands that are known to produce pheromones and that likewise are fully expressed in adults only. Anat Rec, 299:943-950, 2016. © 2016 Wiley Periodicals, Inc. PMID:27084295

  4. Immunohistochemical demonstration of salmon olfactory glutathione S-transferase class pi (N24) in the olfactory system of lacustrine sockeye salmon during ontogenesis and cell proliferation.

    PubMed

    Yanagi, S; Kudo, H; Doi, Y; Yamauchi, K; Ueda, H

    2004-06-01

    In mammals, glutathione S-transferase (GST) in the olfactory epithelium is involved in assistance of the olfactory reception by the xenobiotic metabolism. We previously reported the protein and gene expressions of salmon olfactory GST class pi (soGST) in the olfactory receptor cells (ORCs) of the salmonid fish. However, the chronological appearances of soGST in ORCs during ontogeny and cell proliferation are still unknown in this species. In this study, we performed immunohistochemistry of soGST using an antibody specific to soGST in the olfactory system (olfactory placode, olfactory pit, olfactory epithelium, olfactory nerve and olfactory bulb) of lacustrine sockeye salmon ( Oncorhynchus nerka) embryos and 5-bromo-2'-deoxyuridine (BrdU) experimental fish. The projection of olfactory nerve bundles from the olfactory pit to the presumptive olfactory bulb was identified at embryonic day 28 after fertilization. The olfactory cilia were first detected on the apical surface of ORCs at day 43. soGST-immunoreactivity was first detected within the olfactory pit cells at day 55. At 58 day, the number of soGST-immunoreactive cells increased markedly in the olfactory epithelia, and soGST-immunoreactive fibers were observed in the olfactory nerves and olfactory bulbs. By in vivo uptake of BrdU in 1-year-old fish, we observed for the first time at day 7 after labeling that the olfactory epithelia showed ORCs in which both soGST-immunoreactivity and BrdU coexisted. These results indicate that soGST is synthesized in the mature ORCs of lacustrine sockeye salmon after cell formation and differentiation. PMID:15156400

  5. Functional MRI of the Olfactory System in Conscious Dogs

    PubMed Central

    Jia, Hao; Pustovyy, Oleg M.; Waggoner, Paul; Beyers, Ronald J.; Schumacher, John; Wildey, Chester; Barrett, Jay; Morrison, Edward; Salibi, Nouha; Denney, Thomas S.; Vodyanoy, Vitaly J.; Deshpande, Gopikrishna

    2014-01-01

    We depend upon the olfactory abilities of dogs for critical tasks such as detecting bombs, landmines, other hazardous chemicals and illicit substances. Hence, a mechanistic understanding of the olfactory system in dogs is of great scientific interest. Previous studies explored this aspect at the cellular and behavior levels; however, the cognitive-level neural substrates linking them have never been explored. This is critical given the fact that behavior is driven by filtered sensory representations in higher order cognitive areas rather than the raw odor maps of the olfactory bulb. Since sedated dogs cannot sniff, we investigated this using functional magnetic resonance imaging of conscious dogs. We addressed the technical challenges of head motion using a two pronged strategy of behavioral training to keep dogs' head as still as possible and a single camera optical head motion tracking system to account for residual jerky movements. We built a custom computer-controlled odorant delivery system which was synchronized with image acquisition, allowing the investigation of brain regions activated by odors. The olfactory bulb and piriform lobes were commonly activated in both awake and anesthetized dogs, while the frontal cortex was activated mainly in conscious dogs. Comparison of responses to low and high odor intensity showed differences in either the strength or spatial extent of activation in the olfactory bulb, piriform lobes, cerebellum, and frontal cortex. Our results demonstrate the viability of the proposed method for functional imaging of the olfactory system in conscious dogs. This could potentially open up a new field of research in detector dog technology. PMID:24466054

  6. Relationship between olfactory and visual stimuli during host plant recognition in immature and adult glassy-winged sharpshooter.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An olfactometer was designed to assess the relative effects of visual, olfactory, and visual x olfactory stimuli on host plant detection in adult and immature glassy-winged sharpshooter, Homalodisca coagulata. Factorial designs were used in no-choice tests to measure responses to binary combination...

  7. Disruption of Adult Neurogenesis in the Olfactory Bulb Affects Social Interaction but not Maternal Behavior

    PubMed Central

    Feierstein, Claudia E.; Lazarini, Françoise; Wagner, Sebastien; Gabellec, Marie-Madeleine; de Chaumont, Fabrice; Olivo-Marin, Jean-Christophe; Boussin, François D.; Lledo, Pierre-Marie; Gheusi, Gilles

    2010-01-01

    Adult-born neurons arrive to the olfactory bulb (OB) and integrate into the existing circuit throughout life. Despite the prevalence of this phenomenon, its functional impact is still poorly understood. Recent studies point to the importance of newly generated neurons to olfactory learning and memory. Adult neurogenesis is regulated by a variety of factors, notably by instances related to reproductive behavior, such as exposure to mating partners, pregnancy and lactation, and exposure to offspring. To study the contribution of olfactory neurogenesis to maternal behavior and social recognition, here we selectively disrupted OB neurogenesis using focal irradiation of the subventricular zone in adult female mice. We show that reduction of olfactory neurogenesis results in an abnormal social interaction pattern with male, but not female, conspecifics; we suggest that this effect could result from the inability to detect or discriminate male odors and could therefore have implications for the recognition of potential mating partners. Disruption of OB neurogenesis, however, neither impaired maternal-related behaviors, nor did it affect the ability of mothers to discriminate their own progeny from others. PMID:21160552

  8. Virtual vision system with actual flavor by olfactory display

    NASA Astrophysics Data System (ADS)

    Sakamoto, Kunio; Kanazawa, Fumihiro

    2010-11-01

    The authors have researched multimedia system and support system for nursing studies on and practices of reminiscence therapy and life review therapy. The concept of the life review is presented by Butler in 1963. The process of thinking back on one's life and communicating about one's life to another person is called life review. There is a famous episode concerning the memory. It is called as Proustian effects. This effect is mentioned on the Proust's novel as an episode that a story teller reminds his old memory when he dipped a madeleine in tea. So many scientists research why smells trigger the memory. The authors pay attention to the relation between smells and memory although the reason is not evident yet. Then we have tried to add an olfactory display to the multimedia system so that the smells become a trigger of reminding buried memories. An olfactory display is a device that delivers smells to the nose. It provides us with special effects, for example to emit smell as if you were there or to give a trigger for reminding us of memories. The authors have developed a tabletop display system connected with the olfactory display. For delivering a flavor to user's nose, the system needs to recognition and measure positions of user's face and nose. In this paper, the authors describe an olfactory display which enables to detect the nose position for an effective delivery.

  9. Cell migration in the developing rodent olfactory system.

    PubMed

    Huilgol, Dhananjay; Tole, Shubha

    2016-07-01

    The components of the nervous system are assembled in development by the process of cell migration. Although the principles of cell migration are conserved throughout the brain, different subsystems may predominantly utilize specific migratory mechanisms, or may display unusual features during migration. Examining these subsystems offers not only the potential for insights into the development of the system, but may also help in understanding disorders arising from aberrant cell migration. The olfactory system is an ancient sensory circuit that is essential for the survival and reproduction of a species. The organization of this circuit displays many evolutionarily conserved features in vertebrates, including molecular mechanisms and complex migratory pathways. In this review, we describe the elaborate migrations that populate each component of the olfactory system in rodents and compare them with those described in the well-studied neocortex. Understanding how the components of the olfactory system are assembled will not only shed light on the etiology of olfactory and sexual disorders, but will also offer insights into how conserved migratory mechanisms may have shaped the evolution of the brain. PMID:26994098

  10. Adult Born Olfactory Bulb Dopaminergic Interneurons: Molecular Determinants and Experience-Dependent Plasticity

    PubMed Central

    Bonzano, Sara; Bovetti, Serena; Gendusa, Claudio; Peretto, Paolo; De Marchis, Silvia

    2016-01-01

    The olfactory bulb (OB) is a highly plastic brain region involved in the early processing of olfactory information. A remarkably feature of the OB circuits in rodents is the constitutive integration of new neurons that takes place during adulthood. Newborn cells in the adult OB are mostly inhibitory interneurons belonging to chemically, morphologically and functionally heterogeneous types. Although there is general agreement that adult neurogenesis in the OB plays a key role in sensory information processing and olfaction-related plasticity, the contribution of each interneuron subtype to such functions is far to be elucidated. Here, we focus on the dopaminergic (DA) interneurons: we highlight recent findings about their morphological features and then describe the molecular factors required for the specification/differentiation and maintenance of the DA phenotype in adult born neurons. We also discuss dynamic changes of the DA interneuron population related to age, environmental stimuli and lesions, and their possible functional implications. PMID:27199651

  11. Adult Born Olfactory Bulb Dopaminergic Interneurons: Molecular Determinants and Experience-Dependent Plasticity.

    PubMed

    Bonzano, Sara; Bovetti, Serena; Gendusa, Claudio; Peretto, Paolo; De Marchis, Silvia

    2016-01-01

    The olfactory bulb (OB) is a highly plastic brain region involved in the early processing of olfactory information. A remarkably feature of the OB circuits in rodents is the constitutive integration of new neurons that takes place during adulthood. Newborn cells in the adult OB are mostly inhibitory interneurons belonging to chemically, morphologically and functionally heterogeneous types. Although there is general agreement that adult neurogenesis in the OB plays a key role in sensory information processing and olfaction-related plasticity, the contribution of each interneuron subtype to such functions is far to be elucidated. Here, we focus on the dopaminergic (DA) interneurons: we highlight recent findings about their morphological features and then describe the molecular factors required for the specification/differentiation and maintenance of the DA phenotype in adult born neurons. We also discuss dynamic changes of the DA interneuron population related to age, environmental stimuli and lesions, and their possible functional implications. PMID:27199651

  12. A Robust Feedforward Model of the Olfactory System

    PubMed Central

    Zhang, Yilun; Sharpee, Tatyana O.

    2016-01-01

    Most natural odors have sparse molecular composition. This makes the principles of compressed sensing potentially relevant to the structure of the olfactory code. Yet, the largely feedforward organization of the olfactory system precludes reconstruction using standard compressed sensing algorithms. To resolve this problem, recent theoretical work has shown that signal reconstruction could take place as a result of a low dimensional dynamical system converging to one of its attractor states. However, the dynamical aspects of optimization slowed down odor recognition and were also found to be susceptible to noise. Here we describe a feedforward model of the olfactory system that achieves both strong compression and fast reconstruction that is also robust to noise. A key feature of the proposed model is a specific relationship between how odors are represented at the glomeruli stage, which corresponds to a compression, and the connections from glomeruli to third-order neurons (neurons in the olfactory cortex of vertebrates or Kenyon cells in the mushroom body of insects), which in the model corresponds to reconstruction. We show that should this specific relationship hold true, the reconstruction will be both fast and robust to noise, and in particular to the false activation of glomeruli. The predicted connectivity rate from glomeruli to third-order neurons can be tested experimentally. PMID:27065441

  13. Coding and transformations in the olfactory system.

    PubMed

    Uchida, Naoshige; Poo, Cindy; Haddad, Rafi

    2014-01-01

    How is sensory information represented in the brain? A long-standing debate in neural coding is whether and how timing of spikes conveys information to downstream neurons. Although we know that neurons in the olfactory bulb (OB) exhibit rich temporal dynamics, the functional relevance of temporal coding remains hotly debated. Recent recording experiments in awake behaving animals have elucidated highly organized temporal structures of activity in the OB. In addition, the analysis of neural circuits in the piriform cortex (PC) demonstrated the importance of not only OB afferent inputs but also intrinsic PC neural circuits in shaping odor responses. Furthermore, new experiments involving stimulation of the OB with specific temporal patterns allowed for testing the relevance of temporal codes. Together, these studies suggest that the relative timing of neuronal activity in the OB conveys odor information and that neural circuits in the PC possess various mechanisms to decode temporal patterns of OB input. PMID:24905594

  14. Response of olfactory axons to loss of synaptic targets in the adult mouse

    PubMed Central

    Ardiles, Yona; de la Puente, Rafael; Toledo, Rafael; Isgor, Ceylan; Guthrie, Kathleen

    2007-01-01

    Glomerular convergence has been proposed to rely on interactions between like olfactory axons, however topographic targeting is influenced by guidance molecules encountered in the olfactory bulb. Disruption of these cues during development misdirects sensory axons, however little is known about the role of bulb-derived signals in later life, as new axons arise during turnover of the olfactory sensory neuron (OSN) population. To evaluate the contribution of bulb neurons in maintaining topographic projections in adults, we ablated them with N-methyl-D-aspartate (NMDA) in P2-IRES-tauLacZ mice and examined how sensory axons responded to loss of their postsynaptic partners. NMDA lesion eliminated bulb neurons without damage to sensory axons or olfactory ensheathing glia. P2 axons contained within glomeruli at the time of lesion maintained convergence at these locations; there was no evidence of compensatory growth into the remnant tissue. Delayed apoptosis of OSNs in the target-deprived epithelium led to declines in P2 neuron number as well as the gradual atrophy, and in some cases complete loss, of P2 glomeruli in lesioned bulbs by three weeks. Increased cell proliferation in the epithelium partially restored the OSN population, and by eight weeks, new P2 axons distributed within diverse locations in the bulb remnant and within the anterior olfactory nucleus. Prior studies have suggested that initial development of olfactory topography does not rely on synapse formation with target neurons, however the present data demonstrate that continued maintenance of the sensory map requires the presence of sufficient numbers and/or types of available bulbar synaptic targets. PMID:17674970

  15. PERVASIVE OLFACTORY IMPAIRMENT AFTER BILATERAL LIMBIC SYSTEM DESTRUCTION

    PubMed Central

    Tranel, Daniel; Welsh-Bohmer, Kathleen A.

    2012-01-01

    What pattern of brain damage could completely obliterate the sense of olfaction in humans? We had an opportunity to address this intriguing question in patient B., who has extensive bilateral damage to most of the limbic system, including the medial and lateral temporal lobes, orbital frontal cortex, insular cortex, anterior cingulate cortex, and basal forebrain, caused by herpes simplex encephalitis. The patient demonstrated profound impairments in odor identification and recognition. Moreover, he could not discriminate between olfactory stimuli and he had severe impairments in odor detection. Reliable stimulus detection was obtained only for solutions of the organic solvent acetone and highly concentrated solutions of ethanol. In contrast to the more circumscribed olfactory deficits demonstrated in patients with damage confined to either the temporal lobes or orbitofrontal cortex (which tend to involve odor identification but not odor detection), patient B. demonstrates a strikingly severe and complete anosmia. This contrast in olfactory abilities and deficits as a result of different anatomical pathology affords new insights into the neural substrates of olfactory processing in humans. PMID:22220560

  16. Either main or accessory olfactory system signaling can mediate the rewarding effects of estrous female chemosignals in sexually naive male mice.

    PubMed

    Korzan, Wayne J; Freamat, Mihael; Johnson, Adam G; Cherry, James A; Baum, Michael J

    2013-10-01

    A long-held view has been that interest of male mice in female body odors reflects an activation of reward circuits in the male brain following their detection by the vomeronasal organ (VNO) and processing via the accessory olfactory system. We found that adult, sexually naive male mice acquired a conditioned place preference (CPP) after repeatedly receiving estrous female urine on the nose and being placed in an initially nonpreferred chamber with soiled estrous bedding on the floor. CPP was not acquired in control mice that received saline on the nose before being placed in a nonpreferred chamber with clean bedding. Robust acquisition of a CPP using estrous female odors as the reward persisted in separate groups of mice in which VNO-accessory olfactory function was disrupted by bilateral lesioning of the accessory olfactory bulb (AOB) or in which main olfactory function was disrupted by zinc sulfate lesions of the main olfactory epithelium (MOE). By contrast, no CPP was acquired for estrous odors in males that received combined AOB and MOE lesions. Either the main or the accessory olfactory system suffices to mediate the rewarding effects of estrous female odors in the male mouse, even in the absence of prior mating experience. The main olfactory system is part of the circuitry that responds to chemosignals involved in motivated behavior, a role that may be particularly important for humans who lack a functional accessory olfactory system. PMID:23978150

  17. Dual processing of sulfated steroids in the olfactory system of an anuran amphibian

    PubMed Central

    Sansone, Alfredo; Hassenklöver, Thomas; Offner, Thomas; Fu, Xiaoyan; Holy, Timothy E.; Manzini, Ivan

    2015-01-01

    Chemical communication is widespread in amphibians, but if compared to later diverging tetrapods the available functional data is limited. The existing information on the vomeronasal system of anurans is particularly sparse. Amphibians represent a transitional stage in the evolution of the olfactory system. Most species have anatomically separated main and vomeronasal systems, but recent studies have shown that in anurans their molecular separation is still underway. Sulfated steroids function as migratory pheromones in lamprey and have recently been identified as natural vomeronasal stimuli in rodents. Here we identified sulfated steroids as the first known class of vomeronasal stimuli in the amphibian Xenopus laevis. We show that sulfated steroids are detected and concurrently processed by the two distinct olfactory subsystems of larval Xenopus laevis, the main olfactory system and the vomeronasal system. Our data revealed a similar but partially different processing of steroid-induced responses in the two systems. Differences of detection thresholds suggest that the two information channels are not just redundant, but rather signal different information. Furthermore, we found that larval and adult animals excrete multiple sulfated compounds with physical properties consistent with sulfated steroids. Breeding tadpole and frog water including these compounds activated a large subset of sensory neurons that also responded to synthetic steroids, showing that sulfated steroids are likely to convey intraspecific information. Our findings indicate that sulfated steroids are conserved vomeronasal stimuli functioning in phylogenetically distant classes of tetrapods living in aquatic and terrestrial habitats. PMID:26441543

  18. Developmental, tract-tracing and immunohistochemical study of the peripheral olfactory system in a basal vertebrate: insights on Pax6 neurons migrating along the olfactory nerve.

    PubMed

    Quintana-Urzainqui, Idoia; Rodríguez-Moldes, Isabel; Candal, Eva

    2014-01-01

    The olfactory system represents an excellent model for studying different aspects of the development of the nervous system ranging from neurogenesis to mechanisms of axon growth and guidance. Important findings in this field come from comparative studies. We have analyzed key events in the development of the olfactory system of the shark Scyliorhinus canicula by combining immunohistochemical and tract-tracing methods. We describe for the first time in a cartilaginous fish an early population of pioneer HuC/D-immunoreactive (ir) neurons that seemed to delaminate from the olfactory pit epithelium and migrate toward the telencephalon before the olfactory nerve was identifiable. A distinct, transient cell population, namely the migratory mass, courses later on in apposition to the developing olfactory nerve. It contains olfactory ensheathing glial (GFAP-ir) cells and HuC/D-ir neurons, some of which course toward an extrabulbar region. We also demonstrate that Pax6-ir cells coursing along the developing olfactory pathways in S. canicula are young migrating (HuC/D and DCX-ir) neurons of the migratory mass that do not form part of the terminal nerve pathway. Evidences that these Pax6 neurons originate in the olfactory epithelium are also reported. As Pax6 neurons in the olfactory epithelium show characteristics of olfactory receptor neurons, and migrating Pax6-ir neurons formed transient corridors along the course of olfactory axons at the entrance of the olfactory bulb, we propose that these neurons could play a role as guideposts for axons of olfactory receptor neurons growing toward the olfactory bulb. PMID:23224251

  19. A Robust Feedforward Model of the Olfactory System

    NASA Astrophysics Data System (ADS)

    Zhang, Yilun; Sharpee, Tatyana

    Most natural odors have sparse molecular composition. This makes the principles of compressing sensing potentially relevant to the structure of the olfactory code. Yet, the largely feedforward organization of the olfactory system precludes reconstruction using standard compressed sensing algorithms. To resolve this problem, recent theoretical work has proposed that signal reconstruction could take place as a result of a low dimensional dynamical system converging to one of its attractor states. The dynamical aspects of optimization, however, would slow down odor recognition and were also found to be susceptible to noise. Here we describe a feedforward model of the olfactory system that achieves both strong compression and fast reconstruction that is also robust to noise. A key feature of the proposed model is a specific relationship between how odors are represented at the glomeruli stage, which corresponds to a compression, and the connections from glomeruli to Kenyon cells, which in the model corresponds to reconstruction. We show that provided this specific relationship holds true, the reconstruction will be both fast and robust to noise, and in particular to failure of glomeruli. The predicted connectivity rate from glomeruli to the Kenyon cells can be tested experimentally. This research was supported by James S. McDonnell Foundation, NSF CAREER award IIS-1254123, NSF Ideas Lab Collaborative Research IOS 1556388.

  20. How Can An Olfactory System Deal With Fluctuations At Different Scales?

    NASA Astrophysics Data System (ADS)

    Liljenström, Hans; Gu, Yuqiao

    2005-11-01

    Neural systems have to function efficiently in the presence of noise, which occurs at all levels of neural information processing. We use a computational model of the insect olfactory system in order to investigate how this system can deal with external and internal noise. We compare our results with previous models of the mammalian olfactory system. We address questions, such as, how can the system suppress noise, or maybe even make use of it? Could noise-induced oscillations and stochastic resonance also exist in the insect olfactory system? Our simulation results indicate a positive role for noise also in the insect olfactory system, but many questions are still open.

  1. The Sox gene Dichaete is expressed in local interneurons and functions in development of the Drosophila adult olfactory circuit

    PubMed Central

    Melnattur, Krishna V.; Berdnik, Daniela; Rusan, Zeid; Ferreira, Christopher J.; Nambu, John R.

    2012-01-01

    In insects, the primary sites of integration for olfactory sensory input are the glomeruli in the antennal lobes. Here, axons of olfactory receptor neurons synapse with dendrites of the projection neurons that relay olfactory input to higher brain centers, such as the mushroom bodies and lateral horn. Interactions between olfactory receptor neurons and projection neurons are modulated by excitatory and inhibitory input from a group of local interneurons. While significant insight has been gleaned into the differentiation of olfactory receptor and projection neurons, much less is known about the development and function of the local interneurons. We have found that Dichaete, a conserved Sox HMG box gene, is strongly expressed in a cluster of LAAL cells located adjacent to each antennal lobe in the adult brain. Within these clusters, Dichaete protein expression is detected in both cholinergic and GABAergic local interneurons. In contrast, Dichaete expression is not detected in mature or developing projection neurons, or developing olfactory receptor neurons. Analysis of novel viable Dichaete mutant alleles revealed misrouting of specific projection neuron dendrites and axons, and alterations in glomeruli organization. These results suggest non-cell autonomous functions of Dichaete in projection neuron differentiation as well as a potential role for Dichaete-expressing local interneurons in development of the adult olfactory circuitry. PMID:22648855

  2. The sox gene Dichaete is expressed in local interneurons and functions in development of the Drosophila adult olfactory circuit.

    PubMed

    Melnattur, Krishna V; Berdnik, Daniela; Rusan, Zeid; Ferreira, Christopher J; Nambu, John R

    2013-02-01

    In insects, the primary sites of integration for olfactory sensory input are the glomeruli in the antennal lobes. Here, axons of olfactory receptor neurons synapse with dendrites of the projection neurons that relay olfactory input to higher brain centers, such as the mushroom bodies and lateral horn. Interactions between olfactory receptor neurons and projection neurons are modulated by excitatory and inhibitory input from a group of local interneurons. While significant insight has been gleaned into the differentiation of olfactory receptor and projection neurons, much less is known about the development and function of the local interneurons. We have found that Dichaete, a conserved Sox HMG box gene, is strongly expressed in a cluster of LAAL cells located adjacent to each antennal lobe in the adult brain. Within these clusters, Dichaete protein expression is detected in both cholinergic and GABAergic local interneurons. In contrast, Dichaete expression is not detected in mature or developing projection neurons, or developing olfactory receptor neurons. Analysis of novel viable Dichaete mutant alleles revealed misrouting of specific projection neuron dendrites and axons, and alterations in glomeruli organization. These results suggest noncell autonomous functions of Dichaete in projection neuron differentiation as well as a potential role for Dichaete-expressing local interneurons in development of the adult olfactory circuitry. PMID:22648855

  3. The interplay between reproductive social stimuli and adult olfactory bulb neurogenesis.

    PubMed

    Peretto, Paolo; Schellino, Roberta; De Marchis, Silvia; Fasolo, Aldo

    2014-01-01

    Adult neurogenesis is a striking form of structural plasticity that adapts the brain to the changing world. Accordingly, new neuron production is involved in cognitive functions, such as memory, learning, and pattern separation. Recent data in rodents indicate a close link between adult neurogenesis and reproductive social behavior. This provides a key to unravel the functional meaning of adult neurogenesis in biological relevant contexts and, in parallel, opens new perspectives to explore the way the brain is processing social stimuli. In this paper we will summarize some of the major achievements on cues and mechanisms modulating adult neurogenesis during social behaviors related to reproduction and possible role/s played by olfactory newborn neurons in this context. We will point out that newborn interneurons in the accessory olfactory bulb (AOB) represent a privileged cellular target for social stimuli that elicit reproductive behaviors and that such cues modulate adult neurogenesis at two different levels increasing both proliferation of neuronal progenitors in the germinative regions and integration of newborn neurons into functional circuits. This dual mechanism provides fresh neurons that can be involved in critical activities for the individual fitness, that is, the processing of social stimuli driving the parental behavior and partner recognition. PMID:25140258

  4. The Interplay between Reproductive Social Stimuli and Adult Olfactory Bulb Neurogenesis

    PubMed Central

    De Marchis, Silvia; Fasolo, Aldo

    2014-01-01

    Adult neurogenesis is a striking form of structural plasticity that adapts the brain to the changing world. Accordingly, new neuron production is involved in cognitive functions, such as memory, learning, and pattern separation. Recent data in rodents indicate a close link between adult neurogenesis and reproductive social behavior. This provides a key to unravel the functional meaning of adult neurogenesis in biological relevant contexts and, in parallel, opens new perspectives to explore the way the brain is processing social stimuli. In this paper we will summarize some of the major achievements on cues and mechanisms modulating adult neurogenesis during social behaviors related to reproduction and possible role/s played by olfactory newborn neurons in this context. We will point out that newborn interneurons in the accessory olfactory bulb (AOB) represent a privileged cellular target for social stimuli that elicit reproductive behaviors and that such cues modulate adult neurogenesis at two different levels increasing both proliferation of neuronal progenitors in the germinative regions and integration of newborn neurons into functional circuits. This dual mechanism provides fresh neurons that can be involved in critical activities for the individual fitness, that is, the processing of social stimuli driving the parental behavior and partner recognition. PMID:25140258

  5. Anosmin-1a is required for fasciculation and terminal targeting of olfactory sensory neuron axons in the zebrafish olfactory system.

    PubMed

    Yanicostas, Constantin; Herbomel, Eric; Dipietromaria, Aurélie; Soussi-Yanicostas, Nadia

    2009-11-27

    The KAL-1 gene underlies the X-linked form of Kallmann syndrome (KS), a neurological disorder that impairs the development of the olfactory and GnRH systems. KAL-1 encodes anosmin-1, a cell matrix protein that shows cell adhesion, neurite outgrowth, and axon-guidance and -branching activities. We used zebrafish embryos as model to better understand the role of this protein during olfactory system (OS) development. First, we detected the protein in olfactory sensory neurons from 22 h post-fertilization (hpf) onward, i.e. prior their pioneer axons reached presumptive olfactory bulbs (OBs). We found that anosmin-1a depletion impaired the fasciculation of olfactory axons and their terminal targeting within OBs. Last, we showed that kal1a inactivation induced a severe decrease in the number of GABAergic and dopaminergic OB neurons. Though the phenotypes induced following anosmin-1a depletion in zebrafish embryos did not match precisely the defects observed in KS patients, our results provide the first demonstration of a direct requirement for anosmin-1 in OS development in vertebrates and stress the role of OB innervation on OB neuron differentiation. PMID:19464344

  6. The Olfactory System as a Model to Study Axonal Growth Patterns and Morphology In Vivo

    PubMed Central

    Hassenklöver, Thomas; Manzini, Ivan

    2014-01-01

    The olfactory system has the unusual capacity to generate new neurons throughout the lifetime of an organism. Olfactory stem cells in the basal portion of the olfactory epithelium continuously give rise to new sensory neurons that extend their axons into the olfactory bulb, where they face the challenge to integrate into existing circuitry. Because of this particular feature, the olfactory system represents a unique opportunity to monitor axonal wiring and guidance, and to investigate synapse formation. Here we describe a procedure for in vivo labeling of sensory neurons and subsequent visualization of axons in the olfactory system of larvae of the amphibian Xenopus laevis. To stain sensory neurons in the olfactory organ we adopt the electroporation technique. In vivo electroporation is an established technique for delivering fluorophore-coupled dextrans or other macromolecules into living cells. Stained sensory neurons and their axonal processes can then be monitored in the living animal either using confocal laser-scanning or multiphoton microscopy. By reducing the number of labeled cells to few or single cells per animal, single axons can be tracked into the olfactory bulb and their morphological changes can be monitored over weeks by conducting series of in vivo time lapse imaging experiments. While the described protocol exemplifies the labeling and monitoring of olfactory sensory neurons, it can also be adopted to other cell types within the olfactory and other systems. PMID:25406975

  7. From progenitors to integrated neurons: role of neurotransmitters in adult olfactory neurogenesis.

    PubMed

    Bovetti, Serena; Gribaudo, Simona; Puche, Adam C; De Marchis, Silvia; Fasolo, Aldo

    2011-12-01

    Adult neurogenesis is due to the persistence of pools of constitutive stem cells able to give rise to a progeny of proliferating progenitors. In rodents, adult neurogenic niches have been found in the subventricular zone (SVZ) along the lateral ventricles and in the subgranular zone of the dentate gyrus in the hippocampus. SVZ progenitors undergo a unique process of tangential migration from the lateral ventricle to the olfactory bulb (OB) where they differentiate mainly into GABAergic interneurons in the granule and glomerular layers. SVZ progenitor proliferation, migration and differentiation into fully integrated neurons, are strictly related processes regulated by complex interactions between cell intrinsic and extrinsic influences. Numerous observations demonstrate that neurotrasmitters are involved in all steps of the adult neurogenic process, but the understanding of their role is hampered by their intricate mechanism of action and by the highly complex network in which neurotransmitters work. By considering the three main steps of olfactory adult neurogenesis (proliferation, migration and integration), this review will discuss recent advances in the study of neurotransmitters, highlighting the regulatory mechanisms upstream and downstream their action. PMID:21641990

  8. Developmental origin of wiring specificity in the olfactory system of Drosophila.

    PubMed

    Jefferis, Gregory S X E; Vyas, Raj M; Berdnik, Daniela; Ramaekers, Ariane; Stocker, Reinhard F; Tanaka, Nobuaki K; Ito, Kei; Luo, Liqun

    2004-01-01

    In both insects and mammals, olfactory receptor neurons (ORNs) expressing specific olfactory receptors converge their axons onto specific glomeruli, creating a spatial map in the brain. We have previously shown that second order projection neurons (PNs) in Drosophila are prespecified by lineage and birth order to send their dendrites to one of approximately 50 glomeruli in the antennal lobe. How can a given class of ORN axons match up with a given class of PN dendrites? Here, we examine the cellular and developmental events that lead to this wiring specificity. We find that, before ORN axon arrival, PN dendrites have already created a prototypic map that resembles the adult glomerular map, by virtue of their selective dendritic localization. Positional cues that create this prototypic dendritic map do not appear to be either from the residual larval olfactory system or from glial processes within the antennal lobe. We propose instead that this prototypic map might originate from both patterning information external to the developing antennal lobe and interactions among PN dendrites. PMID:14645123

  9. A Comparison of the Olfactory Gene Repertoires of Adults and Larvae in the Noctuid Moth Spodoptera littoralis

    PubMed Central

    Poivet, Erwan; Gallot, Aurore; Montagné, Nicolas; Glaser, Nicolas; Legeai, Fabrice; Jacquin-Joly, Emmanuelle

    2013-01-01

    To better understand the olfactory mechanisms in a lepidopteran pest model species, the cotton leafworm Spodoptera littoralis, we have recently established a partial transcriptome from adult antennae. Here, we completed this transcriptome using next generation sequencing technologies, namely 454 and Illumina, on both adult antennae and larval tissues, including caterpillar antennae and maxillary palps. All sequences were assembled in 77,643 contigs. Their analysis greatly enriched the repertoire of chemosensory genes in this species, with a total of 57 candidate odorant-binding and chemosensory proteins, 47 olfactory receptors, 6 gustatory receptors and 17 ionotropic receptors. Using RT-PCR, we conducted the first exhaustive comparison of olfactory gene expression between larvae and adults in a lepidopteran species. All the 127 candidate olfactory genes were profiled for expression in male and female adult antennae and in caterpillar antennae and maxillary palps. We found that caterpillars expressed a smaller set of olfactory genes than adults, with a large overlap between these two developmental stages. Two binding proteins appeared to be larvae-specific and two others were adult-specific. Interestingly, comparison between caterpillar antennae and maxillary palps revealed numerous organ-specific transcripts, suggesting the complementary involvement of these two organs in larval chemosensory detection. Adult males and females shared the same set of olfactory transcripts, except two male-specific candidate pheromone receptors, two male-specific and two female-specific odorant-binding proteins. This study identified transcripts that may be important for sex-specific or developmental stage-specific chemosensory behaviors. PMID:23565215

  10. Olfactory systems and neural circuits that modulate predator odor fear

    PubMed Central

    Takahashi, Lorey K.

    2014-01-01

    When prey animals detect the odor of a predator a constellation of fear-related autonomic, endocrine, and behavioral responses rapidly occur to facilitate survival. How olfactory sensory systems process predator odor and channel that information to specific brain circuits is a fundamental issue that is not clearly understood. However, research in the last 15 years has begun to identify some of the essential features of the sensory detection systems and brain structures that underlie predator odor fear. For instance, the main (MOS) and accessory olfactory systems (AOS) detect predator odors and different types of predator odors are sensed by specific receptors located in either the MOS or AOS. However, complex predator chemosignals may be processed by both the MOS and AOS, which complicate our understanding of the specific neural circuits connected directly and indirectly from the MOS and AOS to activate the physiological and behavioral components of unconditioned and conditioned fear. Studies indicate that brain structures including the dorsal periaqueductal gray (DPAG), paraventricular nucleus (PVN) of the hypothalamus, and the medial amygdala (MeA) appear to be broadly involved in predator odor induced autonomic activity and hypothalamic-pituitary-adrenal (HPA) stress hormone secretion. The MeA also plays a key role in predator odor unconditioned fear behavior and retrieval of contextual fear memory associated with prior predator odor experiences. Other neural structures including the bed nucleus of the stria terminalis and the ventral hippocampus (VHC) appear prominently involved in predator odor fear behavior. The basolateral amygdala (BLA), medial hypothalamic nuclei, and medial prefrontal cortex (mPFC) are also activated by some but not all predator odors. Future research that characterizes how distinct predator odors are uniquely processed in olfactory systems and neural circuits will provide significant insights into the differences of how diverse predator

  11. Patterns of olfactory bulb neurogenesis in the adult zebrafish are altered following reversible deafferentation.

    PubMed

    Trimpe, Darcy M; Byrd-Jacobs, Christine A

    2016-09-01

    Adult brain plasticity can be investigated using reversible methods that remove afferent innervation but allow return of sensory input. Repeated intranasal irrigation with Triton X-100 in adult zebrafish diminishes innervation to the olfactory bulb, resulting in a number of alterations in bulb structure and function, and cessation of the treatment allows for reinnervation and recovery. Using bromodeoxyuridine, Hu, and caspase-3 immunoreactivity we examined cell proliferation, differentiation, migration, and survival under conditions of acute and chronic deafferentation and reafferentation. Cell proliferation within the olfactory bulb was not influenced by acute or chronic deafferentation or reafferentation, but cell fate (including differentiation, migration, and/or survival of newly formed cells) was affected. We found that chronic deafferentation caused a bilateral increase in the number of newly formed cells that migrated into the bulb, although the amount of cell death of these new cells was significantly increased compared to untreated fish. Reafferentation also increased the number of newly formed cells migrating into both bulbs, suggesting that the deafferentation effect on cell fate was maintained. Reafferentation resulted in a decrease in newly formed cells that became neurons and, although death of newly formed cells was not altered from control levels, survival was reduced in relation to that seen in chronically deafferented fish. The potential effect of age on cell genesis was also examined. While the amount of cell migration into the olfactory bulbs was not affected by fish age, more of the newly formed cells became neurons in older fish. Younger fish displayed more cell death under conditions of chronic deafferentation. In sum, our results show that reversible deafferentation affects several aspects of cell fate, including cell differentiation, migration, and survival, and age of the fish influences the response to deafferentation. PMID:27343831

  12. Artificial olfactory system with fault-tolerant sensor array.

    PubMed

    Lotfivand, Nasser; Abdolzadeh, Vida; Hamidon, Mohd Nizar

    2016-07-01

    Numerous applications of artificial olfaction resulting from research in many branches of sciences have caused considerable interest in the enhancement of these systems. In this paper, we offer an architecture which is suitable for critical applications, such as medical diagnosis, where reliability and precision are deemed important. The proposed architecture is able to tolerate failures in the sensors of the array. In this study, the discriminating ability of the proposed architecture in detecting complex odors, as well as the performance of the proposed architecture in encountering sensor failure, were investigated and compared with the generic architecture. The results demonstrated that by applying the proposed architecture in the artificial olfactory system, the performance of system in the healthy mode was identical to the classic structure. However, in the faulty situation, the proposed architecture implied high identification ability of odor samples, while the generic architecture showed very poor performance in the same situation. Based on the results, it was possible to achieve high odor identification through the developed artificial olfactory system using the proposed architecture. PMID:27038885

  13. Sensory Cell Proliferation within the Olfactory Epithelium of Developing Adult Manduca sexta (Lepidoptera)

    PubMed Central

    Franco, Marie-dominique; Bohbot, Jonathan; Fernandez, Kenny; Hanna, Jayd; Poppy, James; Vogt, Richard

    2007-01-01

    Background Insects detect a multitude of odors using a broad array of phenotypically distinct olfactory organs referred to as olfactory sensilla. Each sensillum contains one to several sensory neurons and at least three support cells; these cells arise from mitotic activities from one or a small group of defined precursor cells. Sensilla phenotypes are defined by distinct morphologies, and specificities to specific odors; these are the consequence of developmental programs expressed by associated neurons and support cells, and by selection and expression of subpopulations of olfactory genes encoding such proteins as odor receptors, odorant binding proteins, and odor degrading enzymes. Methodology/Principal Findings We are investigating development of the olfactory epithelium of adult M. sexta, identifying events which might establish sensilla phenotypes. In the present study, antennal tissue was examined during the first three days of an 18 day development, a period when sensory mitotic activity was previously reported to occur. Each antenna develops as a cylinder with an outward facing sensory epithelium divided into approximately 80 repeat units or annuli. Mitotic proliferation of sensory cells initiated about 20–24 hrs after pupation (a.p.), in pre-existing zones of high density cells lining the proximal and distal borders of each annulus. These high density zones were observed as early as two hr. a.p., and expanded with mitotic activity to fill the mid-annular regions by about 72 hrs a.p. Mitotic activity initiated at a low rate, increasing dramatically after 40–48 hrs a.p.; this activity was enhanced by ecdysteroids, but did not occur in animals entering pupal diapause (which is also ecdysteroid sensitive). Conclusions/Significance Sensory proliferation initiates in narrow zones along the proximal and distal borders of each annulus; these zones rapidly expand to fill the mid-annular regions. These zones exist prior to any mitotic activity as regions of

  14. CD36 is involved in oleic acid detection by the murine olfactory system

    PubMed Central

    Oberland, Sonja; Ackels, Tobias; Gaab, Stefanie; Pelz, Thomas; Spehr, Jennifer; Spehr, Marc; Neuhaus, Eva M.

    2015-01-01

    Olfactory signals influence food intake in a variety of species. To maximize the chances of finding a source of calories, an animal’s preference for fatty foods and triglycerides already becomes apparent during olfactory food search behavior. However, the molecular identity of both receptors and ligands mediating olfactory-dependent fatty acid recognition are, so far, undescribed. We here describe that a subset of olfactory sensory neurons expresses the fatty acid receptor CD36 and demonstrate a receptor-like localization of CD36 in olfactory cilia by STED microscopy. CD36-positive olfactory neurons share olfaction-specific transduction elements and project to numerous glomeruli in the ventral olfactory bulb. In accordance with the described roles of CD36 as fatty acid receptor or co-receptor in other sensory systems, the number of olfactory neurons responding to oleic acid, a major milk component, in Ca2+ imaging experiments is drastically reduced in young CD36 knock-out mice. Strikingly, we also observe marked age-dependent changes in CD36 localization, which is prominently present in the ciliary compartment only during the suckling period. Our results support the involvement of CD36 in fatty acid detection by the mammalian olfactory system. PMID:26441537

  15. Electrophysiological Evidence for a Direct Link between the Main and Accessory Olfactory Bulbs in the Adult Rat

    PubMed Central

    Vargas-Barroso, Victor; Ordaz-Sánchez, Benito; Peña-Ortega, Fernando; Larriva-Sahd, Jorge A.

    2016-01-01

    It is accepted that the main- and accessory- olfactory systems exhibit overlapping responses to pheromones and odorants. We performed whole-cell patch-clamp recordings in adult rat olfactory bulb slices to define a possible interaction between the first central relay of these systems: the accessory olfactory bulb (AOB) and the main olfactory bulb (MOB). This was tested by applying electrical field stimulation in the dorsal part of the MOB while recording large principal cells (LPCs) of the anterior AOB (aAOB). Additional recordings of LPCs were performed at either side of the plane of intersection between the aAOB and posterior-AOB (pAOB) halves, or linea alba, while applying field stimulation to the opposite half. A total of 92 recorded neurons were filled during whole-cell recordings with biocytin and studied at the light microscope. Neurons located in the aAOB (n = 6, 8%) send axon collaterals to the MOB since they were antidromically activated in the presence of glutamate receptor antagonists (APV and CNQX). Recorded LPCs evoked orthodromic excitatory post-synaptic responses (n = 6, aAOB; n = 1, pAOB) or antidromic action potentials (n = 8, aAOB; n = 7, pAOB) when applying field stimulation to the opposite half of the recording site (e.g., recording in aAOB; stimulating in pAOB, and vice-versa). Observation of the filled neurons revealed that indeed, LPCs send axon branches that cross the linea alba to resolve in the internal cellular layer. Additionally, LPCs of the aAOB send axon collaterals to dorsal-MOB territory. Notably, while performing AOB recordings we found a sub-population of neurons (24% of the total) that exhibited voltage-dependent bursts of action potentials. Our findings support the existence of: 1. a direct projection from aAOB LPCs to dorsal-MOB, 2. physiologically active synapses linking aAOB and pAOB, and 3. pacemaker-like neurons in both AOB halves. This work was presented in the form of an Abstract on SfN 2014 (719.14/EE17). PMID:26858596

  16. Electrophysiological Evidence for a Direct Link between the Main and Accessory Olfactory Bulbs in the Adult Rat.

    PubMed

    Vargas-Barroso, Victor; Ordaz-Sánchez, Benito; Peña-Ortega, Fernando; Larriva-Sahd, Jorge A

    2015-01-01

    It is accepted that the main- and accessory- olfactory systems exhibit overlapping responses to pheromones and odorants. We performed whole-cell patch-clamp recordings in adult rat olfactory bulb slices to define a possible interaction between the first central relay of these systems: the accessory olfactory bulb (AOB) and the main olfactory bulb (MOB). This was tested by applying electrical field stimulation in the dorsal part of the MOB while recording large principal cells (LPCs) of the anterior AOB (aAOB). Additional recordings of LPCs were performed at either side of the plane of intersection between the aAOB and posterior-AOB (pAOB) halves, or linea alba, while applying field stimulation to the opposite half. A total of 92 recorded neurons were filled during whole-cell recordings with biocytin and studied at the light microscope. Neurons located in the aAOB (n = 6, 8%) send axon collaterals to the MOB since they were antidromically activated in the presence of glutamate receptor antagonists (APV and CNQX). Recorded LPCs evoked orthodromic excitatory post-synaptic responses (n = 6, aAOB; n = 1, pAOB) or antidromic action potentials (n = 8, aAOB; n = 7, pAOB) when applying field stimulation to the opposite half of the recording site (e.g., recording in aAOB; stimulating in pAOB, and vice-versa). Observation of the filled neurons revealed that indeed, LPCs send axon branches that cross the linea alba to resolve in the internal cellular layer. Additionally, LPCs of the aAOB send axon collaterals to dorsal-MOB territory. Notably, while performing AOB recordings we found a sub-population of neurons (24% of the total) that exhibited voltage-dependent bursts of action potentials. Our findings support the existence of: 1. a direct projection from aAOB LPCs to dorsal-MOB, 2. physiologically active synapses linking aAOB and pAOB, and 3. pacemaker-like neurons in both AOB halves. This work was presented in the form of an Abstract on SfN 2014 (719.14/EE17). PMID:26858596

  17. Mapping of the mouse olfactory system with manganese-enhanced magnetic resonance imaging and diffusion tensor imaging.

    PubMed

    Gutman, David A; Magnuson, Matthew; Majeed, Waqas; Keifer, Orion P; Davis, Michael; Ressler, Kerry J; Keilholz, Shella

    2013-03-01

    As the power of studying mouse genetics and behavior advances, research tools to examine systems level connectivity in the mouse are critically needed. In this study, we compared statistical mapping of the olfactory system in adult mice using manganese-enhanced MRI (MEMRI) and diffusion tensor imaging (DTI) with probabilistic tractography. The primary goal was to determine whether these complementary techniques can determine mouse olfactory bulb (OB) connectivity consistent with known anatomical connections. For MEMRI, 3D T1-weighted images were acquired before and after bilateral nasal administration of MnCl(2) solution. Concomitantly, high-resolution diffusion-tensor images were obtained ex vivo from a second group of mice and processed with a probabilistic tractography algorithm originating in the OB. Incidence maps were created by co-registering and overlaying data from the two scan modalities. The resulting maps clearly show pathways between the OB and amygdala, piriform cortex, caudate putamen, and olfactory cortex in both the DTI and MEMRI techniques that are consistent with the known anatomical connections. These data demonstrate that MEMRI and DTI are complementary, high-resolution neuroimaging tools that can be applied to mouse genetic models of olfactory and limbic system connectivity. PMID:22527121

  18. Chitosan/siRNA nanoparticle targeting demonstrates a requirement for single-minded during larval and pupal olfactory system development of the vector mosquito Aedes aegypti

    PubMed Central

    2014-01-01

    Background Essentially nothing is known about the genetic regulation of olfactory system development in vector mosquitoes, which use olfactory cues to detect blood meal hosts. Studies in Drosophila melanogaster have identified a regulatory matrix of transcription factors that controls pupal/adult odorant receptor (OR) gene expression in olfactory receptor neurons (ORNs). However, it is unclear if transcription factors that function in the D. melanogaster regulatory matrix are required for OR expression in mosquitoes. Furthermore, the regulation of OR expression during development of the larval olfactory system, which is far less complex than that of pupae/adults, is not well understood in any insect, including D. melanogaster. Here, we examine the regulation of OR expression in the developing larval olfactory system of Aedes aegypti, the dengue vector mosquito. Results A. aegypti bears orthologs of eight transcription factors that regulate OR expression in D. melanogaster pupae/adults. These transcription factors are expressed in A. aegypti larval antennal sensory neurons, and consensus binding sites for these transcription factors reside in the 5’ flanking regions of A. aegypti OR genes. Consensus binding sites for Single-minded (Sim) are located adjacent to over half the A. aegypti OR genes, suggesting that this transcription factor functions as a major regulator of mosquito OR expression. To functionally test this hypothesis, chitosan/siRNA nanoparticles were used to target sim during larval olfactory development. These experiments demonstrated that Sim positively regulates expression of a large subset of OR genes, including orco, the obligate co-receptor in the assembly and function of heteromeric OR/Orco complexes. Decreased innervation of the antennal lobe was also noted in sim knockdown larvae. These OR expression and antennal lobe defects correlated with a larval odorant tracking behavioral defect. OR expression and antennal lobe defects were also

  19. Nasal Administration of Cholera Toxin as a Mucosal Adjuvant Damages the Olfactory System in Mice

    PubMed Central

    Fukuyama, Yoshiko; Okada, Kazunari; Yamaguchi, Masahiro; Kiyono, Hiroshi; Mori, Kensaku; Yuki, Yoshikazu

    2015-01-01

    Cholera toxin (CT) induces severe diarrhea in humans but acts as an adjuvant to enhance immune responses to vaccines when administered orally. Nasally administered CT also acts as an adjuvant, but CT and CT derivatives, including the B subunit of CT (CTB), are taken up from the olfactory epithelium and transported to the olfactory bulbs and therefore may be toxic to the central nervous system. To assess the toxicity, we investigated whether nasally administered CT or CT derivatives impair the olfactory system. In mice, nasal administration of CT, but not CTB or a non-toxic CT derivative, reduced the expression of olfactory marker protein (OMP) in the olfactory epithelium and olfactory bulbs and impaired odor responses, as determined with behavioral tests and optical imaging. Thus, nasally administered CT, like orally administered CT, is toxic and damages the olfactory system in mice. However, CTB and a non-toxic CT derivative, do not damage the olfactory system. The optical imaging we used here will be useful for assessing the safety of nasal vaccines and adjuvants during their development for human use and CT can be used as a positive control in this test. PMID:26422280

  20. The Role of Adult-Born Neurons in the Constantly Changing Olfactory Bulb Network

    PubMed Central

    Malvaut, Sarah; Saghatelyan, Armen

    2016-01-01

    The adult mammalian brain is remarkably plastic and constantly undergoes structurofunctional modifications in response to environmental stimuli. In many regions plasticity is manifested by modifications in the efficacy of existing synaptic connections or synapse formation and elimination. In a few regions, however, plasticity is brought by the addition of new neurons that integrate into established neuronal networks. This type of neuronal plasticity is particularly prominent in the olfactory bulb (OB) where thousands of neuronal progenitors are produced on a daily basis in the subventricular zone (SVZ) and migrate along the rostral migratory stream (RMS) towards the OB. In the OB, these neuronal precursors differentiate into local interneurons, mature, and functionally integrate into the bulbar network by establishing output synapses with principal neurons. Despite continuous progress, it is still not well understood how normal functioning of the OB is preserved in the constantly remodelling bulbar network and what role adult-born neurons play in odor behaviour. In this review we will discuss different levels of morphofunctional plasticity effected by adult-born neurons and their functional role in the adult OB and also highlight the possibility that different subpopulations of adult-born cells may fulfill distinct functions in the OB neuronal network and odor behaviour. PMID:26839709

  1. The Role of Astrocytes in the Generation, Migration, and Integration of New Neurons in the Adult Olfactory Bulb

    PubMed Central

    Gengatharan, Archana; Bammann, Rodrigo R.; Saghatelyan, Armen

    2016-01-01

    In mammals, new neurons in the adult olfactory bulb originate from a pool of neural stem cells in the subventricular zone of the lateral ventricles. Adult-born cells play an important role in odor information processing by adjusting the neuronal network to changing environmental conditions. Olfactory bulb neurogenesis is supported by several non-neuronal cells. In this review, we focus on the role of astroglial cells in the generation, migration, integration, and survival of new neurons in the adult forebrain. In the subventricular zone, neural stem cells with astrocytic properties display regional and temporal specificity when generating different neuronal subtypes. Non-neurogenic astrocytes contribute to the establishment and maintenance of the neurogenic niche. Neuroblast chains migrate through the rostral migratory stream ensheathed by astrocytic processes. Astrocytes play an important regulatory role in neuroblast migration and also assist in the development of a vasculature scaffold in the migratory stream that is essential for neuroblast migration in the postnatal brain. In the olfactory bulb, astrocytes help to modulate the network through a complex release of cytokines, regulate blood flow, and provide metabolic support, which may promote the integration and survival of new neurons. Astrocytes thus play a pivotal role in various processes of adult olfactory bulb neurogenesis, and it is likely that many other functions of these glial cells will emerge in the near future. PMID:27092050

  2. The Role of Astrocytes in the Generation, Migration, and Integration of New Neurons in the Adult Olfactory Bulb.

    PubMed

    Gengatharan, Archana; Bammann, Rodrigo R; Saghatelyan, Armen

    2016-01-01

    In mammals, new neurons in the adult olfactory bulb originate from a pool of neural stem cells in the subventricular zone of the lateral ventricles. Adult-born cells play an important role in odor information processing by adjusting the neuronal network to changing environmental conditions. Olfactory bulb neurogenesis is supported by several non-neuronal cells. In this review, we focus on the role of astroglial cells in the generation, migration, integration, and survival of new neurons in the adult forebrain. In the subventricular zone, neural stem cells with astrocytic properties display regional and temporal specificity when generating different neuronal subtypes. Non-neurogenic astrocytes contribute to the establishment and maintenance of the neurogenic niche. Neuroblast chains migrate through the rostral migratory stream ensheathed by astrocytic processes. Astrocytes play an important regulatory role in neuroblast migration and also assist in the development of a vasculature scaffold in the migratory stream that is essential for neuroblast migration in the postnatal brain. In the olfactory bulb, astrocytes help to modulate the network through a complex release of cytokines, regulate blood flow, and provide metabolic support, which may promote the integration and survival of new neurons. Astrocytes thus play a pivotal role in various processes of adult olfactory bulb neurogenesis, and it is likely that many other functions of these glial cells will emerge in the near future. PMID:27092050

  3. Ultrastructural and histochemical properties of the olfactory system in the japanese jungle crow, Corvus macrorhynchos.

    PubMed

    Kondoh, Daisuke; Nashimoto, Mai; Kanayama, Shunsaku; Nakamuta, Nobuaki; Taniguchi, Kazuyuki

    2011-08-01

    Although it has been commonly believed that birds are more dependent on the vision and audition than the olfaction, recent studies indicate that the olfaction of birds is related to the reproductive, homing, and predatory behaviors. In an attempt to reveal the dependence on the olfactory system in crows, we examined the olfactory system of the Japanese jungle crow (Corvus macrorhynchos) by histological, ultrastructural, and lectin histochemical methods. The olfactory epithelium (OE) of the crow occupied remarkably a small area of the nasal cavity (NC) and had the histological and ultrastructural features like other birds. The olfactory bulb (OB) of the crow was remarkably small and did not possess the olfactory ventricle. The left and right halves of the OB were fused in many cases. In the lectin histochemistry, soybean agglutinin (SBA) and Vicia villosa agglutinin (VVA) stained a small number of the receptor cells (RCs) in the OE and the olfactory nerve layer (ONL) and glomerular layer (GL) on the dorsocaudal region of the OB. Phaseolus vulgaris agglutinin-E (PHA-E) stained several RCs in the OE and the ONL and GL on the ventral region of the OB. These results suggest that 1) the crow has less-developed olfactory system than other birds, and 2) the dedicated olfactory receptor cells project their axons to the specific regions of the OB in the crow. PMID:21478653

  4. Impaired sense of smell and altered olfactory system in RAG-1−∕− immunodeficient mice

    PubMed Central

    Rattazzi, Lorenza; Cariboni, Anna; Poojara, Ridhika; Shoenfeld, Yehuda; D'Acquisto, Fulvio

    2015-01-01

    Immune deficiencies are often associated with a number of physical manifestations including loss of sense of smell and an increased level of anxiety. We have previously shown that T and B cell-deficient recombinase activating gene (RAG-1)−∕− knockout mice have an increased level of anxiety-like behavior and altered gene expression involved in olfaction. In this study, we expanded these findings by testing the structure and functional development of the olfactory system in RAG-1−∕− mice. Our results show that these mice have a reduced engagement in different types of odors and this phenotype is associated with disorganized architecture of glomerular tissue and atrophy of the main olfactory epithelium. Most intriguingly this defect manifests specifically in adult age and is not due to impairment in the patterning of the olfactory neuron staining at the embryo stage. Together these findings provide a formerly unreported biological evidence for an altered function of the olfactory system in RAG-1−∕− mice. PMID:26441494

  5. Odour enrichment increases adult-born dopaminergic neurons in the mouse olfactory bulb.

    PubMed

    Bonzano, Sara; Bovetti, Serena; Fasolo, Aldo; Peretto, Paolo; De Marchis, Silvia

    2014-11-01

    The olfactory bulb (OB) is the first brain region involved in the processing of olfactory information. In adult mice, the OB is highly plastic, undergoing cellular/molecular dynamic changes that are modulated by sensory experience. Odour deprivation induces down-regulation of tyrosine hydroxylase (TH) expression in OB dopaminergic interneurons located in the glomerular layer (GL), resulting in decreased dopamine in the OB. Although the effect of sensory deprivation is well established, little is known about the influence of odour enrichment on dopaminergic cells. Here we report that prolonged odour enrichment on C57BL/6J strain mice selectively increases TH-immunopositive cells in the GL by nearly 20%. Following odour enrichment on TH-green fluorescent protein (GFP) transgenic mice, in which GFP identified both mature TH-positive cells and putative immature dopaminergic cells expressing TH mRNA but not TH protein, we found a similar 20% increase in GFP-expressing cells, with no changes in the ratio between TH-positive and TH-negative cells. These data suggest that enriched conditions induce an expansion in the whole dopaminergic lineage. Accordingly, by using 5-bromo-2-deoxyuridine injections to label adult-generated cells in the GL of TH-GFP mice, we found an increase in the percentage of 5-bromo-2-deoxyuridine-positive dopaminergic cells in enriched compared with control conditions, whereas no differences were found for calretinin- and calbindin-positive subtypes. Strikingly, the fraction of newborn cells among the dopaminergic population doubled in enriched conditions. On the whole, our results demonstrate that odour enrichment drives increased integration of adult-generated dopaminergic cells that could be critical to adapt the OB circuits to the environmental incoming information. PMID:25216299

  6. COUP-TFI controls activity-dependent tyrosine hydroxylase expression in adult dopaminergic olfactory bulb interneurons.

    PubMed

    Bovetti, Serena; Bonzano, Sara; Garzotto, Donatella; Giannelli, Serena Gea; Iannielli, Angelo; Armentano, Maria; Studer, Michèle; De Marchis, Silvia

    2013-12-01

    COUP-TFI is an orphan nuclear receptor acting as a strong transcriptional regulator in different aspects of forebrain embryonic development. In this study, we investigated COUP-TFI expression and function in the mouse olfactory bulb (OB), a highly plastic telencephalic region in which continuous integration of newly generated inhibitory interneurons occurs throughout life. OB interneurons belong to different populations that originate from distinct progenitor lineages. Here, we show that COUP-TFI is highly expressed in tyrosine hydroxylase (TH)-positive dopaminergic interneurons in the adult OB glomerular layer (GL). We found that odour deprivation, which is known to downregulate TH expression in the OB, also downregulates COUP-TFI in dopaminergic cells, indicating a possible correlation between TH- and COUP-TFI-activity-dependent action. Moreover, we demonstrate that conditional inactivation of COUP-TFI in the EMX1 lineage results in a significant reduction of both TH and ZIF268 expression in the GL. Finally, lentiviral vector-mediated COUP-TFI deletion in adult-generated interneurons confirmed that COUP-TFI acts cell-autonomously in the control of TH and ZIF268 expression. These data indicate that COUP-TFI regulates TH expression in OB cells through an activity-dependent mechanism involving ZIF268 induction and strongly argue for a maintenance rather than establishment function of COUP-TFI in dopaminergic commitment. Our study reveals a previously unknown role for COUP-TFI in the adult brain as a key regulator in the control of sensory-dependent plasticity in olfactory dopaminergic neurons. PMID:24227652

  7. Changes in adult olfactory bulb neurogenesis in mice expressing the A30P mutant form of alpha-synuclein.

    PubMed

    Marxreiter, Franz; Nuber, Silke; Kandasamy, Mahesh; Klucken, Jochen; Aigner, Robert; Burgmayer, Ralf; Couillard-Despres, Sebastien; Riess, Olaf; Winkler, Jürgen; Winner, Beate

    2009-03-01

    In familial and sporadic forms of Parkinson's disease (PD), alpha-synuclein pathology is present in the brain stem nuclei and olfactory bulb (OB) long before Lewy bodies are detected in the substantia nigra. The OB is an active region of adult neurogenesis, where newly generated neurons physiologically integrate. While accumulation of wild-type alpha-synuclein is one of the pathogenic hallmarks of non-genetic forms of PD, the A30P alpha-synuclein mutation results in an earlier disease onset and a severe clinical phenotype. Here, we study the regulation of adult neurogenesis in the subventricular zone (SVZ)/OB system in a tetracycline-suppressive (tet-off) transgenic model of synucleinopathies, expressing human mutant A30P alpha-synuclein under the control of the calcium/calmodulin-dependent protein kinase II alpha (CaMK) promoter. In A30P transgenic mice alpha-synuclein was abundant at the site of integration in the glomerular cell layer of the OB. Without changes in proliferation in the SVZ, significantly fewer newly generated neurons were observed in the OB granule cell and glomerular layers of A30P transgenic mice than in controls, most probably due to increased cell death. By tetracycline-dependent abrogation of A30P alpha-synuclein expression, OB neurogenesis and programmed cell death was restored to control levels. Our results indicate that, using A30P conditional (tet-off) mice, A30P alpha-synuclein has a negative impact on olfactory neurogenesis and suppression of A30P alpha-synuclein enhances survival of newly generated neurons. This finding suggests that interfering with alpha-synuclein pathology can rescue newly generated neurons, possibly leading to new targets for therapeutic interventions in synucleinopathies. PMID:19291219

  8. Flexible responses to visual and olfactory stimuli by foraging Manduca sexta: larval nutrition affects adult behaviour

    PubMed Central

    Goyret, Joaquín; Kelber, Almut; Pfaff, Michael; Raguso, Robert A.

    2009-01-01

    Here, we show that the consequences of deficient micronutrient (β-carotene) intake during larval stages of Manduca sexta are carried across metamorphosis, affecting adult behaviour. Our manipulation of larval diet allowed us to examine how developmental plasticity impacts the interplay between visual and olfactory inputs on adult foraging behaviour. Larvae of M. sexta were reared on natural (Nicotiana tabacum) and artificial laboratory diets containing different concentrations of β-carotene (standard diet, low β-carotene, high β-carotene and cornmeal). This vitamin-A precursor has been shown to be crucial for photoreception sensitivity in the retina of M. sexta. After completing development, post-metamorphosis, starved adults were presented with artificial feeders that could be either scented or unscented. Regardless of their larval diet, adult moths fed with relatively high probabilities on scented feeders. When feeders were unscented, moths reared on tobacco were more responsive than moths reared on β-carotene-deficient artificial diets. Strikingly, moths reared on artificial diets supplemented with increasing amounts of β-carotene (low β and high β) showed increasing probabilities of response to scentless feeders. We discuss these results in relationship to the use of complex, multi-modal sensory information by foraging animals. PMID:19419987

  9. Role of the Retinoblastoma protein, Rb, during adult neurogenesis in the olfactory bulb

    PubMed Central

    Naser, Rayan; Vandenbosch, Renaud; Omais, Saad; Hayek, Dayana; Jaafar, Carine; Al Lafi, Sawsan; Saliba, Afaf; Baghdadi, Maarouf; Skaf, Larissa; Ghanem, Noël

    2016-01-01

    Adult neural stem cells (aNSCs) are relatively quiescent populations that give rise to distinct neuronal subtypes throughout life, yet, at a very low rate and restricted differentiation potential. Thus, identifying the molecular mechanisms that control their cellular expansion is critical for regeneration after brain injury. Loss of the Retinoblastoma protein, Rb, leads to several defects in cell cycle as well as neuronal differentiation and migration during brain development. Here, we investigated the role of Rb during adult neurogenesis in the olfactory bulb (OB) by inducing its temporal deletion in aNSCs and progenitors. Loss of Rb was associated with increased proliferation of adult progenitors in the subventricular zone (SVZ) and the rostral migratory stream (RMS) but did not alter self-renewal of aNSCs or neuroblasts subsequent migration and terminal differentiation. Hence, one month after their birth, Rb-null neuroblasts were able to differentiate into distinct subtypes of GABAergic OB interneurons but were gradually lost after 3 months. Similarly, Rb controlled aNSCs/progenitors proliferation in vitro without affecting their differentiation capacity. This enhanced SVZ/OB neurogenesis associated with loss of Rb was only transient and negatively affected by increased apoptosis indicating a critical requirement for Rb in the long-term survival of adult-born OB interneurons. PMID:26847607

  10. Role of the Retinoblastoma protein, Rb, during adult neurogenesis in the olfactory bulb.

    PubMed

    Naser, Rayan; Vandenbosch, Renaud; Omais, Saad; Hayek, Dayana; Jaafar, Carine; Al Lafi, Sawsan; Saliba, Afaf; Baghdadi, Maarouf; Skaf, Larissa; Ghanem, Noël

    2016-01-01

    Adult neural stem cells (aNSCs) are relatively quiescent populations that give rise to distinct neuronal subtypes throughout life, yet, at a very low rate and restricted differentiation potential. Thus, identifying the molecular mechanisms that control their cellular expansion is critical for regeneration after brain injury. Loss of the Retinoblastoma protein, Rb, leads to several defects in cell cycle as well as neuronal differentiation and migration during brain development. Here, we investigated the role of Rb during adult neurogenesis in the olfactory bulb (OB) by inducing its temporal deletion in aNSCs and progenitors. Loss of Rb was associated with increased proliferation of adult progenitors in the subventricular zone (SVZ) and the rostral migratory stream (RMS) but did not alter self-renewal of aNSCs or neuroblasts subsequent migration and terminal differentiation. Hence, one month after their birth, Rb-null neuroblasts were able to differentiate into distinct subtypes of GABAergic OB interneurons but were gradually lost after 3 months. Similarly, Rb controlled aNSCs/progenitors proliferation in vitro without affecting their differentiation capacity. This enhanced SVZ/OB neurogenesis associated with loss of Rb was only transient and negatively affected by increased apoptosis indicating a critical requirement for Rb in the long-term survival of adult-born OB interneurons. PMID:26847607

  11. Search behavior in various breeds of adult dogs (Canis familiaris): object permanence and olfactory cues.

    PubMed

    Gagnon, S; Doré, F Y

    1992-03-01

    Human analog tests of object permanence were administered to various breeds of adult dogs (Canis familiaris). Experiment 1 showed that the performance of terriers, sporting, and working dogs did not differ. Dogs succeeded in solving invisible displacement problems, but performance was lower than in visible displacement tests. Familiarity with the task had some influence because invisible displacement tests were more successful if they were preceded by visible displacement tests. In Experiment 2, odor cues from the target object and the hiding screens were available or were masked. Results confirmed that success was lower in invisible than in visible displacement tests and that these problems were solved on the basis of representation of visual information rather than on the basis of olfactory cues or of local rule learning. Dogs are compared with other species that display Stage 6 object permanence. PMID:1365009

  12. Olfactory Perceptual Learning Requires Action of Noradrenaline in the Olfactory Bulb: Comparison with Olfactory Associative Learning

    ERIC Educational Resources Information Center

    Vinera, Jennifer; Kermen, Florence; Sacquet, Joëlle; Didier, Anne; Mandairon, Nathalie; Richard, Marion

    2015-01-01

    Noradrenaline contributes to olfactory-guided behaviors but its role in olfactory learning during adulthood is poorly documented. We investigated its implication in olfactory associative and perceptual learning using local infusion of mixed a1-ß adrenergic receptor antagonist (labetalol) in the adult mouse olfactory bulb. We reported that…

  13. Neuroblast lineage-specific origin of the neurons of the Drosophila larval olfactory system

    PubMed Central

    Das, Abhijit; Gupta, Tripti; Davla, Sejal; Godino, Laura Lucia Prieto; Diegelmann, Sören; Reddy, O. Venkateswara; VijayRaghavan, K.; Reichert, Heinrich; Lovick, Jennifer; Hartenstein, Volker

    2014-01-01

    The complete neuronal repertoire of the central brain of Drosophila originates from only approximately 100 pairs of neural stem cells, or neuroblasts. Each neuroblast produces a highly stereotyped lineage of neurons which innervate specific compartments of the brain. Neuroblasts undergo two rounds of mitotic activity: embryonic divisions produce lineages of primary neurons that build the larval nervous system; after a brief quiescence, the neuroblasts go through a second round of divisions in larval stage to produce secondary neurons which are integrated into the adult nervous system. Here we investigate the lineages that are associated with the larval antennal lobe, one of the most widely studied neuronal systems in fly. We find that the same five neuroblasts responsible for the adult antennal lobe also produce the antennal lobe of the larval brain. However, there are notable differences in the composition of larval (primary) lineages and their adult (secondary) counterparts. Significantly, in the adult, two lineages (lNB/BAlc and adNB/BAmv3) produce uniglomerular projection neurons connecting the antennal lobe with the mushroom body and lateral horn; another lineage, vNB/BAla1, generates multiglomerular neurons reaching the lateral horn directly. lNB/BAlc, as well as a fourth lineage, vlNB/BAla2, generate a diversity of local interneurons. We describe a fifth, previously unknown lineage, BAlp4, which connects the posterior part of the antennal lobe and the neighboring tritocerebrum (gustatory center) with a higher brain center located adjacent to the mushroom body. In the larva, only one of these lineages, adNB/BAmv3, generates all uniglomerular projection neurons. Also as in the adult, lNB/BAlc and vlNB/BAla2 produce local interneurons which, in terms of diversity in architecture and transmitter expression, resemble their adult counterparts. In addition, lineages lNB/BAlc and vNB/BAla1, as well as the newly described BAlp4, form numerous types of projection

  14. Neuroblast lineage-specific origin of the neurons of the Drosophila larval olfactory system.

    PubMed

    Das, Abhijit; Gupta, Tripti; Davla, Sejal; Prieto-Godino, Lucia L; Diegelmann, Sören; Reddy, O Venkateswara; Raghavan, K Vijay; Reichert, Heinrich; Lovick, Jennifer; Hartenstein, Volker

    2013-01-15

    The complete neuronal repertoire of the central brain of Drosophila originates from only approximately 100 pairs of neural stem cells, or neuroblasts. Each neuroblast produces a highly stereotyped lineage of neurons which innervate specific compartments of the brain. Neuroblasts undergo two rounds of mitotic activity: embryonic divisions produce lineages of primary neurons that build the larval nervous system; after a brief quiescence, the neuroblasts go through a second round of divisions in larval stage to produce secondary neurons which are integrated into the adult nervous system. Here we investigate the lineages that are associated with the larval antennal lobe, one of the most widely studied neuronal systems in fly. We find that the same five neuroblasts responsible for the adult antennal lobe also produce the antennal lobe of the larval brain. However, there are notable differences in the composition of larval (primary) lineages and their adult (secondary) counterparts. Significantly, in the adult, two lineages (lNB/BAlc and adNB/BAmv3) produce uniglomerular projection neurons connecting the antennal lobe with the mushroom body and lateral horn; another lineage, vNB/BAla1, generates multiglomerular neurons reaching the lateral horn directly. lNB/BAlc, as well as a fourth lineage, vlNB/BAla2, generate a diversity of local interneurons. We describe a fifth, previously unknown lineage, BAlp4, which connects the posterior part of the antennal lobe and the neighboring tritocerebrum (gustatory center) with a higher brain center located adjacent to the mushroom body. In the larva, only one of these lineages, adNB/BAmv3, generates all uniglomerular projection neurons. Also as in the adult, lNB/BAlc and vlNB/BAla2 produce local interneurons which, in terms of diversity in architecture and transmitter expression, resemble their adult counterparts. In addition, lineages lNB/BAlc and vNB/BAla1, as well as the newly described BAlp4, form numerous types of projection

  15. Explosives and landmine detection using an artificial olfactory system

    NASA Astrophysics Data System (ADS)

    White, Joel E.; Waggoner, L. Paul; Kauer, John S.

    2004-09-01

    We are developing a portable, artificial olfactory system based on multiple attributes of the sense of smell to identify air-borne odors, including those associated with buried landmines. Brief (1-2 sec) air samples are drawn over an array of optically-interrogated, cross-reactive chemical sensors. These consist of polymers with high sensitivity and relatively narrow specificity for nitroaromatics (Timothy Swager, MIT), as well as those with broader responses, thus permitting discrimination among substances that may be confused for nitroaromatics. Biologically-based pattern matching algorithms automatically identify odors as one of several to which the device has been trained. In discrimination tests, after training to one concentration of 6 odors, the device gave 95% correct identification when tested at the original plus three different concentrations. Thus, as required in real world applications, the device can identify odors at multiple concentrations without explicitly training on each. In sensitivity tests, the device showed 100% detection and no false alarms for the landmine-related compound DNT at concentrations as low as 500 pp-trillion (quantified by GC/MS) - 10 times lower than average canine behavioral thresholds. To investigate landmine detection capabilities, field studies were conducted at Ft. Leonard Wood, MO. In calibration tests, signals from buried PMA1A anti-personnel landmines were clearly discriminated from background. In a limited 9 site "blind" test, PMA1A detection was 100% with false alarms of 40%. Although requiring further development, these data indicate that a device with appropriate sensors and exploiting olfactory principles can detect and discriminate low concentration vapor signatures, including those of buried landmines.

  16. Principal cell activity induces spine relocation of adult-born interneurons in the olfactory bulb.

    PubMed

    Breton-Provencher, Vincent; Bakhshetyan, Karen; Hardy, Delphine; Bammann, Rodrigo Roberto; Cavarretta, Francesco; Snapyan, Marina; Côté, Daniel; Migliore, Michele; Saghatelyan, Armen

    2016-01-01

    Adult-born neurons adjust olfactory bulb (OB) network functioning in response to changing environmental conditions by the formation, retraction and/or stabilization of new synaptic contacts. While some changes in the odour environment are rapid, the synaptogenesis of adult-born neurons occurs over a longer time scale. It remains unknown how the bulbar network functions when rapid and persistent changes in environmental conditions occur but when new synapses have not been formed. Here we reveal a new form of structural remodelling where mature spines of adult-born but not early-born neurons relocate in an activity-dependent manner. Principal cell activity induces directional growth of spine head filopodia (SHF) followed by spine relocation. Principal cell-derived glutamate and BDNF regulate SHF motility and directional spine relocation, respectively; and spines with SHF are selectively preserved following sensory deprivation. Our three-dimensional model suggests that spine relocation allows fast reorganization of OB network with functional consequences for odour information processing. PMID:27578235

  17. Adult neurogenesis and specific replacement of interneuron subtypes in the mouse main olfactory bulb

    PubMed Central

    Bagley, Joshua; LaRocca, Greg; Jimenez, Daniel A; Urban, Nathaniel N

    2007-01-01

    Background New neurons are generated in the adult brain from stem cells found in the subventricular zone (SVZ). These cells proliferate in the SVZ, generating neuroblasts which then migrate to the main olfactory bulb (MOB), ending their migration in the glomerular layer (GLL) and the granule cell layer (GCL) of the MOB. Neuronal populations in these layers undergo turnover throughout life, but whether all neuronal subtypes found in these areas are replaced and when neurons begin to express subtype-specific markers is not known. Results Here we use BrdU injections and immunohistochemistry against (calretinin, calbindin, N-copein, tyrosine hydroxylase and GABA) and show that adult-generated neurons express markers of all major subtypes of neurons in the GLL and GCL. Moreover, the fractions of new neurons that express subtype-specific markers at 40 and 75 days post BrdU injection are very similar to the fractions of all neurons expressing these markers. We also show that many neurons in the glomerular layer do not express NeuN, but are readily and specifically labeled by the fluorescent nissl stain Neurotrace. Conclusion The expression of neuronal subtype-specific markers by new neurons in the GLL and GCL changes rapidly during the period from 14–40 days after BrdU injection before reaching adult levels. This period may represent a critical window for cell fate specification similar to that observed for neuronal survival. PMID:17996088

  18. An endocannabinoid system is present in the mouse olfactory epithelium but does not modulate olfaction

    PubMed Central

    Hutch, Chelsea; Hillard, Cecilia J.; Jia, Cuihong; Hegg, Colleen C.

    2015-01-01

    Endocannabinoids modulate a diverse array of functions including progenitor cell proliferation in the central nervous system, and odorant detection and food intake in the mammalian central olfactory system and larval Xenopus laevis peripheral olfactory system. However, the presence and role of endocannabinoids in the peripheral olfactory epithelium has not been examined in mammals. We found the presence of cannabinoid type 1 (CB1) and cannabinoid type 2 (CB2) receptor protein and mRNA in the olfactory epithelium. Using either immunohistochemistry or calcium imaging we localized CB1 receptors on neurons, glia like sustentacular cells, microvillous cells and progenitor-like basal cells. To examine the role of endocannabinoids, CB1 and CB2 receptor deficient (CB1−/−/CB2−/−) mice were used. The endocannabinoid 2-arachidonylglycerol (2-AG) was present at high levels in both C57BL/6 wildtype and CB1−/−/CB2−/− mice. 2-AG synthetic and degradative enzymes are expressed in wildtype mice. A small but significant decrease in basal cell and olfactory sensory neuron numbers was observed in CB1−/−/CB2−/− mice compared to wildtype mice. The decrease in olfactory sensory neurons did not translate to impairment in olfactory-mediated behaviors assessed by the buried food test and habituation/dishabituation test. Collectively, these data indicate the presence of an endocannabinoid system in the mouse olfactory epithelium. However, unlike in tadpoles, endocannabinoids do not modulate olfaction. Further investigation on the role of endocannabinoids in progenitor cell function in the olfactory epithelium is warranted. PMID:26037800

  19. Temporal Processing in the Olfactory System: Can We See a Smell?

    PubMed Central

    Gire, David H.; Restrepo, Diego; Sejnowski, Terrence J.; Greer, Charles; De Carlos, Juan A.; Lopez-Mascaraque, Laura

    2013-01-01

    Sensory processing circuits in the visual and olfactory systems receive input from complex, rapidly changing environments. Although patterns of light and plumes of odor create different distributions of activity in the retina and olfactory bulb, both structures use what appears on the surface similar temporal coding strategies to convey information to higher areas in the brain. We compare temporal coding in the early stages of the olfactory and visual systems, highlighting recent progress in understanding the role of time in olfactory coding during active sensing by behaving animals. We also examine studies that address the divergent circuit mechanisms that generate temporal codes in the two systems, and find that they provide physiological information directly related to functional questions raised by neuroanatomical studies of Ramon y Cajal over a century ago. Consideration of differences in neural activity in sensory systems contributes to generating new approaches to understand signal processing. PMID:23664611

  20. Molecular and neuronal homology between the olfactory systems of zebrafish and mouse.

    PubMed

    Saraiva, Luis R; Ahuja, Gaurav; Ivandic, Ivan; Syed, Adnan S; Marioni, John C; Korsching, Sigrun I; Logan, Darren W

    2015-01-01

    Studies of the two major olfactory organs of rodents, the olfactory mucosa (OM) and the vomeronasal organ (VNO), unraveled the molecular basis of smell in vertebrates. However, some vertebrates lack a VNO. Here we generated and analyzed the olfactory transcriptome of the zebrafish and compared it to the olfactory transcriptomes of mouse to investigate the evolutionary and molecular relationship between single and dual olfactory systems. Our analyses revealed a high degree of molecular conservation, with orthologs of mouse olfactory cell-specific markers and all but one of their chemosensory receptor classes expressed in the single zebrafish olfactory organ. Zebrafish chemosensory receptor genes are expressed across a large dynamic range and their RNA abundance correlates positively with the number of neurons expressing that RNA. Thus we estimate the relative proportions of neuronal sub-types expressing different chemosensory receptors. Receptor repertoire size drives the absolute abundance of different classes of neurons, but we find similar underlying patterns in both species. Finally, we identified novel marker genes that characterize rare neuronal populations in both mouse and zebrafish. In sum, we find that the molecular and cellular mechanisms underpinning olfaction in teleosts and mammals are similar despite 430 million years of evolutionary divergence. PMID:26108469

  1. Molecular and neuronal homology between the olfactory systems of zebrafish and mouse

    PubMed Central

    Saraiva, Luis R.; Ahuja, Gaurav; Ivandic, Ivan; Syed, Adnan S.; Marioni, John C.; Korsching, Sigrun I.; Logan, Darren W.

    2015-01-01

    Studies of the two major olfactory organs of rodents, the olfactory mucosa (OM) and the vomeronasal organ (VNO), unraveled the molecular basis of smell in vertebrates. However, some vertebrates lack a VNO. Here we generated and analyzed the olfactory transcriptome of the zebrafish and compared it to the olfactory transcriptomes of mouse to investigate the evolutionary and molecular relationship between single and dual olfactory systems. Our analyses revealed a high degree of molecular conservation, with orthologs of mouse olfactory cell-specific markers and all but one of their chemosensory receptor classes expressed in the single zebrafish olfactory organ. Zebrafish chemosensory receptor genes are expressed across a large dynamic range and their RNA abundance correlates positively with the number of neurons expressing that RNA. Thus we estimate the relative proportions of neuronal sub-types expressing different chemosensory receptors. Receptor repertoire size drives the absolute abundance of different classes of neurons, but we find similar underlying patterns in both species. Finally, we identified novel marker genes that characterize rare neuronal populations in both mouse and zebrafish. In sum, we find that the molecular and cellular mechanisms underpinning olfaction in teleosts and mammals are similar despite 430 million years of evolutionary divergence. PMID:26108469

  2. Olfactory and solitary chemosensory cells: two different chemosensory systems in the nasal cavity of the American alligator, Alligator mississippiensis

    PubMed Central

    Hansen, Anne

    2007-01-01

    Background The nasal cavity of all vertebrates houses multiple chemosensors, either innervated by the Ist (olfactory) or the Vth (trigeminal) cranial nerve. Various types of receptor cells are present, either segregated in different compartments (e.g. in rodents) or mingled in one epithelium (e.g. fish). In addition, solitary chemosensory cells have been reported for several species. Alligators which seek their prey both above and under water have only one nasal compartment. Information about their olfactory epithelium is limited. Since alligators seem to detect both volatile and water-soluble odour cues, I tested whether different sensory cell types are present in the olfactory epithelium. Results Electron microscopy and immunocytochemistry were used to examine the sensory epithelium of the nasal cavity of the American alligator. Almost the entire nasal cavity is lined with olfactory (sensory) epithelium. Two types of olfactory sensory neurons are present. Both types bear cilia as well as microvilli at their apical endings and express the typical markers for olfactory neurons. The density of these olfactory neurons varies along the nasal cavity. In addition, solitary chemosensory cells innervated by trigeminal nerve fibres, are intermingled with olfactory sensory neurons. Solitary chemosensory cells express components of the PLC-transduction cascade found in solitary chemosensory cells in rodents. Conclusion The nasal cavity of the American alligator contains two different chemosensory systems incorporated in the same sensory epithelium: the olfactory system proper and solitary chemosensory cells. The olfactory system contains two morphological distinct types of ciliated olfactory receptor neurons. PMID:17683564

  3. Identification of G protein α subunits in the main olfactory system and vomeronasal system of the Japanese Striped snake, Elaphe quadrivirgata.

    PubMed

    Kondoh, Daisuke; Koshi, Katsuo; Ono, Hisaya K; Sasaki, Kuniaki; Nakamuta, Nobuaki; Taniguchi, Kazuyuki

    2013-01-01

    In the olfactory system, G proteins couple to the olfactory receptors, and G proteins expressed in the main olfactory system and vomeronasal system vary according to animal species. In this study, G protein α subunits expressed in the main olfactory system and vomeronasal system of the snake were identified by immunohistochemistry. In the olfactory epithelium, only anti-Gαolf/s antibody labeled the cilia of the receptor cells. In the vomeronasal epithelium, only anti-Gαo antibody labeled the microvilli of the receptor cells. In the accessory olfactory bulb, anti-Gαo antibody stained the whole glomerular layer. These results suggest that the main olfactory system and the vomeronasal system of the snake express Gαolf and Gαo as G proteins coupling to the olfactory receptors, respectively. PMID:23090693

  4. Biological complexity and adaptability of simple mammalian olfactory memory systems.

    PubMed

    Brennan, P; Keverne, E B

    2015-03-01

    Chemosensory systems play vital roles in the lives of most mammals, including the detection and identification of predators, as well as sex and reproductive status and the identification of individual conspecifics. All of these capabilities require a process of recognition involving a combination of innate (kairomonal/pheromonal) and learned responses. Across very different phylogenies, the mechanisms for pheromonal and odour learning have much in common. They are frequently associated with plasticity of GABA-ergic feedback at the initial level of processing the chemosensory information, which enhances its pattern separation capability. Association of odourant features into an odour object primarily involves anterior piriform cortex for non-social odours. However, the medial amygdala appears to be involved in both the recognition of social odours and their association with chemosensory information sensed by the vomeronasal system. Unusually not only the sensory neurons themselves, but also the GABA-ergic interneurons in the olfactory bulb are continually being replaced, with implications for the induction and maintenance of learned chemosensory responses. PMID:25451762

  5. Adult depression-like behavior, amygdala and olfactory cortex functions are restored by odor previously paired with shock during infant's sensitive period attachment learning

    PubMed Central

    Sevelinges, Yannick; Mouly, Anne-Marie; Raineki, Charlis; Moriceau, Stéphanie; Forest, Christina; Sullivan, Regina M.

    2010-01-01

    Maltreatment from the caregiver induces vulnerability to later life psychopathologies, yet attraction and comfort is sometimes provided by cues associated with early life maltreatment. We used a rat model of early life maltreatment with odor-0.5mA shock conditioning to produce depressive-like behaviors and questioned whether stimuli associated with maltreatment would restore emotional neurobehavioral function to control levels. Pups received daily novel odor-0.5mA shock conditioning from postnatal day 8 to 12. This procedure produces a new maternal odor that controls pups' attachment behaviors. In adulthood, either with or without the infant odor, animals received a Forced Swim Test, Sucrose Preference Test or assessment of amygdala and olfactory system functioning using field potential signal evoked by olfactory bulb paired-pulse electrical stimulation. Following neonatal odor-shock pairings, but not unpaired controls, adults without the odor present showed increased depression-like behavior in the Forced Swim Test and Sucrose Preference Test and a deficit in paired-pulse inhibition in amygdala and piriform (olfactory) cortex. All effects were brought to control levels when the infant conditioned odor was presented during behavioral and neural tests. The ability of cues associated with early life maltreatment to normalize behavior and amygdala activity suggests these cues provide adaptive value in adulthood. PMID:21037982

  6. Influence of Dietary Experience on the Induction of Preference of Adult Moths and Larvae for a New Olfactory Cue

    PubMed Central

    Petit, Christophe; Le Ru, Bruno; Dupas, Stéphane; Frérot, Brigitte; Ahuya, Peter; Kaiser-Arnauld, Laure; Harry, Myriam; Calatayud, Paul-André

    2015-01-01

    In Lepidoptera, host plant selection is first conditioned by oviposition site preference of adult females followed by feeding site preference of larvae. Dietary experience to plant volatile cues can induce larval and adult host plant preference. We investigated how the parent’s and self-experience induce host preference in adult females and larvae of three lepidopteran stem borer species with different host plant ranges, namely the polyphagous Sesamia nonagrioides, the oligophagous Busseola fusca and the monophagous Busseola nairobica, and whether this induction can be linked to a neurophysiological phenotypic plasticity. The three species were conditioned to artificial diet enriched with vanillin from the neonate larvae to the adult stage during two generations. Thereafter, two-choice tests on both larvae and adults using a Y-tube olfactometer and electrophysiological (electroantennography [EAG] recordings) experiments on adults were carried out. In the polyphagous species, the induction of preference for a new olfactory cue (vanillin) by females and 3rd instar larvae was determined by parents’ and self-experiences, without any modification of the sensitivity of the females antennae. No preference induction was found in the oligophagous and monophagous species. Our results suggest that lepidopteran stem borers may acquire preferences for new olfactory cues from the larval to the adult stage as described by Hopkins’ host selection principle (HHSP), neo-Hopkins’ principle, and the concept of ‘chemical legacy.’ PMID:26288070

  7. A neonicotinoid impairs olfactory learning in Asian honey bees (Apis cerana) exposed as larvae or as adults

    PubMed Central

    Tan, Ken; Chen, Weiwen; Dong, Shihao; Liu, Xiwen; Wang, Yuchong; Nieh, James C.

    2015-01-01

    Xenobiotics such as the neonicotinoid pesticide, imidacloprid, are used globally, but their effects on native bee species are poorly understood. We studied the effects of sublethal doses of imidacloprid on olfactory learning in the native honey bee species, Apis cerana, an important pollinator of agricultural and native plants throughout Asia. We provide the first evidence that imidacloprid can impair learning in A. cerana workers exposed as adults or as larvae. Adults that ingested a single imidacloprid dose as low as 0.1 ng/bee had significantly reduced olfactory learning acquisition, which was 1.6-fold higher in control bees. Longer-term learning (1-17 h after the last learning trial) was also impaired. Bees exposed as larvae to a total dose of 0.24 ng/bee did not have reduced survival to adulthood. However, these larval-treated bees had significantly impaired olfactory learning when tested as adults: control bees exhibited up to 4.8-fold better short-term learning acquisition, though longer-term learning was not affected. Thus, sublethal cognitive deficits elicited by neonicotinoids on a broad range of native bee species deserve further study. PMID:26086769

  8. Fragile X Mental Retardation Protein Regulates New Neuron Differentiation in the Adult Olfactory Bulb

    PubMed Central

    Scotto-Lomassese, Sophie; Nissant, Antoine; Mota, Tatiana; Néant-Féry, Marie; Oostra, Ben A.; Greer, Charles A.; Lledo, Pierre-Marie; Trembleau, Alain; Caillé, Isabelle

    2013-01-01

    The fragile X mental retardation protein (FMRP) is an RNA-binding protein essential for multiple aspects of neuronal mRNA metabolism. Its absence leads to the fragile X syndrome, the most prevalent genetic form of mental retardation. The anatomical landmark of the disease, also present in the Fmr1 knock-out (KO) mice, is the hyperabundance of immature-looking lengthened dendritic spines. We used the well known continuous production of adult-born granule cells (GCs) in the mouse olfactory bulb (OB) to analyze the consequences of Fmrp loss on the differentiation of GCs. Morphological analysis of GCs in the Fmr1 KO mice showed an increase in spine density without a change in spine length. We developed an RNA interference strategy to cell-autonomously mutate Fmr1 in a wild-type OB network. Mutated GCs displayed an increase in spine density and spine length. Detailed analysis of the spines through immunohistochemistry, electron microscopy, and electrophysiology surprisingly showed that, despite these abnormalities, spines receive normal glutamatergic synapses, and thus that mutated adult-born neurons are synaptically integrated into the OB circuitry. Time-course analysis of the spine defects showed that Fmrp cell-autonomously downregulates the level and rate of spine production and limits their overgrowth. Finally, we report that Fmrp does not regulate dendritogenesis in standard conditions but is necessary for activity-dependent dendritic remodeling. Overall, our study of Fmrp in the context of adult neurogenesis has enabled us to carry out a precise dissection of the role of Fmrp in neuronal differentiation and underscores its pleiotropic involvement in both spinogenesis and dendritogenesis. PMID:21307257

  9. Reduced olfactory bulb volume in adults with a history of childhood maltreatment.

    PubMed

    Croy, Ilona; Negoias, Simona; Symmank, Anja; Schellong, Julia; Joraschky, Peter; Hummel, Thomas

    2013-10-01

    The human olfactory bulb (OB) is the first relay station of the olfactory pathway and may have the potential for postnatal neurogenesis in early childhood. In animals, chronic stress affects the OB and olfactory functioning. For humans, it has been shown that major depressive disorder is accompanied by reduced OB volume and reduced olfactory function. However, it is not clear if major stress in childhood development also affects olfactory functioning and OB volume in humans. OB volume was measured and olfactory function was tested in 17 depressive patients with and 10 without a history of severe childhood maltreatment (CM). CM patients exhibited a significantly reduced olfactory threshold and identification ability. The OB volume of the CM patients was significantly reduced to 80% of the non-CM patients. In conclusion, postnatal neurogenesis might be by reduced in CM, which may affect olfactory function of the brain in later life. Alternatively, a reduced OB volume may enhance psychological vulnerability in the presence of adverse childhood conditions although other areas not analyzed in this study may also be involved. PMID:24051351

  10. Morphological study on the olfactory systems of the snapping turtle, Chelydra serpentina.

    PubMed

    Nakamuta, Nobuaki; Nakamuta, Shoko; Kato, Hideaki; Yamamoto, Yoshio

    2016-06-01

    In this study, the olfactory system of a semi-aquatic turtle, the snapping turtle, has been morphologically investigated by electron microscopy, immunohistochemistry, and lectin histochemistry. The nasal cavity of snapping turtle was divided into the upper and lower chambers, lined by the sensory epithelium containing ciliated and non-ciliated olfactory receptor neurons, respectively. Each neuron expressed both Gαolf, the α-subunit of G-proteins coupling to the odorant receptors, and Gαo, the α-subunit of G-proteins coupling to the type 2 vomeronasal receptors. The axons originating from the upper chamber epithelium projected to the ventral part of the olfactory bulb, while those from the lower chamber epithelium to the dorsal part of the olfactory bulb. Despite the identical expression of G-protein α-subunits in the olfactory receptor neurons, these two projections were clearly distinguished from each other by the differential expression of glycoconjugates. In conclusion, these data indicate the presence of two types of olfactory systems in the snapping turtle. Topographic arrangement of the upper and lower chambers and lack of the associated glands in the lower chamber epithelium suggest their possible involvement in the detection of odorants: upper chamber epithelium in the air and the lower chamber epithelium in the water. PMID:27059760

  11. Phylogenic studies on the olfactory system in vertebrates.

    PubMed

    Taniguchi, Kazuyuki; Taniguchi, Kazumi

    2014-06-01

    The olfactory receptor organs and their primary centers are classified into several types. The receptor organs are divided into fish-type olfactory epithelium (OE), mammal-type OE, middle chamber epithelium (MCE), lower chamber epithelium (LCE), recess epithelium, septal olfactory organ of Masera (SO), mammal-type vomeronasal organ (VNO) and snake-type VNO. The fish-type OE is observed in flatfish and lungfish, while the mammal-type OE is observed in amphibians, reptiles, birds and mammals. The MCE and LCE are unique to Xenopus and turtles, respectively. The recess epithelium is unique to lungfish. The SO is observed only in mammals. The mammal-type VNO is widely observed in amphibians, lizards and mammals, while the snake-type VNO is unique to snakes. The VNO itself is absent in turtles and birds. The mammal-type OE, MCE, LCE and recess epithelium seem to be descendants of the fish-type OE that is derived from the putative primitive OE. The VNO may be derived from the recess epithelium or fish-type OE and differentiate into the mammal-type VNO and snake-type VNO. The primary olfactory centers are divided into mammal-type main olfactory bulbs (MOB), fish-type MOB and mammal-type accessory olfactory bulbs (AOB). The mammal-type MOB first appears in amphibians and succeeds to reptiles, birds and mammals. The fish-type MOB, which is unique to fish, may be the ancestor of the mammal-type MOB. The mammal-type AOB is observed in amphibians, lizards, snakes and mammals and may be the remnant of the fish-type MOB. PMID:24531771

  12. Phylogenic Studies on the Olfactory System in Vertebrates

    PubMed Central

    TANIGUCHI, Kazuyuki; TANIGUCHI, Kazumi

    2014-01-01

    ABSTRACT The olfactory receptor organs and their primary centers are classified into several types. The receptor organs are divided into fish-type olfactory epithelium (OE), mammal-type OE, middle chamber epithelium (MCE), lower chamber epithelium (LCE), recess epithelium, septal olfactory organ of Masera (SO), mammal-type vomeronasal organ (VNO) and snake-type VNO. The fish-type OE is observed in flatfish and lungfish, while the mammal-type OE is observed in amphibians, reptiles, birds and mammals. The MCE and LCE are unique to Xenopus and turtles, respectively. The recess epithelium is unique to lungfish. The SO is observed only in mammals. The mammal-type VNO is widely observed in amphibians, lizards and mammals, while the snake-type VNO is unique to snakes. The VNO itself is absent in turtles and birds. The mammal-type OE, MCE, LCE and recess epithelium seem to be descendants of the fish-type OE that is derived from the putative primitive OE. The VNO may be derived from the recess epithelium or fish-type OE and differentiate into the mammal-type VNO and snake-type VNO. The primary olfactory centers are divided into mammal-type main olfactory bulbs (MOB), fish-type MOB and mammal-type accessory olfactory bulbs (AOB). The mammal-type MOB first appears in amphibians and succeeds to reptiles, birds and mammals. The fish-type MOB, which is unique to fish, may be the ancestor of the mammal-type MOB. The mammal-type AOB is observed in amphibians, lizards, snakes and mammals and may be the remnant of the fish-type MOB. PMID:24531771

  13. Strong links between genomic and anatomical diversity in both mammalian olfactory chemosensory systems.

    PubMed

    Garrett, Eva C; Steiper, Michael E

    2014-05-22

    Mammalian olfaction comprises two chemosensory systems: the odorant-detecting main olfactory system (MOS) and the pheromone-detecting vomeronasal system (VNS). Mammals are diverse in their anatomical and genomic emphases on olfactory chemosensation, including the loss or reduction of these systems in some orders. Despite qualitative evidence linking the genomic evolution of the olfactory systems to specific functions and phenotypes, little work has quantitatively tested whether the genomic aspects of the mammalian olfactory chemosensory systems are correlated to anatomical diversity. We show that the genomic and anatomical variation in these systems is tightly linked in both the VNS and the MOS, though the signature of selection is different in each system. Specifically, the MOS appears to vary based on absolute organ and gene family size while the VNS appears to vary according to the relative proportion of functional genes and relative anatomical size and complexity. Furthermore, there is little evidence that these two systems are evolving in a linked fashion. The relationships between genomic and anatomical diversity strongly support a role for natural selection in shaping both the anatomical and genomic evolution of the olfactory chemosensory systems in mammals. PMID:24718758

  14. Photoperiod Mediated Changes in Olfactory Bulb Neurogenesis and Olfactory Behavior in Male White-Footed Mice (Peromyscus leucopus)

    PubMed Central

    Weil, Zachary M.; Nelson, Randy J.

    2012-01-01

    Brain plasticity, in relation to new adult mammalian neurons generated in the subgranular zone of the hippocampus, has been well described. However, the functional outcome of new adult olfactory neurons born in the subventricular zone of the lateral ventricles is not clearly defined, as manipulating neurogenesis through various methods has given inconsistent and conflicting results in lab mice. Several small rodent species, including Peromyscus leucopus, display seasonal (photoperiodic) brain plasticity in brain volume, hippocampal function, and hippocampus-dependent behaviors; plasticity in the olfactory system of photoperiodic rodents remains largely uninvestigated. We exposed adult male P. leucopus to long day lengths (LD) and short day lengths (SD) for 10 to 15 weeks and then examined olfactory bulb cell proliferation and survival using the thymidine analog BrdU, olfactory bulb granule cell morphology using Golgi-Cox staining, and behavioral investigation of same-sex conspecific urine. SD mice did not differ from LD counterparts in granular cell morphology of the dendrites or in dendritic spine density. Although there were no differences due to photoperiod in habituation to water odor, SD mice rapidly habituated to male urine, whereas LD mice did not. In addition, short day induced changes in olfactory behavior were associated with increased neurogenesis in the caudal plexiform and granule cell layers of the olfactory bulb, an area known to preferentially respond to water-soluble odorants. Taken together, these data demonstrate that photoperiod, without altering olfactory bulb neuronal morphology, alters olfactory bulb neurogenesis and olfactory behavior in Peromyscus leucopus. PMID:22912730

  15. Role of a ubiquitously expressed receptor in the vertebrate olfactory system.

    PubMed

    DeMaria, Shannon; Berke, Allison P; Van Name, Eric; Heravian, Anisa; Ferreira, Todd; Ngai, John

    2013-09-18

    Odorant cues are recognized by receptors expressed on olfactory sensory neurons, the primary sensory neurons of the olfactory epithelium. Odorant receptors typically obey the "one receptor, one neuron" rule, in which the receptive field of the olfactory neuron is determined by the singular odorant receptor that it expresses. Odor-evoked receptor activity across the population of olfactory neurons is then interpreted by the brain to identify the molecular nature of the odorant stimulus. In the present study, we characterized the properties of a C family G-protein-coupled receptor that, unlike most other odorant receptors, is expressed in a large population of microvillous sensory neurons in the zebrafish olfactory epithelium and the mouse vomeronasal organ. We found that this receptor, OlfCc1 in zebrafish and its murine ortholog Vmn2r1, is a calcium-dependent, low-sensitivity receptor specific for the hydrophobic amino acids isoleucine, leucine, and valine. Loss-of-function experiments in zebrafish embryos demonstrate that OlfCc1 is required for olfactory responses to a diverse mixture of polar, nonpolar, acidic, and basic amino acids. OlfCc1 was also found to promote localization of other OlfC receptor family members to the plasma membrane in heterologous cells. Together, these results suggest that the broadly expressed OlfCc1 is required for amino acid detection by the olfactory system and suggest that it plays a role in the function and/or intracellular trafficking of other olfactory and vomeronasal receptors with which it is coexpressed. PMID:24048853

  16. Processing by the main olfactory system of chemosignals that facilitate mammalian reproduction.

    PubMed

    Baum, Michael J; Cherry, James A

    2015-02-01

    This article is part of a Special Issue "Chemosignals and Reproduction". Most mammalian species possess two parallel circuits that process olfactory information. One of these circuits, the accessory system, originates with sensory neurons in the vomeronasal organ (VNO). This system has long been known to detect non-volatile pheromonal odorants from conspecifics that influence numerous aspects of social communication, including sexual attraction and mating as well as the release of luteinizing hormone from the pituitary gland. A second circuit, the main olfactory system, originates with sensory neurons in the main olfactory epithelium (MOE). This system detects a wide range of non-pheromonal odors relevant to survival (e.g., food and predator odors). Over the past decade evidence has accrued showing that the main olfactory system also detects a range of volatile odorants that function as pheromones to facilitate mate recognition and activate the hypothalamic-pituitary-gonadal neuroendocrine axis. We review early studies as well as the new literature supporting the view that the main olfactory system processes a variety of different pheromonal cues that facilitate mammalian reproduction. PMID:24929017

  17. Olfactory system gamma oscillations: the physiological dissection of a cognitive neural system

    PubMed Central

    Rojas-Líbano, Daniel

    2008-01-01

    Oscillatory phenomena have been a focus of dynamical systems research since the time of the classical studies on the pendulum by Galileo. Fast cortical oscillations also have a long and storied history in neurophysiology, and olfactory oscillations have led the way with a depth of explanation not present in the literature of most other cortical systems. From the earliest studies of odor-evoked oscillations by Adrian, many reports have focused on mechanisms and functional associations of these oscillations, in particular for the so-called gamma oscillations. As a result, much information is now available regarding the biophysical mechanisms that underlie the oscillations in the mammalian olfactory system. Recent studies have expanded on these and addressed functionality directly in mammals and in the analogous insect system. Sub-bands within the rodent gamma oscillatory band associated with specific behavioral and cognitive states have also been identified. All this makes oscillatory neuronal networks a unique interdisciplinary platform from which to study neurocognitive and dynamical phenomena in intact, freely behaving animals. We present here a summary of what has been learned about the functional role and mechanisms of gamma oscillations in the olfactory system as a guide for similar studies in other cortical systems. PMID:19003484

  18. Olfactory Dysfunction in Older Adults is Associated with Feelings of Depression and Loneliness.

    PubMed

    Sivam, Anita; Wroblewski, Kristen E; Alkorta-Aranburu, Gorka; Barnes, Lisa L; Wilson, Robert S; Bennett, David A; Pinto, Jayant M

    2016-05-01

    Olfactory dysfunction is a common complaint among physician visits. Olfactory loss affects quality of life and impairs function and activities of daily living. The purpose of our study was to assess the degree of odor identification associated with mental health. Olfactory function was measured using the brief smell identification test. Depressive symptoms were measured by the Center for Epidemiologic Studies Depression scale. Loneliness was assessed by the de Jong-Gierveld Loneliness Scale. Cognition was measured by a battery of 19 cognitive tests. The frequency of olfactory dysfunction in our study was ~40%. Older subjects had worse olfactory performance, as previously found. More loneliness was associated with worse odor identification. Similarly, symptoms of depression were associated with worse olfaction (among men). Although better global cognitive function was strongly associated with better odor identification, after controlling for multiple factors, the associations with depression and loneliness were unchanged. Clinicians should assess these mental health conditions when treating older patients who present with olfactory deficits. PMID:26809485

  19. The olfactory sensory system develops from coordinated movements within the neural plate

    PubMed Central

    Torres-Paz, Jorge

    2014-01-01

    Background The peripheral olfactory sensory system arises from morphologically identifiable structures called placodes. Placodes are relatively late developing structures, evident only well after the initiation of somitogenesis. Placodes are generally described as being induced from the ectoderm suggesting that their development is separate from the coordinated cell movements generating the central nervous system. Results With the advent of modern techniques it is possible to follow the development of the neurectoderm giving rise to the anterior neural tube, including the olfactory placodes. The cell movements giving rise to the optic cup are coordinated with those generating the olfactory placodes and adjacent telencephalon. The formation of the basal lamina separating the placode from the neural tube is coincident with the anterior migration of cranial neural crest. Conclusions Olfactory placodes are transient morphological structures arising from a continuous sheet of neurectoderm that gives rise to the peripheral and central nervous system. This field of cells is specified at the end of gastrulation and not secondarily induced from ectoderm. The separation of olfactory placodes and telencephalon occurs through complex cell movements within the developing neural plate similar to that observed for the developing optic cup. PMID:25255735

  20. Sensational placodes: Neurogenesis in the otic and olfactory systems

    PubMed Central

    Maier, Esther C.; Saxena, Ankur; Alsina, Berta; Bronner, Marianne E.; Whitfield, Tanya T.

    2014-01-01

    For both the intricate morphogenetic layout of the sensory cells in the ear and the elegantly radial arrangement of the sensory neurons in the nose, numerous signaling molecules and genetic determinants are required in concert to generate these specialized neuronal populations that help connect us to our environment. In this review, we outline many of the proteins and pathways that play essential roles in the differentiation of otic and olfactory neurons and their integration into their non-neuronal support structures. In both cases, well-known signaling pathways together with region-specific factors transform thickened ectodermal placodes into complex sense organs containing numerous, diverse neuronal subtypes. Olfactory and otic placodes, in combination with migratory neural crest stem cells, generate highly specialized subtypes of neuronal cells that sense sound, position and movement in space, odors and pheromones throughout our lives. PMID:24508480

  1. The wiring diagram of a glomerular olfactory system.

    PubMed

    Berck, Matthew E; Khandelwal, Avinash; Claus, Lindsey; Hernandez-Nunez, Luis; Si, Guangwei; Tabone, Christopher J; Li, Feng; Truman, James W; Fetter, Rick D; Louis, Matthieu; Samuel, Aravinthan Dt; Cardona, Albert

    2016-01-01

    The sense of smell enables animals to react to long-distance cues according to learned and innate valences. Here, we have mapped with electron microscopy the complete wiring diagram of the Drosophila larval antennal lobe, an olfactory neuropil similar to the vertebrate olfactory bulb. We found a canonical circuit with uniglomerular projection neurons (uPNs) relaying gain-controlled ORN activity to the mushroom body and the lateral horn. A second, parallel circuit with multiglomerular projection neurons (mPNs) and hierarchically connected local neurons (LNs) selectively integrates multiple ORN signals already at the first synapse. LN-LN synaptic connections putatively implement a bistable gain control mechanism that either computes odor saliency through panglomerular inhibition, or allows some glomeruli to respond to faint aversive odors in the presence of strong appetitive odors. This complete wiring diagram will support experimental and theoretical studies towards bridging the gap between circuits and behavior. PMID:27177418

  2. Chemotopic Odorant Coding in a Mammalian Olfactory System

    PubMed Central

    Johnson, Brett A.; Leon, Michael

    2008-01-01

    Systematic mapping studies involving 365 odorant chemicals have shown that glomerular responses in the rat olfactory bulb are organized spatially in patterns that are related to the chemistry of the odorant stimuli. This organization involves the spatial clustering of principal responses to numerous odorants that share key aspects of chemistry such as functional groups, hydrocarbon structural elements, and/or overall molecular properties related to water solubility. In several of the clusters, responses shift progressively in position according to odorant carbon chain length. These response domains appear to be constructed from orderly projections of sensory neurons in the olfactory epithelium and may also involve chromatography across the nasal mucosa. The spatial clustering of glomerular responses may serve to “tune” the principal responses of bulbar projection neurons by way of inhibitory interneuronal networks, allowing the projection neurons to respond to a narrower range of stimuli than their associated sensory neurons. When glomerular activity patterns are viewed relative to the overall level of glomerular activation, the patterns accurately predict the perception of odor quality, thereby supporting the notion that spatial patterns of activity are the key factors underlying that aspect of the olfactory code. A critical analysis suggests that alternative coding mechanisms for odor quality, such as those based on temporal patterns of responses, enjoy little experimental support. PMID:17480025

  3. Notch Is Required in Adult Drosophila Sensory Neurons for Morphological and Functional Plasticity of the Olfactory Circuit

    PubMed Central

    Struhl, Gary

    2015-01-01

    Olfactory receptor neurons (ORNs) convey odor information to the central brain, but like other sensory neurons were thought to play a passive role in memory formation and storage. Here we show that Notch, part of an evolutionarily conserved intercellular signaling pathway, is required in adult Drosophila ORNs for the structural and functional plasticity of olfactory glomeruli that is induced by chronic odor exposure. Specifically, we show that Notch activity in ORNs is necessary for the odor specific increase in the volume of glomeruli that occurs as a consequence of prolonged odor exposure. Calcium imaging experiments indicate that Notch in ORNs is also required for the chronic odor induced changes in the physiology of ORNs and the ensuing changes in the physiological response of their second order projection neurons (PNs). We further show that Notch in ORNs acts by both canonical cleavage-dependent and non-canonical cleavage-independent pathways. The Notch ligand Delta (Dl) in PNs switches the balance between the pathways. These data define a circuit whereby, in conjunction with odor, N activity in the periphery regulates the activity of neurons in the central brain and Dl in the central brain regulates N activity in the periphery. Our work highlights the importance of experience dependent plasticity at the first olfactory synapse. PMID:26011623

  4. Copper-induced deregulation of microRNA expression in the zebrafish olfactory system

    PubMed Central

    Wang, Lu; Bammler, Theo K.; Beyer, Richard P.; Gallagher, Evan P.

    2016-01-01

    Although environmental trace metals, such as copper (Cu), can disrupt normal olfactory function in fish, the underlying molecular mechanisms of metal-induced olfactory injury have not been elucidated. Current research has suggested the involvement of epigenetic modifications. To address this hypothesis, we analyzed microRNA (miRNA) profiles in the olfactory system of Cu-exposed zebrafish. Our data revealed 2, 10, and 28 differentially expressed miRNAs in a dose-response manner corresponding to three increasing Cu concentrations. Numerous deregulated miRNAs were involved in neurogenesis (e.g. let-7, miR-7a, miR-128 and miR-138), indicating a role for Cu-mediated toxicity via interference with neurogenesis processes. Putative gene targets of deregulated miRNAs were identified when interrogating our previously published microarray database, including those involved in cell growth and proliferation, cell death, and cell morphology. Moreover, several miRNAs (e.g. miR-203a, miR-199*, miR-16a, miR-16c, and miR-25) may contribute to decreased mRNA levels of their host genes involved in olfactory signal transduction pathways and other critical neurological processes via a post-transcriptional mechanism. Our findings provide novel insight into the epigenetic regulatory mechanisms of metal-induced neurotoxicity of the fish olfactory system, and identify novel miRNA biomarkers of metal exposures. PMID:23745839

  5. Copper-induced deregulation of microRNA expression in the zebrafish olfactory system.

    PubMed

    Wang, Lu; Bammler, Theo K; Beyer, Richard P; Gallagher, Evan P

    2013-07-01

    Although environmental trace metals, such as copper (Cu), can disrupt normal olfactory function in fish, the underlying molecular mechanisms of metal-induced olfactory injury have not been elucidated. Current research has suggested the involvement of epigenetic modifications. To address this hypothesis, we analyzed microRNA (miRNA) profiles in the olfactory system of Cu-exposed zebrafish. Our data revealed 2, 10, and 28 differentially expressed miRNAs in a dose-response manner corresponding to three increasing Cu concentrations. Numerous deregulated miRNAs were involved in neurogenesis (e.g., let-7, miR-7a, miR-128, and miR-138), indicating a role for Cu-mediated toxicity via interference with neurogenesis processes. Putative gene targets of deregulated miRNAs were identified when interrogating our previously published microarray database, including those involved in cell growth and proliferation, cell death, and cell morphology. Moreover, several miRNAs (e.g., miR-203a, miR-199*, miR-16a, miR-16c, and miR-25) may contribute to decreased mRNA levels of their host genes involved in olfactory signal transduction pathways and other critical neurological processes via a post-transcriptional mechanism. Our findings provide novel insight into the epigenetic regulatory mechanisms of metal-induced neurotoxicity of the fish olfactory system and identify novel miRNA biomarkers of metal exposures. PMID:23745839

  6. Long-term in vivo single-cell tracking reveals the switch of migration patterns in adult-born juxtaglomerular cells of the mouse olfactory bulb.

    PubMed

    Liang, Yajie; Li, Kaizhen; Riecken, Kristoffer; Maslyukov, Anatoliy; Gomez-Nicola, Diego; Kovalchuk, Yury; Fehse, Boris; Garaschuk, Olga

    2016-07-01

    The behavior of adult-born cells can be easily monitored in cell culture or in lower model organisms, but longitudinal observation of individual mammalian adult-born cells in their native microenvironment still proves to be a challenge. Here we have established an approach named optical cell positioning system for long-term in vivo single-cell tracking, which integrates red-green-blue cell labeling with repeated angiography. By combining this approach with in vivo two-photon imaging technique, we characterized the in vivo migration patterns of adult-born neurons in the olfactory bulb. In contrast to the traditional view of mere radial migration of adult-born cells within the bulb, we found that juxtaglomerular cells switch from radial migration to long distance lateral migration upon arrival in their destination layer. This unique long-distance lateral migration has characteristic temporal (stop-and-go) and spatial (migratory, unidirectional or multidirectional) patterns, with a clear cell age-dependent decrease in the migration speed. The active migration of adult-born cells coincides with the time period of initial fate determination and is likely to impact on the integration sites of adult-born cells, their odor responsiveness, as well as their survival rate. PMID:27174051

  7. Monoclonal antibodies reveal cell-type-specific antigens in the sexually dimorphic olfactory system of Manduca sexta. II. Expression of antigens during postembryonic development.

    PubMed

    Hishinuma, A; Hockfield, S; McKay, R; Hildebrand, J G

    1988-01-01

    Two classes of monoclonal antibodies specific to the olfactory system of Manduca sexta have been isolated: the olfactory-specific antibody (OSA), which specifically recognizes many or all olfactory receptor cells (ORCs) in both males and females, and the male olfactory-specific antibody (MOSA), which stains male-specific receptor cells (principally or exclusively sex-pheromone receptors present only in antennae of males; Hishinuma et al., 1988). In the investigation reported here, we examined the expression of the antigens during postembryonic development in order to correlate the presence of particular antigens with the status of differentiation of the ORCs or with their acquisition of particular functions. As assessed immunocytochemically, the OSA recognizes certain epithelial cells in the antennal imaginal disk of the fifth-instar larva. Later, during the first 70 hr of adult development, when differentiative cell divisions are occurring in the antennal epithelium to generate ORCs and the other cells that make up olfactory sensilla, no cells are stained. Immediately after this period of mitoses, the OSA immunoreactivity reappears exclusively in the ORCs, which begin to elaborate axons as an early event in their differentiation. On immunoblots, the OSA recognizes specific sets of molecules (distinguished on the basis of their apparent molecular weights): 53,000 and 59,000 Da antigens in the disk epithelial cells in the last-instar larva; 53,000, 59,000, and 66,000 Da antigens in the ORCs from 15 to 60% of metamorphic adult development; and 42,000, 59,000, and 66,000 Da antigens in the ORCs from 60 to 100% of adult development. The MOSA also recognizes a subset of the epithelial cells in the antennal disks in male and female larvae.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3339412

  8. Anosmin-1 over-expression increases adult neurogenesis in the subventricular zone and neuroblast migration to the olfactory bulb.

    PubMed

    García-González, Diego; Murcia-Belmonte, Verónica; Esteban, Pedro F; Ortega, Felipe; Díaz, David; Sánchez-Vera, Irene; Lebrón-Galán, Rafael; Escobar-Castañondo, Laura; Martínez-Millán, Luis; Weruaga, Eduardo; García-Verdugo, José Manuel; Berninger, Benedikt; de Castro, Fernando

    2016-01-01

    New subventricular zone (SVZ)-derived neuroblasts that migrate via the rostral migratory stream are continuously added to the olfactory bulb (OB) of the adult rodent brain. Anosmin-1 (A1) is an extracellular matrix protein that binds to FGF receptor 1 (FGFR1) to exert its biological effects. When mutated as in Kallmann syndrome patients, A1 is associated with severe OB morphogenesis defects leading to anosmia and hypogonadotropic hypogonadism. Here, we show that A1 over-expression in adult mice strongly increases proliferation in the SVZ, mainly with symmetrical divisions, and produces substantial morphological changes in the normal SVZ architecture, where we also report the presence of FGFR1 in almost all SVZ cells. Interestingly, for the first time we show FGFR1 expression in the basal body of primary cilia in neural progenitor cells. Additionally, we have found that A1 over-expression also enhances neuroblast motility, mainly through FGFR1 activity. Together, these changes lead to a selective increase in several GABAergic interneuron populations in different OB layers. These specific alterations in the OB would be sufficient to disrupt the normal processing of sensory information and consequently alter olfactory memory. In summary, this work shows that FGFR1-mediated A1 activity plays a crucial role in the continuous remodelling of the adult OB. PMID:25300351

  9. Functional promiscuity in a mammalian chemosensory system: extensive expression of vomeronasal receptors in the main olfactory epithelium of mouse lemurs

    PubMed Central

    Hohenbrink, Philipp; Dempewolf, Silke; Zimmermann, Elke; Mundy, Nicholas I.; Radespiel, Ute

    2014-01-01

    The vomeronasal organ (VNO) is functional in most terrestrial mammals, though progressively reduced in the primate lineage, and is used for intraspecific communication and predator recognition. Vomeronasal receptor (VR) genes comprise two families of chemosensory genes (V1R and V2R) that have been considered to be specific for the VNO. However, recently a large number of VRs were reported to be expressed in the main olfactory epithelium (MOE) of mice, but there is little knowledge of the expression of these genes outside of rodents. To explore the function of VR genes in mammalian evolution, we analyzed and compared the expression of 64 V1R and 2 V2R genes in the VNO and the MOE of the gray mouse lemur (Microcebus murinus), the primate with the largest known VR repertoire. We furthermore compared expression patterns in adults of both sexes and seasons, and in an infant. A large proportion (83–97%) of the VR loci was expressed in the VNO of all individuals. The repertoire in the infant was as rich as in adults, indicating reliance on olfactory communication from early postnatal development onwards. In concordance with mice, we also detected extensive expression of VRs in the MOE, with proportions of expressed loci in individuals ranging from 29 to 45%. TRPC2, which encodes a channel protein crucial for signal transduction via VRs, was co-expressed in the MOE in all individuals indicating likely functionality of expressed VR genes in the MOE. In summary, the large VR repertoire in mouse lemurs seems to be highly functional. Given the differences in the neural pathways of MOE and VNO signals, which project to higher cortical brain centers or the limbic system, respectively, this raises the intriguing possibility that the evolution of MOE-expression of VRs enabled mouse lemurs to adaptively diversify the processing of VR-encoded olfactory information. PMID:25309343

  10. Functional promiscuity in a mammalian chemosensory system: extensive expression of vomeronasal receptors in the main olfactory epithelium of mouse lemurs.

    PubMed

    Hohenbrink, Philipp; Dempewolf, Silke; Zimmermann, Elke; Mundy, Nicholas I; Radespiel, Ute

    2014-01-01

    The vomeronasal organ (VNO) is functional in most terrestrial mammals, though progressively reduced in the primate lineage, and is used for intraspecific communication and predator recognition. Vomeronasal receptor (VR) genes comprise two families of chemosensory genes (V1R and V2R) that have been considered to be specific for the VNO. However, recently a large number of VRs were reported to be expressed in the main olfactory epithelium (MOE) of mice, but there is little knowledge of the expression of these genes outside of rodents. To explore the function of VR genes in mammalian evolution, we analyzed and compared the expression of 64 V1R and 2 V2R genes in the VNO and the MOE of the gray mouse lemur (Microcebus murinus), the primate with the largest known VR repertoire. We furthermore compared expression patterns in adults of both sexes and seasons, and in an infant. A large proportion (83-97%) of the VR loci was expressed in the VNO of all individuals. The repertoire in the infant was as rich as in adults, indicating reliance on olfactory communication from early postnatal development onwards. In concordance with mice, we also detected extensive expression of VRs in the MOE, with proportions of expressed loci in individuals ranging from 29 to 45%. TRPC2, which encodes a channel protein crucial for signal transduction via VRs, was co-expressed in the MOE in all individuals indicating likely functionality of expressed VR genes in the MOE. In summary, the large VR repertoire in mouse lemurs seems to be highly functional. Given the differences in the neural pathways of MOE and VNO signals, which project to higher cortical brain centers or the limbic system, respectively, this raises the intriguing possibility that the evolution of MOE-expression of VRs enabled mouse lemurs to adaptively diversify the processing of VR-encoded olfactory information. PMID:25309343

  11. Brief embryonic cadmium exposure induces a stress response and cell death in the developing olfactory system followed by long-term olfactory deficits in juvenile zebrafish

    SciTech Connect

    Blechinger, Scott R.; Kusch, Robin C.; Haugo, Kristine; Matz, Carlyn; Chivers, Douglas P.; Krone, Patrick H.

    2007-10-01

    The toxic effects of cadmium and other metals have been well established. A primary target of these metals is known to be the olfactory system, and fish exposed to a number of different waterborne metals display deficiencies in olfaction. Importantly, exposure over embryonic/larval development periods can cause deficits in chemosensory function in juvenile fish, but the specific cell types affected are unknown. We have previously characterized a transgenic zebrafish strain expressing the green fluorescent protein (eGFP) gene linked to the hsp70 gene promoter, and shown it to be a useful tool for examining cell-specific toxicity in living embryos and larvae. Here we show that the hsp70/eGFP transgene is strongly and specifically upregulated within the olfactory sensory neurons (OSNs) of transgenic zebrafish larvae following a brief 3-h exposure to water-borne cadmium. This molecular response was closely correlated to an endpoint for tissue damage within the olfactory placode, namely cell death. Furthermore, cadmium-induced olfactory cytotoxicity in zebrafish larvae gives rise to more permanent effects. Juvenile zebrafish briefly exposed to cadmium during early larval development display deficits in olfactory-dependent predator avoidance behaviors 4-6 weeks after a return to clean water. Lateral line neuromasts of exposed zebrafish larvae also activate both the endogenous hsp70 gene and the hsp70/eGFP transgene. The data reveal that even a very brief exposure period that gives rise to cell death within the developing olfactory placode results in long-term deficits in olfaction, and that hsp70/eGFP may serve as an effective indicator of sublethal cadmium exposure in sensory cells.

  12. The olfactory system as the gateway to the neural correlates of consciousness

    PubMed Central

    Merrick, Christina; Godwin, Christine A.; Geisler, Mark W.; Morsella, Ezequiel

    2014-01-01

    How consciousness is generated by the nervous system remains one of the greatest mysteries in science. Investigators from diverse fields have begun to unravel this puzzle by contrasting conscious and unconscious processes. In this way, it has been revealed that the two kinds of processes differ in terms of the underlying neural events and associated cognitive mechanisms. We propose that, for several reasons, the olfactory system provides a unique portal through which to examine this contrast. For this purpose, the olfactory system is beneficial in terms of its (a) neuroanatomical aspects, (b) phenomenological and cognitive/mechanistic properties, and (c) neurodynamic (e.g., brain oscillations) properties. In this review, we discuss how each of these properties and aspects of the olfactory system can illuminate the contrast between conscious and unconscious processing in the brain. We conclude by delineating the most fruitful avenues of research and by entertaining hypotheses that, in order for an olfactory content to be conscious, that content must participate in a network that is large-scale, both in terms of the neural systems involved and the scope of information integration. PMID:24454300

  13. The olfactory system as the gateway to the neural correlates of consciousness.

    PubMed

    Merrick, Christina; Godwin, Christine A; Geisler, Mark W; Morsella, Ezequiel

    2014-01-10

    How consciousness is generated by the nervous system remains one of the greatest mysteries in science. Investigators from diverse fields have begun to unravel this puzzle by contrasting conscious and unconscious processes. In this way, it has been revealed that the two kinds of processes differ in terms of the underlying neural events and associated cognitive mechanisms. We propose that, for several reasons, the olfactory system provides a unique portal through which to examine this contrast. For this purpose, the olfactory system is beneficial in terms of its (a) neuroanatomical aspects, (b) phenomenological and cognitive/mechanistic properties, and (c) neurodynamic (e.g., brain oscillations) properties. In this review, we discuss how each of these properties and aspects of the olfactory system can illuminate the contrast between conscious and unconscious processing in the brain. We conclude by delineating the most fruitful avenues of research and by entertaining hypotheses that, in order for an olfactory content to be conscious, that content must participate in a network that is large-scale, both in terms of the neural systems involved and the scope of information integration. PMID:24454300

  14. The wiring diagram of a glomerular olfactory system

    PubMed Central

    Berck, Matthew E; Khandelwal, Avinash; Claus, Lindsey; Hernandez-Nunez, Luis; Si, Guangwei; Tabone, Christopher J; Li, Feng; Truman, James W; Fetter, Rick D; Louis, Matthieu; Samuel, Aravinthan DT; Cardona, Albert

    2016-01-01

    The sense of smell enables animals to react to long-distance cues according to learned and innate valences. Here, we have mapped with electron microscopy the complete wiring diagram of the Drosophila larval antennal lobe, an olfactory neuropil similar to the vertebrate olfactory bulb. We found a canonical circuit with uniglomerular projection neurons (uPNs) relaying gain-controlled ORN activity to the mushroom body and the lateral horn. A second, parallel circuit with multiglomerular projection neurons (mPNs) and hierarchically connected local neurons (LNs) selectively integrates multiple ORN signals already at the first synapse. LN-LN synaptic connections putatively implement a bistable gain control mechanism that either computes odor saliency through panglomerular inhibition, or allows some glomeruli to respond to faint aversive odors in the presence of strong appetitive odors. This complete wiring diagram will support experimental and theoretical studies towards bridging the gap between circuits and behavior. DOI: http://dx.doi.org/10.7554/eLife.14859.001 PMID:27177418

  15. Evolving a Neural Olfactorimotor System in Virtual and Real Olfactory Environments

    PubMed Central

    Rhodes, Paul A.; Anderson, Todd O.

    2012-01-01

    To provide a platform to enable the study of simulated olfactory circuitry in context, we have integrated a simulated neural olfactorimotor system with a virtual world which simulates both computational fluid dynamics as well as a robotic agent capable of exploring the simulated plumes. A number of the elements which we developed for this purpose have not, to our knowledge, been previously assembled into an integrated system, including: control of a simulated agent by a neural olfactorimotor system; continuous interaction between the simulated robot and the virtual plume; the inclusion of multiple distinct odorant plumes and background odor; the systematic use of artificial evolution driven by olfactorimotor performance (e.g., time to locate a plume source) to specify parameter values; the incorporation of the realities of an imperfect physical robot using a hybrid model where a physical robot encounters a simulated plume. We close by describing ongoing work toward engineering a high dimensional, reversible, low power electronic olfactory sensor which will allow olfactorimotor neural circuitry evolved in the virtual world to control an autonomous olfactory robot in the physical world. The platform described here is intended to better test theories of olfactory circuit function, as well as provide robust odor source localization in realistic environments. PMID:23112772

  16. The Combined Role of the Main Olfactory and Vomeronasal Systems in Social Communication in Mammals

    PubMed Central

    Kelliher, Kevin R

    2009-01-01

    The main olfactory and the vomeronasal systems are the two systems by which most vertebrates detect chemosensory cues that mediate social behavior. Much research has focused on how one system or the other is critical for particular behaviors. This has lead to a vision of two distinct and complexly autonomous olfactory systems. A closer look at research over the past 30 years reveals a different picture however. These two seemingly distinct systems are much more integrated than previously thought. One novel set of chemosensory cues in particular (MHC Class I peptide ligands) can show us how both systems are capable of detecting the same chemosensory cues, through different mechanisms yet provide the same general information (genetic individuality). Future research will need to now focus on how two seemingly distinct chemosensory systems together detect pheromones and mediate social behaviors. Do these systems work independently, synergistically or competitively in communicating between individuals of the same species? PMID:17959176

  17. Pheromones from males of different familiarity exert divergent effects on adult neurogenesis in the female accessory olfactory bulb.

    PubMed

    Wu, Jyun-Han; Han, Yueh-Ting; Yu, Jenn-Yah; Wang, Tsu-Wei

    2013-08-01

    Pheromones from urine of unfamiliar conspecific male animals can reinitiate a female's estrus cycle to cause pregnancy block through the vomeronasal organ (VNO)-accessory olfactory bulb (AOB)-hypothalamic pathway. This phenomenon is called the Bruce effect. Pheromones from the mate of the female, however, do not trigger re-entrance of the estrus cycle because an olfactory memory toward its mate is formed. The activity of the VNO-AOB-hypothalamic pathway is negatively modulated by GABAergic granule cells in the AOB. Since these cells are constantly replenished by neural stem cells in the subventricular zone (SVZ) of the lateral ventricle throughout adulthood and adult neurogenesis is required for mate recognition and fertility, we tested the hypothesis that pheromones from familiar and unfamiliar males may have different effects on adult AOB neurogenesis in female mice. When female mice were exposed to bedding used by a male or lived with one, cell proliferation and neuroblast production in the SVZ were increased. Furthermore, survival of newly generated cells in the AOB was enhanced. This survival effect was transient and mediated by norepinephrine. Interestingly, male bedding-induced newborn cell survival in the AOB but not cell proliferation in the SVZ was attenuated when females were subjected to bedding from an unfamiliar male. Our results indicate that male pheromones from familiar and unfamiliar males exert different effects on neurogenesis in the adult female AOB. Given that adult neurogenesis is required for reproductive behaviors, these divergent pheromonal effects may provide a mechanism for the Bruce effect. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 73: 632-645, 2013. PMID:23696538

  18. Recent Trend in Development of Olfactory Displays

    NASA Astrophysics Data System (ADS)

    Yanagida, Yasuyuki

    An olfactory display is a device that generates scented air with desired concentration of aroma, and delivers it to the user's olfactory organ. In this article, the nature of olfaction is briefly described from the view point of how to configure olfactory displays. Next, component technologies to compose olfactory displays, i.e., making scents and delivering scents, are categorized. Several existing olfactory display systems are introduced to show the current status of research and development of olfactory displays.

  19. How to escape from Haller's rule: Olfactory system complexity in small and large Trichogramma evanescens parasitic wasps.

    PubMed

    van der Woude, Emma; Smid, Hans M

    2016-06-15

    While Haller's rule states that small animals have relatively larger brains, minute Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) parasitic wasps scale brain size linearly with body size. This linear brain scaling allows them to decrease brain size beyond the predictions of Haller's rule, and is facilitated by phenotypic plasticity in brain size. In the present study we addressed whether this plasticity resulted in adaptations to the complexity of the morphology of the olfactory system of small and large T. evanescens. We used confocal laser scanning microscopy to compare size and number of glomeruli in the antennal lobe in the brain, and scanning electron microscopy to compare length and number of olfactory sensilla on the antennae. The results show a similar level of complexity of the olfactory system morphology of small and large wasps. Wasps with a similar genotype but very different brain and body size have similarly sized olfactory sensilla and most of them occur in equal numbers on the antennae. Small and large wasps also have a similar number of glomeruli in the antennal lobe. Glomeruli in small brains are, however, smaller in both absolute and relative volume. These similarities between small and large wasps may indicate that plasticity in brain size does not require plasticity in the gross morphology of the olfactory system. It may be vital for wasps of all sizes to have a large number of olfactory receptor types, to maintain olfactory precision in their search for suitable hosts, and consequently maintain their reproductive success and Darwinian fitness. PMID:26560192

  20. Disruption of Aedes aegypti Olfactory System Development through Chitosan/siRNA Nanoparticle Targeting of semaphorin-1a

    PubMed Central

    Mysore, Keshava; Flannery, Ellen M.; Tomchaney, Michael; Severson, David W.; Duman-Scheel, Molly

    2013-01-01

    Despite the devastating impact of mosquito-borne illnesses on human health, surprisingly little is known about mosquito developmental biology, including development of the olfactory system, a tissue of vector importance. Analysis of mosquito olfactory developmental genetics has been hindered by a lack of means to target specific genes during the development of this sensory system. In this investigation, chitosan/siRNA nanoparticles were used to target semaphorin-1a (sema1a) during olfactory system development in the dengue and yellow fever vector mosquito Aedes aegypti. Immunohistochemical analyses and anterograde tracing of antennal sensory neurons, which were used to track the progression of olfactory development in this species, revealed antennal lobe defects in sema1a knockdown fourth instar larvae. These findings, which correlated with a larval odorant tracking behavioral phenotype, identified previously unreported roles for Sema1a in the developing insect larval olfactory system. Analysis of sema1a knockdown pupae also revealed a number of olfactory phenotypes, including olfactory receptor neuron targeting and projection neuron defects coincident with a collapse in the structure and shape of the antennal lobe and individual glomeruli. This study, which is to our knowledge the first functional genetic analysis of insect olfactory development outside of D. melanogaster, identified critical roles for Sema1a during Ae. aegypti larval and pupal olfactory development and advocates the use of chitosan/siRNA nanoparticles as an effective means of targeting genes during post-embryonic Ae. aegypti development. Use of siRNA nanoparticle methodology to understand sensory developmental genetics in mosquitoes will provide insight into the evolutionary conservation and divergence of key developmental genes which could be exploited in the development of both common and species-specific means for intervention. PMID:23696908

  1. A Screen for Genes Expressed in the Olfactory Organs of Drosophila melanogaster Identifies Genes Involved in Olfactory Behaviour

    PubMed Central

    Tunstall, Narelle E.; Herr, Anabel; de Bruyne, Marien; Warr, Coral G.

    2012-01-01

    Background For insects the sense of smell and associated olfactory-driven behaviours are essential for survival. Insects detect odorants with families of olfactory receptor proteins that are very different to those of mammals, and there are likely to be other unique genes and genetic pathways involved in the function and development of the insect olfactory system. Methodology/Principal Findings We have performed a genetic screen of a set of 505 Drosophila melanogaster gene trap insertion lines to identify novel genes expressed in the adult olfactory organs. We identified 16 lines with expression in the olfactory organs, many of which exhibited expression of the trapped genes in olfactory receptor neurons. Phenotypic analysis showed that six of the lines have decreased olfactory responses in a behavioural assay, and for one of these we showed that precise excision of the P element reverts the phenotype to wild type, confirming a role for the trapped gene in olfaction. To confirm the identity of the genes trapped in the lines we performed molecular analysis of some of the insertion sites. While for many lines the reported insertion sites were correct, we also demonstrated that for a number of lines the reported location of the element was incorrect, and in three lines there were in fact two pGT element insertions. Conclusions/Significance We identified 16 new genes expressed in the Drosophila olfactory organs, the majority in neurons, and for several of the gene trap lines demonstrated a defect in olfactory-driven behaviour. Further characterisation of these genes and their roles in olfactory system function and development will increase our understanding of how the insect olfactory system has evolved to perform the same essential function to that of mammals, but using very different molecular genetic mechanisms. PMID:22530061

  2. Pax6 Is Essential for the Maintenance and Multi-Lineage Differentiation of Neural Stem Cells, and for Neuronal Incorporation into the Adult Olfactory Bulb

    PubMed Central

    Curto, Gloria G.; Nieto-Estévez, Vanesa; Hurtado-Chong, Anahí; Valero, Jorge; Gómez, Carmela; Alonso, José R.; Weruaga, Eduardo

    2014-01-01

    The paired type homeobox 6 (Pax6) transcription factor (TF) regulates multiple aspects of neural stem cell (NSC) and neuron development in the embryonic central nervous system. However, less is known about the role of Pax6 in the maintenance and differentiation of adult NSCs and in adult neurogenesis. Using the +/SeyDey mouse, we have analyzed how Pax6 heterozygosis influences the self-renewal and proliferation of adult olfactory bulb stem cells (aOBSCs). In addition, we assessed its influence on neural differentiation, neuronal incorporation, and cell death in the adult OB, both in vivo and in vitro. Our results indicate that the Pax6 mutation alters Nestin+-cell proliferation in vivo, as well as self-renewal, proliferation, and survival of aOBSCs in vitro although a subpopulation of +/SeyDey progenitors is able to expand partially similar to wild-type progenitors. This mutation also impairs aOBSC differentiation into neurons and oligodendrocytes, whereas it increases cell death while preserving astrocyte survival and differentiation. Furthermore, Pax6 heterozygosis causes a reduction in the variety of neurochemical interneuron subtypes generated from aOBSCs in vitro and in the incorporation of newly generated neurons into the OB in vivo. Our findings support an important role of Pax6 in the maintenance of aOBSCs by regulating cell death, self-renewal, and cell fate, as well as in neuronal incorporation into the adult OB. They also suggest that deregulation of the cell cycle machinery and TF expression in aOBSCs which are deficient in Pax6 may be at the origin of the phenotypes observed in this adult NSC population. PMID:25117830

  3. Analysis of discrimination mechanisms in the mammalian olfactory system using a model nose

    NASA Astrophysics Data System (ADS)

    Persaud, Krishna; Dodd, George

    1982-09-01

    Olfaction exhibits both high sensitivity for odours and high discrimination between them1. We suggest that to make fine discriminations between complex odorant mixtures containing varying ratios of odorants without the necessity for highly specialized peripheral receptors, the olfactory systems makes use of feature detection using broadly tuned receptor cells organized in a convergent neurone pathway. As a test of this hypothesis we have constructed an electronic nose using semiconductor transducers and incorporating design features suggested by our proposal. We report here that this device can reproducibly discriminate between a wide variety of odours, and its properties show that discrimination in an olfactory system could be achieved without the use of highly specific receptors.

  4. Cobalt Chloride Treatment Used to Ablate the Lateral Line System Also Impairs the Olfactory System in Three Freshwater Fishes

    PubMed Central

    Butler, Julie M.; Field, Karen E.; Maruska, Karen P.

    2016-01-01

    Fishes use multimodal signals during both inter- and intra-sexual displays to convey information about their sex, reproductive state, and social status. These complex behavioral displays can include visual, auditory, olfactory, tactile, and hydrodynamic signals, and the relative role of each sensory channel in these complex multi-sensory interactions is a common focus of neuroethology. The mechanosensory lateral line system of fishes detects near-body water movements and is implicated in a variety of behaviors including schooling, rheotaxis, social communication, and prey detection. Cobalt chloride is commonly used to chemically ablate lateral line neuromasts, thereby eliminating water-movement cues to test for mechanosensory-mediated behavioral functions. However, cobalt acts as a nonspecific calcium channel antagonist and could potentially disrupt function of all superficially located sensory receptor cells, including those for chemosensing. Here, we examined whether CoCl2 treatment used to ablate the lateral line system also impairs olfaction in three freshwater fishes, the African cichlid fish Astatotilapia burtoni, goldfish Carassius auratus, and the Mexican blind cavefish Astyanax mexicanus. To examine the impact of CoCl2 on the activity of peripheral receptors, we quantified DASPEI fluorescence intensity of the olfactory epithelium from fish exposed to control and CoCl2 solutions. In addition, we examined brain activation in olfactory processing regions of A. burtoni immersed in either control or cobalt solutions. All three species exposed to CoCl2 had decreased DASPEI staining of the olfactory epithelium, and in A. burtoni, cobalt treatment caused reduced neural activation in olfactory processing regions of the brain. To our knowledge this is the first empirical evidence demonstrating that the same CoCl2 treatment used to ablate the lateral line system also impairs olfactory function. These data have important implications for the use of CoCl2 in future

  5. Cobalt Chloride Treatment Used to Ablate the Lateral Line System Also Impairs the Olfactory System in Three Freshwater Fishes.

    PubMed

    Butler, Julie M; Field, Karen E; Maruska, Karen P

    2016-01-01

    Fishes use multimodal signals during both inter- and intra-sexual displays to convey information about their sex, reproductive state, and social status. These complex behavioral displays can include visual, auditory, olfactory, tactile, and hydrodynamic signals, and the relative role of each sensory channel in these complex multi-sensory interactions is a common focus of neuroethology. The mechanosensory lateral line system of fishes detects near-body water movements and is implicated in a variety of behaviors including schooling, rheotaxis, social communication, and prey detection. Cobalt chloride is commonly used to chemically ablate lateral line neuromasts, thereby eliminating water-movement cues to test for mechanosensory-mediated behavioral functions. However, cobalt acts as a nonspecific calcium channel antagonist and could potentially disrupt function of all superficially located sensory receptor cells, including those for chemosensing. Here, we examined whether CoCl2 treatment used to ablate the lateral line system also impairs olfaction in three freshwater fishes, the African cichlid fish Astatotilapia burtoni, goldfish Carassius auratus, and the Mexican blind cavefish Astyanax mexicanus. To examine the impact of CoCl2 on the activity of peripheral receptors, we quantified DASPEI fluorescence intensity of the olfactory epithelium from fish exposed to control and CoCl2 solutions. In addition, we examined brain activation in olfactory processing regions of A. burtoni immersed in either control or cobalt solutions. All three species exposed to CoCl2 had decreased DASPEI staining of the olfactory epithelium, and in A. burtoni, cobalt treatment caused reduced neural activation in olfactory processing regions of the brain. To our knowledge this is the first empirical evidence demonstrating that the same CoCl2 treatment used to ablate the lateral line system also impairs olfactory function. These data have important implications for the use of CoCl2 in future

  6. Inhibition of glycogen synthase kinase-3 enhances the differentiation and reduces the proliferation of adult human olfactory epithelium neural precursors

    SciTech Connect

    Manceur, Aziza P.; Tseng, Michael; Holowacz, Tamara; Witterick, Ian; Weksberg, Rosanna; McCurdy, Richard D.; Warsh, Jerry J.; Audet, Julie

    2011-09-10

    The olfactory epithelium (OE) contains neural precursor cells which can be easily harvested from a minimally invasive nasal biopsy, making them a valuable cell source to study human neural cell lineages in health and disease. Glycogen synthase kinase-3 (GSK-3) has been implicated in the etiology and treatment of neuropsychiatric disorders and also in the regulation of murine neural precursor cell fate in vitro and in vivo. In this study, we examined the impact of decreased GSK-3 activity on the fate of adult human OE neural precursors in vitro. GSK-3 inhibition was achieved using ATP-competitive (6-bromoindirubin-3'-oxime and CHIR99021) or substrate-competitive (TAT-eIF2B) inhibitors to eliminate potential confounding effects on cell fate due to off-target kinase inhibition. GSK-3 inhibitors decreased the number of neural precursor cells in OE cell cultures through a reduction in proliferation. Decreased proliferation was not associated with a reduction in cell survival but was accompanied by a reduction in nestin expression and a substantial increase in the expression of the neuronal differentiation markers MAP1B and neurofilament (NF-M) after 10 days in culture. Taken together, these results suggest that GSK-3 inhibition promotes the early stages of neuronal differentiation in cultures of adult human neural precursors and provide insights into the mechanisms by which alterations in GSK-3 signaling affect adult human neurogenesis, a cellular process strongly suspected to play a role in the etiology of neuropsychiatric disorders.

  7. Perception of Odors Linked to Precise Timing in the Olfactory System

    PubMed Central

    Rebello, Michelle R.; McTavish, Thomas S.; Willhite, David C.; Short, Shaina M.; Shepherd, Gordon M.; Verhagen, Justus V.

    2014-01-01

    While the timing of neuronal activity in the olfactory bulb (OB) relative to sniffing has been the object of many studies, the behavioral relevance of timing information generated by patterned activation within the bulbar response has not been explored. Here we show, using sniff-triggered, dynamic, 2-D, optogenetic stimulation of mitral/tufted cells, that virtual odors that differ by as little as 13 ms are distinguishable by mice. Further, mice are capable of discriminating a virtual odor movie based on an optically imaged OB odor response versus the same virtual odor devoid of temporal dynamics—independently of the sniff-phase. Together with studies showing the behavioral relevance of graded glomerular responses and the response timing relative to odor sampling, these results imply that the mammalian olfactory system is capable of very high transient information transmission rates. PMID:25514030

  8. Faecal bile acids are natural ligands of the mouse accessory olfactory system.

    PubMed

    Doyle, Wayne I; Dinser, Jordan A; Cansler, Hillary L; Zhang, Xingjian; Dinh, Daniel D; Browder, Natasha S; Riddington, Ian M; Meeks, Julian P

    2016-01-01

    The accessory olfactory system (AOS) guides behaviours that are important for survival and reproduction, but understanding of AOS function is limited by a lack of identified natural ligands. Here we report that mouse faeces are a robust source of AOS chemosignals and identify bile acids as a class of natural AOS ligands. Single-unit electrophysiological recordings from accessory olfactory bulb neurons in ex vivo preparations show that AOS neurons are strongly and selectively activated by peripheral stimulation with mouse faecal extracts. Faecal extracts contain several unconjugated bile acids that cause concentration-dependent neuronal activity in the AOS. Many AOS neurons respond selectively to bile acids that are variably excreted in male and female mouse faeces, and others respond to bile acids absent in mouse faeces. These results identify faeces as a natural source of AOS information, and suggest that bile acids may be mammalian pheromones and kairomones. PMID:27324439

  9. Faecal bile acids are natural ligands of the mouse accessory olfactory system

    PubMed Central

    Doyle, Wayne I.; Dinser, Jordan A.; Cansler, Hillary L.; Zhang, Xingjian; Dinh, Daniel D.; Browder, Natasha S.; Riddington, Ian M.; Meeks, Julian P.

    2016-01-01

    The accessory olfactory system (AOS) guides behaviours that are important for survival and reproduction, but understanding of AOS function is limited by a lack of identified natural ligands. Here we report that mouse faeces are a robust source of AOS chemosignals and identify bile acids as a class of natural AOS ligands. Single-unit electrophysiological recordings from accessory olfactory bulb neurons in ex vivo preparations show that AOS neurons are strongly and selectively activated by peripheral stimulation with mouse faecal extracts. Faecal extracts contain several unconjugated bile acids that cause concentration-dependent neuronal activity in the AOS. Many AOS neurons respond selectively to bile acids that are variably excreted in male and female mouse faeces, and others respond to bile acids absent in mouse faeces. These results identify faeces as a natural source of AOS information, and suggest that bile acids may be mammalian pheromones and kairomones. PMID:27324439

  10. Rapid Nipah virus entry into the central nervous system of hamsters via the olfactory route.

    PubMed

    Munster, Vincent J; Prescott, Joseph B; Bushmaker, Trenton; Long, Dan; Rosenke, Rebecca; Thomas, Tina; Scott, Dana; Fischer, Elizabeth R; Feldmann, Heinz; de Wit, Emmie

    2012-01-01

    Encephalitis is a hallmark of Nipah virus (NiV) infection in humans. The exact route of entry of NiV into the central nervous system (CNS) is unknown. Here, we performed a spatio-temporal analysis of NiV entry into the CNS of hamsters. NiV initially predominantly targeted the olfactory epithelium in the nasal turbinates. From there, NiV infected neurons were visible extending through the cribriform plate into the olfactory bulb, providing direct evidence of rapid CNS entry. Subsequently, NiV disseminated to the olfactory tubercle and throughout the ventral cortex. Transmission electron microscopy on brain tissue showed extravasation of plasma cells, neuronal degeneration and nucleocapsid inclusions in affected tissue and axons, providing further evidence for axonal transport of NiV. NiV entry into the CNS coincided with the occurrence of respiratory disease, suggesting that the initial entry of NiV into the CNS occurs simultaneously with, rather than as a result of, systemic virus replication. PMID:23071900

  11. Functional Analysis Of The Guanylyl Cyclase Type D Signaling System In The Olfactory Epithelium

    PubMed Central

    Cockerham, Renee E.; Leinders-Zufall, Trese; Munger, Steven D.; Zufall, Frank

    2013-01-01

    The mammalian olfactory system recognizes a wide range of chemical stimuli. The majority of cells in the main olfactory epithelium (MOE) use a cAMP-mediated signaling system to transduce odor signals. However, a subset of MOE neurons instead expresses components of a cGMP signaling cascade, including the receptor guanylyl cyclase GC-D and the cyclic nucleotide-gated channel subunit CNGA3. We used a combination of molecular biological, physiological and imaging approaches to characterize this neuronal population. Neurons expressing GC-D show excitatory responses to the natriuretic peptide hormones uroguanylin and guanylin, as well as to stimuli present in urine, that are dependent on both GC-D and CNGA3. Though all GC-D-expressing neurons are highly sensitive to these stimuli, individual cells are differentially tuned to either one or both of the peptides. Together, these findings suggest that neurons expressing GC-D are part of a specialized olfactory subsystem that is responsive to semiochemicals. PMID:19686132

  12. Rapid Nipah virus entry into the central nervous system of hamsters via the olfactory route

    PubMed Central

    Munster, Vincent J.; Prescott, Joseph B.; Bushmaker, Trenton; Long, Dan; Rosenke, Rebecca; Thomas, Tina; Scott, Dana; Fischer, Elizabeth R.; Feldmann, Heinz; de Wit, Emmie

    2012-01-01

    Encephalitis is a hallmark of Nipah virus (NiV) infection in humans. The exact route of entry of NiV into the central nervous system (CNS) is unknown. Here, we performed a spatio-temporal analysis of NiV entry into the CNS of hamsters. NiV initially predominantly targeted the olfactory epithelium in the nasal turbinates. From there, NiV infected neurons were visible extending through the cribriform plate into the olfactory bulb, providing direct evidence of rapid CNS entry. Subsequently, NiV disseminated to the olfactory tubercle and throughout the ventral cortex. Transmission electron microscopy on brain tissue showed extravasation of plasma cells, neuronal degeneration and nucleocapsid inclusions in affected tissue and axons, providing further evidence for axonal transport of NiV. NiV entry into the CNS coincided with the occurrence of respiratory disease, suggesting that the initial entry of NiV into the CNS occurs simultaneously with, rather than as a result of, systemic virus replication. PMID:23071900

  13. Metamorphic remodeling of the olfactory organ of the African clawed frog, Xenopus laevis.

    PubMed

    Dittrich, Katarina; Kuttler, Josua; Hassenklöver, Thomas; Manzini, Ivan

    2016-04-01

    The amphibian olfactory system undergoes massive remodeling during metamorphosis. The transition from aquatic olfaction in larvae to semiaquatic or airborne olfaction in adults requires anatomical, cellular, and molecular modifications. These changes are particularly pronounced in Pipidae, whose adults have secondarily adapted to an aquatic life style. In the fully aquatic larvae of Xenopus laevis, the main olfactory epithelium specialized for sensing water-borne odorous substances lines the principal olfactory cavity (PC), whereas a separate olfactory epithelium lies in the vomeronasal organ (VNO). During metamorphosis, the epithelium of the PC is rearranged into the adult "air nose," whereas a new olfactory epithelium, the adult "water nose," forms in the emerging middle cavity (MC). Here we performed a stage-by-stage investigation of the anatomical changes of the Xenopus olfactory organ during metamorphosis. We quantified cell death in all olfactory epithelia and found massive cell death in the PC and the VNO, suggesting that the majority of larval sensory neurons is replaced during metamorphosis in both sensory epithelia. The moderate cell death in the MC shows that during the formation of this epithelium some cells are sorted out. Our results show that during MC formation some supporting cells, but not sensory neurons, are relocated from the PC to the MC and that they are eventually eliminated during metamorphosis. Together our findings illustrate the structural and cellular changes of the Xenopus olfactory organ during metamorphosis. PMID:26294036

  14. Olfactory Receptors in Non-Chemosensory Organs: The Nervous System in Health and Disease

    PubMed Central

    Ferrer, Isidro; Garcia-Esparcia, Paula; Carmona, Margarita; Carro, Eva; Aronica, Eleonora; Kovacs, Gabor G.; Grison, Alice; Gustincich, Stefano

    2016-01-01

    Olfactory receptors (ORs) and down-stream functional signaling molecules adenylyl cyclase 3 (AC3), olfactory G protein α subunit (Gαolf), OR transporters receptor transporter proteins 1 and 2 (RTP1 and RTP2), receptor expression enhancing protein 1 (REEP1), and UDP-glucuronosyltransferases (UGTs) are expressed in neurons of the human and murine central nervous system (CNS). In vitro studies have shown that these receptors react to external stimuli and therefore are equipped to be functional. However, ORs are not directly related to the detection of odors. Several molecules delivered from the blood, cerebrospinal fluid, neighboring local neurons and glial cells, distant cells through the extracellular space, and the cells’ own self-regulating internal homeostasis can be postulated as possible ligands. Moreover, a single neuron outside the olfactory epithelium expresses more than one receptor, and the mechanism of transcriptional regulation may be different in olfactory epithelia and brain neurons. OR gene expression is altered in several neurodegenerative diseases including Parkinson’s disease (PD), Alzheimer’s disease (AD), progressive supranuclear palsy (PSP) and sporadic Creutzfeldt-Jakob disease (sCJD) subtypes MM1 and VV2 with disease-, region- and subtype-specific patterns. Altered gene expression is also observed in the prefrontal cortex in schizophrenia with a major but not total influence of chlorpromazine treatment. Preliminary parallel observations have also shown the presence of taste receptors (TASRs), mainly of the bitter taste family, in the mammalian brain, whose function is not related to taste. TASRs in brain are also abnormally regulated in neurodegenerative diseases. These seminal observations point to the need for further studies on ORs and TASRs chemoreceptors in the mammalian brain. PMID:27458372

  15. Olfactory Receptors in Non-Chemosensory Organs: The Nervous System in Health and Disease.

    PubMed

    Ferrer, Isidro; Garcia-Esparcia, Paula; Carmona, Margarita; Carro, Eva; Aronica, Eleonora; Kovacs, Gabor G; Grison, Alice; Gustincich, Stefano

    2016-01-01

    Olfactory receptors (ORs) and down-stream functional signaling molecules adenylyl cyclase 3 (AC3), olfactory G protein α subunit (Gαolf), OR transporters receptor transporter proteins 1 and 2 (RTP1 and RTP2), receptor expression enhancing protein 1 (REEP1), and UDP-glucuronosyltransferases (UGTs) are expressed in neurons of the human and murine central nervous system (CNS). In vitro studies have shown that these receptors react to external stimuli and therefore are equipped to be functional. However, ORs are not directly related to the detection of odors. Several molecules delivered from the blood, cerebrospinal fluid, neighboring local neurons and glial cells, distant cells through the extracellular space, and the cells' own self-regulating internal homeostasis can be postulated as possible ligands. Moreover, a single neuron outside the olfactory epithelium expresses more than one receptor, and the mechanism of transcriptional regulation may be different in olfactory epithelia and brain neurons. OR gene expression is altered in several neurodegenerative diseases including Parkinson's disease (PD), Alzheimer's disease (AD), progressive supranuclear palsy (PSP) and sporadic Creutzfeldt-Jakob disease (sCJD) subtypes MM1 and VV2 with disease-, region- and subtype-specific patterns. Altered gene expression is also observed in the prefrontal cortex in schizophrenia with a major but not total influence of chlorpromazine treatment. Preliminary parallel observations have also shown the presence of taste receptors (TASRs), mainly of the bitter taste family, in the mammalian brain, whose function is not related to taste. TASRs in brain are also abnormally regulated in neurodegenerative diseases. These seminal observations point to the need for further studies on ORs and TASRs chemoreceptors in the mammalian brain. PMID:27458372

  16. Morphology and physiology of the olfactory system of blood-feeding insects.

    PubMed

    Guidobaldi, F; May-Concha, I J; Guerenstein, P G

    2014-01-01

    Several blood-feeding (hematophagous) insects are vectors of a number of diseases including dengue, Chagas disease and leishmaniasis which persistently affect public health throughout Latin America. The vectors of those diseases include mosquitoes, triatomine bugs and sandflies. As vector control is an efficient way to prevent these illnesses it is important to understand the sensory biology of those harmful insects. We study the physiology of the olfactory system of those insects and apply that knowledge on the development of methods to manipulate their behavior. Here we review some of the latest information on insect olfaction with emphasis on hematophagous insects. The insect olfactory sensory neurons are housed inside hair-like organs called sensilla which are mainly distributed on the antenna and mouthparts. The identity of many of the odor compounds that those neurons detect are already known in hematophagous insects. They include several constituents of host (vertebrate) odor, sex, aggregation and alarm pheromones, and compounds related to egg-deposition behavior. Recent work has contributed significant knowledge on how odor information is processed in the insect first odor-processing center in the brain, the antennal lobe. The quality, quantity, and temporal features of the odor stimuli are encoded by the neural networks of the antennal lobe. Information regarding odor mixtures is also encoded. While natural mixtures evoke strong responses, synthetic mixtures that deviate from their natural counterparts in terms of key constituents or proportions of those constituents evoke weaker responses. The processing of olfactory information is largely unexplored in hematophagous insects. However, many aspects of their olfactory behavior are known. As in other insects, responses to relevant single odor compounds are weak while natural mixtures evoke strong responses. Future challenges include studying how information about odor mixtures is processed in their brain

  17. Olfactory sensitivity in mammalian species.

    PubMed

    Wackermannová, M; Pinc, L; Jebavý, L

    2016-07-18

    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. PMID:27070753

  18. Chinook salmon (Oncorhynchus tshawytscha) and rainbow trout (Oncorhynchus mykiss) exposed to copper: Neurophysiological and histological effects on the olfactory system

    SciTech Connect

    Hansen, J.A.; Rose, J.D.; Jenkins, R.A.; Gerow, K.G.; Bergman, H.L.

    1999-09-01

    Olfactory epithelial structure and olfactory bulb neurophysiological responses were measured in chinook salmon and rainbow trout in response to 25 to 300 {micro}g copper (Cu)/L. Using confocal laser scanning microscopy, the number of olfactory receptors was significantly reduced in chinook salmon exposed to {ge}50 {micro}g Cu/L and in rainbow trout exposed to {ge}200 {micro}g cu/L for 1 h. The number of receptors was significantly reduced in both species following exposure to 25 {micro}g Cu/L for 4 h. Transmission electron microscopy of olfactory epithelial tissue indicated that the loss of receptors was from cellular necrosis. Olfactory bulk electroencephalogram (EEG) responses to 10{sup {minus}3} M L-serine were initially reduced by all Cu concentrations but were virtually eliminated in chinook salmon exposed to {ge}50 {micro}g Cu/L and in rainbow trout exposed to {ge}200 {micro}g Cu/L within 1 h of exposure. Following Cu exposure, EEG response recovery rates were slower in fish exposed to higher Cu concentrations. The higher sensitivity of the chinook salmon olfactory system to Cu-induced histological damage and neurophysiological impairment parallels the relative species sensitivity observed in behavioral avoidance experiments. This difference in species sensitivity may reduce the survival and reproductive potential of chinook salmon compared with that of rainbow trout in Cu-contaminated waters.

  19. Tumorigenic Potential of Olfactory Bulb-Derived Human Adult Neural Stem Cells Associates with Activation of TERT and NOTCH1

    PubMed Central

    Ricci-Vitiani, Lucia; Cenciarelli, Carlo; Petrucci, Giovanna; Milazzo, Luisa; Montano, Nicola; Tabolacci, Elisabetta; Maira, Giulio; Larocca, Luigi M.; Pallini, Roberto

    2009-01-01

    Background Multipotent neural stem cells (NSCs) have been isolated from neurogenic regions of the adult brain. Reportedly, these cells can be expanded in vitro under prolonged mitogen stimulation without propensity to transform. However, the constitutive activation of the cellular machinery required to bypass apoptosis and senescence places these cells at risk for malignant transformation. Methodology/Principal Findings Using serum-free medium supplemented with epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF), we established clonally derived NS/progenitor cell (NS/PC) cultures from the olfactory bulb (OB) of five adult patients. The NS/PC cultures obtained from one OB specimen lost growth factor dependence and neuronal differentiation at early passage. These cells developed glioblastoma tumors upon xenografting in immunosuppressed mice. The remaining NS/PC cultures were propagated either as floating neurospheres or as adherent monolayers with mainteinance of growth factor dependence and multipotentiality at late passage. These cells were engrafted onto the CNS of immunosuppressed rodents. Overall, the grafted NS/PCs homed in the host parenchyma showing ramified morphology and neuronal marker expression. However, a group of animals transplanted with NS/PCs obtained from an adherent culture developed fast growing tumors histologically resembling neuroesthesioblastoma. Cytogenetic and molecular analyses showed that the NS/PC undergo chromosomal changes with repeated in vitro passages under mitogen stimulation, and that up-regulation of hTERT and NOTCH1 associates with in vivo tumorigenicity. Conclusions/Significance Using culturing techniques described in current literature, NS/PCs arise from the OB of adult patients which in vivo either integrate in the CNS parenchyma showing neuron-like features or initiate tumor formation. Extensive xenografting studies on each human derived NS cell line appear mandatory before any use of these cells in the

  20. The Adult Ventricular-Subventricular Zone (V-SVZ) and Olfactory Bulb (OB) Neurogenesis.

    PubMed

    Lim, Daniel A; Alvarez-Buylla, Arturo

    2016-01-01

    A large population of neural stem/precursor cells (NSCs) persists in the ventricular-subventricular zone (V-SVZ) located in the walls of the lateral brain ventricles. V-SVZ NSCs produce large numbers of neuroblasts that migrate a long distance into the olfactory bulb (OB) where they differentiate into local circuit interneurons. Here, we review a broad range of discoveries that have emerged from studies of postnatal V-SVZ neurogenesis: the identification of NSCs as a subpopulation of astroglial cells, the neurogenic lineage, new mechanisms of neuronal migration, and molecular regulators of precursor cell proliferation and migration. It has also become evident that V-SVZ NSCs are regionally heterogeneous, with NSCs located in different regions of the ventricle wall generating distinct OB interneuron subtypes. Insights into the developmental origins and molecular mechanisms that underlie the regional specification of V-SVZ NSCs have also begun to emerge. Other recent studies have revealed new cell-intrinsic molecular mechanisms that enable lifelong neurogenesis in the V-SVZ. Finally, we discuss intriguing differences between the rodent V-SVZ and the corresponding human brain region. The rapidly expanding cellular and molecular knowledge of V-SVZ NSC biology provides key insights into postnatal neural development, the origin of brain tumors, and may inform the development regenerative therapies from cultured and endogenous human neural precursors. PMID:27048191

  1. Exotic models may offer unique opportunities to decipher specific scientific question: the case of Xenopus olfactory system.

    PubMed

    Gascuel, Jean; Amano, Tosikazu

    2013-09-01

    The fact that olfactory systems are highly conserved in all animal species from insects to mammals allow the generalization of findings from one species to another. Most of our knowledge about the anatomy and physiology of the olfactory system comes from data obtained in a very limited number of biological models such as rodents, Zebrafish, Drosophila, and a worm, Caenorhabditis elegans. These models have proved useful to answer most questions in the field of olfaction, and thus concentrating on these few models appear to be a pragmatic strategy. However, the diversity of the organization and physiology of the olfactory system amongst phyla appear to be greater than generally assumed and the four models alone may not be sufficient to address all the questions arising from the study of olfaction. In this article, we will illustrate the idea that we should take advantage of biological diversity to address specific scientific questions and will show that the Xenopus olfactory system is a very good model to investigate: first, olfaction in aerial versus aquatic conditions and second, mechanisms underlying postnatal reorganization of the olfactory system especially those controlled by tyroxine hormone. PMID:23904180

  2. Comparative analyses of olfactory systems in terrestrial crabs (Brachyura): evidence for aerial olfaction?

    PubMed Central

    Krieger, Jakob; Braun, Philipp; Rivera, Nicole T.; Schubart, Christoph D.; Müller, Carsten H.G.

    2015-01-01

    Adaptations to a terrestrial lifestyle occurred convergently multiple times during the evolution of the arthropods. This holds also true for the “true crabs” (Brachyura), a taxon that includes several lineages that invaded land independently. During an evolutionary transition from sea to land, animals have to develop a variety of physiological and anatomical adaptations to a terrestrial life style related to respiration, reproduction, development, circulation, ion and water balance. In addition, sensory systems that function in air instead of in water are essential for an animal’s life on land. Besides vision and mechanosensory systems, on land, the chemical senses have to be modified substantially in comparison to their function in water. Among arthropods, insects are the most successful ones to evolve aerial olfaction. Various aspects of terrestrial adaptation have also been analyzed in those crustacean lineages that evolved terrestrial representatives including the taxa Anomala, Brachyura, Amphipoda, and Isopoda. We are interested in how the chemical senses of terrestrial crustaceans are modified to function in air. Therefore, in this study, we analyzed the brains and more specifically the structure of the olfactory system of representatives of brachyuran crabs that display different degrees of terrestriality, from exclusively marine to mainly terrestrial. The methods we used included immunohistochemistry, detection of autofluorescence- and confocal microscopy, as well as three-dimensional reconstruction and morphometry. Our comparative approach shows that both the peripheral and central olfactory pathways are reduced in terrestrial members in comparison to their marine relatives, suggesting a limited function of their olfactory system on land. We conclude that for arthropod lineages that invaded land, evolving aerial olfaction is no trivial task. PMID:26713228

  3. Comparative analyses of olfactory systems in terrestrial crabs (Brachyura): evidence for aerial olfaction?

    PubMed

    Krieger, Jakob; Braun, Philipp; Rivera, Nicole T; Schubart, Christoph D; Müller, Carsten H G; Harzsch, Steffen

    2015-01-01

    Adaptations to a terrestrial lifestyle occurred convergently multiple times during the evolution of the arthropods. This holds also true for the "true crabs" (Brachyura), a taxon that includes several lineages that invaded land independently. During an evolutionary transition from sea to land, animals have to develop a variety of physiological and anatomical adaptations to a terrestrial life style related to respiration, reproduction, development, circulation, ion and water balance. In addition, sensory systems that function in air instead of in water are essential for an animal's life on land. Besides vision and mechanosensory systems, on land, the chemical senses have to be modified substantially in comparison to their function in water. Among arthropods, insects are the most successful ones to evolve aerial olfaction. Various aspects of terrestrial adaptation have also been analyzed in those crustacean lineages that evolved terrestrial representatives including the taxa Anomala, Brachyura, Amphipoda, and Isopoda. We are interested in how the chemical senses of terrestrial crustaceans are modified to function in air. Therefore, in this study, we analyzed the brains and more specifically the structure of the olfactory system of representatives of brachyuran crabs that display different degrees of terrestriality, from exclusively marine to mainly terrestrial. The methods we used included immunohistochemistry, detection of autofluorescence- and confocal microscopy, as well as three-dimensional reconstruction and morphometry. Our comparative approach shows that both the peripheral and central olfactory pathways are reduced in terrestrial members in comparison to their marine relatives, suggesting a limited function of their olfactory system on land. We conclude that for arthropod lineages that invaded land, evolving aerial olfaction is no trivial task. PMID:26713228

  4. Mutual influences between the main olfactory and vomeronasal systems in development and evolution

    PubMed Central

    Suárez, Rodrigo; García-González, Diego; de Castro, Fernando

    2012-01-01

    The sense of smell plays a crucial role in the sensory world of animals. Two chemosensory systems have been traditionally thought to play-independent roles in mammalian olfaction. According to this, the main olfactory system (MOS) specializes in the detection of environmental odorants, while the vomeronasal system (VNS) senses pheromones and semiochemicals produced by individuals of the same or different species. Although both systems differ in their anatomy and function, recent evidence suggests they act synergistically in the perception of scents. These interactions include similar responses to some ligands, overlap of telencephalic connections and mutual influences in the regulation of olfactory-guided behavior. In the present work, we propose the idea that the relationships between systems observed at the organismic level result from a constant interaction during development and reflects a common history of ecological adaptations in evolution. We review the literature to illustrate examples of developmental and evolutionary processes that evidence these interactions and propose that future research integrating both systems may shed new light on the mechanisms of olfaction. PMID:23269914

  5. The cholinergic system in the olfactory center of the terrestrial slug Limax.

    PubMed

    Matsuo, Ryota; Kobayashi, Suguru; Wakiya, Kyoko; Yamagishi, Miki; Fukuoka, Masayuki; Ito, Etsuro

    2014-09-01

    Acetylcholine plays various important roles in the central nervous system of invertebrates as well as vertebrates. In the olfactory center of the terrestrial slug Limax, the local field potential (LFP) oscillates, and the change in its oscillatory frequency is thought to correlate with the detection of odor that potentially changes an ongoing behavior of the animal. Acetylcholine is known to upregulate the frequency of the LFP oscillation, and is one of the candidates for the neurotransmitters that are involved in such higher cognitive functions. However, there have been no histological data on the cholinergic system in gastropods, nor are there data on the receptors that are responsible for the upregulation of the oscillatory frequency of LFP due to the lack of analytical tools (such as antibodies or cDNA sequence information on cholinergic system-related genes). Here we cloned the cDNAs of choline acetyltransferase (ChAT), acetylcholinesterase, vesicular acetylcholine transporter, and several nicotinic acetylcholine receptors (nAChRs), and investigated their localization in the brain of Limax. We also generated a polyclonal antibody against ChAT to examine its localization, and investigated pharmacologically the involvement of nAChRs in the LFP oscillation. Our data showed: 1) dense distribution of the neurons expressing mRNAs of ChAT and vesicular acetylcholine transporter in the olfactory center; 2) spatially unique expression patterns of different nAChRs in the olfactory center; 3) involvement of nAChRs in the upregulation of the oscillation; 4) localization of ChAT protein in nerve fibers and/or terminals; and 5) the presence of cholinergic nerves in the tentacles. PMID:24523205

  6. The indirect role of fibroblast growth factor-8 in defining neurogenic niches of the olfactory/GnRH systems.

    PubMed

    Forni, Paolo Emanuele; Bharti, Kapil; Flannery, Ellen M; Shimogori, Tomomi; Wray, Susan

    2013-12-11

    Bone morphogenic protein-4 (BMP4) and fibroblast growth factor-8 (FGF8) are thought to have opposite roles in defining epithelial versus neurogenic fate in the developing olfactory/vomeronasal system. In particular, FGF8 has been implicated in specification of olfactory and gonadotropin releasing hormone-1 (GnRH) neurons, as well as in controlling olfactory stem cell survival. Using different knock-in mouse lines and Cre-lox-mediated lineage tracing, Fgf8 expression and cell lineage was analyzed in the developing nose in relation to the expression of Bmp4 and its antagonist Noggin (Nog). FGF8 is expressed by cells that acquire an epidermal, respiratory cell fate and not by stem cells that acquire neuronal olfactory or vomeronasal cell fate. Ectodermal and mesenchymal sources of BMP4 control the expression of BMP/TGFβ antagonist Nog, whereas mesenchymal sources of Nog define the neurogenic borders of the olfactory pit. Fgf8 hypomorph mouse models, Fgf8(neo/neo) and Fgf8(neo/null), displayed severe craniofacial defects together with overlapping defects in the olfactory pit including (1) lack of neuronal formation ventrally, where GnRH neurons normally form, and (2) altered expression of Bmp4 and Nog, with Nog ectopically expressed in the nasal mesenchyme and no longer defining the GnRH and vomeronasal neurogenic border. Together our data show that (1) FGF8 is not sufficient to induce ectodermal progenitors of the olfactory pit to acquire neural fate and (2) altered neurogenesis and lack of GnRH neuron specification after chronically reduced Fgf8 expression reflected dysgenesis of the nasal region and loss of a specific neurogenic permissive milieu that was defined by mesenchymal signals. PMID:24336726

  7. Gene Expression Profile of Adult Human Olfactory Bulb and Embryonic Neural Stem Cell Suggests Distinct Signaling Pathways and Epigenetic Control

    PubMed Central

    Marei, Hany E. S.; Ahmed, Abd-Elmaksoud; Michetti, Fabrizio; Pescatori, Mario; Pallini, Roberto; Casalbore, Patricia; Cenciarelli, Carlo; Elhadidy, Mohamed

    2012-01-01

    Global gene expression profiling was performed using RNA from human embryonic neural stem cells (hENSC), and adult human olfactory bulb-derived neural stem cells (OBNSCs), to define a gene expression pattern and signaling pathways that are specific for each cell lineage. We have demonstrated large differences in the gene expression profile of human embryonic NSC, and adult human OBNSCs, but less variability between parallel cultures. Transcripts of genes involved in neural tube development and patterning (ALDH1A2, FOXA2), progenitor marker genes (LMX1a, ALDH1A1, SOX10), proliferation of neural progenitors (WNT1 and WNT3a), neuroplastin (NPTN), POU3F1 (OCT6), neuroligin (NLGN4X), MEIS2, and NPAS1 were up-regulated in both cell populations. By Gene Ontology, 325 out of 3875 investigated gene sets were scientifically different. 41 out of the 307 investigated Cellular Component (CC) categories, 45 out of the 620 investigated Molecular Function (MF) categories, and 239 out of the 2948 investigated Biological Process (BP) categories were significant. KEGG Pathway Class Comparison had revealed that 75 out of 171 investigated gene sets passed the 0.005 significance threshold. Levels of gene expression were explored in three signaling pathways, Notch, Wnt, and mTOR that are known to be involved in NS cell fates determination. The transcriptional signature also deciphers the role of genes involved in epigenetic modifications. SWI/SNF DNA chromatin remodeling complex family, including SMARCC1 and SMARCE1, were found specifically up-regulated in our OBNSC but not in hENSC. Differences in gene expression profile of transcripts controlling epigenetic modifications, and signaling pathways might indicate differences in the therapeutic potential of our examined two cell populations in relation to in cell survival, proliferation, migration, and differentiation following engraftments in different CNS insults. PMID:22485144

  8. Chemosensory signals and their receptors in the olfactory neural system.

    PubMed

    Ihara, S; Yoshikawa, K; Touhara, K

    2013-12-19

    Chemical communication is widely used among various organisms to obtain essential information from their environment required for life. Although a large variety of molecules have been shown to act as chemical cues, the molecular and neural basis underlying the behaviors elicited by these molecules has been revealed for only a limited number of molecules. Here, we review the current knowledge regarding the signaling molecules whose flow from receptor to specific behavior has been characterized. Discussing the molecules utilized by mice, insects, and the worm, we focus on how each organism has optimized its reception system to suit its living style. We also highlight how the production of these signaling molecules is regulated, an area in which considerable progress has been recently made. PMID:24045101

  9. Plasticity of Glomeruli and Olfactory-Mediated Behavior in Zebrafish Following Detergent Lesioning of the Olfactory Epithelium

    PubMed Central

    White, Evan J.; Kounelis, Savannah K.; Byrd-Jacobs, Christine A.

    2014-01-01

    The zebrafish olfactory system is a valuable model for examining neural regeneration after damage due to the remarkable plasticity of this sensory system and of fish species. We applied detergent to the olfactory organ and examined the effects on both morphology and function of the olfactory system in adult zebrafish. Olfactory organs were treated once with Triton X-100 unilaterally to study glomerular innervation patterns or bilaterally to study odor detection. Fish were allowed to recover for 4–10 days and were compared to untreated control fish. Axonal projections were analyzed using whole mount immunocytochemistry with anti-keyhole limpet hemocyanin, a marker of olfactory axons in teleosts. Chemical lesioning of the olfactory organ with a single dose of Triton X-100 had profound effects on glomerular distribution in the olfactory bulb at 4 days after treatment, with the most significant effects in the medial region of the bulb. Glomeruli had returned by 7 days post-treatment. Analysis of the ability of the fish to detect cocktails of amino acids or bile salts consisted of counting the number of turns the fish made before and after odorant delivery. Control fish turned more after exposure to both odorants. Fish tested 4 and 7 days after chemical lesioning made more turns in response to amino acids but did not respond to bile salts. At 10 days post-lesion, these fish had regained the ability to detect bile salts. Thus, the changes seen in bulbar innervation patterns correlated to odorant-mediated behavior. We show that the adult zebrafish brain has the capacity to recover rapidly from detergent damage of the olfactory epithelium, with both glomerular distribution and odorant-mediated behavior returning in 10 days. PMID:25450960

  10. Plasticity of glomeruli and olfactory-mediated behavior in zebrafish following detergent lesioning of the olfactory epithelium.

    PubMed

    White, E J; Kounelis, S K; Byrd-Jacobs, C A

    2015-01-22

    The zebrafish olfactory system is a valuable model for examining neural regeneration after damage due to the remarkable plasticity of this sensory system and of fish species. We applied detergent to the olfactory organ and examined the effects on both morphology and function of the olfactory system in adult zebrafish. Olfactory organs were treated once with Triton X-100 unilaterally to study glomerular innervation patterns or bilaterally to study odor detection. Fish were allowed to recover for 4-10 days and were compared to untreated control fish. Axonal projections were analyzed using whole mount immunocytochemistry with anti-keyhole limpet hemocyanin, a marker of olfactory axons in teleosts. Chemical lesioning of the olfactory organ with a single dose of Triton X-100 had profound effects on glomerular distribution in the olfactory bulb at 4 days after treatment, with the most significant effects in the medial region of the bulb. Glomeruli had returned by 7 days post-treatment. Analysis of the ability of the fish to detect cocktails of amino acids or bile salts consisted of counting the number of turns the fish made before and after odorant delivery. Control fish turned more after exposure to both odorants. Fish tested 4 and 7 days after chemical lesioning made more turns in response to amino acids but did not respond to bile salts. At 10 days post-lesion, these fish had regained the ability to detect bile salts. Thus, the changes seen in bulbar innervation patterns correlated to odorant-mediated behavior. We show that the adult zebrafish brain has the capacity to recover rapidly from detergent damage of the olfactory epithelium, with both glomerular distribution and odorant-mediated behavior returning in 10 days. PMID:25450960

  11. Distribution and function of splash, an achaete-scute homolog in the adult olfactory organ of the Caribbean spiny lobster Panulirus argus.

    PubMed

    Tadesse, Tizeta; Schmidt, Manfred; Walthall, William W; Tai, Phang C; Derby, Charles D

    2011-04-01

    achaete-scute complex (ASC) genes, which encode basic helix-loop-helix transcription factors, regulate embryonic and adult neurogenesis in many animals. In adult arthropods, including crustaceans, ASC homologs have been identified but rarely functionally characterized. We took advantage of the recently identified crustacean homolog, splash (spiny lobster achaete scute homolog), in the olfactory organ of the Caribbean spiny lobster Panulirus argus to examine its role in adult neurogenesis. We tested the hypothesis that splash is associated with but not restricted to sensory neuron formation in the olfactory organ, the antennular lateral flagellum (LF), of adult spiny lobsters. We demonstrated splash labeling in epithelial cells across LF developmental zones (i.e., proliferation and mature zones), in auxiliary cells surrounding dendrites of olfactory receptor neurons (ORNs), and in immature and mature ORNs, but not in granulocytes or chromatophores. Since ORN proliferation varies with molt stage, we examined splash expression across molt stages and found that molt stage affected splash expression in the ORN mature zone but not in the proliferation zone. In vivo incorporation of bromodeoxyuridine (BrdU) showed no correlation in the cellular pattern of splash expression and BrdU labeling. The intensity of splash labeling was dramatically enhanced in the proliferation zones following LF damage, suggesting enhanced splash expression during repair and/or regeneration. We conclude that splash is not closely associated with the formation of sensory neurons under normal physiological conditions, and we propose that splash is involved in repair and regeneration. We also propose that splash has additional roles other than neurogenesis in adult crustaceans. PMID:21394934

  12. Prenatal Stress Inhibits Hippocampal Neurogenesis but Spares Olfactory Bulb Neurogenesis

    PubMed Central

    Belnoue, Laure; Grosjean, Noelle; Ladevèze, Elodie

    2013-01-01

    The dentate gyrus (DG) and the olfactory bulb (OB) are two regions of the adult brain in which new neurons are integrated daily in the existing networks. It is clearly established that these newborn neurons are implicated in specific functions sustained by these regions and that different factors can influence neurogenesis in both structures. Among these, life events, particularly occurring during early life, were shown to profoundly affect adult hippocampal neurogenesis and its associated functions like spatial learning, but data regarding their impact on adult bulbar neurogenesis are lacking. We hypothesized that prenatal stress could interfere with the development of the olfactory system, which takes place during the prenatal period, leading to alterations in adult bulbar neurogenesis and in olfactory capacities. To test this hypothesis we exposed pregnant C57Bl/6J mice to gestational restraint stress and evaluated behavioral and anatomic consequences in adult male offspring. We report that prenatal stress has no impact on adult bulbar neurogenesis, and does not alter olfactory functions in adult male mice. However, it decreases cell proliferation and neurogenesis in the DG of the hippocampus, thus confirming previous reports on rats. Altogether our data support a selective and cross-species long-term impact of prenatal stress on neurogenesis. PMID:24009723

  13. Olfactory organ of Octopus vulgaris: morphology, plasticity, turnover and sensory characterization.

    PubMed

    Polese, Gianluca; Bertapelle, Carla; Di Cosmo, Anna

    2016-01-01

    The cephalopod olfactory organ was described for the first time in 1844 by von Kölliker, who was attracted to the pair of small pits of ciliated cells on each side of the head, below the eyes close to the mantle edge, in both octopuses and squids. Several functional studies have been conducted on decapods but very little is known about octopods. The morphology of the octopus olfactory system has been studied, but only to a limited extent on post-hatching specimens, and the only paper on adult octopus gives a minimal description of the olfactory organ. Here, we describe the detailed morphology of young male and female Octopus vulgaris olfactory epithelium, and using a combination of classical morphology and 3D reconstruction techniques, we propose a new classification for O. vulgaris olfactory sensory neurons. Furthermore, using specific markers such as olfactory marker protein (OMP) and proliferating cell nuclear antigen (PCNA) we have been able to identify and differentially localize both mature olfactory sensory neurons and olfactory sensory neurons involved in epithelium turnover. Taken together, our data suggest that the O. vulgaris olfactory organ is extremely plastic, capable of changing its shape and also proliferating its cells in older specimens. PMID:27069253

  14. Olfactory organ of Octopus vulgaris: morphology, plasticity, turnover and sensory characterization

    PubMed Central

    Polese, Gianluca; Bertapelle, Carla

    2016-01-01

    ABSTRACT The cephalopod olfactory organ was described for the first time in 1844 by von Kölliker, who was attracted to the pair of small pits of ciliated cells on each side of the head, below the eyes close to the mantle edge, in both octopuses and squids. Several functional studies have been conducted on decapods but very little is known about octopods. The morphology of the octopus olfactory system has been studied, but only to a limited extent on post-hatching specimens, and the only paper on adult octopus gives a minimal description of the olfactory organ. Here, we describe the detailed morphology of young male and female Octopus vulgaris olfactory epithelium, and using a combination of classical morphology and 3D reconstruction techniques, we propose a new classification for O. vulgaris olfactory sensory neurons. Furthermore, using specific markers such as olfactory marker protein (OMP) and proliferating cell nuclear antigen (PCNA) we have been able to identify and differentially localize both mature olfactory sensory neurons and olfactory sensory neurons involved in epithelium turnover. Taken together, our data suggest that the O. vulgaris olfactory organ is extremely plastic, capable of changing its shape and also proliferating its cells in older specimens. PMID:27069253

  15. Properties and mechanisms of olfactory learning and memory

    PubMed Central

    Tong, Michelle T.; Peace, Shane T.; Cleland, Thomas A.

    2014-01-01

    Memories are dynamic physical phenomena with psychometric forms as well as characteristic timescales. Most of our understanding of the cellular mechanisms underlying the neurophysiology of memory, however, derives from one-trial learning paradigms that, while powerful, do not fully embody the gradual, representational, and statistical aspects of cumulative learning. The early olfactory system—particularly olfactory bulb—comprises a reasonably well-understood and experimentally accessible neuronal network with intrinsic plasticity that underlies both one-trial (adult aversive, neonatal) and cumulative (adult appetitive) odor learning. These olfactory circuits employ many of the same molecular and structural mechanisms of memory as, for example, hippocampal circuits following inhibitory avoidance conditioning, but the temporal sequences of post-conditioning molecular events are likely to differ owing to the need to incorporate new information from ongoing learning events into the evolving memory trace. Moreover, the shapes of acquired odor representations, and their gradual transformation over the course of cumulative learning, also can be directly measured, adding an additional representational dimension to the traditional metrics of memory strength and persistence. In this review, we describe some established molecular and structural mechanisms of memory with a focus on the timecourses of post-conditioning molecular processes. We describe the properties of odor learning intrinsic to the olfactory bulb and review the utility of the olfactory system of adult rodents as a memory system in which to study the cellular mechanisms of cumulative learning. PMID:25071492

  16. The Dlx5 and Foxg1 transcription factors, linked via miRNA-9 and -200, are required for the development of the olfactory and GnRH system

    PubMed Central

    Garaffo, Giulia; Conte, Daniele; Provero, Paolo; Tomaiuolo, Daniela; Luo, Zheng; Pinciroli, Patrizia; Peano, Clelia; D'Atri, Ilaria; Gitton, Yorick; Etzion, Talya; Gothilf, Yoav; Gays, Dafne; Santoro, Massimo M.; Merlo, Giorgio R.

    2015-01-01

    During neuronal development and maturation, microRNAs (miRs) play diverse functions ranging from early patterning, proliferation and commitment to differentiation, survival, homeostasis, activity and plasticity of more mature and adult neurons. The role of miRs in the differentiation of olfactory receptor neurons (ORNs) is emerging from the conditional inactivation of Dicer in immature ORN, and the depletion of all mature miRs in this system. Here, we identify specific miRs involved in olfactory development, by focusing on mice null for Dlx5, a homeogene essential for both ORN differentiation and axon guidance and connectivity. Analysis of miR expression in Dlx5−/− olfactory epithelium pointed to reduced levels of miR-9, miR-376a and four miRs of the -200 class in the absence of Dlx5. To functionally examine the role of these miRs, we depleted miR-9 and miR-200 class in reporter zebrafish embryos and observed delayed ORN differentiation, altered axonal trajectory/targeting, and altered genesis and position of olfactory-associated GnRH neurons, i.e. a phenotype known as Kallmann syndrome in humans. miR-9 and miR-200-class negatively control Foxg1 mRNA, a fork-head transcription factor essential for development of the olfactory epithelium and of the forebrain, known to maintain progenitors in a stem state. Increased levels of z-foxg1 mRNA resulted in delayed ORN differentiation and altered axon trajectory, in zebrafish embryos. This work describes for the first time the role of specific miR (-9 and -200) in olfactory/GnRH development, and uncovers a Dlx5–Foxg1 regulation whose alteration affects receptor neuron differentiation, axonal targeting, GnRH neuron development, the hallmarks of the Kallmann syndrome. PMID:25937343

  17. Neural crest and placode contributions to olfactory development.

    PubMed

    Suzuki, Jun; Osumi, Noriko

    2015-01-01

    Olfaction is the sense of smell that influences many primitive behaviors for survival, e.g., feeding, reproduction, social interaction, and fear response. The olfactory system is an evolutionarily ancient sensory system and composed of the olfactory epithelium (OE), the olfactory bulb (OB), and the olfactory cortex. The OE gives rise to olfactory receptor neurons (ORNs), i.e., primary sensory receptor cells whose axons project directly to the OB. The ORNs are unique in the way that they are continuously replaced during physiological turnover or following injury throughout life. In the OE, horizontal basal cells, i.e., flat and quiescent cells attached to the basal lamina, are now thought to be tissue stem cells. Although OE cells, especially ORNs, were hypothesized to be derived from the olfactory placode (OP), recent genetic fate-mapping studies using Cre reporter mice indicate a dual origin, i.e., the OP and neural crest (NC), of the olfactory system. The NC is a transient embryonic tissue that is formed between the dorsal neuroepithelium and epidermis. Neural crest cells (NCCs) are multipotent cells that migrate into various target tissues and differentiate into various cell types, including neurons and glia of the peripheral nervous system, cranial cartilage and bone, and melanocytes. Recent studies have revealed that neural crest-derived cells (NCDCs) are widely distributed in adult tissues, and that a subset of NCDCs still possesses NCC-like multipotency. Here, we review classical and recent studies of the olfactory system, especially focusing on the contribution of the NC and OP to the OE development. PMID:25662265

  18. Acetylcholine and Olfactory Perceptual Learning

    PubMed Central

    Wilson, Donald A.; Fletcher, Max L.; Sullivan, Regina M.

    2007-01-01

    Olfactory perceptual learning is a relatively long-term, learned increase in perceptual acuity, and has been described in both humans and animals. Data from recent electrophysiological studies have indicated that olfactory perceptual learning may be correlated with changes in odorant receptive fields of neurons in the olfactory bulb and piriform cortex. These changes include enhanced representation of the molecular features of familiar odors by mitral cells in the olfactory bulb, and synthetic coding of multiple coincident odorant features into odor objects by cortical neurons. In this paper, data are reviewed that show the critical role of acetylcholine (Ach) in olfactory system function and plasticity, and cholinergic modulation of olfactory perceptual learning at both the behavioral and cortical level. PMID:14747514

  19. Over-Expression of hNGF in Adult Human Olfactory Bulb Neural Stem Cells Promotes Cell Growth and Oligodendrocytic Differentiation

    PubMed Central

    Marei, Hany E. S.; Althani, Asmaa; Afifi, Nahla; Abd-Elmaksoud, Ahmed; Bernardini, Camilla; Michetti, Fabrizio; Barba, Marta; Pescatori, Mario; Maira, Giulio; Paldino, Emanuela; Manni, Luigi; Casalbore, Patrizia; Cenciarelli, Carlo

    2013-01-01

    The adult human olfactory bulb neural stem/progenitor cells (OBNC/PC) are promising candidate for cell-based therapy for traumatic and neurodegenerative insults. Exogenous application of NGF was suggested as a promising therapeutic strategy for traumatic and neurodegenerative diseases, however effective delivery of NGF into the CNS parenchyma is still challenging due mainly to its limited ability to cross the blood–brain barrier, and intolerable side effects if administered into the brain ventricular system. An effective method to ensure delivery of NGF into the parenchyma of CNS is the genetic modification of NSC to overexpress NGF gene. Overexpression of NGF in adult human OBNSC is expected to alter their proliferation and differentiation nature, and thus might enhance their therapeutic potential. In this study, we genetically modified adult human OBNS/PC to overexpress human NGF (hNGF) and green fluorescent protein (GFP) genes to provide insight about the effects of hNGF and GFP genes overexpression in adult human OBNS/PC on their in vitro multipotentiality using DNA microarray, immunophenotyping, and Western blot (WB) protocols. Our analysis revealed that OBNS/PC-GFP and OBNS/PC-GFP-hNGF differentiation is a multifaceted process involving changes in major biological processes as reflected in alteration of the gene expression levels of crucial markers such as cell cycle and survival markers, stemness markers, and differentiation markers. The differentiation of both cell classes was also associated with modulations of key signaling pathways such MAPK signaling pathway, ErbB signaling pathway, and neuroactive ligand-receptor interaction pathway for OBNS/PC-GFP, and axon guidance, calcium channel, voltage-dependent, gamma subunit 7 for OBNS/PC-GFP-hNGF as revealed by GO and KEGG. Differentiated OBNS/PC-GFP-hNGF displayed extensively branched cytoplasmic processes, a significant faster growth rate and up modulated the expression of oligodendroglia precursor cells

  20. Extinction reverses olfactory fear-conditioned increases in neuron number and glomerular size.

    PubMed

    Morrison, Filomene G; Dias, Brian G; Ressler, Kerry J

    2015-10-13

    Although much work has investigated the contribution of brain regions such as the amygdala, hippocampus, and prefrontal cortex to the processing of fear learning and memory, fewer studies have examined the role of sensory systems, in particular the olfactory system, in the detection and perception of cues involved in learning and memory. The primary sensory receptive field maps of the olfactory system are exquisitely organized and respond dynamically to cues in the environment, remaining plastic from development through adulthood. We have previously demonstrated that olfactory fear conditioning leads to increased odorant-specific receptor representation in the main olfactory epithelium and in glomeruli within the olfactory bulb. We now demonstrate that olfactory extinction training specific to the conditioned odor stimulus reverses the conditioning-associated freezing behavior and odor learning-induced structural changes in the olfactory epithelium and olfactory bulb in an odorant ligand-specific manner. These data suggest that learning-induced freezing behavior, structural alterations, and enhanced neural sensory representation can be reversed in adult mice following extinction training. PMID:26420875

  1. Extinction reverses olfactory fear-conditioned increases in neuron number and glomerular size

    PubMed Central

    Morrison, Filomene G.; Dias, Brian G.; Ressler, Kerry J.

    2015-01-01

    Although much work has investigated the contribution of brain regions such as the amygdala, hippocampus, and prefrontal cortex to the processing of fear learning and memory, fewer studies have examined the role of sensory systems, in particular the olfactory system, in the detection and perception of cues involved in learning and memory. The primary sensory receptive field maps of the olfactory system are exquisitely organized and respond dynamically to cues in the environment, remaining plastic from development through adulthood. We have previously demonstrated that olfactory fear conditioning leads to increased odorant-specific receptor representation in the main olfactory epithelium and in glomeruli within the olfactory bulb. We now demonstrate that olfactory extinction training specific to the conditioned odor stimulus reverses the conditioning-associated freezing behavior and odor learning-induced structural changes in the olfactory epithelium and olfactory bulb in an odorant ligand-specific manner. These data suggest that learning-induced freezing behavior, structural alterations, and enhanced neural sensory representation can be reversed in adult mice following extinction training. PMID:26420875

  2. Effect of salinity changes on olfactory memory-related genes and hormones in adult chum salmon Oncorhynchus keta.

    PubMed

    Kim, Na Na; Choi, Young Jae; Lim, Sang-Gu; Jeong, Minhwan; Jin, Deuk-Hee; Choi, Cheol Young

    2015-09-01

    Studies of memory formation have recently concentrated on the possible role of N-methyl-d-aspartate receptors (NRs). We examined changes in the expression of three NRs (NR1, NR2B, and NR2C), olfactory receptor (OR), and adrenocorticotropic hormone (ACTH) in chum salmon Oncorhynchus keta using quantitative polymerase chain reaction (QPCR) during salinity change (seawater→50% seawater→freshwater). NRs were significantly detected in the diencephalon and telencephalon and OR was significantly detected in the olfactory epithelium. The expression of NRs, OR, and ACTH increased after the transition to freshwater. We also determined that treatment with MK-801, an antagonist of NRs, decreased NRs in telencephalon cells. In addition, a reduction in salinity was associated with increased levels of dopamine, ACTH, and cortisol (in vivo). Reductions in salinity evidently caused NRs and OR to increase the expression of cortisol and dopamine. We concluded that memory capacity and olfactory imprinting of salmon is related to the salinity of the environment during the migration to spawning sites. Furthermore, salinity affects the memory/imprinting and olfactory abilities, and cortisol and dopamine is also related with olfactory-related memories during migration. PMID:25933936

  3. Olfactory-mediated stream-finding behavior of migratory adult sea lamprey (Petromyzon marinus)

    USGS Publications Warehouse

    Vrieze, L.A.; Bergstedt, R.A.; Sorensen, P.W.

    2011-01-01

    Stream-finding behavior of adult sea lamprey (Petromyzon marinus), an anadromous fish that relies on pheromones to locate spawning streams, was documented in the vicinity of an important spawning river in the Great Lakes. Untreated and anosmic migrating sea lampreys were implanted with acoustic transmitters and then released outside the Ocqueoc River. Lampreys swam only at night and then actively. When outside of the river plume, lampreys pursued relatively straight bearings parallel to the shoreline while making frequent vertical excursions. In contrast, when within the plume, lampreys made large turns and exhibited a weak bias towards the river mouth, which one-third of them entered. The behavior of anosmic lampreys resembled that of untreated lampreys outside of the plume, except they pursued a more northerly compass bearing. To locate streams, sea lampreys appear to employ a three-phase odor-mediated strategy that involves an initial search along shorelines while casting vertically, followed by river-water-induced turning that brings them close to the river's mouth, which they then enter using rheotaxis. This novel strategy differs from that of salmonids and appears to offer this poor swimmer adaptive flexibility and suggests ways that pheromonal odors might be used to manage this invasive species.

  4. Functional Rehabilitation of Cadmium-Induced Neurotoxicity Despite Persistent Peripheral Pathophysiology in the Olfactory System

    PubMed Central

    Czarnecki, Lindsey A.; Moberly, Andrew H.; Turkel, Daniel J.; Rubinstein, Tom; Pottackal, Joseph; Rosenthal, Michelle C.; McCandlish, Elizabeth F. K.; Buckley, Brian; McGann, John P.

    2012-01-01

    Intranasal exposure to the heavy metal cadmium has been linked to olfactory dysfunction and neurotoxicity. Here, we combine optical imaging of in vivo neurophysiology, genetically defined anatomical tract tracing, mass spectrometry, and behavioral psychophysical methods to evaluate the persistent harmful effects of acute intranasal exposure to cadmium in a mouse model and to investigate the functional consequences of sensory rehabilitation training. We find that an acute intranasal instillation of cadmium chloride leads to an accumulation of cadmium in the brain's olfactory bulb that persists for at least 4 weeks. This is accompanied by persistent severe pathophysiology of the olfactory nerve, a gradual reduction in axonal projections from the olfactory epithelium, and complete impairment on an olfactory detection task. Remarkably, 2 weeks of odorant-guided operant conditioning training proved sufficient to restore olfactory detection performance to control levels in cadmium-exposed mice. Optical imaging from rehabilitated mice showed that this training did not cause any detectable restoration of olfactory nerve function, suggesting that the recovery of function was mediated by central neuroplasticity in which the brain learned to interpret the degraded sensory input. These data demonstrate that sensory learning can mask even severe damage from neurotoxicants and suggest that explicit sensory training may be useful in rehabilitation of olfactory dysfunction. PMID:22287023

  5. Development of the olfactory pathways in platypus and echidna.

    PubMed

    Ashwell, Ken W S

    2012-01-01

    The two groups of living monotremes (platypus and echidnas) have remarkably different olfactory structures in the adult. The layers of the main olfactory bulb of the short-beaked echidna are extensively folded, whereas those of the platypus are not. Similarly, the surface area of the piriform cortex of the echidna is large and its lamination complex, whereas in the platypus it is small and simple. It has been argued that the modern echidnas are derived from a platypus-like ancestor, in which case the extensive olfactory specializations of the modern echidnas would have developed relatively recently in monotreme evolution. In this study, the development of the constituent structures of the olfactory pathway was studied in sectioned platypus and echidna embryos and post-hatchlings at the Museum für Naturkunde, Berlin, Germany. The aim was to determine whether the olfactory structures follow a similar maturational path in the two monotremes during embryonic and early post-hatching ages or whether they show very different developmental paths from the outset. The findings indicate that anatomical differences in the central olfactory system between the short-beaked echidna and the platypus begin to develop immediately before hatching, although details of differences in nasal cavity architecture emerge progressively during late post-hatching life. These findings are most consistent with the proposition that the two modern monotreme lineages have followed independent evolutionary paths from a less olfaction-specialized ancestor. The monotreme olfactory pathway does not appear to be sufficiently structurally mature at birth to allow olfaction-mediated behaviour, because central components of both the main and accessory olfactory system have not differentiated at the time of hatching. PMID:22156550

  6. Trade-Off between Information Format and Capacity in the Olfactory System

    PubMed Central

    Stopfer, Mark A.

    2015-01-01

    As information about the sensory environment passes between layers within the nervous system, the format of the information often changes. To examine how information format affects the capacity of neurons to represent stimuli, we measured the rate of information transmission in olfactory neurons in intact, awake locusts (Schistocerca americana) while pharmacologically manipulating patterns of correlated neuronal activity. Blocking the periodic inhibition underlying odor-elicited neural oscillatory synchronization increased information transmission rates. This suggests oscillatory synchrony, which serves other information processing roles, comes at a cost to the speed with which neurons can transmit information. Our results provide an example of a trade-off between benefits and costs in neural information processing. PMID:25632129

  7. Lhx2-dependent specification of olfactory sensory neurons is required for successful integration of olfactory, vomeronasal, and GnRH neurons.

    PubMed

    Berghard, Anna; Hägglund, Anna-Carin; Bohm, Staffan; Carlsson, Leif

    2012-08-01

    Inactivation of the LIM-homeodomain 2 gene (Lhx2) results in a severe defect in specification of olfactory sensory neurons (OSNs). However, the ramifications of lack of Lhx2-dependent OSN specification for formation of the primary olfactory pathway have not been addressed, since mutant mice die in utero. We have analyzed prenatal and postnatal consequences of conditionally inactivating Lhx2 selectively in OSNs. A cell-autonomous effect is that OSN axons cannot innervate their target, the olfactory bulb. Moreover, the lack of Lhx2 in OSNs causes unpredicted, non-cell-autonomous phenotypes. First, the olfactory bulb shows pronounced hypoplasia in adults, and the data suggest that innervation by correctly specified OSNs is necessary for adult bulb size and organization. Second, absence of an olfactory nerve in the conditional mutant reveals that the vomeronasal nerve is dependent on olfactory nerve formation. Third, the lack of a proper vomeronasal nerve prevents migration of gonadotropin-releasing hormone (GnRH) cells the whole distance to their final positions in the hypothalamus during embryo development. As adults, the conditional mutants do not pass puberty, and these findings support the view of an exclusive nasal origin of GnRH neurons in the mouse. Thus, Lhx2 in OSNs is required for functional development of three separate systems. PMID:22581782

  8. acj6: a gene affecting olfactory physiology and behavior in Drosophila.

    PubMed Central

    Ayer, R K; Carlson, J

    1991-01-01

    Mutations affecting olfactory behavior provide material for use in molecular studies of olfaction in Drosophila melanogaster. Using the electroantennogram (EAG), a measure of antennal physiology, we have found an adult antennal defect in the olfactory behavioral mutant abnormal chemosensory jump 6 (acj6). The acj6 EAG defect was mapped to a single locus and the same mutation was found to be responsible for both reduction in EAG amplitude and diminished behavioral response, as if reduced antennal responsiveness to odorant is responsible for abnormal chemosensory behavior in the mutant. acj6 larval olfactory behavior is also abnormal; the mutation seems to alter cellular processes necessary for olfaction at both developmental stages. The acj6 mutation exhibits specificity in that visual system function appears normal in larvae and adults. These experiments provide evidence that the acj6 gene encodes a product required for olfactory signal transduction. Images PMID:1905022

  9. Maternal Olfactory Cues Synchronize the Circadian System of Artificially Raised Newborn Rabbits

    PubMed Central

    Montúfar-Chaveznava, Rodrigo; Trejo-Muñoz, Lucero; Hernández-Campos, Oscar; Navarrete, Erika; Caldelas, Ivette

    2013-01-01

    In European newborn rabbits, once-daily nursing acts as a strong non-photic entraining cue for the pre-visual circadian system. Nevertheless, there is a lack of information regarding which of the non-photic cues are capable of modulating pup circadian system. In this study, for the first time, we determined that the mammary pheromone 2-methylbut-2-enal (2MB2) presented in the maternal milk acts as a non-photic entraining cue. We evaluated the effect of once-daily exposure to maternal olfactory cues on the temporal pattern of core body temperature, gross locomotor activity and metabolic variables (liver weight, serum glucose, triacylglycerides, free fatty acids, cholecystokinin and cholesterol levels) in newborn rabbits. Rabbit pups were separated from their mothers from postnatal day 1 (P1) to P8 and were randomly assigned to one of the following conditions: nursed by a lactating doe (NAT); exposed to a 3-min pulse of maternal milk (M-Milk), mammary pheromone (2MB2), or water (H2O). To eliminate maternal stimulation, the pups of the last three groups were artificially fed once every 24-h. On P8, the rabbits were sacrificed at different times of the day. In temperature and activity, the NAT, M-Milk and 2MB2 groups exhibited clear diurnal rhythmicity with a conspicuous anticipatory rise hours prior to nursing. In contrast, the H2O group exhibited atypical rhythmicity in both parameters, lacking the anticipatory component. At the metabolic level, all of the groups exhibited a diurnal pattern with similar phases in liver weight and metabolites examined. The results obtained in this study suggest that during pre-visual stages of development, the circadian system of newborn rabbits is sensitive to the maternal olfactory cues contained in milk, indicating that these cues function as non-photic entraining signals mainly for the central oscillators regulating the expression of temperature and behavior, whereas in metabolic diurnal rhythmicity, these cues lack an effect

  10. Connectivity of Pathology: The Olfactory System as a Model for Network-Driven Mechanisms of Alzheimer’s Disease Pathogenesis

    PubMed Central

    Franks, Katherine H.; Chuah, Meng Inn; King, Anna E.; Vickers, James C.

    2015-01-01

    The pathogenesis of Alzheimer’s disease (AD) has been postulated to preferentially impact specific neural networks in the brain. The olfactory system is a well-defined network that has been implicated in early stages of the disease, marked by impairment in olfaction and the presence of pathological hallmarks of the disease, even before clinical presentation. Discovering the cellular mechanisms involved in the connectivity of pathology will provide insight into potential targets for treatment. We review evidence from animal studies on sensory alteration through denervation or enrichment, which supports the notion of using the olfactory system to investigate the implications of connectivity and activity in the spread of pathology in AD. PMID:26696886

  11. Cytoarchitecture and Ultrastructure of Neural Stem Cell Niches and Neurogenic Complexes Maintaining Adult Neurogenesis in the Olfactory Midbrain of Spiny Lobsters, Panulirus argus

    PubMed Central

    Schmidt, Manfred; Derby, Charles D.

    2013-01-01

    New interneurons are continuously generated in small proliferation zones within neuronal somata clusters in the olfactory deutocerebrum of adult decapod crustaceans. Each proliferation zone is connected to a clump of cells containing one neural stem cell (i.e., adult neuroblast), thus forming a “neurogenic complex.” Here we provide a detailed analysis of the cytoarchitecture of neurogenic complexes in adult spiny lobsters, Panulirus argus, based on transmission electron microscopy and labeling with cell-type-selective markers. The clump of cells is composed of unique bipolar clump-forming cells that collectively completely envelop the adult neuroblast and are themselves ensheathed by a layer of processes of multipolar cell body glia. An arteriole is attached to the clump of cells, but dye perfusion experiments show that hemolymph has no access to the interior of the clump of cells. Thus, the clump of cells fulfills morphological criteria of a protective stem cell niche, with clump-forming cells constituting the adult neuroblast’s microenvironment together with the cell body glia processes separating it from other tissue components. Bromodeoxyuridine pulse-chase experiments with short survival times suggest that adult neuroblasts are not quiescent but rather cycle actively during daytime. We propose a cell lineage model in which an asymmetrically dividing adult neuroblast repopulates the pool of neuronal progenitor cells in the associated proliferation zone. In conclusion, as in mammalian brains, adult neurogenesis in crustacean brains is fueled by neural stem cells that are maintained by stem cell niches that preserve elements of the embryonic microenvironment and contain glial and vascular elements. PMID:21523781

  12. Quantum Dot Distribution in the Olfactory Epithelium After Nasal Delivery

    NASA Astrophysics Data System (ADS)

    Garzotto, D.; De Marchis, S.

    2010-10-01

    Nanoparticles are used in a wide range of human applications from industrial to bio-medical fields. However, the unique characteristics of nanoparticles, such as the small size, large surface area per mass and high reactivity raises great concern on the adverse effects of these particles on ecological systems and human health. There are several pioneer studies reporting translocation of inhaled particulates to the brain through a potential neuronal uptake mediated by the olfactory nerve (1, 2, 3). However, no direct evidences have been presented up to now on the pathway followed by the nanoparticles from the nose to the brain. In addition to a neuronal pathway, nanoparticles could gain access to the central nervous system through extracellular pathways (perineuronal, perivascular and cerebrospinal fluid paths). In the present study we investigate the localization of intranasally delivered fluorescent nanoparticles in the olfactory epithelium. To this purpose we used quantum dots (QDs), a model of innovative fluorescent semiconductor nanocrystals commonly used in cell and animal biology (4). Intranasal treatments with QDs were performed acutely on adult CD1 mice. The olfactory epithelium was collected and analysed by confocal microscopy at different survival time after treatment. Data obtained indicate that the neuronal components of the olfactory epithelium are not preferentially involved in QDs uptake, thus suggesting nanoparticles can cross the olfactory epithelium through extracellular pathways.

  13. Preliminary Modeling and Simulation Study on Olfactory Cell Sensation

    NASA Astrophysics Data System (ADS)

    Zhou, Jun; Yang, Wei; Chen, Peihua; Liu, Qingjun; Wang, Ping

    2009-05-01

    This paper introduced olfactory sensory neuron's whole-cell model with a concrete voltage-gated ionic channels and simulation. Though there are many models in olfactory sensory neuron and olfactory bulb, it remains uncertain how they express the logic of olfactory information processing. In this article, the olfactory neural network model is also introduced. This model specifies the connections among neural ensembles of the olfactory system. The simulation results of the neural network model are consistent with the observed olfactory biological characteristics such as 1/f-type power spectrum and oscillations.

  14. Preliminary Modeling and Simulation Study on Olfactory Cell Sensation

    SciTech Connect

    Zhou Jun; Chen Peihua; Liu Qingjun; Wang Ping; Yang Wei

    2009-05-23

    This paper introduced olfactory sensory neuron's whole-cell model with a concrete voltage-gated ionic channels and simulation. Though there are many models in olfactory sensory neuron and olfactory bulb, it remains uncertain how they express the logic of olfactory information processing. In this article, the olfactory neural network model is also introduced. This model specifies the connections among neural ensembles of the olfactory system. The simulation results of the neural network model are consistent with the observed olfactory biological characteristics such as 1/f-type power spectrum and oscillations.

  15. A spiking neural network model of self-organized pattern recognition in the early mammalian olfactory system

    PubMed Central

    Kaplan, Bernhard A.; Lansner, Anders

    2014-01-01

    Olfactory sensory information passes through several processing stages before an odor percept emerges. The question how the olfactory system learns to create odor representations linking those different levels and how it learns to connect and discriminate between them is largely unresolved. We present a large-scale network model with single and multi-compartmental Hodgkin–Huxley type model neurons representing olfactory receptor neurons (ORNs) in the epithelium, periglomerular cells, mitral/tufted cells and granule cells in the olfactory bulb (OB), and three types of cortical cells in the piriform cortex (PC). Odor patterns are calculated based on affinities between ORNs and odor stimuli derived from physico-chemical descriptors of behaviorally relevant real-world odorants. The properties of ORNs were tuned to show saturated response curves with increasing concentration as seen in experiments. On the level of the OB we explored the possibility of using a fuzzy concentration interval code, which was implemented through dendro-dendritic inhibition leading to winner-take-all like dynamics between mitral/tufted cells belonging to the same glomerulus. The connectivity from mitral/tufted cells to PC neurons was self-organized from a mutual information measure and by using a competitive Hebbian–Bayesian learning algorithm based on the response patterns of mitral/tufted cells to different odors yielding a distributed feed-forward projection to the PC. The PC was implemented as a modular attractor network with a recurrent connectivity that was likewise organized through Hebbian–Bayesian learning. We demonstrate the functionality of the model in a one-sniff-learning and recognition task on a set of 50 odorants. Furthermore, we study its robustness against noise on the receptor level and its ability to perform concentration invariant odor recognition. Moreover, we investigate the pattern completion capabilities of the system and rivalry dynamics for odor mixtures. PMID

  16. A spiking neural network model of self-organized pattern recognition in the early mammalian olfactory system.

    PubMed

    Kaplan, Bernhard A; Lansner, Anders

    2014-01-01

    Olfactory sensory information passes through several processing stages before an odor percept emerges. The question how the olfactory system learns to create odor representations linking those different levels and how it learns to connect and discriminate between them is largely unresolved. We present a large-scale network model with single and multi-compartmental Hodgkin-Huxley type model neurons representing olfactory receptor neurons (ORNs) in the epithelium, periglomerular cells, mitral/tufted cells and granule cells in the olfactory bulb (OB), and three types of cortical cells in the piriform cortex (PC). Odor patterns are calculated based on affinities between ORNs and odor stimuli derived from physico-chemical descriptors of behaviorally relevant real-world odorants. The properties of ORNs were tuned to show saturated response curves with increasing concentration as seen in experiments. On the level of the OB we explored the possibility of using a fuzzy concentration interval code, which was implemented through dendro-dendritic inhibition leading to winner-take-all like dynamics between mitral/tufted cells belonging to the same glomerulus. The connectivity from mitral/tufted cells to PC neurons was self-organized from a mutual information measure and by using a competitive Hebbian-Bayesian learning algorithm based on the response patterns of mitral/tufted cells to different odors yielding a distributed feed-forward projection to the PC. The PC was implemented as a modular attractor network with a recurrent connectivity that was likewise organized through Hebbian-Bayesian learning. We demonstrate the functionality of the model in a one-sniff-learning and recognition task on a set of 50 odorants. Furthermore, we study its robustness against noise on the receptor level and its ability to perform concentration invariant odor recognition. Moreover, we investigate the pattern completion capabilities of the system and rivalry dynamics for odor mixtures. PMID

  17. A population of glomerular glutamatergic neurons controls sensory information transfer in the mouse olfactory bulb

    PubMed Central

    Tatti, Roberta; Seal, Rebecca P.; Edwards, Robert H.; Rodriguez, Ivan; Carleton, Alan

    2014-01-01

    In sensory systems, peripheral organs convey sensory inputs to relay networks where information is shaped by local microcircuits before being transmitted to cortical areas. In the olfactory system, odorants evoke specific patterns of sensory neuron activity which are transmitted to output neurons in olfactory bulb glomeruli. How sensory information is transferred and shaped at this level remains still unclear. Here we employ mouse genetics, 2-photon microscopy, electrophysiology and optogenetics, to identify a novel population of glutamatergic neurons (VGLUT3+) in the glomerular layer of the adult mouse olfactory bulb as well as several of their synaptic targets. Both peripheral and serotoninergic inputs control VGLUT3+ neurons firing. Furthermore, we show that VGLUT3+ neurons photostimulation in vivo strongly suppresses both spontaneous and odor-evoked firing of bulbar output neurons. In conclusion, we identify and characterize here a microcircuit controlling the transfer of sensory information at an early stage of the olfactory pathway. PMID:24804702

  18. Trpc2 is expressed in two olfactory subsystems, the main and the vomeronasal system of larval Xenopus laevis

    PubMed Central

    Sansone, Alfredo; Syed, Adnan S.; Tantalaki, Evangelia; Korsching, Sigrun I.; Manzini, Ivan

    2014-01-01

    Complete segregation of the main olfactory epithelium (MOE) and the vomeronasal epithelium is first observed in amphibians. In contrast, teleost fishes possess a single olfactory surface, in which genetic components of the main and vomeronasal olfactory systems are intermingled. The transient receptor potential channel TRPC2, a marker of vomeronasal neurons, is present in the single fish sensory surface, but is already restricted to the vomeronasal epithelium in a terrestrial amphibian, the red-legged salamander (Plethodon shermani). Here we examined the localization of TRPC2 in an aquatic amphibian and cloned the Xenopus laevis trpc2 gene. We show that it is expressed in both the MOE and the vomeronasal epithelium. This is the first description of a broad trpc2 expression in the MOE of a tetrapod. The expression pattern of trpc2 in the MOE is virtually undistinguishable from that of MOE-specific v2rs, indicating that they are co-expressed in the same neuronal subpopulation. PMID:24737764

  19. Roles of Specific Membrane Lipid Domains in EGF Receptor Activation and Cell Adhesion Molecule Stabilization in a Developing Olfactory System

    PubMed Central

    Gibson, Nicholas J.; Tolbert, Leslie P.; Oland, Lynne A.

    2009-01-01

    Background Reciprocal interactions between glial cells and olfactory receptor neurons (ORNs) cause ORN axons entering the brain to sort, to fasciculate into bundles destined for specific glomeruli, and to form stable protoglomeruli in the developing olfactory system of an experimentally advantageous animal species, the moth Manduca sexta. Epidermal growth factor receptors (EGFRs) and the cell adhesion molecules (IgCAMs) neuroglian and fasciclin II are known to be important players in these processes. Methodology/Principal Findings We report in situ and cell-culture studies that suggest a role for glycosphingolipid-rich membrane subdomains in neuron-glia interactions. Disruption of these subdomains by the use of methyl-β-cyclodextrin results in loss of EGFR activation, depletion of fasciclin II in ORN axons, and loss of neuroglian stabilization in the membrane. At the cellular level, disruption leads to aberrant ORN axon trajectories, small antennal lobes, abnormal arrays of olfactory glomerul, and loss of normal glial cell migration. Conclusions/Significance We propose that glycosphingolipid-rich membrane subdomains (possible membrane rafts or platforms) are essential for IgCAM-mediated EGFR activation and for anchoring of neuroglian to the cytoskeleton, both required for normal extension and sorting of ORN axons. PMID:19787046

  20. Trpc2 is expressed in two olfactory subsystems, the main and the vomeronasal system of larval Xenopus laevis.

    PubMed

    Sansone, Alfredo; Syed, Adnan S; Tantalaki, Evangelia; Korsching, Sigrun I; Manzini, Ivan

    2014-07-01

    Complete segregation of the main olfactory epithelium (MOE) and the vomeronasal epithelium is first observed in amphibians. In contrast, teleost fishes possess a single olfactory surface, in which genetic components of the main and vomeronasal olfactory systems are intermingled. The transient receptor potential channel TRPC2, a marker of vomeronasal neurons, is present in the single fish sensory surface, but is already restricted to the vomeronasal epithelium in a terrestrial amphibian, the red-legged salamander (Plethodon shermani). Here we examined the localization of TRPC2 in an aquatic amphibian and cloned the Xenopus laevis trpc2 gene. We show that it is expressed in both the MOE and the vomeronasal epithelium. This is the first description of a broad trpc2 expression in the MOE of a tetrapod. The expression pattern of trpc2 in the MOE is virtually undistinguishable from that of MOE-specific v2rs, indicating that they are co-expressed in the same neuronal subpopulation. PMID:24737764

  1. Olfactory exploration: State of the art.

    PubMed

    Nguyen, D T; Rumeau, C; Gallet, P; Jankowski, R

    2016-04-01

    Olfactory disorders are fairly common in the general population. Exploration, on the other hand, is seldom performed by ENT specialists, even in reference centers. There may be three reasons for this: this particular sensory modality may seem unimportant to patients and/or physicians; available treatments may be underestimated, although admittedly much yet remains to be done; and olfactory exploration is not covered by the national health insurance scheme in France. Advances in research in recent decades have shed light on olfactory system functioning. At the same time, several techniques have been developed to allow maximally objective olfactory assessment, as olfactory disorder is sometimes the first sign of neurodegenerative pathology. Moreover, objective olfactory assessment may be needed in a medico-legal context. The present paper updates the techniques currently available for olfactory exploration. PMID:26384780

  2. Robust encoding of stimulus identity and concentration in the accessory olfactory system.

    PubMed

    Arnson, Hannah A; Holy, Timothy E

    2013-08-14

    Sensory systems represent stimulus identity and intensity, but in the neural periphery these two variables are typically intertwined. Moreover, stable detection may be complicated by environmental uncertainty; stimulus properties can differ over time and circumstance in ways that are not necessarily biologically relevant. We explored these issues in the context of the mouse accessory olfactory system, which specializes in detection of chemical social cues and infers myriad aspects of the identity and physiological state of conspecifics from complex mixtures, such as urine. Using mixtures of sulfated steroids, key constituents of urine, we found that spiking responses of individual vomeronasal sensory neurons encode both individual compounds and mixtures in a manner consistent with a simple model of receptor-ligand interactions. Although typical neurons did not accurately encode concentration over a large dynamic range, from population activity it was possible to reliably estimate the log-concentration of pure compounds over several orders of magnitude. For binary mixtures, simple models failed to accurately segment the individual components, largely because of the prevalence of neurons responsive to both components. By accounting for such overlaps during model tuning, we show that, from neuronal firing, one can accurately estimate log-concentration of both components, even when tested across widely varying concentrations. With this foundation, the difference of logarithms, log A - log B = log A/B, provides a natural mechanism to accurately estimate concentration ratios. Thus, we show that a biophysically plausible circuit model can reconstruct concentration ratios from observed neuronal firing, representing a powerful mechanism to separate stimulus identity from absolute concentration. PMID:23946396

  3. Olfactory maps, circuits and computations.

    PubMed

    Giessel, Andrew J; Datta, Sandeep Robert

    2014-02-01

    Sensory information in the visual, auditory and somatosensory systems is organized topographically, with key sensory features ordered in space across neural sheets. Despite the existence of a spatially stereotyped map of odor identity within the olfactory bulb, it is unclear whether the higher olfactory cortex uses topography to organize information about smells. Here, we review recent work on the anatomy, microcircuitry and neuromodulation of two higher-order olfactory areas: the piriform cortex and the olfactory tubercle. The piriform is an archicortical region with an extensive local associational network that constructs representations of odor identity. The olfactory tubercle is an extension of the ventral striatum that may use reward-based learning rules to encode odor valence. We argue that in contrast to brain circuits for other sensory modalities, both the piriform and the olfactory tubercle largely discard any topography present in the bulb and instead use distributive afferent connectivity, local learning rules and input from neuromodulatory centers to build behaviorally relevant representations of olfactory stimuli. PMID:24492088

  4. Rapid and continuous activity-dependent plasticity of olfactory sensory input

    PubMed Central

    Cheetham, Claire E. J.; Park, Una; Belluscio, Leonardo

    2016-01-01

    Incorporation of new neurons enables plasticity and repair of circuits in the adult brain. Adult neurogenesis is a key feature of the mammalian olfactory system, with new olfactory sensory neurons (OSNs) wiring into highly organized olfactory bulb (OB) circuits throughout life. However, neither when new postnatally generated OSNs first form synapses nor whether OSNs retain the capacity for synaptogenesis once mature, is known. Therefore, how integration of adult-born OSNs may contribute to lifelong OB plasticity is unclear. Here, we use a combination of electron microscopy, optogenetic activation and in vivo time-lapse imaging to show that newly generated OSNs form highly dynamic synapses and are capable of eliciting robust stimulus-locked firing of neurons in the mouse OB. Furthermore, we demonstrate that mature OSN axons undergo continuous activity-dependent synaptic remodelling that persists into adulthood. OSN synaptogenesis, therefore, provides a sustained potential for OB plasticity and repair that is much faster than OSN replacement alone. PMID:26898529

  5. Expression of stathmin and SCG10 proteins in the olfactory neurogenesis during development and after lesion in the adulthood.

    PubMed

    Camoletto, P; Colesanti, A; Ozon, S; Sobel, A; Fasolo, A

    2001-01-01

    Stathmin and SCG10 belong to a family of phosphoproteins associated to cell proliferation and differentiation. In the present study, we have analyzed immunocytochemically the distribution of these proteins during neurogenesis in the mouse olfactory system, from midgestation to adulthood. Data show that already at embryonic day 12, stathmin and SCG10 immunoreactivities were present in the olfactory and vomeronasal neurons, and their number increased greatly, colocalizing with neuronal specific tubulin, a marker of immature neurons. Later on up to adulthood, the distribution of stathmin and SCG10 became progressively restricted to a few immature receptor and chemosensory neurons. Significantly, in the olfactory epithelium, stathmin was seen in immature neurons and also in basal cells representing precursors of neuronal elements. Interestingly, before birth stathmin and SCG10 immunopositive cells were seen outside the olfactory epithelium, seemingly migrating toward the olfactory bulb. After regeneration in the adult following peripheral lesion of the olfactory epithelium, stathmin and SCG10 were again strongly expressed and generally colocalized with neuronal specific tubulin immunoreactivity. Overall these results indicate that stathmin and SCG10 are expressed in immature olfactory neurons as well as in the migrating cells generated from the olfactory epithelium, supporting the role of these proteins in neurogenesis and cell migration. PMID:11226711

  6. Norepinephrine and Learning-Induced Plasticity in Infant Rat Olfactory System

    PubMed Central

    Sullivan, Regina M.; Wilson, Donald A.; Leon, Michael

    2007-01-01

    Postnatal olfactory learning produces both a conditioned behavioral response and a modified olfactory bulb neural response to the learned odor. The present report describes the role of norepinephrine (NE) on both of these learned responses in neonatal rat pups. Pups received olfactory classical conditioning training from postnatal days (PN) 1-18. Training consisted of 18 trials with an intertrial interval of 24 hr. For the experimental group, a trial consisted of a pairing of unconditioned stimulus (UCS, stroking/tactile stimulation) and the conditioned stimulus (CS, odor). Control groups received either only the CS (Odor only) or only the UCS (Stroke only). Within each training condition, pups were injected with either the NE β-receptor agonist isoproterenol (1, 20, or 4 mg/kg), the NE β-receptor antagonist propranolol (10, 20, 40 mg/kg), or saline 30 min prior to training. On day 20, pups received one of the following tests: (1) behavioral conditioned responding, (2) injection with 14C-2-deoxyglucase (2-DG) and exposed to the CS odor, or (3) tested for olfactory bulb mitral/tufted cell single-unit responses to the CS odor. The results indicated that training with either: (1) Odor-Stroke-Saline, (2) Odor-Stroke-lsoproterenol-Propranolol, or (3) Odor only-lsoproterenol (2 mg/kg) was sufficient to produce a learned behavioral odor preference, enhanced uptake of 14C-2-DG in the odor-specific foci within the bulb, and a modified output signal from the bulb as measured by single-cell recordings of mitral/tufted cells. Moreover, propranolol injected prior to Odor-Stroke training blocked the acquisition of both the learned behavior and olfactory bulb responses. PMID:2585063

  7. Cytokines and olfactory bulb microglia in response to bacterial challenge in the compromised primary olfactory pathway

    PubMed Central

    2012-01-01

    Background The primary olfactory pathway is a potential route through which microorganisms from the periphery could potentially access the central nervous system. Our previous studies demonstrated that if the olfactory epithelium was damaged, bacteria administered into the nasal cavity induced nitric oxide production in olfactory ensheathing cells. This study investigates the cytokine profile of olfactory tissues as a consequence of bacterial challenge and establishes whether or not the bacteria are able to reach the olfactory bulb in the central nervous system. Methods The olfactory epithelium of C57BL/6 mice was damaged by unilateral Triton X-100 nasal washing, and Staphylococcus aureus was administered ipsilaterally 4 days later. Olfactory mucosa and bulb were harvested 6 h, 24 h and 5 days after inoculation and their cytokine profile compared to control tissues. The fate of S. aureus and the response of bulbar microglia were examined using fluorescence microscopy and transmission electron microscopy. Results In the olfactory mucosa, administered S. aureus was present in supporting cells of the olfactory epithelium, and macrophages and olfactory nerve bundles in the lamina propria. Fluorescein isothiocyanate-conjugated S. aureus was observed within the olfactory mucosa and bulb 6 h after inoculation, but remained restricted to the peripheral layers up to 5 days later. At the 24-h time point, the level of interleukin-6 (IL-6) and tumour necrosis factor-α in the compromised olfactory tissues challenged with bacteria (12,466 ± 956 pg/ml and 552 ± 193 pg/ml, respectively) was significantly higher than that in compromised olfactory tissues alone (6,092 ± 1,403 pg/ml and 80 ± 2 pg/ml, respectively). Immunohistochemistry confirmed that IL-6 was present in several cell types including olfactory ensheathing cells and mitral cells of the olfactory bulb. Concurrently, there was a 4.4-, 4.5- and 2.8-fold increase in the density of i

  8. Calcium-binding protein parvalbumin-immunoreactive neurons in the rat olfactory bulb. 1. Distribution and structural features in adult rat.

    PubMed

    Kosaka, K; Heizmann, C W; Kosaka, T

    1994-01-01

    The laminar distribution and morphological features of parvalbumin-immunoreactive [PV(+)] neurons, one of the subpopulations of GABAergic neurons, were studied in the rat olfactory bulb at a light microscopic level. In the main olfactory bulb of adult rats, PV(+) neurons were mainly located in the external plexiform layer (EPL), and a few were scattered in the glomerular layer (GL), mitral cell layer (ML), and granule cell layer (GRL); whereas PV(+) neurons were rarely seen in the accessory olfactory bulb. The inner and outer sublayers of the EPL (ISL and OSL) appeared to be somewhat different in the distribution of PV(+) somata and features of PV(+) processes. PV(+) somata were located throughout the OSL, and PV(+) processes intermingled with one another, making a dense meshwork in the OSL; whereas, in the ISL, PV(+) somata were mainly located near the inner border of the EPL, and PV(+) processes made a sparser meshwork than that in the OSL. PV(+) neurons in the EPL were apparently heterogeneous in their structural features and appeared to be classifiable into several groups. Among them there appeared five distinctive types of PV(+) neurons. The most prominent group of PV(+) neurons in the OSL were superficial short-axon cells, located in the superficial portion of this sublayer and giving rise to relatively thick processes, in horizontal or oblique directions, which usually bore spines and varicosities. Another prominent group of PV(+) neurons extended several short, branched dendrites with spines and varicosities, which appeared to intermingle with one another, making a relatively small, spherical or ovoid dendritic field around the cell bodies; most of them resembled Van Gehuchten cells reported in previous Golgi studies. A third distinctive and most numerous group of PV(+) neurons were of the multipolar type; their somata and processes were located throughout the EPL. Their relatively smooth processes with frequent varicosities and a few spines were extended

  9. Histochemical demonstration of mercury in the olfactory system of salmon (Salmo salar L. ) following treatments with dietary methylmercuric chloride and dissolved mercuric chloride

    SciTech Connect

    Baatrup, E.; Doving, K.B. )

    1990-12-01

    The deposition of organic and inorganic mercury compounds was studied histochemically in the salmon (Salmo salar L.) olfactory system. One group of salmon was given fodder pellets containing methylmercuric chloride (CH{sub 3}HgCl, 99 micrograms Hg/g) for 4 weeks. Other groups of fish were exposed to dissolved mercuric chloride (HgCl{sub 2}, 270 micrograms Hg/liter) for 2, 6, and 12 hr, respectively. In both series of experiments, the radioisotope {sup 203}Hg was included in order to determine the accumulation of mercury in the olfactory system. Gamma-spectrometry showed that both mercury compounds accumulated in the olfactory rosettes and their nerves. Tissue sections from the rosettes and olfactory nerves were subjected to autometallographic silver enhancement, thereby rendering mercury deposits visible for light and electron microscopy. Microscopic analysis demonstrated an intense and comprehensive Hg deposition in the axons and Schwann cells of both methylmercury- and inorganic mercury-exposed fish. On the other hand, the two mercury compounds showed different staining patterns in the sensory epithelium. The silver grains evoked by methylmercury were localized predominantly in lysosome-like inclusions within the receptor cells, while those produced by HgCl{sub 2} exposure were situated mainly along the borders of neighboring cells. The present findings that organic and inorganic mercury compounds were deposited in the olfactory system along its whole length, from the receptor cell apices to the brain, support the electrophysiological results presented elsewhere.

  10. Dopamine reward circuitry: two projection systems from the ventral midbrain to the nucleus accumbens-olfactory tubercle complex

    PubMed Central

    Ikemoto, Satoshi

    2007-01-01

    Anatomical and functional refinements of the meso-limbic dopamine system of the rat are discussed. Present experiments suggest that dopaminergic neurons localized in the posteromedial ventral tegmental area (VTA) and central linear nucleus raphe selectively project to the ventromedial striatum (medial olfactory tubercle and medial nucleus accumbens shell), whereas the anteromedial VTA has few if any projections to the ventral striatum, and the lateral VTA largely projects to the ventrolateral striatum (accumbens core, lateral shell and lateral tubercle). These findings complement the recent behavioral findings that cocaine and amphetamine are more rewarding when administered into the ventromedial striatum than into the ventrolateral striatum. Drugs such as nicotine and opiates are more rewarding when administered into the posterior VTA or the central linear nucleus than into the anterior VTA. A review of the literature suggests that: (1) the midbrain has corresponding zones for the accumbens core and medial shell; (2) the striatal portion of the olfactory tubercle is a ventral extension of the nucleus accumbens shell; (3) a model of two dopamine projection systems from the ventral midbrain to the ventral striatum is useful for understanding reward function. The medial projection system is important in the regulation of arousal characterized by affect and drive, and plays a different role in goal-directed learning than the lateral projection system, as described in the variation-selection hypothesis of striatal functional organization. PMID:17574681

  11. Olfactory Ensheathing Cells Express α7 Integrin to Mediate Their Migration on Laminin

    PubMed Central

    Ingram, Norianne T.; Khankan, Rana R.; Phelps, Patricia E.

    2016-01-01

    The unique glia located in the olfactory system, called olfactory ensheathing cells (OECs), are implicated as an attractive choice for transplantation therapy following spinal cord injury because of their pro-regenerative characteristics. Adult OECs are thought to improve functional recovery and regeneration after injury by secreting neurotrophic factors and making cell-to-cell contacts with regenerating processes, but the mechanisms are not well understood. We show first that α7 integrin, a laminin receptor, is highly expressed at the protein level by OECs throughout the olfactory system, i.e., in the olfactory mucosa, olfactory nerve, and olfactory nerve layer of the olfactory bulb. Then we asked if OECs use the α7 integrin receptor directly to promote neurite outgrowth on permissive and neutral substrates, in vitro. We co-cultured α7+/+ and α7lacZ/lacZ postnatal cerebral cortical neurons with α7+/+ or α7lacZ/lacZ OECs and found that genotype did not effect the ability of OECs to enhance neurite outgrowth by direct contact. Loss of α7 integrin did however significantly decrease the motility of adult OECs in transwell experiments. Twice as many α7+/+ OECs migrated through laminin-coated transwells compared to α7+/+ OECs on poly-L-lysine (PLL). This is in contrast to α7lacZ/lacZ OECs, which showed no migratory preference for laminin substrate over PLL. These results demonstrate that OECs express α7 integrin, and that laminin and its α7 integrin receptor contribute to adult OEC migration in vitro and perhaps also in vivo. PMID:27078717

  12. Olfactory Ensheathing Cells Express α7 Integrin to Mediate Their Migration on Laminin.

    PubMed

    Ingram, Norianne T; Khankan, Rana R; Phelps, Patricia E

    2016-01-01

    The unique glia located in the olfactory system, called olfactory ensheathing cells (OECs), are implicated as an attractive choice for transplantation therapy following spinal cord injury because of their pro-regenerative characteristics. Adult OECs are thought to improve functional recovery and regeneration after injury by secreting neurotrophic factors and making cell-to-cell contacts with regenerating processes, but the mechanisms are not well understood. We show first that α7 integrin, a laminin receptor, is highly expressed at the protein level by OECs throughout the olfactory system, i.e., in the olfactory mucosa, olfactory nerve, and olfactory nerve layer of the olfactory bulb. Then we asked if OECs use the α7 integrin receptor directly to promote neurite outgrowth on permissive and neutral substrates, in vitro. We co-cultured α7+/+ and α7lacZ/lacZ postnatal cerebral cortical neurons with α7+/+ or α7lacZ/lacZ OECs and found that genotype did not effect the ability of OECs to enhance neurite outgrowth by direct contact. Loss of α7 integrin did however significantly decrease the motility of adult OECs in transwell experiments. Twice as many α7+/+ OECs migrated through laminin-coated transwells compared to α7+/+ OECs on poly-L-lysine (PLL). This is in contrast to α7lacZ/lacZ OECs, which showed no migratory preference for laminin substrate over PLL. These results demonstrate that OECs express α7 integrin, and that laminin and its α7 integrin receptor contribute to adult OEC migration in vitro and perhaps also in vivo. PMID:27078717

  13. Signal transduction for taurocholic acid in the olfactory system of Atlantic salmon.

    PubMed

    Lo, Y H; Bellis, S L; Cheng, L J; Pang, J; Bradley, T M; Rhoads, D E

    1994-10-01

    Conjugated bile acids such as taurocholic acid (TChA) are potent olfactory stimuli for Atlantic salmon (Salmo salar). A plasma membrane rich fraction was derived from salmon olfactory rosettes and used to investigate TChA signal transduction and receptor binding. In the presence of GTP gamma S, TChA caused dose-dependent stimulation of phosphatidylinositol 4,5-bisphosphate (PIP2) breakdown, half maximal at less than 10(-7) M TChA. Stimulation of PIP2 breakdown by TChA required GTP gamma S, was blocked by GDP beta S, and was mimicked by A1F4-, consistent with a G protein requirement. A1F4- and Ca2+ stimulated breakdown of PIP2, but not phosphatidylcholine, arguing against a non-specific lipase activation. Stimulation of PIP2 breakdown by TChA was maximal at low Ca2+ concentration, < or = 10 nM. Conventional binding analysis with 3H-TChA was inconclusive due to a high degree of non-specific binding and to lack of tissue specificity expected for an olfactory receptor. Analysis of odorant amino acid binding indicated possible interaction of TChA with a putative acidic amino acid receptor but no interaction of TChA with a putative neutral amino acid receptor. We conclude that olfactory discrimination between amino acids and bile acids occurs in part at the receptor level while both classes of odors appear to use the same signal transduction mechanism, G protein mediated activation of phosphoinositide specific phospholipase C (PLC). PMID:7881971

  14. Probability model for molecular recognition in biological receptor repertoires: significance to the olfactory system.

    PubMed

    Lancet, D; Sadovsky, E; Seidemann, E

    1993-04-15

    A generalized phenomenological model is presented for stereospecific recognition between biological receptors and their ligands. We ask what is the distribution of binding constants psi(K) between an arbitrary ligand and members of a large receptor repertoire, such as immunoglobulins or olfactory receptors. For binding surfaces with B potential subsite and S different types of subsite configurations, the number of successful elementary interactions obeys a binomial distribution. The discrete probability function psi(K) is then derived with assumptions on alpha, the free energy contribution per elementary interaction. The functional form of psi(K) may be universal, although the parameter values could vary for different ligand types. An estimate of the parameter values of psi(K) for iodovanillin, an analog of odorants and immunological haptens, is obtained by equilibrium dialysis experiments with nonimmune antibodies. Based on a simple relationship, predicted by the model, between the size of a receptor repertoire and its average maximal affinity toward an arbitrary ligand, the size of the olfactory receptor repertoire (Nolf) is calculated as 300-1000, in very good agreement with recent molecular biological studies. A very similar estimate, Nolf = 500, is independently derived by relating a theoretical distribution of maxima for psi(K) with published human olfactory threshold variations. The present model also has implications to the question of olfactory coding and to the analysis of specific anosmias, genetic deficits in perceiving particular odorants. More generally, the proposed model provides a better understanding of ligand specificity in biological receptors and could help in understanding their evolution. PMID:8475121

  15. Probability model for molecular recognition in biological receptor repertoires: significance to the olfactory system.

    PubMed Central

    Lancet, D; Sadovsky, E; Seidemann, E

    1993-01-01

    A generalized phenomenological model is presented for stereospecific recognition between biological receptors and their ligands. We ask what is the distribution of binding constants psi(K) between an arbitrary ligand and members of a large receptor repertoire, such as immunoglobulins or olfactory receptors. For binding surfaces with B potential subsite and S different types of subsite configurations, the number of successful elementary interactions obeys a binomial distribution. The discrete probability function psi(K) is then derived with assumptions on alpha, the free energy contribution per elementary interaction. The functional form of psi(K) may be universal, although the parameter values could vary for different ligand types. An estimate of the parameter values of psi(K) for iodovanillin, an analog of odorants and immunological haptens, is obtained by equilibrium dialysis experiments with nonimmune antibodies. Based on a simple relationship, predicted by the model, between the size of a receptor repertoire and its average maximal affinity toward an arbitrary ligand, the size of the olfactory receptor repertoire (Nolf) is calculated as 300-1000, in very good agreement with recent molecular biological studies. A very similar estimate, Nolf = 500, is independently derived by relating a theoretical distribution of maxima for psi(K) with published human olfactory threshold variations. The present model also has implications to the question of olfactory coding and to the analysis of specific anosmias, genetic deficits in perceiving particular odorants. More generally, the proposed model provides a better understanding of ligand specificity in biological receptors and could help in understanding their evolution. PMID:8475121

  16. A role for the androgen receptor in the sexual differentiation of the olfactory system in mice

    PubMed Central

    Bodo, Cristian

    2008-01-01

    Olfactory signals play a central role in the identification of a mating partner in rodents, and the behavioral response to these cues varies markedly between the sexes. As several other sexually dimorphic traits, this response is thought to differentiate as a result of exposure of the developing individual to gonadal steroids, but both the identity of the specific steroid signal and the neural structures targeted for differentiation on this particular case are largely unknown. The present review summarizes results obtained in our lab using genetic males affected by the testicular feminization syndrome (Tfm) as experimental model, and that led to the identification of a role for non-aromatized gonadal steroids acting through the androgen receptor (AR) in the differentiation of olfactory cues processing in mice. The existing literature about AR-mediated sexual differentiation of the CNS in animal models is discussed, along with potential targets for the action of non-aromatized gonadal steroids in either one of the subsystems that detect and process olfactory information in rodents. PMID:17915335

  17. Attention and olfactory consciousness.

    PubMed

    Keller, Andreas

    2011-01-01

    Understanding the relation between attention and consciousness is an important part of our understanding of consciousness. Attention, unlike consciousness, can be systematically manipulated in psychophysical experiments and a law-like relation between attention and consciousness is waiting to be discovered. Most attempts to discover the nature of this relation are focused on a special type of attention: spatial visual attention. In this review I want to introduce another type of attention to the discussion: attention to the olfactory modality. I will first clarify the position of attention to smells in a general taxonomy of attention. I will then review the mechanisms and neuroanatomy of attention and consciousness in the olfactory system before using the newly introduced system to provide evidence that attention is necessary for consciousness. PMID:22203813

  18. Olfactory neuroblastoma

    SciTech Connect

    O'Connor, T.A.; McLean, P.; Juillard, G.J.; Parker, R.G.

    1989-06-15

    Fifteen patients with olfactory neuroblastoma were treated during the 17-year period of 1969 to 1986. Data was analyzed with respect to age at presentation, sex, presenting signs and symptoms, stage, and results of treatment. Age ranged from 4 to 67 years with the median age being 27 years. Median follow-up was 8 years. Local control was achieved in nine of nine patients or 100% with successful surgical resection, i.e., minimal residual disease, followed by postoperative radiation therapy (45 to 65 Gy) was employed. There were no distant failures when the primary site was controlled. Regional lymph node metastases were infrequent: only 13% (two of 15 patients) presented with positive nodes. Three of four patients treated initially with surgery alone had a local recurrence, two of which were successfully salvaged by combined therapy. There were four patients treated with radiation therapy alone: three had persistent disease after radiation therapy, and one patient was controlled with 65 Gy. Olfactory neuroblastoma has a propensity to recur locally when treated with surgery alone. The authors' experience suggests excellent local control can be achieved with surgery immediately followed by radiation therapy. Thus the authors recommend planned combined treatment for all resectable lesions.

  19. Phylogeny of the vomeronasal system and of receptor cell types in the olfactory and vomeronasal epithelia of vertebrates.

    PubMed

    Eisthen, H L

    1992-10-01

    In this paper, the evolutionary origin of the vomeronasal system as a discrete sensory system separate from olfaction is examined. The presence of a discrete vomeronasal system appears to be a derived character in tetrapods, and its presence in larval amphibians indicates that the system did not arise as a terrestrial adaptation. The vomeronasal system has been lost independently in several taxa, including crocodilians, some bats, cetaceans, and some primates. The presence of microvillar receptor cells in the vomeronasal epithelium appears to be the ancestral condition for tetrapods, and alternative hypotheses concerning the ancestral condition for receptor cell types in the vertebrate olfactory epithelium are discussed. Finally, the possibility that the vomeronasal system is present in some fishes in a form that has not been recognized is discussed in relation to the phylogenetic distribution of receptor cell types in vertebrates. PMID:1392068

  20. Structural differences in the drone olfactory system of two phylogenetically distant Apis species, A. florea and A. mellifera.

    PubMed

    Brockmann, A; Brückner, D

    2001-02-01

    mating behavior, the queen's mandibular gland secretion is the main pheromone regulating queen-worker interactions (Free 1987). In this context, several studies have demonstrated the behavioral significance of single components (Slessor et al. 1988) and differences in the composition of the secretion between Apis species (Plettner et al. 1996, 1997; Keeling et al. 2000). Regarding the interspecific differences in the queen's signal, the question arises whether this variation is reflected in the olfactory system of drones and workers of the various species. PMID:11320892

  1. Human olfactory receptor responses to odorants

    PubMed Central

    Mainland, Joel D; Li, Yun R; Zhou, Ting; Liu, Wen Ling L; Matsunami, Hiroaki

    2015-01-01

    Although the human olfactory system is capable of discriminating a vast number of odors, we do not currently understand what chemical features are encoded by olfactory receptors. In large part this is due to a paucity of data in a search space covering the interactions of hundreds of receptors with billions of odorous molecules. Of the approximately 400 intact human odorant receptors, only 10% have a published ligand. Here we used a heterologous luciferase assay to screen 73 odorants against a clone library of 511 human olfactory receptors. This dataset will allow other researchers to interrogate the combinatorial nature of olfactory coding. PMID:25977809

  2. Drosophila Avoids Parasitoids by Sensing Their Semiochemicals via a Dedicated Olfactory Circuit

    PubMed Central

    Ebrahim, Shimaa A. M.; Dweck, Hany K. M.; Stökl, Johannes; Hofferberth, John E.; Trona, Federica; Weniger, Kerstin; Rybak, Jürgen; Seki, Yoichi; Stensmyr, Marcus C.; Sachse, Silke; Hansson, Bill S.; Knaden, Markus

    2015-01-01

    Detecting danger is one of the foremost tasks for a neural system. Larval parasitoids constitute clear danger to Drosophila, as up to 80% of fly larvae become parasitized in nature. We show that Drosophila melanogaster larvae and adults avoid sites smelling of the main parasitoid enemies, Leptopilina wasps. This avoidance is mediated via a highly specific olfactory sensory neuron (OSN) type. While the larval OSN expresses the olfactory receptor Or49a and is tuned to the Leptopilina odor iridomyrmecin, the adult expresses both Or49a and Or85f and in addition detects the wasp odors actinidine and nepetalactol. The information is transferred via projection neurons to a specific part of the lateral horn known to be involved in mediating avoidance. Drosophila has thus developed a dedicated circuit to detect a life-threatening enemy based on the smell of its semiochemicals. Such an enemy-detecting olfactory circuit has earlier only been characterized in mice and nematodes. PMID:26674493

  3. Distribution of EphA5 receptor protein in the developing and adult mouse nervous system

    PubMed Central

    Cooper, Margaret A.; Crockett, David P.; Nowakowski, Richard S.; Gale, Nicholas W.; Zhou, Renping

    2009-01-01

    The EphA5 receptor tyrosine kinase plays key roles in axon guidance during development. However, the presence of EphA5 protein in the nervous system has not been fully characterized. To better examine EphA5 localization, mutant mice, in which the EphA5 cytoplasmic domain was replaced with β-galactosidase, were analyzed for both temporal and regional changes in the distribution of EphA5 protein in the developing and adult nervous system. During embryonic development, high levels of EphA5 protein were found in the retina, olfactory bulb, cerebral neocortex, hippocampus, pretectum, tectum, cranial nerve nuclei, and the spinal cord. Variations in intensity were observed as development proceeded. Staining of pretectal nuclei, tectal nuclei, and other areas of the mesencephalon became more diffuse after maturity whereas the cerebral neocortex gained more robust intensity. In the adult, receptor protein continued to be detected in many areas including the olfactory nuclei, neocortex, piriform cortex, induseum griseum, hippocampus, thalamus, amygdala, hypothalamus and septum. In addition, EphA5 protein was found in the claustrum, stria terminalis, barrel cortex, striatal patches, and along discrete axon tracts within the corpus callosum of the adult. These observations suggest that EphA5 function is not limited to the developing mouse brain and may play a role in synaptic plasticity in the adult. PMID:19326470

  4. Evidence of a novel transduction pathway mediating detection of polyamines by the zebrafish olfactory system.

    PubMed

    Michel, W C; Sanderson, M J; Olson, J K; Lipschitz, D L

    2003-05-01

    To better understand the full extent of the odorant detection capabilities of fish, we investigated the olfactory sensitivity of zebrafish to a monoamine and several polyamines using electrophysiological and activity-dependent labeling techniques. Electro-olfactogram (EOG) recording methods established the relative stimulatory effectiveness of these odorants as: spermine > spermidine approximately agmatine > glutamine > putrescine >or= cadaverine >or= histamine > artificial freshwater. The detection threshold for the potent polyamines was approximately 1 micromol l(-1). Cross-adaptation experiments suggested that multiple receptors are involved in polyamine detection. Three observations indicated that polyamine signaling may involve a transduction cascade distinct from those used by either amino acids or bile salts. Like bile salts and the adenylate cyclase activator forskolin, but unlike amino acid odorants, polyamines failed to stimulate activity-dependent labeling of olfactory sensory neurons with the cation channel permeant probe agmatine, suggesting a signaling pathway different from that used by amino acid stimuli. Also supporting distinct amino acid and polyamine signaling pathways is the finding that altering phospholipase C activity with the inhibitor U-73122 significantly reduced amino acid-evoked responses, but had little effect on polyamine- (or bile salt-) evoked responses. Altering cyclic nucleotide-mediated signaling by adenylate cyclase activation with forskolin, which significantly reduced responses to bile salts, failed to attenuate polyamine responses, suggesting that polyamines and bile salts do not share a common transduction cascade. Collectively, these findings suggest that polyamines are a new class of olfactory stimuli transduced by a receptor-mediated, second messenger signaling pathway that is distinct from those used by amino acids or bile salts. PMID:12682101

  5. Neuromodulation of Olfactory Sensitivity in the Peripheral Olfactory Organs of the American Cockroach, Periplaneta americana

    PubMed Central

    Jung, Je Won; Kim, Jin-Hee; Pfeiffer, Rita; Ahn, Young-Joon; Page, Terry L.; Kwon, Hyung Wook

    2013-01-01

    Olfactory sensitivity exhibits daily fluctuations. Several studies have suggested that the olfactory system in insects is modulated by both biogenic amines and neuropeptides. However, molecular and neural mechanisms underlying olfactory modulation in the periphery remain unclear since neuronal circuits regulating olfactory sensitivity have not been identified. Here, we investigated the structure and function of these signaling pathways in the peripheral olfactory system of the American cockroach, Periplaneta americana, utilizing in situ hybridization, qRT-PCR, and electrophysiological approaches. We showed that tachykinin was co-localized with the octopamine receptor in antennal neurons located near the antennal nerves. In addition, the tachykinin receptor was found to be expressed in most of the olfactory receptor neurons in antennae. Functionally, the effects of direct injection of tachykinin peptides, dsRNAs of tachykinin, tachykinin receptors, and octopamine receptors provided further support for the view that both octopamine and tachykinin modulate olfactory sensitivity. Taken together, these findings demonstrated that octopamine and tachykinin in antennal neurons are olfactory regulators in the periphery. We propose here the hypothesis that octopamine released from neurons in the brain regulates the release of tachykinin from the octopamine receptor neurons in antennae, which in turn modulates the olfactory sensitivity of olfactory receptor neurons, which house tachykinin receptors. PMID:24244739

  6. Monoclonal antibodies reveal cell-type-specific antigens in the sexually dimorphic olfactory system of Manduca sexta. I. Generation of monoclonal antibodies and partial characterization of the antigens.

    PubMed

    Hishinuma, A; Hockfield, S; McKay, R; Hildebrand, J G

    1988-01-01

    The olfactory system of the moth Manduca sexta is sexually dimorphic. Male moths possess a male-specific olfactory "subsystem," comprising olfactory receptor cells (ORCs) and CNS neurons and synaptic areas associated with the detection of female sex pheromones, in addition to elements common to males and females. In order to explore the molecular differences between cells that subserve the sexual dimorphism and odor-specificity of components of the olfactory system, we generated monoclonal antibodies (Mabs) against tissue of the olfactory system of the moth. In 2 fusions, we screened 1105 hybridoma lines and obtained 272 lines that secreted antibodies against Manduca nervous tissue, as assayed immunocytochemically on sections of the primary olfactory center (the antennal lobe) in the brain of Manduca. We describe here 3 classes of Mabs exemplifying the several cell-type-specific antibodies obtained through the screening procedure. Seven hybridoma lines secrete antibodies that specifically recognize cell bodies, axons, and initial segments of dendrites of many or all ORCs of both males and females (classified as olfactory-specific antibodies, OSAs). Electron-microscopic studies of 2 of the Mabs in this class showed that they recognize antigens associated with the cell membrane and that the immunoreactive ORC axons are bundled together in fascicles in the antennal nerve. On immunoblots, one of the OSA Mabs recognizes 3 distinct protein bands of apparent Mrs 42,000, 59,000, and 66,000 Da. When tissue samples enriched in either receptor cell bodies, dendrites, and initial segments of axons or in distal segments of axons and their terminals and synapses were extracted separately, different patterns of bands were detected--42,000 and 59,000 Da bands from cell bodies and initial segments of axons and dendrites, and 42,000 and 66,000 Da bands from distal segments of axons and their terminals--suggesting that the 59,000 Da protein is modified to the 66,000 Da protein during

  7. The spatiotemporal segregation of GAD forms defines distinct GABA signaling functions in the developing mouse olfactory system and provides novel insights into the origin and migration of GnRH neurons.

    PubMed

    Vastagh, Csaba; Schwirtlich, Marija; Kwakowsky, Andrea; Erdélyi, Ferenc; Margolis, Frank L; Yanagawa, Yuchio; Katarova, Zoya; Szabó, Gábor

    2015-03-01

    Gamma-aminobutyric acid (GABA) has a dual role as an inhibitory neurotransmitter in the adult central nervous system (CNS) and as a signaling molecule exerting largely excitatory actions during development. The rate-limiting step of GABA synthesis is catalyzed by two glutamic acid decarboxylase isoforms GAD65 and GAD67 coexpressed in the GABAergic neurons of the CNS. Here we report that the two GADs show virtually nonoverlapping expression patterns consistent with distinct roles in the developing peripheral olfactory system. GAD65 is expressed exclusively in undifferentiated neuronal progenitors confined to the proliferative zones of the sensory vomeronasal and olfactory epithelia In contrast GAD67 is expressed in a subregion of the nonsensory epithelium/vomeronasal organ epithelium containing the putative Gonadotropin-releasing hormone (GnRH) progenitors and GnRH neurons migrating from this region through the frontonasal mesenchyme into the basal forebrain. Only GAD67+, but not GAD65+ cells accumulate detectable GABA. We further demonstrate that GAD67 and its embryonic splice variant embryonic GAD (EGAD) concomitant with GnRH are dynamically regulated during GnRH neuronal migration in vivo and in two immortalized cell lines representing migratory (GN11) and postmigratory (GT1-7) stage GnRH neurons, respectively. Analysis of GAD65/67 single and double knock-out embryos revealed that the two GADs play complementary (inhibitory) roles in GnRH migration ultimately modulating the speed and/or direction of GnRH migration. Our results also suggest that GAD65 and GAD67/EGAD characterized by distinct subcellular localization and kinetics have disparate functions during olfactory system development mediating proliferative and migratory responses putatively through specific subcellular GABA pools. PMID:25125027

  8. Evidence for functional asymmetry in the olfactory system of the Senegalese sole (Solea senegalensis).

    PubMed

    Velez, Zélia; Hubbard, Peter C; Barata, Eduardo N; Canário, Adelino V M

    2005-01-01

    The two olfactory epithelia of flatfish of the family Soleidae are essentially in contact with two distinct environments; the upper (right) side samples open water while the lower (left) side samples interstitial water. This study assessed whether there are differences in the responsiveness of the two epithelia by use of the electro-olfactogram in the Senegalese sole (Solea senegalensis). The upper epithelium was significantly more responsive to the basic amino acids (L-lysine and L-arginine), glycine, and L-threonine than the lower epithelium. The lower epithelium was significantly more responsive to aromatic amino acids (L-tryptophan, L-tyrosine, L-DOPA, and L-phenylalanine), L-leucine, and L-asparagine than the upper. Both epithelia had similar responsiveness to the sulphur-containing amino acids (L-cysteine and L-methionine), L-alanine, L-serine, and L-glutamine. Neither side was responsive to the acidic amino acids (L-aspartate and L-glutamate) or the D-isomers of any amino acid tested. The upper olfactory organ was much more responsive to conspecific-derived stimuli (bile and intestinal fluid) than the lower organ. We suggest that these differences in responsiveness may be related to different functional roles of the upper and lower epithelia in feeding and chemical communication. PMID:16059846

  9. Neural Correlates of Olfactory Learning: Critical Role of Centrifugal Neuromodulation

    ERIC Educational Resources Information Center

    Fletcher, Max L.; Chen, Wei R.

    2010-01-01

    The mammalian olfactory system is well established for its remarkable capability of undergoing experience-dependent plasticity. Although this process involves changes at multiple stages throughout the central olfactory pathway, even the early stages of processing, such as the olfactory bulb and piriform cortex, can display a high degree of…

  10. Olfactory Epithelium Grafts in the Cerebral Cortex: An Immunohistochemical Analysis

    PubMed Central

    Holbrook, Eric H.; DiNardo, Laurence J.; Costanzo, Richard M.

    2009-01-01

    Objective To develop an alternative model for studying the regenerative capacity of olfactory neurons. Study Design An immunohistochemical analysis of mouse olfactory epithelium transplanted to the cerebral cortex. Methods Strips of olfactory epithelium removed from donor mice at postnatal day 5 to day 20 were inserted into the parietal cortex of adult mice. Recipient animals were allowed to survive for 25 to 120 days and then perfused with 4% paraformaldehyde 1 hour after bromodeoxyuridine injection. The brains were processed, and frozen sections were obtained. Sections through transplant tissue were analyzed using immunohistochemistry and compared with normal olfactory epithelium. Results Graft survival approached 85% with mature olfactory neurons detected in 35% of the transplants stained for olfactory marker protein. Transplant epithelium resembled normal olfactory epithelium containing mature olfactory neurons and axon bundles. Conclusions Studies of olfactory neuron regeneration have been limited by the inability to produce cultures with long-term viability. Olfactory epithelial grafts to the cerebral cortex provide an alternative approach to the study of olfactory neuron regeneration. PMID:11801979

  11. Evolution of insect olfactory receptors

    PubMed Central

    Missbach, Christine; Dweck, Hany KM; Vogel, Heiko; Vilcinskas, Andreas; Stensmyr, Marcus C; Hansson, Bill S; Grosse-Wilde, Ewald

    2014-01-01

    The olfactory sense detects a plethora of behaviorally relevant odor molecules; gene families involved in olfaction exhibit high diversity in different animal phyla. Insects detect volatile molecules using olfactory (OR) or ionotropic receptors (IR) and in some cases gustatory receptors (GRs). While IRs are expressed in olfactory organs across Protostomia, ORs have been hypothesized to be an adaptation to a terrestrial insect lifestyle. We investigated the olfactory system of the primary wingless bristletail Lepismachilis y-signata (Archaeognatha), the firebrat Thermobia domestica (Zygentoma) and the neopteran leaf insect Phyllium siccifolium (Phasmatodea). ORs and the olfactory coreceptor (Orco) are with very high probability lacking in Lepismachilis; in Thermobia we have identified three Orco candidates, and in Phyllium a fully developed OR/Orco-based system. We suggest that ORs did not arise as an adaptation to a terrestrial lifestyle, but evolved later in insect evolution, with Orco being present before the appearance of ORs. DOI: http://dx.doi.org/10.7554/eLife.02115.001 PMID:24670956

  12. Neuropeptide Y in the olfactory microvillar cells.

    PubMed

    Montani, Giorgia; Tonelli, Simone; Elsaesser, Rebecca; Paysan, Jacques; Tirindelli, Roberto

    2006-07-01

    This paper examines a possible role of microvillar cells in coordinating cell death and regeneration of olfactory epithelial neurons. The olfactory neuroepithelium of mammals is a highly dynamic organ. Olfactory neurons periodically degenerate by apoptosis and as a consequence of chemical or physical damage. To compensate for this loss of cells, the olfactory epithelium maintains a lifelong ability to regenerate from a pool of resident multipotent stem cells. To assure functional continuity and histological integrity of the olfactory epithelium over a period of many decades, apoptosis and regeneration require to be precisely coordinated. Among the factors that have been implicated in mediating this regulation is the neuropeptide Y (NPY). Knockout mice that lack functional expression of this neurogenic peptide show defects in embryonic development of the olfactory epithelium and in its ability to regenerate in the adult. Here we show that, in postnatal olfactory epithelia, NPY is exclusively expressed by a specific population of microvillar cells. We previously characterized these cells as a novel type of putative chemosensory cells, which are provided with a phosphatidyl-inositol-mediated signal transduction cascade. Our findings allow for the first time to suggest that microvillar cells are involved in connecting apoptosis to neuronal regeneration by stimulus-induced release of NPY. PMID:16800866

  13. Weakened Immune System and Adult Vaccination

    MedlinePlus

    ... for Healthcare Professionals Weakened Immune System and Adult Vaccination Recommend on Facebook Tweet Share Compartir Vaccines are ... up to age 26 years Learn about adult vaccination and other health conditions Asplenia Diabetes Type 1 ...

  14. The Pig Olfactory Brain: A Primer.

    PubMed

    Brunjes, Peter C; Feldman, Sanford; Osterberg, Stephen K

    2016-06-01

    Despite the fact that pigs are reputed to have excellent olfactory abilities, few studies have examined regions of the pig brain involved in the sense of smell. The present study provides an overview of the olfactory bulb, anterior olfactory nucleus, and piriform cortex of adult pigs using several approaches. Nissl, myelin, and Golgi stains were used to produce a general overview of the organization of the regions and confocal microscopy was employed to examine 1) projection neurons, 2) GABAergic local circuit neurons that express somatostatin, parvalbumin, vasoactive intestinal polypeptide, or calretinin, 3) neuromodulatory fibers (cholinergic and serotonergic), and 4) glia (astrocytes and microglia). The findings revealed that pig olfactory structures are quite large, highly organized and follow the general patterns observed in mammals. PMID:26936231

  15. The Pig Olfactory Brain: A Primer

    PubMed Central

    Feldman, Sanford; Osterberg, Stephen K.

    2016-01-01

    Despite the fact that pigs are reputed to have excellent olfactory abilities, few studies have examined regions of the pig brain involved in the sense of smell. The present study provides an overview of the olfactory bulb, anterior olfactory nucleus, and piriform cortex of adult pigs using several approaches. Nissl, myelin, and Golgi stains were used to produce a general overview of the organization of the regions and confocal microscopy was employed to examine 1) projection neurons, 2) GABAergic local circuit neurons that express somatostatin, parvalbumin, vasoactive intestinal polypeptide, or calretinin, 3) neuromodulatory fibers (cholinergic and serotonergic), and 4) glia (astrocytes and microglia). The findings revealed that pig olfactory structures are quite large, highly organized and follow the general patterns observed in mammals. PMID:26936231

  16. Olfactory Receptor Neuron Dysfunction in Schizophrenia

    PubMed Central

    Turetsky, Bruce I; Hahn, Chang-Gyu; Arnold, Steven E; Moberg, Paul J

    2012-01-01

    Olfactory impairments are a common feature of schizophrenia. Impairments in odor detection and odor identification are present early in the course of illness and among those at risk for the disorder. These behavioral impairments have been linked to both physiological and anatomical abnormalities in the neural substrates subserving olfaction, including relatively peripheral elements of the olfactory system. The location of olfactory receptor neurons in the nasal epithelium allows noninvasive access to these neurons in living subjects. This offers a unique opportunity to directly assess neuronal integrity in vivo in patients. The peripheral olfactory receptor neuron response to odor stimulation was assessed in 21 schizophrenia patients and 18 healthy comparison subjects. The electroolfactogram, representing the electrical depolarization of the olfactory receptor neurons, was recording following stimulation with different doses and durations of hydrogen sulfide, a pure olfactory nerve stimulant. Schizophrenia patients had abnormally large depolarization responses following odor stimulation, independent of clinical symptomatology, antipsychotic medication dosage or smoking history. Although the precise pathophysiological mechanism is unknown, this olfactory receptor neuron abnormality is consistent with several lines of evidence suggesting altered proliferation or maturation of olfactory receptor neuron cell lineages in schizophrenia. It is also consistent with emerging evidence of disruptions of cyclic AMP-mediated intracellular signaling mechanisms, and may be a marker of these disruptions. It unambiguously demonstrates that neurophysiological disturbances in schizophrenia are not limited to cortical and subcortical structures, but rather include even the most peripheral sensory neurons. PMID:18754006

  17. Olfactory receptor neuron dysfunction in schizophrenia.

    PubMed

    Turetsky, Bruce I; Hahn, Chang-Gyu; Arnold, Steven E; Moberg, Paul J

    2009-02-01

    Olfactory impairments are a common feature of schizophrenia. Impairments in odor detection and odor identification are present early in the course of illness and among those at risk for the disorder. These behavioral impairments have been linked to both physiological and anatomical abnormalities in the neural substrates subserving olfaction, including relatively peripheral elements of the olfactory system. The location of olfactory receptor neurons in the nasal epithelium allows noninvasive access to these neurons in living subjects. This offers a unique opportunity to directly assess neuronal integrity in vivo in patients. The peripheral olfactory receptor neuron response to odor stimulation was assessed in 21 schizophrenia patients and 18 healthy comparison subjects. The electroolfactogram, representing the electrical depolarization of the olfactory receptor neurons, was recording following stimulation with different doses and durations of hydrogen sulfide, a pure olfactory nerve stimulant. Schizophrenia patients had abnormally large depolarization responses following odor stimulation, independent of clinical symptomatology, antipsychotic medication dosage or smoking history. Although the precise pathophysiological mechanism is unknown, this olfactory receptor neuron abnormality is consistent with several lines of evidence suggesting altered proliferation or maturation of olfactory receptor neuron cell lineages in schizophrenia. It is also consistent with emerging evidence of disruptions of cyclic AMP-mediated intracellular signaling mechanisms, and may be a marker of these disruptions. It unambiguously demonstrates that neurophysiological disturbances in schizophrenia are not limited to cortical and subcortical structures, but rather include even the most peripheral sensory neurons. PMID:18754006

  18. Paraneoplastic syndromes in olfactory neuroblastoma

    PubMed Central

    Gabrych, Anna; Czapiewski, Piotr; Sworczak, Krzysztof

    2015-01-01

    Olfactory neuroblastoma (ONB) is a rare malignant neoplasm of sinonasal tract, derived from olfactory epithelium. Unilateral nasal obstruction, epistaxis, sinusitis, and headaches are common symptoms. Olfactory neuroblastoma shows neuroendocrine differentiation and similarly to other neuroendocrine tumors can produce several types of peptic substances and hormones. Excess production of these substances can be responsible for different types of endocrinological paraneoplastic syndromes (PNS). Moreover, besides endocrinological, in ONB may also occur neurological PNS, caused by immune cross-reactivity between tumor and normal host tissues in the nervous system. Paraneoplastic syndromes in ONB include: syndrome of inappropriate ADH secretion (SIADH), ectopic ACTH syndrome (EAS), humoral hypercalcemia of malignancy (HHM), hypertension due to catecholamine secretion by tumor, opsoclonus-myoclonus-ataxia (OMA) and paraneoplastic cerebellar degeneration. Paraneoplastic syndromes in ONB tend to have atypical features, therefore diagnosis may be difficult. In this review, we described initial symptoms, patterns of presentation, treatment and outcome of paraneoplastic syndromes in ONB, reported in the literature. PMID:26199564

  19. Monoallelic Expression of Olfactory Receptors

    PubMed Central

    Monahan, Kevin; Lomvardas, Stavros

    2016-01-01

    The sense of smell collects vital information about the environment by detecting a multitude of chemical odorants. Breadth and sensitivity are provided by a huge number of chemosensory receptor proteins, including more than 1,400 olfactory receptors (ORs). Organizing the sensory information generated by these receptors so that it can be processed and evaluated by the central nervous system is a major challenge. This challenge is overcome by monogenic and monoallelic expression of OR genes. The single OR expressed by each olfactory sensory neuron determines the neuron’s odor sensitivity and the axonal connections it will make to downstream neurons in the olfactory bulb. The expression of a single OR per neuron is accomplished by coupling a slow chromatin-mediated activation process to a fast negative-feedback signal that prevents activation of additional ORs. Singular OR activation is likely orchestrated by a network of interchromosomal enhancer interactions and large-scale changes in nuclear architecture. PMID:26359778

  20. Neuronal organization of olfactory bulb circuits

    PubMed Central

    Nagayama, Shin; Homma, Ryota; Imamura, Fumiaki

    2014-01-01

    Olfactory sensory neurons extend their axons solely to the olfactory bulb, which is dedicated to odor information processing. The olfactory bulb is divided into multiple layers, with different types of neurons found in each of the layers. Therefore, neurons in the olfactory bulb have conventionally been categorized based on the layers in which their cell bodies are found; namely, juxtaglomerular cells in the glomerular layer, tufted cells in the external plexiform layer, mitral cells in the mitral cell layer, and granule cells in the granule cell layer. More recently, numerous studies have revealed the heterogeneous nature of each of these cell types, allowing them to be further divided into subclasses based on differences in morphological, molecular, and electrophysiological properties. In addition, technical developments and advances have resulted in an increasing number of studies regarding cell types other than the conventionally categorized ones described above, including short-axon cells and adult-generated interneurons. Thus, the expanding diversity of cells in the olfactory bulb is now being acknowledged. However, our current understanding of olfactory bulb neuronal circuits is mostly based on the conventional and simplest classification of cell types. Few studies have taken neuronal diversity into account for understanding the function of the neuronal circuits in this region of the brain. This oversight may contribute to the roadblocks in developing more precise and accurate models of olfactory neuronal networks. The purpose of this review is therefore to discuss the expanse of existing work on neuronal diversity in the olfactory bulb up to this point, so as to provide an overall picture of the olfactory bulb circuit. PMID:25232305

  1. The evolutionary function of conscious information processing is revealed by its task-dependency in the olfactory system

    PubMed Central

    Keller, Andreas

    2014-01-01

    Although many responses to odorous stimuli are mediated without olfactory information being consciously processed, some olfactory behaviors require conscious information processing. I will here contrast situations in which olfactory information is processed consciously to situations in which it is processed non-consciously. This contrastive analysis reveals that conscious information processing is required when an organism is faced with tasks in which there are many behavioral options available. I therefore propose that it is the evolutionary function of conscious information processing to guide behaviors in situations in which the organism has to choose between many possible responses. PMID:24550876

  2. Expression patterns of nicotinic subunits α2, α7, α8, and β1 affect the kinetics and pharmacology of ACh-induced currents in adult bee olfactory neuropiles.

    PubMed

    Dupuis, Julien Pierre; Gauthier, Monique; Raymond-Delpech, Valérie

    2011-10-01

    Acetylcholine (ACh) is the main excitatory neurotransmitter of the insect brain, where nicotinic acetylcholine receptors (nAChRs) mediate fast cholinergic synaptic transmission. In the honeybee Apis mellifera, nAChRs are expressed in diverse structures including the primary olfactory centers of the brain, the antennal lobes (ALs) and the mushroom bodies (MBs), where they participate in olfactory information processing. To understand the nature and properties of the nAChRs involved in these processes, we performed a pharmacological and molecular characterization of nAChRs on cultured Kenyon cells of the MBs, using whole cell patch-clamp recordings combined with single-cell RT-PCR. In all cells, applications of ACh as well as nicotinic agonists such as nicotine and imidacloprid induced inward currents with fast desensitization. These currents were fully blocked by saturating doses of the antagonists α-bungarotoxin (α-BGT), dihydroxy-β-erythroidine (DHE), and methyllycaconitine (MLA) (MLA ≥ α-BGT ≥ DHE). Molecular analysis of ACh-responding cells revealed that of the 11 nicotinic receptor subunits encoded within the honeybee genome, α2, α8, and β1 subunits were expressed in adult Kenyon cells. Comparison with the expression pattern of adult AL cells revealed the supplementary presence of subunit α7, which could be responsible for the kinetic and pharmacological differences observed when comparing ACh-induced currents from AL and Kenyon cells. Together, our data demonstrate the existence of functional nAChRs on adult MB Kenyon cells that differ from nAChRs on AL cells in both their molecular composition and pharmacological properties, suggesting that changing receptor subsets could mediate different processing functions depending on the brain structure within the olfactory pathway. PMID:21734106

  3. Systemic injection of kainic acid: Gliosis in olfactory and limbic brain regions quantified with ( sup 3 H)PK 11195 binding autoradiography

    SciTech Connect

    Altar, C.A.; Baudry, M. )

    1990-09-01

    Neurodegenerative diseases may result from excessive stimulation of excitatory amino acid receptors by endogenous ligands. Because neuronal degeneration is associated with glial proliferation and hypertrophy, the degenerative changes throughout rat brain following the systemic administration of kainic acid (12 mg/kg) were mapped with quantitative autoradiography of (3H)PK 11195. This radioligand binds to a mitochondrial benzodiazepine binding site (MBBS) on microglia and astrocytes. Analysis of eight horizontal and four coronal brain levels revealed up to 16-fold increases in (3H)PK 11195 binding from 1 to 5 weeks but not 1 day after kainate injection. Increases in (3H)PK 11195 binding were predominantly in ventral limbic brain regions and olfactory projections to neocortical areas, with the olfactory cortex greater than subiculum/CA1 greater than anterior olfactory nucleus, medial thalamic nucleus, and piriform cortex greater than cingulate cortex and rostral hippocampus greater than dentate gyrus, septum, and amygdala greater than entorhinal cortex and temporal cortex. Little or no enhancement of (3H)PK 11195 binding was observed in numerous regions including the caudate-putamen, substantia nigra, nucleus accumbens, olfactory tubercle, cerebellum, thalamic nuclei, choroid plexus, medulla, parietal or occipital cortex, or pons. A 2-fold greater extent of neurodegeneration was obtained in ventral portions of the olfactory bulb, entorhinal cortex, temporal cortex, and dentate gyrus compared with the dorsal portions of these structures. The pattern of increase in (3H)PK 11195 binding closely matched the patterns of neuronal degeneration reported following parenteral kainate injection. These findings strengthen the notion that quantitative autoradiography of (3H)PK 11195 is a valuable tool to quantify the extent of neuronal degeneration.

  4. Carnosine, nerve growth factor receptor and tyrosine hydroxylase expression during the ontogeny of the rat olfactory system.

    PubMed

    Biffo, S; Martí, E; Fasolo, A

    1992-01-01

    The localizations of carnosine, nerve growth factor (NGF) receptor and tyrosine hydroxylase (TH) were studied in the embryonic and postnatal rat olfactory bulb and epithelium by means of single- and double-immunostaining methods. Tyrosine hydroxylase ontogeny was also evaluated at the mRNA level by in situ hybridization. All these molecules were expressed in the olfactory bulb but with different developmental patterns and cellular localization: carnosine immunoreactivity is seen from embryonic day 17 in primary olfactory neurons scattered in the nasal cavity and in fibres projecting from them to the olfactory bulb. Nerve growth factor-receptor immunoreactivity associated with small glial-like cells is visible in some glomeruli starting from the second day of postnatal life. At postnatal day 10 NGF-receptor immunoreactivity is extended to all glomeruli. Periglomerular neurons expressing TH mRNA and protein are present prenatally and their number sharply increases during the early postnatal development. Double-staining methods show that TH and NGF-receptor immunoreactivity do not overlap in cell bodies and processes. In addition, NGF-receptor immunoreactivity is not colocalized with carnosine. These findings definitely exclude NGF-receptor expression in periglomerular and primary olfactory neurons, suggesting that at least part of NGF-receptor expression in the olfactory bulb is associated with glial cells. In addition, they provide the first immunohistochemical data on carnosine ontogeny and confirm at the mRNA level previous studies on the ontogeny of TH protein. PMID:1376608

  5. Human olfactory lateralization requires trigeminal activation.

    PubMed

    Croy, Ilona; Schulz, Max; Blumrich, Anna; Hummel, Cornelia; Gerber, Johannes; Hummel, Thomas

    2014-09-01

    Rats are able to lateralize odors. This ability involves specialized neurons in the orbitofrontal cortex which are able to process the left, right and bilateral presentation of stimuli. However, it is not clear whether this function is preserved in humans. Humans are in general not able to differentiate whether a selective olfactory stimulant has been applied to the left or right nostril; however exceptions have been reported. Following a screening of 152 individuals with an olfactory lateralization test, we identified 19 who could lateralize odors above chance level. 15 of these "lateralizers" underwent olfactory fMRI scanning in a block design and were compared to 15 controls matched for age and sex distribution. As a result, both groups showed comparable activation of olfactory eloquent brain areas. However, subjects with lateralization ability had a significantly enhanced activation of cerebral trigeminal processing areas (somatosensory cortex, intraparietal sulcus). In contrast to controls, lateralizers furthermore exhibited no suppression in the area of the trigeminal principal sensory nucleus. An exploratory study with an olfactory change detection paradigm furthermore showed that lateralizers oriented faster towards changes in the olfactory environment. Taken together, our study suggests that the trigeminal system is activated to a higher degree by the odorous stimuli in the group of "lateralizers". We conclude that humans are not able to lateralize odors based on the olfactory input alone, but vary in the degree to which the trigeminal system is recruited. PMID:24825502

  6. Olfactory adventures of elephantine pheromones.

    PubMed

    Rasmussen, L E; Lazar, J; Greenwood, D R

    2003-02-01

    Understanding the linkage between behaviour of mammals in their natural environment and the molecular basis of their sensory modalities presents challenges to biologists. Our olfactory investigations that involve the largest extant land mammal, the elephant, offer some clues of how these events mesh in sequence. Proboscideans have developed a sophisticatedly organized society and they rank with primates and cetaceans with respect to cognitive abilities. Our studies of discrete, quantifiable pheromone-elicited behaviours demonstrate that Asian elephants utilize their olfactory senses during fundamental, life-strategy decisions, including mate choice, female bonding and male hierarchical sorting. How biologically relevant odorants traverse mucous interfaces to interact with cognate odorant receptors remains a basic question in vertebrate olfaction. We have partially tracked the molecular odour reception trail of behaviourally distinct pheromones, ( Z )-7-dodecenyl acetate and frontalin (1,5-dimethyl-6,8-dioxabicyclo[3.2.1]octane), using approaches developed for insect studies and taking advantage of the extensive, highly mucoidal olfactory and vomeronasal systems that permit detailed investigations of pheromone-binding proteins. We have combined studies of quantifiable responses and behaviours with biochemical and biophysical investigations of the properties of protein-ligand complexes, their sequential pathways and associated protein-ligand fluxes. In the delineation of these sequential integrations of behavioural, biochemical and molecular events, we have discovered novel spatial and temporal adaptations in both the main olfactory and vomeronasal systems. PMID:12546671

  7. Information Systems: An Introduction for Adult Educators.

    ERIC Educational Resources Information Center

    Caldwell, Phyllis A.

    In this paper, the author's primary focus is on a marketing information system and its potential importance for adult educators. The content is in seven sections. The first two sections briefly introduce information systems in general and their relevance for adult educators. The third section briefly describes general management information…

  8. Localization of Nav 1.7 in the normal and injured rodent olfactory system indicates a critical role in olfaction, pheromone sensing and immune function.

    PubMed

    Rupasinghe, Darshani B; Knapp, Oliver; Blomster, Linda V; Schmid, Annina B; Adams, David J; King, Glenn F; Ruitenberg, Marc J

    2012-01-01

    Loss-of-function mutations in the pore-forming α subunit of the voltage-gated sodium channel 1.7 (Nav 1.7) cause congenital indifference to pain and anosmia. We used immunohistochemical techniques to study Nav 1.7 localization in the rat olfactory system in order to better understand its role in olfaction. We confirm that Nav 1.7 is expressed on olfactory sensory axons and report its presence on vomeronasal axons, indicating an important role for Nav 1.7 in transmission of pheromonal cues. Following neuroepithelial injury, Nav 1.7 was transiently expressed by cells of monocytic lineage. These findings support an emerging role for Nav 1.7 in immune function. This sodium channel may provide an important pharmacological target for treatment of inflammatory injury and inflammatory pain syndromes. PMID:22622154

  9. Olfactory Classical Conditioning in Neonates

    PubMed Central

    Sullivan, Regina M.; Taborsky-Barba, Suzanne; Mendoza, Raffael; Itano, Alison; Leon, Michael; Cotman, Carl W.; Payne, Terrence F.; Lott, Ira

    2007-01-01

    One-day-old, awake infants underwent an olfactory classical conditioning procedure to assess associative learning within the olfactory system of newborns. Experimental infants received ten 30-second pairings of a novel olfactory conditioned stimulus (a citrus odor of neutral value) and tactile stimulation provided by stroking as the reinforcing unconditioned stimulus (a stimulus with positive properties). Control babies received only the odor, only the stroking, or the stroking followed by the odor presentation. The next day, all infants, in either the awake or sleep state, were given five 30-second presentations of the odor. Results were analyzed from video tapes scored by an observer unaware of the infants’ training condition. The results indicate that only those infants who received the forward pairings of the odor and stroking exhibited conditioned responding (head turning toward the odor) to the citrus odor. The performance of the conditioned response was not affected by the state of the baby during testing, because both awake and sleeping infants exhibited conditioned responses. Furthermore, the expression of the conditioned response was odor specific; a novel floral odor presented during testing did not elicit conditioned responses in the experimental babies. These results suggest that complex associative olfactory learning is seen in newborns within the first 48 hours of life. These baseline findings may serve as normative data against which observation from neonates at risk for neurological sequelae may be compared. PMID:2011429

  10. An odor detection system based on automatically trained mice by relative go no-go olfactory operant conditioning

    PubMed Central

    He, Jing; Wei, JingKuan; Rizak, Joshua D.; Chen, YanMei; Wang, JianHong; Hu, XinTian; Ma, YuanYe

    2015-01-01

    Odor detection applications are needed by human societies in various circumstances. Rodent offers unique advantages in developing biologic odor detection systems. This report outlines a novel apparatus designed to train maximum 5 mice automatically to detect odors using a new olfactory, relative go no-go, operant conditioning paradigm. The new paradigm offers the chance to measure real-time reliability of individual animal’s detection behavior with changing responses. All of 15 water-deprivation mice were able to learn to respond to unpredictable delivering of the target odor with higher touch frequencies via a touch sensor. The mice were continually trained with decreasing concentrations of the target odor (n-butanol), the average correct percent significantly dropped when training at 0.01% solution concentration; the alarm algorithm showed excellent recognition of odor detection behavior of qualified mice group through training. Then, the alarm algorithm was repeatedly tested against simulated scenario for 4 blocks. The mice acted comparable to the training period during the tests, and provided total of 58 warnings for the target odor out of 59 random deliveries and 0 false alarm. The results suggest this odor detection method is promising for further development in respect to various types of odor detection applications. PMID:25944031

  11. An odor detection system based on automatically trained mice by relative go no-go olfactory operant conditioning.

    PubMed

    He, Jing; Wei, JingKuan; Rizak, Joshua D; Chen, YanMei; Wang, JianHong; Hu, XinTian; Ma, YuanYe

    2015-01-01

    Odor detection applications are needed by human societies in various circumstances. Rodent offers unique advantages in developing biologic odor detection systems. This report outlines a novel apparatus designed to train maximum 5 mice automatically to detect odors using a new olfactory, relative go no-go, operant conditioning paradigm. The new paradigm offers the chance to measure real-time reliability of individual animal's detection behavior with changing responses. All of 15 water-deprivation mice were able to learn to respond to unpredictable delivering of the target odor with higher touch frequencies via a touch sensor. The mice were continually trained with decreasing concentrations of the target odor (n-butanol), the average correct percent significantly dropped when training at 0.01% solution concentration; the alarm algorithm showed excellent recognition of odor detection behavior of qualified mice group through training. Then, the alarm algorithm was repeatedly tested against simulated scenario for 4 blocks. The mice acted comparable to the training period during the tests, and provided total of 58 warnings for the target odor out of 59 random deliveries and 0 false alarm. The results suggest this odor detection method is promising for further development in respect to various types of odor detection applications. PMID:25944031

  12. Effects of handedness on olfactory event-related potentials in a simple olfactory task.

    PubMed

    Gottschlich, Marie; Hummel, Thomas

    2015-06-01

    The purpose of the present study was to re-investigate the influence of handedness on simple olfactory tasks to further clarify the role of handedness in chemical senses. Similar to language and other sensory systems, effects of handedness should be expected. Young, healthy subjects participated in this study, including 24 left-handers and 24 right-handers, with no indication of any major nasal or health problems. The two groups did not differ in terms of sex and age (14 women and 10 men in each group). They had a mean age of 24.0 years. Olfactory event-related potentials were recorded after left or right olfactory stimulation with the rose-like odor phenyl ethyl alcohol (PEA) or the smell of rotten eggs (hydrogen sulfide, H2S). Results suggested that handedness has no major influence on amplitude or latency of olfactory event-related potentials when it comes to simple olfactory tasks. PMID:26030037

  13. Histochemical and ultrastructural analyses of the lubrication systems in the olfactory organs of soft-shelled turtle

    PubMed Central

    NAKAMUTA, Shoko; YOKOSUKA, Makoto; TANIGUCHI, Kazumi; YAMAMOTO, Yoshio; NAKAMUTA, Nobuaki

    2016-01-01

    In general, the nasal cavity of turtles is divided into two chambers: the upper chamber, lined with the olfactory epithelium containing ciliated olfactory receptor cells, and the lower chamber, lined with the vomeronasal epithelium containing microvillous receptor cells. In the nasal cavity of soft-shelled turtles, however, differences between the upper and lower chamber epithelia are unclear due to the presence of ciliated receptor cells in both epithelia. In the olfactory organ of vertebrates, the surface of sensory epithelium is covered with secretory products of associated glands and supporting cells, playing important roles in the olfaction by dissolving odorants and transporting them to the olfactory receptors. Here, the associated glands and supporting cells in the olfactory organ of soft-shelled turtles were analyzed histochemically and ultrastructurally. The upper chamber epithelium possessed associated glands, constituted by cells containing serous secretory granules; whereas, the lower chamber epithelium did not. In the upper chamber epithelium, secretory granules filled the supranuclear region of supporting cells, while most of the granules were distributed near the free border of supporting cells in the lower chamber epithelium. The secretory granules in the supporting cells of both epithelia were seromucous, but alcian blue stained them differently from each other. In addition, distinct expression of carbohydrates was suggested by the differences in lectin binding. These data indicate the quantitative and qualitative differences in the secretory properties between the upper and lower chamber epithelia, suggesting their distinct roles in the olfaction. PMID:26782135

  14. Histochemical and ultrastructural analyses of the lubrication systems in the olfactory organs of soft-shelled turtle.

    PubMed

    Nakamuta, Shoko; Yokosuka, Makoto; Taniguchi, Kazumi; Yamamoto, Yoshio; Nakamuta, Nobuaki

    2016-06-01

    In general, the nasal cavity of turtles is divided into two chambers: the upper chamber, lined with the olfactory epithelium containing ciliated olfactory receptor cells, and the lower chamber, lined with the vomeronasal epithelium containing microvillous receptor cells. In the nasal cavity of soft-shelled turtles, however, differences between the upper and lower chamber epithelia are unclear due to the presence of ciliated receptor cells in both epithelia. In the olfactory organ of vertebrates, the surface of sensory epithelium is covered with secretory products of associated glands and supporting cells, playing important roles in the olfaction by dissolving odorants and transporting them to the olfactory receptors. Here, the associated glands and supporting cells in the olfactory organ of soft-shelled turtles were analyzed histochemically and ultrastructurally. The upper chamber epithelium possessed associated glands, constituted by cells containing serous secretory granules; whereas, the lower chamber epithelium did not. In the upper chamber epithelium, secretory granules filled the supranuclear region of supporting cells, while most of the granules were distributed near the free border of supporting cells in the lower chamber epithelium. The secretory granules in the supporting cells of both epithelia were seromucous, but alcian blue stained them differently from each other. In addition, distinct expression of carbohydrates was suggested by the differences in lectin binding. These data indicate the quantitative and qualitative differences in the secretory properties between the upper and lower chamber epithelia, suggesting their distinct roles in the olfaction. PMID:26782135

  15. Olfactory and erectile dysfunction association in smoking and non-smoking men.

    PubMed

    Özmen, Süay; Dülger, Seyhan; Çoban, Soner; Özmen, Ömer Afşın; Güzelsoy, Muhammed; Dikiş, Özlem Şengören; Akdeniz, Önder

    2016-06-01

    The studies evaluating the effect of smoking on olfaction reveals opposite results. In vitro and animal studies and epidemiological evidence from volunteers and patients, demonstrated the association between olfaction and erectile functions. In smoking man the reduction of olfactory acuity could adversely affect sexuality. The aim of the present study was to investigate the relationship between erectile dysfunction (ED) and olfactory dysfunction (OD) by comparing a group of healthy adult men with a group of smoking adult men. This prospective study involved 62 volunteers, who were recruited and divided into two groups; one consisted of 35 smoking adult men, and the other included 27 healthy non-smoking men. All participants in both groups were examined in detail for any condition with the potential to cause OD. They all had a normal genitourinary system suffered from no circulatory diseases, diabetes mellitus, hypertension, coronary artery disease nor hyperlipidemia; they had no history of medication affecting genitourinary system. Butanol threshold test and sniffin' stick® (Burghart, Wedel; Germany) screening test was used to asses olfactory functions in both groups. Participants' sexual desire was assessed using an International Index of Erectile Function (IIEF-5) scale. The means of sniffin' sticks scores, butanol threshold scores and IIEF-5 scores were statistically higher in non-smoking group. Butanol threshold scores and sniffin' sticks scores are correlated statistically with IIEF-5 in non-smoking and smoking groups. This study found an association between olfaction and erectile function in smoking and non-smoking men. As far as we know this study is the third published study to show the relationship olfactory and erectile function. In the future studies electrophysiological olfactory methods could be used to confirm in large cohorts the results obtained by the psychophysical approach. PMID:27037193

  16. Olfactory assessment using the NIH Toolbox.

    PubMed

    Dalton, Pamela; Doty, Richard L; Murphy, Claire; Frank, Robert; Hoffman, Howard J; Maute, Christopher; Kallen, Michael A; Slotkin, Jerry

    2013-03-12

    The human olfactory system provides us with information about our environment that is critical to our physical and psychological well-being. Individuals can vary widely in their ability to detect, recognize, and identify odors, but still be within the range of normal function. Although several standardized tests of odor identification are available, few specifically address the issues in testing very young children, most of whom are likely to be unfamiliar with many of the odor stimuli used in adult tests and have limited ability to read and identify labels to select among choices. Based on the format of the San Diego Odor Identification Test and the delivery system of the University of Pennsylvania Smell Identification Test, we developed 2 versions of an odor identification test using standardized odor stimuli in a scratch-and-sniff format in which participants match 5 (children) or 9 (adults) odors to pictures representing the odor source. Results from normative testing and validation showed that for most participants, the test could be completed in 5 minutes or less and that the poorer performance among the youngest children and the elderly was consistent with data from tests with larger numbers of items. Expanding on the pediatric version of the test with adult-specific and public health-relevant odors increased the ecological validity of the test and facilitated comparisons of intraindividual performance across developmental stages. PMID:23479541

  17. Olfactory assessment using the NIH Toolbox

    PubMed Central

    Doty, Richard L.; Murphy, Claire; Frank, Robert; Hoffman, Howard J.; Maute, Christopher; Kallen, Michael A.; Slotkin, Jerry

    2013-01-01

    The human olfactory system provides us with information about our environment that is critical to our physical and psychological well-being. Individuals can vary widely in their ability to detect, recognize, and identify odors, but still be within the range of normal function. Although several standardized tests of odor identification are available, few specifically address the issues in testing very young children, most of whom are likely to be unfamiliar with many of the odor stimuli used in adult tests and have limited ability to read and identify labels to select among choices. Based on the format of the San Diego Odor Identification Test and the delivery system of the University of Pennsylvania Smell Identification Test, we developed 2 versions of an odor identification test using standardized odor stimuli in a scratch-and-sniff format in which participants match 5 (children) or 9 (adults) odors to pictures representing the odor source. Results from normative testing and validation showed that for most participants, the test could be completed in 5 minutes or less and that the poorer performance among the youngest children and the elderly was consistent with data from tests with larger numbers of items. Expanding on the pediatric version of the test with adult-specific and public health–relevant odors increased the ecological validity of the test and facilitated comparisons of intraindividual performance across developmental stages. PMID:23479541

  18. Distribution of carnosine-like peptides in the nervous system of developing and adult zebrafish (Danio rerio) and embryonic effects of chronic carnosine exposure

    PubMed Central

    Azher, Seema; Margolis, Frank L.; Patel, Kamakshi; Mousa, Ahmad; Majid, Arshad

    2013-01-01

    Carnosine-like peptides (carnosine-LP) are a family of histidine derivatives that are present in the nervous system of various species and that exhibit antioxidant, anti-matrix-metalloproteinase, anti-excitotoxic, and free-radical scavenging properties. They are also neuroprotective in animal models of cerebral ischemia. Although the function of carnosine-LP is largely unknown, the hypothesis has been advanced that they play a role in the developing nervous system. Since the zebrafish is an excellent vertebrate model for studying development and disease, we have examined the distribution pattern of carnosine-LP in the adult and developing zebrafish. In the adult, immunoreactivity for carnosine-LP is specifically concentrated in sensory neurons and non-sensory cells of the olfactory epithelium, the olfactory nerve, and the olfactory bulb. Robust staining has also been observed in the retinal outer nuclear layer and the corneal epithelium. Developmental studies have revealed immunostaining for carnosine-LP as early as 18 h, 24 h, and 7 days post-fertilization in, respectively, the olfactory, corneal, and retinal primordia. These data suggest that carnosine-LP are involved in olfactory and visual function. We have also investigated the effects of chronic (7 days) exposure to carnosine on embryonic development and show that 0.01 μM to 10 mM concentrations of carnosine do not elicit significant deleterious effects. Conversely, treatment with 100 mM carnosine results in developmental delay and compromised larval survival. These results indicate that, at lower concentrations, exogenously administered carnosine can be used to explore the role of carnosine in development and developmental disorders of the nervous system. PMID:19440736

  19. Nested expression domains for odorant receptors in zebrafish olfactory epithelium.

    PubMed

    Weth, F; Nadler, W; Korsching, S

    1996-11-12

    The mapping of high-dimensional olfactory stimuli onto the two-dimensional surface of the nasal sensory epithelium constitutes the first step in the neuronal encoding of olfactory input. We have used zebrafish as a model system to analyze the spatial distribution of odorant receptor molecules in the olfactory epithelium by quantitative in situ hybridization. To this end, we have cloned 10 very divergent zebrafish odorant receptor molecules by PCR. Individual genes are expressed in sparse olfactory receptor neurons. Analysis of the position of labeled cells in a simplified coordinate system revealed three concentric, albeit overlapping, expression domains for the four odorant receptors analyzed in detail. Such regionalized expression should result in a corresponding segregation of functional response properties. This might represent the first step of spatial encoding of olfactory input or be essential for the development of the olfactory system. PMID:8917589

  20. Inhibition of Inflammation-Associated Olfactory Loss by Etanercept in an Inducible Olfactory Inflammation Mouse Model

    PubMed Central

    Jung, Yong Gi; Lane, Andrew P.

    2016-01-01

    Objective To determine the effect of a soluble human tumor necrosis factor alpha (TNF-α) receptor blocker (Etanercept) on an inducible olfactory inflammation (IOI) mouse model Study Design An in vivo study using a transgenic mouse model Setting Research laboratory Subjects and Methods To study the impact of chronic inflammation on the olfactory system, a transgenic mouse model of chronic rhinosinusitis (CRS)-associated olfactory loss was utilized (IOI mouse), expressing TNF-α in a temporally-controlled fashion specifically within the olfactory epithelium. In one group of mice (n=4), Etanercept was injected intraperitoneally (100 µg/dose, 3 times/week) concurrent with a 2-week period of TNF-α expression. A second group of mice (n=2) underwent induction of TNF-α expression for 8 weeks, with Etanercept treatment administered during the final 2 weeks of inflammation. Olfactory function was assayed by elecro-olfactogram (EOG), and olfactory tissue was processed for histology and immunohistochemical staining. Each group was compared with equal number of control group. Results Compared to non-treated IOI mice, Etanercept -treated IOI mice showed significantly improved EOG responses after 2 weeks (p<0.001). After 8 weeks of induced inflammation, there was massive loss of olfactory epithelium and no EOG response in non-treated IOI mice. However, in Etanercept - treated mice, regeneration of olfactory epithelium was observed. Conclusion Concomitant administration of Etanercept in IOI mice results in interruption of TNF-α-induced olfactory loss and induction of neuroepithelial regeneration. This demonstrates that Etanercept has potential utility as a tool for elucidating the role of TNF-α in other olfactory inflammation models. PMID:26932943

  1. Methods to measure olfactory behavior in mice

    PubMed Central

    Zou, Junhui; Wang, Wenbin; Pan, Yung-Wei; Lu, Song; Xia, Zhengui

    2015-01-01

    Mice rely on the sense of olfaction to detect food sources, recognize social and mating partners, and avoid predators. Many behaviors of mice including learning and memory, social interaction, fear, and anxiety are closely associated with their function of olfaction, and behavior tasks designed to evaluate those brain functions may use odors as cues. Accurate assessment of olfaction is not only essential for the study of olfactory system but also critical for proper interpretation of various mouse behaviors especially learning and memory, emotionality and affect, and sociality. Here we describe a series of behavior experiments that offer multidimensional and quantitative assessments for mouse’s olfactory function, including olfactory habituation, discrimination, odor preference, odor detection sensitivity, and olfactory memory, to both social and nonsocial odors. PMID:25645244

  2. Effects of total saponins of Panax notoginseng on immature neuroblasts in the adult olfactory bulb following global cerebral ischemia/reperfusion.

    PubMed

    He, Xu; Deng, Feng-Jun; Ge, Jin-Wen; Yan, Xiao-Xin; Pan, Ai-Hua; Li, Zhi-Yuan

    2015-09-01

    The main active components extracted from Panax notoginseng are total saponins. They have been shown to inhibit platelet aggregation, increase cerebral blood flow, improve neurological behavior, decrease infarct volume and promote proliferation and differentiation of neural stem cells in the hippocampus and lateral ventricles. However, there is a lack of studies on whether total saponins of Panax notoginseng have potential benefits on immature neuroblasts in the olfactory bulb following ischemia and reperfusion. This study established a rat model of global cerebral ischemia and reperfusion using four-vessel occlusion. Rats were administered total saponins of Panax notoginseng at 75 mg/kg intraperitoneally 30 minutes after ischemia then once a day, for either 7 or 14 days. Total saponins of Panax notoginseng enhanced the number of doublecortin (DCX)(+) neural progenitor cells and increased co-localization of DCX with neuronal nuclei and phosphorylated cAMP response element-binding/DCX(+) neural progenitor cells in the olfactory bulb at 7 and 14 days post ischemia. These findings indicate that following global brain ischemia/reperfusion, total saponins of Panax notoginseng promote differentiation of DCX(+) cells expressing immature neuroblasts in the olfactory bulb and the underlying mechanism is related to the activation of the signaling pathway of cyclic adenosine monophosphate response element binding protein. PMID:26604906

  3. Anatomical specializations for enhanced olfactory sensitivity in kiwi, Apteryx mantelli.

    PubMed

    Corfield, Jeremy R; Eisthen, Heather L; Iwaniuk, Andrew N; Parsons, Stuart

    2014-01-01

    The ability to function in a nocturnal and ground-dwelling niche requires a unique set of sensory specializations. The New Zealand kiwi has shifted away from vision, instead relying on auditory and tactile stimuli to function in its environment and locate prey. Behavioral evidence suggests that kiwi also rely on their sense of smell, using olfactory cues in foraging and possibly also in communication and social interactions. Anatomical studies appear to support these observations: the olfactory bulbs and tubercles have been suggested to be large in the kiwi relative to other birds, although the extent of this enlargement is poorly understood. In this study, we examine the size of the olfactory bulbs in kiwi and compare them with 55 other bird species, including emus, ostriches, rheas, tinamous, and 2 extinct species of moa (Dinornithiformes). We also examine the cytoarchitecture of the olfactory bulbs and olfactory epithelium to determine if any neural specializations beyond size are present that would increase olfactory acuity. Kiwi were a clear outlier in our analysis, with olfactory bulbs that are proportionately larger than those of any other bird in this study. Emus, close relatives of the kiwi, also had a relative enlargement of the olfactory bulbs, possibly supporting a phylogenetic link to well-developed olfaction. The olfactory bulbs in kiwi are almost in direct contact with the olfactory epithelium, which is indeed well developed and complex, with olfactory receptor cells occupying a large percentage of the epithelium. The anatomy of the kiwi olfactory system supports an enhancement for olfactory sensitivities, which is undoubtedly associated with their unique nocturnal niche. PMID:25376305

  4. Increased doublecortin (DCX) expression and incidence of DCX-immunoreactive multipolar cells in the subventricular zone-olfactory bulb system of suicides

    PubMed Central

    Maheu, Marissa E.; Devorak, Julia; Freibauer, Alexander; Davoli, Maria Antonietta; Turecki, Gustavo; Mechawar, Naguib

    2015-01-01

    Postmortem studies have confirmed the occurrence of adult hippocampal neurogenesis in humans and implicated this process in antidepressant response, yet neurogenesis in other regions remains to be examined in the context of depression. Here we assess the extent of subventricular zone-olfactory bulb (SVZ-OB) neurogenesis in adult humans having died by suicide. Protein expression of proliferative and neurogenic markers Sox2, proliferating cell nuclear antigen, and doublecortin (DCX) were examined in postmortem SVZ and OB samples from depressed suicides and matched sudden-death controls. In the SVZ, DCX-immunoreactive (IR) cells displayed phenotypes typical of progenitors, whereas in the olfactory tract (OT), they were multipolar with variable size and morphologies suggestive of differentiating cells. DCX expression was significantly increased in the OB of suicides, whereas SVZ DCX expression was higher among unmedicated, but not antidepressant-treated, suicides. Although very few DCX-IR cells were present in the control OT, they were considerably more common in suicides and correlated with OB DCX levels. Suicides also displayed higher DCX-IR process volumes. These results support the notion that OB neurogenesis is minimal in adult humans. They further raise the possibility that the differentiation and migration of SVZ-derived neuroblasts may be altered in unmedicated suicides, leading to an accumulation of ectopically differentiating cells in the OT. Normal SVZ DCX expression among suicides receiving antidepressants suggests a potentially novel mode of action of antidepressant medication. Given the modest group sizes and rarity of DCX-IR cells assessed here, a larger-scale characterization will be required before firm conclusions can be made regarding the identity of these cells. PMID:26082689

  5. Investigation of olfactory function in a Panx1 knock out mouse model.

    PubMed

    Kurtenbach, Stefan; Whyte-Fagundes, Paige; Gelis, Lian; Kurtenbach, Sarah; Brazil, Emerson; Zoidl, Christiane; Hatt, Hanns; Shestopalov, Valery I; Zoidl, Georg

    2014-01-01

    Pannexin 1 (Panx1), the most extensively investigated member of a channel-forming protein family, is able to form pores conducting molecules up to 1.5 kDa, like ATP, upon activation. In the olfactory epithelium (OE), ATP modulates olfactory responsiveness and plays a role in proliferation and differentiation of olfactory sensory neurons (OSNs). This process continuously takes place in the OE, as neurons are replaced throughout the whole lifespan. The recent discovery of Panx1 expression in the OE raises the question whether Panx1 mediates ATP release responsible for modulating chemosensory function. In this study, we analyzed pannexin expression in the OE and a possible role of Panx1 in olfactory function using a Panx1(-/-) mouse line with a global ablation of Panx1. This mouse model has been previously used to investigate Panx1 functions in the retina and adult hippocampus. Here, qPCR, in-situ hybridization, and immunohistochemistry (IHC) demonstrated that Panx1 is expressed in axon bundles deriving from sensory neurons of the OE. The localization, distribution, and expression of major olfactory signal transduction proteins were not significantly altered in Panx1(-/-) mice. Further, functional analysis of Panx1(-/-) animals does not reveal any major impairment in odor perception, indicated by electroolfactogram (EOG) measurements and behavioral testing. However, ATP release evoked by potassium gluconate application was reduced in Panx1(-/-) mice. This result is consistent with previous reports on ATP release in isolated erythrocytes and spinal or lumbar cord preparations from Panx1(-/-) mice, suggesting that Panx1 is one of several alternative pathways to release ATP in the olfactory system. PMID:25309319

  6. Investigation of olfactory function in a Panx1 knock out mouse model

    PubMed Central

    Kurtenbach, Stefan; Whyte-Fagundes, Paige; Gelis, Lian; Kurtenbach, Sarah; Brazil, Émerson; Zoidl, Christiane; Hatt, Hanns; Shestopalov, Valery I.; Zoidl, Georg

    2014-01-01

    Pannexin 1 (Panx1), the most extensively investigated member of a channel-forming protein family, is able to form pores conducting molecules up to 1.5 kDa, like ATP, upon activation. In the olfactory epithelium (OE), ATP modulates olfactory responsiveness and plays a role in proliferation and differentiation of olfactory sensory neurons (OSNs). This process continuously takes place in the OE, as neurons are replaced throughout the whole lifespan. The recent discovery of Panx1 expression in the OE raises the question whether Panx1 mediates ATP release responsible for modulating chemosensory function. In this study, we analyzed pannexin expression in the OE and a possible role of Panx1 in olfactory function using a Panx1−/− mouse line with a global ablation of Panx1. This mouse model has been previously used to investigate Panx1 functions in the retina and adult hippocampus. Here, qPCR, in-situ hybridization, and immunohistochemistry (IHC) demonstrated that Panx1 is expressed in axon bundles deriving from sensory neurons of the OE. The localization, distribution, and expression of major olfactory signal transduction proteins were not significantly altered in Panx1−/− mice. Further, functional analysis of Panx1−/− animals does not reveal any major impairment in odor perception, indicated by electroolfactogram (EOG) measurements and behavioral testing. However, ATP release evoked by potassium gluconate application was reduced in Panx1−/− mice. This result is consistent with previous reports on ATP release in isolated erythrocytes and spinal or lumbar cord preparations from Panx1−/− mice, suggesting that Panx1 is one of several alternative pathways to release ATP in the olfactory system. PMID:25309319

  7. Posttraumatic olfactory dysfunction.

    PubMed

    Coelho, Daniel H; Costanzo, Richard M

    2016-04-01

    Impairment of smell may occur following injury to any portion of the olfactory tract, from nasal cavity to brain. A thorough understanding of the anatomy and pathophysiology combined with comprehensively obtained history, physical exam, olfactory testing, and neuroimaging may help to identify the mechanism of dysfunction and suggest possible treatments. Although most olfactory deficits are neuronal mediated and therefore currently unable to be corrected, promising technology may provide novel treatment options for those most affected. Until that day, patient counseling with compensatory strategies and reassurance is essential for the maintenance of safety and QoL in this unique and challenging patient population. PMID:26441369

  8. Ultrastructural study of the primary olfactory pathway in Macaca fascicularis.

    PubMed

    Herrera, Loren P; Casas, Carlos E; Bates, Margaret L; Guest, James D

    2005-08-01

    Olfactory ensheathing glial cells (OEGs) interact with a wide repertoire of cell types and support extension of olfactory axons (OAs) within the olfactory pathway. OEGs are thought to exclude OAs from contact with all other cells between the olfactory epithelium and the glomerulus of the olfactory bulb. These properties have lead to testing to determine whether OEGs support axonal growth following transplantation. The cellular interactions of transplanted OEGs will probably resemble those that occur within the normal pathway where interactions between OEGs and fibroblasts are prominent. No previous primate studies have focused on these interactions, knowledge of which is important if clinical application is envisioned. We describe the detailed intercellular interactions of OAs with supporting cells throughout the olfactory epithelium, the lamina propria, the fila olfactoria, and the olfactory nerve layer by using transmission electron microscopy in adult Macaca fascicularis. Patterns of OEG ensheathment and variations of the endo- and perineurium formed by olfactory nerve fibroblasts are described. OAs mainly interacted with horizontal basal cells, OEGs, and astrocytes. At both transitional ends of the pathway seamless intercellular interactions were observed, and fibroblast processes were absent. Perineurial cells produced surface basal lamina; however, endoneurial, epineurial, and meningeal fibroblasts did not. Perineurial cells contained intermediate filaments and were distinct from other fibroblasts and meningeal cells. OAs had direct contacts with astrocytes near the glia limitans. The properties of OEGs differed depending on whether astrocytic or fibroblastic processes were present. This indicates the importance of the cellular milieu in the structure and function of OEGs in primates. PMID:15973683

  9. Neuropeptide Y Enhances Olfactory Mucosa Responses to Odorant in Hungry Rats

    PubMed Central

    Negroni, Julia; Meunier, Nicolas; Monnerie, Régine; Salesse, Roland; Baly, Christine; Caillol, Monique; Congar, Patrice

    2012-01-01

    Neuropeptide Y (NPY) plays an important role in regulating appetite and hunger in vertebrates. In the hypothalamus, NPY stimulates food intake under the control of the nutritional status. Previous studies have shown the presence of NPY and receptors in rodent olfactory system, and suggested a neuroproliferative role. Interestingly, NPY was also shown to directly modulate olfactory responses evoked by a food-related odorant in hungry axolotls. We have recently demonstrated that another nutritional cue, insulin, modulates the odorant responses of the rat olfactory mucosa (OM). Therefore, the aim of the present study was to investigate the potential effect of NPY on rat OM responses to odorants, in relation to the animal's nutritional state. We measured the potential NPY modulation of OM responses to odorant, using electro-olfactogram (EOG) recordings, in fed and fasted adult rats. NPY application significantly and transiently increased EOG amplitudes in fasted but not in fed rats. The effects of specific NPY-receptor agonists were similarly quantified, showing that NPY operated mainly through Y1 receptors. These receptors appeared as heterogeneously expressed by olfactory neurons in the OM, and western blot analysis showed that they were overexpressed in fasted rats. These data provide the first evidence that NPY modulates the initial events of odorant detection in the rat OM. Because this modulation depends on the nutritional status of the animal, and is ascribed to NPY, the most potent orexigenic peptide in the central nervous system, it evidences a strong supplementary physiological link between olfaction and nutritional processes. PMID:23024812

  10. The role of the olfactory recess in olfactory airflow.

    PubMed

    Eiting, Thomas P; Smith, Timothy D; Perot, J Blair; Dumont, Elizabeth R

    2014-05-15

    The olfactory recess - a blind pocket at the back of the nasal airway - is thought to play an important role in mammalian olfaction by sequestering air outside of the main airstream, thus giving odorants time to re-circulate. Several studies have shown that species with large olfactory recesses tend to have a well-developed sense of smell. However, no study has investigated how the size of the olfactory recess relates to air circulation near the olfactory epithelium. Here we used a computer model of the nasal cavity from a bat (Carollia perspicillata) to test the hypothesis that a larger olfactory recess improves olfactory airflow. We predicted that during inhalation, models with an enlarged olfactory recess would have slower rates of flow through the olfactory region (i.e. the olfactory recess plus airspace around the olfactory epithelium), while during exhalation these models would have little to no flow through the olfactory recess. To test these predictions, we experimentally modified the size of the olfactory recess while holding the rest of the morphology constant. During inhalation, we found that an enlarged olfactory recess resulted in lower rates of flow in the olfactory region. Upon exhalation, air flowed through the olfactory recess at a lower rate in the model with an enlarged olfactory recess. Taken together, these results indicate that an enlarged olfactory recess improves olfactory airflow during both inhalation and exhalation. These findings add to our growing understanding of how the morphology of the nasal cavity may relate to function in this understudied region of the skull. PMID:24577441

  11. Sleep and olfactory cortical plasticity

    PubMed Central

    Barnes, Dylan C.; Wilson, Donald A.

    2014-01-01

    In many systems, sleep plays a vital role in memory consolidation and synaptic homeostasis. These processes together help store information of biological significance and reset synaptic circuits to facilitate acquisition of information in the future. In this review, we describe recent evidence of sleep-dependent changes in olfactory system structure and function which contribute to odor memory and perception. During slow-wave sleep, the piriform cortex becomes hypo-responsive to odor stimulation and instead displays sharp-wave activity similar to that observed within the hippocampal formation. Furthermore, the functional connectivity between the piriform cortex and other cortical and limbic regions is enhanced during slow-wave sleep compared to waking. This combination of conditions may allow odor memory consolidation to occur during a state of reduced external interference and facilitate association of odor memories with stored hedonic and contextual cues. Evidence consistent with sleep-dependent odor replay within olfactory cortical circuits is presented. These data suggest that both the strength and precision of odor memories is sleep-dependent. The work further emphasizes the critical role of synaptic plasticity and memory in not only odor memory but also basic odor perception. The work also suggests a possible link between sleep disturbances that are frequently co-morbid with a wide range of pathologies including Alzheimer’s disease, schizophrenia and depression and the known olfactory impairments associated with those disorders. PMID:24795585

  12. A possible role for the immune system in adult neurogenesis: new insights from an invertebrate model.

    PubMed

    Harzsch, Steffen; von Bohlen Und Halbach, Oliver

    2016-04-01

    Persistent neurogenesis in the adult brain of both vertebrates and invertebrates was previously considered to be driven by self-renewing neuronal stem cells of ectodermal origin. Recent findings in an invertebrate model challenge this view and instead provide evidence for a recruitment of neuronal precursors from a non-neuronal source. In the brain of adult crayfish, a neurogenic niche was identified that contributes progeny to the adult central olfactory pathway. The niche may function in attracting cells from the hemolymph and transforming them into cells with a neuronal fate. This finding implies that the first-generation neuronal precursors located in the crayfish neurogenic niche are not self-renewing. Evidence is summarized in support of a critical re-evaluation of long-term self-renewal of mammalian neuronal stem cells. Latest findings suggest that a tight link between the immune system and the system driving adult neurogenesis may not only exist in the crayfish but also in mammals. PMID:26739123

  13. The development of the olfactory organs in newly hatched monotremes and neonate marsupials

    PubMed Central

    Schneider, Nanette Yvette

    2011-01-01

    Olfactory cues are thought to play a crucial role in the detection of the milk source at birth in mammals. It has been shown that a marsupial, the tammar wallaby, can detect olfactory cues from its mother's pouch at birth. This study investigates whether the main olfactory and accessory olfactory system are similarly well developed in other marsupials and monotremes at birth/hatching as in the tammar. Sections of the head of various marsupial and two monotreme species were investigated by light microscopy. Both olfactory systems were less well developed in the kowari and Eastern quoll. No olfactory or vomeronasal or terminal nerves could be observed; the main olfactory bulb (MOB) had only two layers while no accessory olfactory bulb or ganglion terminale were visible. All other investigated marsupials and monotremes showed further developed olfactory systems with olfactory, vomeronasal and terminal nerves, a three-layered MOB, and in the marsupials a prominent ganglion terminale. The main olfactory system was further developed than the accessory olfactory system in all species investigated. The olfactory systems were the least developed in species in which the mother's birth position removed most of the difficulty in reaching the teat, placing the neonate directly in the pouch. In monotremes they were the furthest developed as Bowman glands were found underlying the main olfactory epithelium. This may reflect the need to locate the milk field each time they drink as they cannot permanently attach to it, unlike therian mammals. While it still needs to be determined how an odour signal could be further processed in the brain, this study suggests that marsupials and monotremes possess well enough developed olfactory systems to be able to detect an odour cue from the mammary area at birth/hatching. It is therefore likely that neonate marsupials and newly hatched monotremes find their way to the milk source using olfactory cues, as has been previously suggested for the

  14. The development of the olfactory organs in newly hatched monotremes and neonate marsupials.

    PubMed

    Schneider, Nanette Yvette

    2011-08-01

    Olfactory cues are thought to play a crucial role in the detection of the milk source at birth in mammals. It has been shown that a marsupial, the tammar wallaby, can detect olfactory cues from its mother's pouch at birth. This study investigates whether the main olfactory and accessory olfactory system are similarly well developed in other marsupials and monotremes at birth/hatching as in the tammar. Sections of the head of various marsupial and two monotreme species were investigated by light microscopy. Both olfactory systems were less well developed in the kowari and Eastern quoll. No olfactory or vomeronasal or terminal nerves could be observed; the main olfactory bulb (MOB) had only two layers while no accessory olfactory bulb or ganglion terminale were visible. All other investigated marsupials and monotremes showed further developed olfactory systems with olfactory, vomeronasal and terminal nerves, a three-layered MOB, and in the marsupials a prominent ganglion terminale. The main olfactory system was further developed than the accessory olfactory system in all species investigated. The olfactory systems were the least developed in species in which the mother's birth position removed most of the difficulty in reaching the teat, placing the neonate directly in the pouch. In monotremes they were the furthest developed as Bowman glands were found underlying the main olfactory epithelium. This may reflect the need to locate the milk field each time they drink as they cannot permanently attach to it, unlike therian mammals. While it still needs to be determined how an odour signal could be further processed in the brain, this study suggests that marsupials and monotremes possess well enough developed olfactory systems to be able to detect an odour cue from the mammary area at birth/hatching. It is therefore likely that neonate marsupials and newly hatched monotremes find their way to the milk source using olfactory cues, as has been previously suggested for the

  15. Surface coatings of ZnO nanoparticles mitigate differentially a host of transcriptional, protein and signalling responses in primary human olfactory cells

    PubMed Central

    2013-01-01

    Background Inhaled nanoparticles have been reported in some instances to translocate from the nostril to the olfactory bulb in exposed rats. In close proximity to the olfactory bulb is the olfactory mucosa, within which resides a niche of multipotent cells. Cells isolated from this area may provide a relevant in vitro system to investigate potential effects of workplace exposure to inhaled zinc oxide nanoparticles. Methods Four types of commercially-available zinc oxide (ZnO) nanoparticles, two coated and two uncoated, were examined for their effects on primary human cells cultured from the olfactory mucosa. Human olfactory neurosphere-derived (hONS) cells from healthy adult donors were analyzed for modulation of cytokine levels, activation of intracellular signalling pathways, changes in gene-expression patterns across the whole genome, and compromised cellular function over a 24 h period following exposure to the nanoparticles suspended in cell culture medium. Results ZnO nanoparticle toxicity in hONS cells was mediated through a battery of mechanisms largely related to cell stress, inflammatory response and apoptosis, but not activation of mechanisms that repair damaged DNA. Surface coatings on the ZnO nanoparticles mitigated these cellular responses to varying degrees. Conclusions The results indicate that care should be taken in the workplace to minimize generation of, and exposure to, aerosols of uncoated ZnO nanoparticles, given the adverse responses reported here using multipotent cells derived from the olfactory mucosa. PMID:24144420

  16. Expression of early growth response protein 1 in vasopressin neurones of the rat anterior olfactory nucleus following social odour exposure

    PubMed Central

    Wacker, Douglas W; Tobin, Vicky A; Noack, Julia; Bishop, Valerie R; Duszkiewicz, Adrian J; Engelmann, Mario; Meddle, Simone L; Ludwig, Mike

    2010-01-01

    The anterior olfactory nucleus (AON), a component of the main olfactory system, is a cortical region that processes olfactory information and acts as a relay between the main olfactory bulbs and higher brain regions such as the piriform cortex. Utilizing a transgenic rat in which an enhanced green fluorescent protein reporter gene is expressed in vasopressin neurones (eGFP-vasopressin), we have discovered a population of vasopressin neurones in the AON. These vasopressin neurones co-express vasopressin V1 receptors. They also co-express GABA and calbinin-D28k indicating that they are neurochemically different from the newly described vasopressin neurons in the main olfactory bulb. We utilized the immediate early gene product, early growth response protein 1 (Egr-1), to examine the functional role of these vasopressin neurons in processing social and non-social odours in the AON. Exposure of adult rats to a conspecific juvenile or a heterospecific predator odour leads to increases in Egr-1 expression in the AON in a subregion specific manner. However, only exposure to a juvenile increases Egr-1 expression in AON vasopressin neurons. These data suggest that vasopressin neurones in the AON may be selectively involved in the coding of social odour information. PMID:20921194

  17. Ionotropic Crustacean Olfactory Receptors

    PubMed Central

    Corey, Elizabeth A.; Bobkov, Yuriy; Ukhanov, Kirill; Ache, Barry W.

    2013-01-01

    The nature of the olfactory receptor in crustaceans, a major group of arthropods, has remained elusive. We report that spiny lobsters, Panulirus argus, express ionotropic receptors (IRs), the insect chemosensory variants of ionotropic glutamate receptors. Unlike insects IRs, which are expressed in a specific subset of olfactory cells, two lobster IR subunits are expressed in most, if not all, lobster olfactory receptor neurons (ORNs), as confirmed by antibody labeling and in situ hybridization. Ligand-specific ORN responses visualized by calcium imaging are consistent with a restricted expression pattern found for other potential subunits, suggesting that cell-specific expression of uncommon IR subunits determines the ligand sensitivity of individual cells. IRs are the only type of olfactory receptor that we have detected in spiny lobster olfactory tissue, suggesting that they likely mediate olfactory signaling. Given long-standing evidence for G protein-mediated signaling in activation of lobster ORNs, this finding raises the interesting specter that IRs act in concert with second messenger-mediated signaling. PMID:23573266

  18. Ionotropic crustacean olfactory receptors.

    PubMed

    Corey, Elizabeth A; Bobkov, Yuriy; Ukhanov, Kirill; Ache, Barry W

    2013-01-01

    The nature of the olfactory receptor in crustaceans, a major group of arthropods, has remained elusive. We report that spiny lobsters, Panulirus argus, express ionotropic receptors (IRs), the insect chemosensory variants of ionotropic glutamate receptors. Unlike insects IRs, which are expressed in a specific subset of olfactory cells, two lobster IR subunits are expressed in most, if not all, lobster olfactory receptor neurons (ORNs), as confirmed by antibody labeling and in situ hybridization. Ligand-specific ORN responses visualized by calcium imaging are consistent with a restricted expression pattern found for other potential subunits, suggesting that cell-specific expression of uncommon IR subunits determines the ligand sensitivity of individual cells. IRs are the only type of olfactory receptor that we have detected in spiny lobster olfactory tissue, suggesting that they likely mediate olfactory signaling. Given long-standing evidence for G protein-mediated signaling in activation of lobster ORNs, this finding raises the interesting specter that IRs act in concert with second messenger-mediated signaling. PMID:23573266

  19. Application of the European Test of Olfactory Capabilities in patients with olfactory impairment.

    PubMed

    Joussain, P; Bessy, M; Faure, F; Bellil, D; Landis, B N; Hugentobler, M; Tuorila, H; Mustonen, S; Vento, S I; Delphin-Combe, F; Krolak-Salmon, P; Rouby, C; Bensafi, M

    2016-02-01

    A central issue in olfaction concerns the characterization of loss of olfactory function: partial (hyposmia) or total (anosmia). This paper reports the application in a clinical setting of the European Test of Olfactory Capabilities (ETOC), combining odor detection and identification. The study included three phases. In phase 1, anosmics, hyposmics and controls were tested with the 16-items version of the ETOC. In phase 2, a short version of the ETOC was developed: patients with and controls without olfactory impairment were tested on a 6-items ETOC. In phase 3, to predict olfactory impairments in new individuals, the 16-items ETOC was administered on samples of young and older adults, and the 6-items version was applied in samples of young, elderly participants and Alzheimer patients. In phase 1, linear discriminant analysis (LDA) of ETOC scores classified patients and controls with 87.5 % accuracy. In phase 2, LDA provided 84 % correct classification. Results of phase 3 revealed: (1) 16-items ETOC: whereas in young adults, 10 % were classified as hyposmic and 90 % as normosmic, in elderly, 1 % were classified as anosmic, 39 % hyposmic and 60 % normosmic; (2) 6-items ETOC: 15 % of the young adults were classified as having olfactory impairment, compared to 28 % in the older group and 83 % in Alzheimer patients. In conclusion, the ETOC enables characterizing the prevalence of olfactory impairment in young subjects and in normal and pathological aging. Whereas the 16-items ETOC is more discriminant, the short ETOC may provide a fast (5-10 min) tool to assess olfaction in clinical settings. PMID:25711735

  20. Structural differences in the drone olfactory system of two phylogenetically distant Apis species, A. florea and A. mellifera

    NASA Astrophysics Data System (ADS)

    Brockmann, Axel; Brückner, Dorothea

    2001-01-01

    Male insects that are attracted by sex pheromones to find their female mates over long distances have specialized olfactory subsystems. Morphologically, these subsystems are characterized by a large number of receptor neurons sensitive to components of the female's pheromones and hypertrophied glomerular subunits ('macroglomeruli' or 'macroglomerular complexes') in the antennal lobes, in which the axons of the receptor neurons converge. The olfactory subsystems are adapted for an increased sensitivity to perceive minute amounts of pheromones. In Apis mellifera, drones have 18,600 olfactory poreplate sensilla per antenna, each equipped with receptor neurons sensitive to the queen's sex pheromone, and four voluminous macroglomeruli (MG1-MG4) in the antennal lobes. In contrast, we show that drones of the phylogenetically distant species, Apis florea, have only 1,200 poreplate sensilla per antenna and only two macroglomeruli in their antennal lobes. These macroglomeruli are homologous in anatomical position to the two most prominent macroglomeruli in A. mellifera, the MG1 and MG2, but they are much smaller in size. The morphological and anatomical differences described here suggest major modifications in the sex-pheromone processing subsystem of both species: (1) less pheromone sensitivity in A. florea and (2) a more complex sex-pheromone processing and thus a more complex sex-pheromone communication in A. mellifera.

  1. Morphometric and ultrastructural comparison of the olfactory system in elasmobranchs: the significance of structure-function relationships based on phylogeny and ecology.

    PubMed

    Schluessel, Vera; Bennett, Michael B; Bleckmann, Horst; Blomberg, Simon; Collin, Shaun P

    2008-11-01

    This study investigated the relationship between olfactory morphology, habitat occupancy, and lifestyle in 21 elasmobranch species in a phylogenetic context. Four measures of olfactory capability, that is, the number of olfactory lamellae, the surface area of the olfactory epithelium, the mass of the olfactory bulb, and the mass of the olfactory rosette were compared between individual species and groups, comprised of species with similar habitat and/or lifestyle. Statistical analyses using generalized least squares phylogenetic regression revealed that bentho-pelagic sharks and rays possess significantly more olfactory lamellae and larger sensory epithelial surface areas than benthic species. There was no significant correlation between either olfactory bulb or rosette mass and habitat type. There was also no significant difference between the number of lamellae or the size of the sensory surface area in groups comprised of species with similar diets, that is, groups preying predominantly on crustaceans, cephalopods, echinoderms, polychaetes, molluscs, or teleosts. However, some groups had significantly larger olfactory bulb or rosette masses than others. There was little evidence to support a correlation between phylogeny and morphology, indicating that differences in olfactory capabilities are the result of functional rather than phylogenetic adaptations. All olfactory epithelia exhibited microvilli and cilia, with microvilli in both nonsensory and sensory areas, and cilia only in sensory areas. Cilia over the sensory epithelia originated from supporting cells. In contrast to teleosts, which possess ciliated and microvillous olfactory receptor types, no ciliated olfactory receptor cells were observed. This is the first comprehensive study comparing olfactory morphology to several aspects of elasmobranch ecology in a phylogenetic context. PMID:18777568

  2. Cell cycle of globose basal cells in rat olfactory epithelium.

    PubMed

    Huard, J M; Schwob, J E

    1995-05-01

    The olfactory epithelium of adult mammals has the unique property of generating olfactory sensory neurons throughout life. Cells of the basal compartment, which include horizontal and globose basal cells, are responsible for the ongoing process of neurogenesis in this system. We report here that the globose basal cells in olfactory epithelium of rats, as in mice, are the predominant type of proliferating cell, and account for 97.6% of the actively dividing cells in the basal compartment of the normal epithelium. Globose basal cells have not been fully characterized in terms of their proliferative properties, and the dynamic aspects of neurogenesis are not well understood. As a consequence, it is uncertain whether cell kinetic properties are under any regulation that could affect the rate of neurogenesis. To address this gap in our knowledge, we have determined the duration of both the synthesis phase (S-phase) and the full cell cycle of globose basal cells in adult rats. The duration of the S-phase was found to be 9 hr in experiments utilizing sequential injections of either IdU followed by BrdU or 3H-thy followed by BrdU. The duration of the cell cycle was determined by varying the time interval between the injections of 3H-thy and BrdU and tracking the set of cells that exit S shortly after the first injection. With this paradigm, the interval required for these cells to traverse G2, M, G1, and a second S-phase, is equivalent to the duration of one mitotic cycle and equals 17 hr. These observations serve as the foundation to assess whether the cell cycle duration is subject to regulation in response to experimental injury, and whether such regulation is partly responsible for changes in the rate of neurogenesis in such settings. PMID:7647371

  3. Suppression of Background Odor Effect in Odor Sensing System Using Olfactory Adaptation Model

    NASA Astrophysics Data System (ADS)

    Ohba, Tsuneaki; Yamanaka, Takao

    In this study, a new method for suppressing the background odor effect is proposed. Since odor sensors response to background odors in addition to a target odor, it is difficult to detect the target odor information. In the conventional odor sensing systems, the effect of the background odors are compensated by subtracting the response to the background odors (the baseline response). Although this simple subtraction method is effective for constant background odors, it fails in the compensation for time-varying background odors. The proposed method for the background suppression is effective even for the time-varying background odors.

  4. Expression of Nogo receptor 1 in the regeneration process of the mouse olfactory epithelium.

    PubMed

    Chen, He-Xin; Zeng, Xian-Ping; Sun, Yue-Qi; Fu, Qing-Ling

    2016-07-01

    Nogo receptor 1 (NgR1) is the most important Nogo-A receptor. By its interaction with myelin-associated inhibitory proteins, NgR1 inhibits the regeneration of axons and is extensively expressed in the central nervous system. However, the expression of NgR1 in regenerable neurons, such as olfactory neurons, and its expression in the regeneration progress of olfactory neurons have not been reported. In this study, we demonstrated that NgR1 was expressed in the cell bodies of certain mature olfactory receptor neurons (ORNs) but was not expressed in immature ORNs in the olfactory epithelium (OE) of normal adult mice. On day 21 after OE injury, NgR1 was expressed not only in the cell bodies of mature ORNs but also in the cell bodies of glial fibrillary acidic protein (GFAP)-positive cells in the top and submucosal layers of the OE. On day 48 after model establishment, NgR1 expression decreased in the cell bodies of the GFAP-positive cells. On day 56 after model establishment, no NgR1 expression was found in the cell bodies of the GFAP-positive cells, and NgR1 was again expressed only in the mature ORNs. Our results demonstrated that NgR1 expression is upregulated in the OE after injury, which suggests that NgR1 might be involved in the regeneration of the OE. PMID:27138950

  5. Comparative analysis of deutocerebral neuropils in Chilopoda (Myriapoda): implications for the evolution of the arthropod olfactory system and support for the Mandibulata concept

    PubMed Central

    2012-01-01

    Background Originating from a marine ancestor, the myriapods most likely invaded land independently of the hexapods. As these two evolutionary lineages conquered land in parallel but separately, we are interested in comparing the myriapod chemosensory system to that of hexapods to gain insights into possible adaptations for olfaction in air. Our study connects to a previous analysis of the brain and behavior of the chilopod (centipede) Scutigera coleoptrata in which we demonstrated that these animals do respond to volatile substances and analyzed the structure of their central olfactory pathway. Results Here, we examined the architecture of the deutocerebral brain areas (which process input from the antennae) in seven additional representatives of the Chilopoda, covering all major subtaxa, by histology, confocal laser-scan microscopy, and 3D reconstruction. We found that in all species that we studied the majority of antennal afferents target two separate neuropils, the olfactory lobe (chemosensory, composed of glomerular neuropil compartments) and the corpus lamellosum (mechanosensory). The numbers of olfactory glomeruli in the different chilopod taxa ranged from ca. 35 up to ca. 90 and the shape of the glomeruli ranged from spheroid across ovoid or drop-shape to elongate. Conclusion A split of the afferents from the (first) pair of antennae into separate chemosensory and mechanosensory components is also typical for Crustacea and Hexapoda, but this set of characters is absent in Chelicerata. We suggest that this character set strongly supports the Mandibulata hypothesis (Myriapoda + (Crustacea + Hexapoda)) as opposed to the Myriochelata concept (Myriapoda + Chelicerata). The evolutionary implications of our findings, particularly the plasticity of glomerular shape, are discussed. PMID:22214384

  6. True navigation in migrating gulls requires intact olfactory nerves.

    PubMed

    Wikelski, Martin; Arriero, Elena; Gagliardo, Anna; Holland, Richard A; Huttunen, Markku J; Juvaste, Risto; Mueller, Inge; Tertitski, Grigori; Thorup, Kasper; Wild, Martin; Alanko, Markku; Bairlein, Franz; Cherenkov, Alexander; Cameron, Alison; Flatz, Reinhard; Hannila, Juhani; Hüppop, Ommo; Kangasniemi, Markku; Kranstauber, Bart; Penttinen, Maija-Liisa; Safi, Kamran; Semashko, Vladimir; Schmid, Heidi; Wistbacka, Ralf

    2015-01-01

    During migratory journeys, birds may become displaced from their normal migratory route. Experimental evidence has shown that adult birds can correct for such displacements and return to their goal. However, the nature of the cues used by migratory birds to perform long distance navigation is still debated. In this experiment we subjected adult lesser black-backed gulls migrating from their Finnish/Russian breeding grounds (from >60°N) to Africa (to < 5°N) to sensory manipulation, to determine the sensory systems required for navigation. We translocated birds westward (1080 km) or eastward (885 km) to simulate natural navigational challenges. When translocated westwards and outside their migratory corridor birds with olfactory nerve section kept a clear directional preference (southerly) but were unable to compensate for the displacement, while intact birds and gulls with the ophthalmic branch of the trigeminal nerve sectioned oriented towards their population-specific migratory corridor. Thus, air-borne olfactory information seems to be important for migrating gulls to navigate successfully in some circumstances. PMID:26597351

  7. True navigation in migrating gulls requires intact olfactory nerves

    PubMed Central

    Wikelski, Martin; Arriero, Elena; Gagliardo, Anna; Holland, Richard A.; Huttunen, Markku J.; Juvaste, Risto; Mueller, Inge; Tertitski, Grigori; Thorup, Kasper; Wild, Martin; Alanko, Markku; Bairlein, Franz; Cherenkov, Alexander; Cameron, Alison; Flatz, Reinhard; Hannila, Juhani; Hüppop, Ommo; Kangasniemi, Markku; Kranstauber, Bart; Penttinen, Maija-Liisa; Safi, Kamran; Semashko, Vladimir; Schmid, Heidi; Wistbacka, Ralf

    2015-01-01

    During migratory journeys, birds may become displaced from their normal migratory route. Experimental evidence has shown that adult birds can correct for such displacements and return to their goal. However, the nature of the cues used by migratory birds to perform long distance navigation is still debated. In this experiment we subjected adult lesser black-backed gulls migrating from their Finnish/Russian breeding grounds (from >60°N) to Africa (to < 5°N) to sensory manipulation, to determine the sensory systems required for navigation. We translocated birds westward (1080 km) or eastward (885 km) to simulate natural navigational challenges. When translocated westwards and outside their migratory corridor birds with olfactory nerve section kept a clear directional preference (southerly) but were unable to compensate for the displacement, while intact birds and gulls with the ophthalmic branch of the trigeminal nerve sectioned oriented towards their population-specific migratory corridor. Thus, air-borne olfactory information seems to be important for migrating gulls to navigate successfully in some circumstances. PMID:26597351

  8. Olfactory sensations produced by high-energy photon irradiation of the olfactory receptor mucosa in humans

    SciTech Connect

    Sagar, S.M.; Thomas, R.J.; Loverock, L.T.; Spittle, M.F. )

    1991-04-01

    During irradiation of volumes that incorporate the olfactory system, a proportion of patients have complained of a pungent smell. A retrospective study was carried out to determine the prevalence of this side-effect. A questionnaire was sent to 40 patients whose treatment volumes included the olfactory region and also to a control group treated away from this region. The irradiated tumor volumes included the frontal lobe, whole brain, nasopharynx, pituitary fossa, and maxillary antrum. Of the 25 patients who replied, 60% experienced odorous symptoms during irradiation. They described the odor as unpleasant and consistent with ozone. Stimulation of olfactory receptors is considered to be caused by the radiochemical formation of ozone and free radicals in the mucus overlying the olfactory mucosa.

  9. Olfactory Mucosa Tissue Based Biosensor for Bioelectronic Nose

    NASA Astrophysics Data System (ADS)

    Liu, Qingjun; Ye, Weiwei; Yu, Hui; Hu, Ning; Cai, Hua; Wang, Ping

    2009-05-01

    Biological olfactory system can distinguish thousands of odors. In order to realize the biomimetic design of electronic nose on the principle of mammalian olfactory system, we have reported bioelectronic nose based on cultured olfactory cells. In this study, the electrical property of the tissue-semiconductor interface was analyzed by the volume conductor theory and the sheet conductor model. Olfactory mucosa tissue of rat was isolated and fixed on the surface of the light-addressable potentiometric sensor (LAPS), with the natural stations of the neuronal populations and functional receptor unit of the cilia well reserved. By the extracellular potentials of the olfactory receptor cells of the mucosa tissue monitored, both the simulation and the experimental results suggested that this tissue-semiconductor hybrid system was sensitive to odorants stimulation.

  10. Integrating temperature with odor processing in the olfactory bulb.

    PubMed

    Kludt, Eugen; Okom, Camille; Brinkmann, Alexander; Schild, Detlev

    2015-05-20

    Temperature perception has long been classified as a somesthetic function solely. However, in recent years several studies brought evidence that temperature perception also takes place in the olfactory system of rodents. Temperature has been described as an effective stimulus for sensory neurons of the Grueneberg ganglion located at the entrance of the nose. Here, we investigate whether a neuronal trace of temperature stimulation can be observed in the glomeruli and mitral cells of the olfactory bulb, using calcium imaging and fast line-scanning microscopy. We show in the Xenopus tadpole system that the γ-glomerulus, which receives input from olfactory neurons, is highly sensitive to temperature drops at the olfactory epithelium. We observed that thermo-induced activity in the γ-glomerulus is conveyed to the mitral cells innervating this specific neuropil. Surprisingly, a substantial number of thermosensitive mitral cells were also chemosensitive. Moreover, we report another unique feature of the γ-glomerulus: it receives ipsilateral and contralateral afferents. The latter fibers pass through the contralateral bulb, cross the anterior commissure, and then run to the ipsilateral olfactory bulb, where they target the γ-glomerulus. Temperature drops at the contralateral olfactory epithelium also induced responses in the γ-glomerulus and in mitral cells. Temperature thus appears to be a relevant physiological input to the Xenopus olfactory system. Each olfactory bulb integrates and codes temperature signals originating from receptor neurons of the ipsilateral and contralateral nasal cavities. Finally, temperature and chemical information is processed in shared cellular networks. PMID:25995474

  11. Odor memories regulate olfactory receptor expression in the sensory periphery.

    PubMed

    Claudianos, Charles; Lim, Julianne; Young, Melanie; Yan, Shanzhi; Cristino, Alexandre S; Newcomb, Richard D; Gunasekaran, Nivetha; Reinhard, Judith

    2014-05-01

    Odor learning induces structural and functional modifications throughout the olfactory system, but it is currently unknown whether this plasticity extends to the olfactory receptors (Or) in the sensory periphery. Here, we demonstrate that odor learning induces plasticity in olfactory receptor expression in the honeybee, Apis mellifera. Using quantitative RT-PCR analysis, we show that six putative floral scent receptors were differentially expressed in the bee antennae depending on the scent environment that the bees experienced. Or151, which we characterized using an in vitro cell expression system as a broadly tuned receptor binding floral odorants such as linalool, and Or11, the specific receptor for the queen pheromone 9-oxo-decenoic acid, were significantly down-regulated after honeybees were conditioned with the respective odorants in an olfactory learning paradigm. Electroantennogram recordings showed that the neural response of the antenna was similarly reduced after odor learning. Long-term odor memory was essential for inducing these changes, suggesting that the molecular mechanisms involved in olfactory memory also regulate olfactory receptor expression. Our study demonstrates for the first time that olfactory receptor expression is experience-dependent and modulated by scent conditioning, providing novel insight into how molecular regulation at the periphery contributes to plasticity in the olfactory system. PMID:24628891

  12. Olfactory lateralization in homing pigeons: initial orientation of birds receiving a unilateral olfactory input.

    PubMed

    Gagliardo, Anna; Pecchia, Tommaso; Savini, Maria; Odetti, Francesca; Ioalè, Paolo; Vallortigara, Giorgio

    2007-03-01

    It has been shown that homing pigeons (Columba livia) rely on olfactory cues to navigate from unfamiliar locations. In fact, the integrity of the olfactory system, from the olfactory mucosa to the piriform cortex, is required for pigeons to navigate over unfamiliar areas. Recently it has been shown that there is a functional asymmetry in the piriform cortex, with the left piriform cortex more involved in the use of the olfactory navigational map than the right piriform cortex. To investigate further the lateralization of the olfactory system in relation to navigational processes in carrier pigeons, we compared their homing performance after either their left or the right nostril was plugged. Contrary to our expectations, we observed an impairment in the initial orientation of the pigeons with their right nostril plugged. However, both groups released with one nostril plugged tended to be poorer than control pigeons in their homing performance. The observed asymmetry in favour of the right nostril might be due to projections from the olfactory bulbs to the contralateral globus pallidum, a structure involved in motor responses. PMID:17425577

  13. Growth Arrest Specific 1 (GAS1) Is Abundantly Expressed in the Adult Mouse Central Nervous System

    PubMed Central

    Zarco, Natanael; Bautista, Elizabeth; Cuéllar, Manola; Vergara, Paula; Flores-Rodriguez, Paola; Aguilar-Roblero, Raúl

    2013-01-01

    Growth arrest specific 1 (GAS1) is a pleiotropic protein that induces apoptosis and cell arrest in different tumors, but it is also involved in the development of the nervous system and other tissues and organs. This dual ability is likely caused by its capacity to interact both by inhibiting the intracellular signaling cascade induced by glial cell-line derived neurotrophic factor and by facilitating the activity of the sonic hedgehog pathway. The presence of GAS1 mRNA has been described in adult mouse brain, and here we corroborated this observation. We then proceeded to determine the distribution of the protein in the adult central nervous system (CNS). We detected, by western blot analysis, expression of GAS1 in olfactory bulb, caudate-putamen, cerebral cortex, hippocampus, mesencephalon, medulla oblongata, cerebellum, and cervical spinal cord. To more carefully map the expression of GAS1, we performed double-label immunohistochemistry and noticed expression of GAS1 in neurons in all brain areas examined. We also observed expression of GAS1 in astroglial cells, albeit the pattern of expression was more restricted than that seen in neurons. Briefly, in the present article, we report the widespread distribution and cellular localization of the GAS1 native protein in adult mammalian CNS. PMID:23813868

  14. Human Neural Cells Transiently Express Reelin during Olfactory Placode Development

    PubMed Central

    Antal, M. Cristina; Samama, Brigitte; Ghandour, M. Said; Boehm, Nelly

    2015-01-01

    Reelin, an extracellular glycoprotein is essential for migration and correct positioning of neurons during development. Since the olfactory system is known as a source of various migrating neuronal cells, we studied Reelin expression in the two chemosensory olfactory systems, main and accessory, during early developmental stages of human foetuses/embryos from Carnegie Stage (CS) 15 to gestational week (GW) 14. From CS 15 to CS 18, but not at later stages, a transient expression of Reelin was detected first in the presumptive olfactory and then in the presumptive vomeronasal epithelium. During the same period, Reelin-positive cells detach from the olfactory/vomeronasal epithelium and migrate through the mesenchyme beneath the telencephalon. Dab 1, an adaptor protein of the Reelin pathway, was simultaneously expressed in the migratory mass from CS16 to CS17 and, at later stages, in the presumptive olfactory ensheathing cells. Possible involvements of Reelin and Dab 1 in the peripheral migrating stream are discussed. PMID:26270645

  15. Human Neural Cells Transiently Express Reelin during Olfactory Placode Development.

    PubMed

    Antal, M Cristina; Samama, Brigitte; Ghandour, M Said; Boehm, Nelly

    2015-01-01

    Reelin, an extracellular glycoprotein is essential for migration and correct positioning of neurons during development. Since the olfactory system is known as a source of various migrating neuronal cells, we studied Reelin expression in the two chemosensory olfactory systems, main and accessory, during early developmental stages of human foetuses/embryos from Carnegie Stage (CS) 15 to gestational week (GW) 14. From CS 15 to CS 18, but not at later stages, a transient expression of Reelin was detected first in the presumptive olfactory and then in the presumptive vomeronasal epithelium. During the same period, Reelin-positive cells detach from the olfactory/vomeronasal epithelium and migrate through the mesenchyme beneath the telencephalon. Dab 1, an adaptor protein of the Reelin pathway, was simultaneously expressed in the migratory mass from CS16 to CS17 and, at later stages, in the presumptive olfactory ensheathing cells. Possible involvements of Reelin and Dab 1 in the peripheral migrating stream are discussed. PMID:26270645

  16. Examination of Endogenous Rotund Expression and Function in Developing Drosophila Olfactory System Using CRISPR-Cas9–Mediated Protein Tagging

    PubMed Central

    Li, Qingyun; Barish, Scott; Okuwa, Sumie; Volkan, Pelin C.

    2015-01-01

    The zinc-finger protein Rotund (Rn) plays a critical role in controlling the development of the fly olfactory system. However, little is known about its molecular function in vivo. Here, we added protein tags to the rn locus using CRISPR-Cas9 technology in Drosophila to investigate its subcellular localization and the genes that it regulates . We previously used a reporter construct to show that rn is expressed in a subset of olfactory receptor neuron (ORN) precursors and it is required for the diversification of ORN fates. Here, we show that tagged endogenous Rn protein is functional based on the analysis of ORN phenotypes. Using this method, we also mapped the expression pattern of the endogenous isoform-specific tags in vivo with increased precision. Comparison of the Rn expression pattern from this study with previously published results using GAL4 reporters showed that Rn is mainly present in early steps in antennal disc patterning, but not in pupal stages when ORNs are born. Finally, using chromatin immunoprecipitation, we showed a direct binding of Rotund to a previously identified regulatory element upstream of the bric-a-brac gene locus in the developing antennal disc. PMID:26497147

  17. Acetylcholine and Olfactory Perceptual Learning

    ERIC Educational Resources Information Center

    Wilson, Donald A.; Fletcher, Max L.; Sullivan, Regina M.

    2004-01-01

    Olfactory perceptual learning is a relatively long-term, learned increase in perceptual acuity, and has been described in both humans and animals. Data from recent electrophysiological studies have indicated that olfactory perceptual learning may be correlated with changes in odorant receptive fields of neurons in the olfactory bulb and piriform…

  18. Neuropeptide S facilitates mice olfactory function through activation of cognate receptor-expressing neurons in the olfactory cortex.

    PubMed

    Shao, Yu-Feng; Zhao, Peng; Dong, Chao-Yu; Li, Jing; Kong, Xiang-Pan; Wang, Hai-Liang; Dai, Li-Rong; Hou, Yi-Ping

    2013-01-01

    Neuropeptide S (NPS) is a newly identified neuromodulator located in the brainstem and regulates various biological functions by selectively activating the NPS receptors (NPSR). High level expression of NPSR mRNA in the olfactory cortex suggests that NPS-NPSR system might be involved in the regulation of olfactory function. The present study was undertaken to investigate the effects of intracerebroventricular (i.c.v.) injection of NPS or co-injection of NPSR antagonist on the olfactory behaviors, food intake, and c-Fos expression in olfactory cortex in mice. In addition, dual-immunofluorescence was employed to identify NPS-induced Fos immunereactive (-ir) neurons that also bear NPSR. NPS (0.1-1 nmol) i.c.v. injection significantly reduced the latency to find the buried food, and increased olfactory differentiation of different odors and the total sniffing time spent in olfactory habituation/dishabituation tasks. NPS facilitated olfactory ability most at the dose of 0.5 nmol, which could be blocked by co-injection of 40 nmol NPSR antagonist [D-Val(5)]NPS. NPS administration dose-dependently inhibited food intake in fasted mice. Ex-vivo c-Fos and NPSR immunohistochemistry in the olfactory cortex revealed that, as compared with vehicle-treated mice, NPS markedly enhanced c-Fos expression in the anterior olfactory nucleus (AON), piriform cortex (Pir), ventral tenia tecta (VTT), the anterior cortical amygdaloid nucleus (ACo) and lateral entorhinal cortex (LEnt). The percentage of Fos-ir neurons that also express NPSR were 88.5% and 98.1% in the AON and Pir, respectively. The present findings demonstrated that NPS, via selective activation of the neurons bearing NPSR in the olfactory cortex, facilitates olfactory function in mice. PMID:23614017

  19. Serotonin is critical for rewarded olfactory short-term memory in Drosophila.

    PubMed

    Sitaraman, Divya; LaFerriere, Holly; Birman, Serge; Zars, Troy

    2012-06-01

    The biogenic amines dopamine, octopamine, and serotonin are critical in establishing normal memories. A common view for the amines in insect memory performance has emerged in which dopamine and octopamine are largely responsible for aversive and appetitive memories. Examination of the function of serotonin begins to challenge the notion of one amine type per memory because altering serotonin function also reduces aversive olfactory memory and place memory levels. Could the function of serotonin be restricted to the aversive domain, suggesting a more specific dopamine/serotonin system interaction? The function of the serotonergic system in appetitive olfactory memory was examined. By targeting the tetanus toxin light chain (TNT) and the human inwardly rectifying potassium channel (Kir2.1) to the serotonin neurons with two different GAL4 driver combinations, the serotonergic system was inhibited. Additional use of the GAL80(ts1) system to control expression of transgenes to the adult stage of the life cycle addressed a potential developmental role of serotonin in appetitive memory. Reduction in appetitive olfactory memory performance in flies with these transgenic manipulations, without altering control behaviors, showed that the serotonergic system is also required for normal appetitive memory. Thus, serotonin appears to have a more general role in Drosophila memory, and implies an interaction with both the dopaminergic and octopaminergic systems. PMID:22436011

  20. Kappe neurons, a novel population of olfactory sensory neurons

    PubMed Central

    Ahuja, Gaurav; Nia, Shahrzad Bozorg; Zapilko, Veronika; Shiriagin, Vladimir; Kowatschew, Daniel; Oka, Yuichiro; Korsching, Sigrun I.

    2014-01-01

    Perception of olfactory stimuli is mediated by distinct populations of olfactory sensory neurons, each with a characteristic set of morphological as well as functional parameters. Beyond two large populations of ciliated and microvillous neurons, a third population, crypt neurons, has been identified in teleost and cartilaginous fishes. We report here a novel, fourth olfactory sensory neuron population in zebrafish, which we named kappe neurons for their characteristic shape. Kappe neurons are identified by their Go-like immunoreactivity, and show a distinct spatial distribution within the olfactory epithelium, similar to, but significantly different from that of crypt neurons. Furthermore, kappe neurons project to a single identified target glomerulus within the olfactory bulb, mdg5 of the mediodorsal cluster, whereas crypt neurons are known to project exclusively to the mdg2 glomerulus. Kappe neurons are negative for established markers of ciliated, microvillous and crypt neurons, but appear to have microvilli. Kappe neurons constitute the fourth type of olfactory sensory neurons reported in teleost fishes and their existence suggests that encoding of olfactory stimuli may require a higher complexity than hitherto assumed already in the peripheral olfactory system. PMID:24509431

  1. Kappe neurons, a novel population of olfactory sensory neurons

    NASA Astrophysics Data System (ADS)

    Ahuja, Gaurav; Nia, Shahrzad Bozorg; Zapilko, Veronika; Shiriagin, Vladimir; Kowatschew, Daniel; Oka, Yuichiro; Korsching, Sigrun I.

    2014-02-01

    Perception of olfactory stimuli is mediated by distinct populations of olfactory sensory neurons, each with a characteristic set of morphological as well as functional parameters. Beyond two large populations of ciliated and microvillous neurons, a third population, crypt neurons, has been identified in teleost and cartilaginous fishes. We report here a novel, fourth olfactory sensory neuron population in zebrafish, which we named kappe neurons for their characteristic shape. Kappe neurons are identified by their Go-like immunoreactivity, and show a distinct spatial distribution within the olfactory epithelium, similar to, but significantly different from that of crypt neurons. Furthermore, kappe neurons project to a single identified target glomerulus within the olfactory bulb, mdg5 of the mediodorsal cluster, whereas crypt neurons are known to project exclusively to the mdg2 glomerulus. Kappe neurons are negative for established markers of ciliated, microvillous and crypt neurons, but appear to have microvilli. Kappe neurons constitute the fourth type of olfactory sensory neurons reported in teleost fishes and their existence suggests that encoding of olfactory stimuli may require a higher complexity than hitherto assumed already in the peripheral olfactory system.

  2. Olfactory Signal Transduction in the Mouse Septal Organ

    PubMed Central

    Ma, Minghong; Grosmaitre, Xavier; Iwema, Carrie L.; Baker, Harriet; Greer, Charles A.; Shepherd, Gordon M.

    2008-01-01

    The septal organ, a distinct chemosensory organ observed in the mammalian nose, is essentially a small island of olfactory neuroepithelium located bilaterally at the ventral base of the nasal septum. Virtually nothing is known about its physiological properties and function. To understand the nature of the sensory neurons in this area, we studied the mechanisms underlying olfactory signal transduction in these neurons. The majority of the sensory neurons in the septal organ express olfactory-specific G-protein and adenylyl cyclase type III, suggesting that the cAMP signaling pathway plays a critical role in the septal organ as in the main olfactory epithelium (MOE). This is further supported by patch-clamp recordings from individual dendritic knobs of the sensory neurons in the septal organ. Odorant responses can be mimicked by an adenylyl cyclase activator and a phosphodiesterase inhibitor, and these responses can be blocked by an adenylyl cyclase inhibitor. There is a small subset of cells in the septal organ expressing a cGMP-stimulated phosphodiesterase (phosphodiesterase 2), a marker for the guanylyl cyclase-D subtype sensory neurons identified in the MOE. The results indicate that the septal organ resembles the MOE in major olfactory signal transduction pathways, odorant response properties, and projection to the main olfactory bulb. Molecular and functional analysis of the septal organ, which constitutes ~1% of the olfactory epithelium, will provide new insights into the organization of the mammalian olfactory system and the unique function this enigmatic organ may serve. PMID:12514230

  3. Olfactory Cilia: Linking Sensory Cilia Function and Human Disease

    PubMed Central

    Jenkins, Paul M.; McEwen, Dyke P.

    2009-01-01

    The olfactory system gives us an awareness of our immediate environment by allowing us to detect airborne stimuli. The components necessary for detection of these odorants are compartmentalized in the cilia of olfactory sensory neurons. Cilia are microtubule-based organelles, which can be found projecting from the surface of almost any mammalian cell, and are critical for proper olfactory function. Mislocalization of ciliary proteins and/or the loss of cilia cause impaired olfactory function, which is now recognized as a clinical manifestation of a broad class of human diseases, termed ciliopathies. Future work investigating the mechanisms of olfactory cilia function will provide us important new information regarding the pathogenesis of human sensory perception diseases. PMID:19406873

  4. Humans can discriminate more than 1 trillion olfactory stimuli.

    PubMed

    Bushdid, C; Magnasco, M O; Vosshall, L B; Keller, A

    2014-03-21

    Humans can discriminate several million different colors and almost half a million different tones, but the number of discriminable olfactory stimuli remains unknown. The lay and scientific literature typically claims that humans can discriminate 10,000 odors, but this number has never been empirically validated. We determined the resolution of the human sense of smell by testing the capacity of humans to discriminate odor mixtures with varying numbers of shared components. On the basis of the results of psychophysical testing, we calculated that humans can discriminate at least 1 trillion olfactory stimuli. This is far more than previous estimates of distinguishable olfactory stimuli. It demonstrates that the human olfactory system, with its hundreds of different olfactory receptors, far outperforms the other senses in the number of physically different stimuli it can discriminate. PMID:24653035

  5. Olfactory dysfunction in Alzheimer's disease.

    PubMed

    Zou, Yong-Ming; Lu, Da; Liu, Li-Ping; Zhang, Hui-Hong; Zhou, Yu-Ying

    2016-01-01

    Alzheimer's disease (AD) is a common neurodegenerative disorder with the earliest clinical symptom of olfactory dysfunction, which is a potential clinical marker for AD severity and progression. However, many questions remain unanswered. This article reviews relevant research on olfactory dysfunction in AD and evaluates the predictive value of olfactory dysfunction for the epidemiological, pathophysiological, and clinical features of AD, as well as for the conversion of cognitive impairment to AD. We summarize problems of existing studies and provide a useful reference for further studies in AD olfactory dysfunction and for clinical applications of olfactory testing. PMID:27143888

  6. High-Frequency Oscillations Are Not Necessary for Simple Olfactory Discriminations in Young Rats

    PubMed Central

    Fletcher, Max L.; Smith, Abigail M.; Best, Aaron R.; Wilson, Donald A.

    2008-01-01

    Individual olfactory bulb mitral/tufted cells respond preferentially to groups of molecularly similar odorants. Bulbar interneurons such as periglomerular and granule cells are thought to influence mitral/tufted odorant receptive fields through mechanisms such as lateral inhibition. The mitral– granule cell circuit is also important in the generation of the odor-evoked fast oscillations seen in the olfactory bulb local field potentials and hypothesized to be an important indicator of odor quality coding. Infant rats, however, lack a majority of these inhibitory interneurons until the second week of life. It is unclear if these developmental differences affect olfactory bulb odor coding or behavioral odor discrimination. The following experiments are aimed at better understanding odor coding and behavioral odor discrimination in the developing olfactory system. Single-unit recordings from mitral/tufted cells and local field-potential recordings from both the olfactory bulb and anterior piriform cortex were performed in freely breathing urethane-anesthetized rats (postnatal day 7 to adult). Age-dependent behavioral odor discrimination to a homologous series of ethyl esters was also examined using a cross-habituation paradigm. Odorants were equated in all experiments for concentration (150 ppm) using a flow dilution olfactometer. In concordance with the reduced interneuron population, local field potentials in neonates lacked detectable odor-evoked γ-frequency oscillations that were observed in mature animals. However, mitral/tufted cell odorant receptive fields and behavioral odor discrimination did not significantly change, despite known substantial changes in local circuitry and neuronal populations, over the age range examined. The results suggest that high-frequency local field-potential oscillations do not reflect processes critical for simple odor discrimination. PMID:15673658

  7. Oxytocin Enhances Social Recognition by Modulating Cortical Control of Early Olfactory Processing.

    PubMed

    Oettl, Lars-Lennart; Ravi, Namasivayam; Schneider, Miriam; Scheller, Max F; Schneider, Peggy; Mitre, Mariela; da Silva Gouveia, Miriam; Froemke, Robert C; Chao, Moses V; Young, W Scott; Meyer-Lindenberg, Andreas; Grinevich, Valery; Shusterman, Roman; Kelsch, Wolfgang

    2016-05-01

    Oxytocin promotes social interactions and recognition of conspecifics that rely on olfaction in most species. The circuit mechanisms through which oxytocin modifies olfactory processing are incompletely understood. Here, we observed that optogenetically induced oxytocin release enhanced olfactory exploration and same-sex recognition of adult rats. Consistent with oxytocin's function in the anterior olfactory cortex, particularly in social cue processing, region-selective receptor deletion impaired social recognition but left odor discrimination and recognition intact outside a social context. Oxytocin transiently increased the drive of the anterior olfactory cortex projecting to olfactory bulb interneurons. Cortical top-down recruitment of interneurons dynamically enhanced the inhibitory input to olfactory bulb projection neurons and increased the signal-to-noise of their output. In summary, oxytocin generates states for optimized information extraction in an early cortical top-down network that is required for social interactions with potential implications for sensory processing deficits in autism spectrum disorders. PMID:27112498

  8. The Mouse Olfactory Peduncle

    PubMed Central

    Brunjes, Peter C; Kay, Rachel B; Arrivillaga, J. P

    2012-01-01

    The olfactory peduncle, the region connecting the olfactory bulb with the basal forebrain, contains several neural areas that have received relatively little attention. The present work includes studies that provide an overview of the region in the mouse. An analysis of cell soma size in pars principalis (pP) of the anterior olfactory nucleus (AON) revealed considerable differences in tissue organization between mice and rats. An unbiased stereological study of neuron number in the cell-dense regions of pars externa (pE) and pP of the AON of 3, 12 and 24 month-old mice indicated that pE has about 16,500 cells in 0.043 mm3and pP about 58,300 cells in 0.307 mm3. Quantitative Golgi studies of pyramidal neurons in pP suggested that mouse neurons are similar though smaller to those of the rat. An immunohistochemical analysis demonstrated that all peduncular regions (pE, pP, the dorsal peduncular cortex, ventral tenia tecta, and anterior olfactory tubercle and piriform cortex) have cells that express either calbindin, calretinin, parvalbumin, somatostatin, vasoactive intestinal polypeptide, neuropeptide Y or cholecystokinin (antigens commonly co-expressed by subspecies of GABAergic neurons), though the relative numbers of each cell type differs between zones. Finally, an electron microscopic comparison of the organization of myelinated fibers in lateral olfactory tract in the anterior and posterior peduncle indicated that the region is less orderly in mice than in the rat. The results provide a caveat for investigators who generalize data between species as both similarities and differences between the laboratory mouse and rat were observed. PMID:21618219

  9. Concurrent modulation of neuronal and behavioural olfactory responses to sex and host plant cues in a male moth

    PubMed Central

    Kromann, Sophie H.; Saveer, Ahmed M.; Binyameen, Muhammad; Bengtsson, Marie; Birgersson, Göran; Hansson, Bill S.; Schlyter, Fredrik; Witzgall, Peter; Ignell, Rickard; Becher, Paul G.

    2015-01-01

    Mating has profound effects on animal physiology and behaviour, not only in females but also in males, which we show here for olfactory responses. In cotton leafworm moths, Spodoptera littoralis, odour-mediated attraction to sex pheromone and plant volatiles are modulated after mating, producing a behavioural response that matches the physiological condition of the male insect. Unmated males are attracted by upwind flight to sex pheromone released by calling females, as well as to volatiles of lilac flowers and green leaves of the host plant cotton, signalling adult food and mating sites, respectively. Mating temporarily abolishes male attraction to females and host plant odour, but does not diminish attraction to flowers. This behavioural modulation is correlated with a response modulation in the olfactory system, as shown by electro-physiological recordings from antennae and by functional imaging of the antennal lobe, using natural odours and synthetic compounds. An effect of mating on the olfactory responses to pheromone and cotton plant volatiles but not to lilac flowers indicates the presence of functionally independent neural circuits within the olfactory system. Our results indicate that these circuits interconnect and weigh perception of social and habitat odour signals to generate appropriate behavioural responses according to mating state. PMID:25621329

  10. Expression of homeobox genes in the mouse olfactory epithelium.

    PubMed

    Parrilla, Marta; Chang, Isabelle; Degl'Innocenti, Andrea; Omura, Masayo

    2016-10-01

    Homeobox genes constitute a large family of genes widely studied because of their role in the establishment of the body pattern. However, they are also involved in many other events during development and adulthood. The main olfactory epithelium (MOE) is an excellent model to study neurogenesis in the adult nervous system. Analyses of homeobox genes during development show that some of these genes are involved in the formation and establishment of cell diversity in the MOE. Moreover, the mechanisms of expression of odorant receptors (ORs) constitute one of the biggest enigmas in the field. Analyses of OR promoters revealed the presence of homeodomain binding sites in their sequences. Here we characterize the expression patterns of a set of 49 homeobox genes in the MOE with in situ hybridization. We found that seven of them (Dlx3, Dlx5, Dlx6, Msx1, Meis1, Isl1, and Pitx1) are zonally expressed. The homeobox gene Emx1 is expressed in three guanylate cyclase(+) populations, two located in the MOE and the third one in an olfactory subsystem known as Grüneberg ganglion located at the entrance of the nasal cavity. The homeobox gene Tshz1 is expressed in a unique patchy pattern across the MOE. Our findings provide new insights to guide functional studies that aim to understand the complexity of transcription factor expression and gene regulation in the MOE. J. Comp. Neurol. 524:2713-2739, 2016. © 2016 Wiley Periodicals, Inc. PMID:27243442

  11. Short-Term Effects of Repeated Olfactory Administration of Homeopathic Sulphur or Pulsatilla on Electroencephalographic Alpha Power in Healthy Young Adults

    PubMed Central

    Bell, Iris R.; Brooks, Audrey J.; Howerter, Amy; Jackson, Nicholas; Schwartz, Gary E.

    2011-01-01

    Introduction Homeopathic pathogenetic trials usually rely on symptom self report measures. Adding objective biomarkers could enhance detection of subtle initial remedy effects. The present feasibility study examined electroencephalographic (EEG) effects of repeated olfactory administration of two polycrest remedies. Methods College student volunteers (ages 18–30, both sexes) from an introductory psychology course were screened for good health and relatively elevated Sulphur OR Pulsatilla symptom scores on the Homeopathic Constitutional Type Questionnaire. Subjects underwent a series of 3 once-weekly double-blind sessions during which they repeatedly sniffed the remedy matched to their CTQ type and solvent controls. Each remedy was given in a 6c, 12c, and 30c potency, one potency per week, in randomly assigned order. Solvent controls included both plain distilled water and a water-ethanol (95%) solution. All sniff test solutions were further diluted just prior to laboratory sessions (0.5 ml test solution in 150 ml distilled water). Within a session, remedies and control solvents were administered via 2-second sniffs (8 sniffs of each of 4 different succussion levels for the potency in randomized order). Primary outcome variable was relative EEG power (alpha 1 8–10 hertz; alpha 2 10–12 hertz) averaged over 19 electrode sites, including all succussions for a given potency. Results Mixed-effect models revealed significant main effects for remedy type (Sulphur>Pulsatilla) in both alpha bands, controlling for gender, baseline resting EEG alpha, and solvent control responses. Additional analyses showed significant non-linear interactions between dilution and time (weekly session) in alpha 2 for both remedies and alpha 1 for Sulphur. Conclusion EEG alpha offers an objective biomarker of remedy effects for future studies and potential method for distinguishing time-dependent effects of specific remedies and remedy potencies from one another. PMID:21962194

  12. Genetic architecture of olfactory behavior in Drosophila melanogaster: differences and similarities across development

    PubMed Central

    Lavagnino, N.J.; Arya, G.H.; Korovaichuk, A.; Fanara, J.J.

    2013-01-01

    In the holometabolous insect Drosophila melanogaster, genetic, physiological and anatomical aspects of olfaction are well known in the adult stage, while larval stages olfactory behavior has received some attention it has been less studied than its adult counterpart. Most of these studies focus on olfactory receptors (Or) genes that produce peripheral odor recognition. In this paper, through a loss-of-function screen using P-element inserted lines and also by means of expression analyses of larval olfaction candidate genes, we extended the uncovering of the genetic underpinnings of D. melanogaster larval olfactory behavior by demonstrating that larval olfactory behavior is, in addition to Or genes, orchestrated by numerous genes with diverse functions. Also, our results points out that the genetic architecture of olfactory behavior in D. melanogaster presents a dynamic and changing organization across environments and ontogeny. PMID:23563598

  13. Olfactory processing: detection of rapid changes.

    PubMed

    Croy, Ilona; Krone, Franziska; Walker, Susannah; Hummel, Thomas

    2015-06-01

    Changes in the olfactory environment have a rather poor chance of being detected. Aim of the present study was to determine, whether the same (cued) or different (uncued) odors can generally be detected at short inter stimulus intervals (ISI) below 2.5 s. Furthermore we investigated, whether inhibition of return, an attentional phenomenon facilitating the detection of new stimuli at longer ISI, is present in the domain of olfaction. Thirteen normosmic people (3 men, 10 women; age range 19-27 years; mean age 23 years) participated. Stimulation was performed using air-dilution olfactometry with 2 odors: phenylethylalcohol and hydrogen disulfide. Reaction time to target stimuli was assessed in cued and uncued conditions at ISIs of 1, 1.5, 2, and 2.5 s. There was a significant main effect of ISI, indicating that odors presented only 1 s apart are missed frequently. Uncued presentation facilitated detection at short ISIs, implying that changes of the olfactory environment are detected better than presentation of the same odor again. Effects in relation to "olfactory inhibition of return," on the other hand, are not supported by our results. This suggests that attention works different for the olfactory system compared with the visual and auditory systems. PMID:25911421

  14. Deep sequencing of the murine olfactory receptor neuron transcriptome.

    PubMed

    Kanageswaran, Ninthujah; Demond, Marilen; Nagel, Maximilian; Schreiner, Benjamin S P; Baumgart, Sabrina; Scholz, Paul; Altmüller, Janine; Becker, Christian; Doerner, Julia F; Conrad, Heike; Oberland, Sonja; Wetzel, Christian H; Neuhaus, Eva M; Hatt, Hanns; Gisselmann, Günter

    2015-01-01

    The ability of animals to sense and differentiate among thousands of odorants relies on a large set of olfactory receptors (OR) and a multitude of accessory proteins within the olfactory epithelium (OE). ORs and related signaling mechanisms have been the subject of intensive studies over the past years, but our knowledge regarding olfactory processing remains limited. The recent development of next generation sequencing (NGS) techniques encouraged us to assess the transcriptome of the murine OE. We analyzed RNA from OEs of female and male adult mice and from fluorescence-activated cell sorting (FACS)-sorted olfactory receptor neurons (ORNs) obtained from transgenic OMP-GFP mice. The Illumina RNA-Seq protocol was utilized to generate up to 86 million reads per transcriptome. In OE samples, nearly all OR and trace amine-associated receptor (TAAR) genes involved in the perception of volatile amines were detectably expressed. Other genes known to participate in olfactory signaling pathways were among the 200 genes with the highest expression levels in the OE. To identify OE-specific genes, we compared olfactory neuron expression profiles with RNA-Seq transcriptome data from different murine tissues. By analyzing different transcript classes, we detected the expression of non-olfactory GPCRs in ORNs and established an expression ranking for GPCRs detected in the OE. We also identified other previously undescribed membrane proteins as potential new players in olfaction. The quantitative and comprehensive transcriptome data provide a virtually complete catalogue of genes expressed in the OE and present a useful tool to uncover candidate genes involved in, for example, olfactory signaling, OR trafficking and recycling, and proliferation. PMID:25590618

  15. Deep Sequencing of the Murine Olfactory Receptor Neuron Transcriptome

    PubMed Central

    Kanageswaran, Ninthujah; Demond, Marilen; Nagel, Maximilian; Schreiner, Benjamin S. P.; Baumgart, Sabrina; Scholz, Paul; Altmüller, Janine; Becker, Christian; Doerner, Julia F.; Conrad, Heike; Oberland, Sonja; Wetzel, Christian H.; Neuhaus, Eva M.; Hatt, Hanns; Gisselmann, Günter

    2015-01-01

    The ability of animals to sense and differentiate among thousands of odorants relies on a large set of olfactory receptors (OR) and a multitude of accessory proteins within the olfactory epithelium (OE). ORs and related signaling mechanisms have been the subject of intensive studies over the past years, but our knowledge regarding olfactory processing remains limited. The recent development of next generation sequencing (NGS) techniques encouraged us to assess the transcriptome of the murine OE. We analyzed RNA from OEs of female and male adult mice and from fluorescence-activated cell sorting (FACS)-sorted olfactory receptor neurons (ORNs) obtained from transgenic OMP-GFP mice. The Illumina RNA-Seq protocol was utilized to generate up to 86 million reads per transcriptome. In OE samples, nearly all OR and trace amine-associated receptor (TAAR) genes involved in the perception of volatile amines were detectably expressed. Other genes known to participate in olfactory signaling pathways were among the 200 genes with the highest expression levels in the OE. To identify OE-specific genes, we compared olfactory neuron expression profiles with RNA-Seq transcriptome data from different murine tissues. By analyzing different transcript classes, we detected the expression of non-olfactory GPCRs in ORNs and established an expression ranking for GPCRs detected in the OE. We also identified other previously undescribed membrane proteins as potential new players in olfaction. The quantitative and comprehensive transcriptome data provide a virtually complete catalogue of genes expressed in the OE and present a useful tool to uncover candidate genes involved in, for example, olfactory signaling, OR trafficking and recycling, and proliferation. PMID:25590618

  16. The System of Adult Education in Yugoslavia. Notes and Essays on Education for Adults, 59.

    ERIC Educational Resources Information Center

    Savicevic, Dusan M.

    Now an integral part of the Yugoslav national educational system, adult education in Yugoslavia is based on the principles of permanence, democracy, decentralization, functional unity, diversity and dynamism, and voluntarism. Adult basic, vocational, general, and other forms of adult education are offered in varying degrees and forms by primary…

  17. Olfactory perceptual stability and discrimination.

    PubMed

    Barnes, Dylan C; Hofacer, Rylon D; Zaman, Ashiq R; Rennaker, Robert L; Wilson, Donald A

    2008-12-01

    No two roses smell exactly alike, but our brain accurately bundles these variations into a single percept 'rose'. We found that ensembles of rat olfactory bulb neurons decorrelate complex mixtures that vary by as little as a single missing component, whereas olfactory (piriform) cortical neural ensembles perform pattern completion in response to an absent component, essentially filling in the missing information and allowing perceptual stability. This piriform cortical ensemble activity predicts olfactory perception. PMID:18978781

  18. The Role of Diverse Institutions in Framing Adult Learning Systems

    ERIC Educational Resources Information Center

    Saar, Ellu; Ure, Odd Bjorn; Desjardins, Richard

    2013-01-01

    This article considers the role of diverse institutions in framing adult learning systems. The focus is on institutional characteristics and configurations in different countries and their potential impact on the extent of adult learning, as well as on inequalities in access to adult learning. Typologies of education and training systems as well…

  19. Neuropeptide complexity in the crustacean central olfactory pathway: immunolocalization of A-type allatostatins and RFamide-like peptides in the brain of a terrestrial hermit crab

    PubMed Central

    2012-01-01

    Background In the olfactory system of malacostracan crustaceans, axonal input from olfactory receptor neurons associated with aesthetascs on the animal’s first pair of antennae target primary processing centers in the median brain, the olfactory lobes. The olfactory lobes are divided into cone-shaped synaptic areas, the olfactory glomeruli where afferents interact with local olfactory interneurons and olfactory projection neurons. The local olfactory interneurons display a large diversity of neurotransmitter phenotypes including biogenic amines and neuropeptides. Furthermore, the malacostracan olfactory glomeruli are regionalized into cap, subcap, and base regions and these compartments are defined by the projection patterns of the afferent olfactory receptor neurons, the local olfactory interneurons, and the olfactory projection neurons. We wanted to know how neurons expressing A-type allatostatins (A-ASTs; synonym dip-allatostatins) integrate into this system, a large family of neuropeptides that share the C-terminal motif –YXFGLamide. Results We used an antiserum that was raised against the A-type Diploptera punctata (Dip)-allatostatin I to analyse the distribution of this peptide in the brain of a terrestrial hermit crab, Coenobita clypeatus (Anomura, Coenobitidae). Allatostatin A-like immunoreactivity (ASTir) was widely distributed in the animal’s brain, including the visual system, central complex and olfactory system. We focussed our analysis on the central olfactory pathway in which ASTir was abundant in the primary processing centers, the olfactory lobes, and also in the secondary centers, the hemiellipsoid bodies. In the olfactory lobes, we further explored the spatial relationship of olfactory interneurons with ASTir to interneurons that synthesize RFamide-like peptides. We found that these two peptides are present in distinct populations of local olfactory interneurons and that their synaptic fields within the olfactory glomeruli are also mostly

  20. Gap junctions in olfactory neurons modulate olfactory sensitivity

    PubMed Central

    2010-01-01

    Background One of the fundamental questions in olfaction is whether olfactory receptor neurons (ORNs) behave as independent entities within the olfactory epithelium. On the basis that mature ORNs express multiple connexins, I postulated that gap junctional communication modulates olfactory responses in the periphery and that disruption of gap junctions in ORNs reduces olfactory sensitivity. The data collected from characterizing connexin 43 (Cx43) dominant negative transgenic mice OlfDNCX, and from calcium imaging of wild type mice (WT) support my hypothesis. Results I generated OlfDNCX mice that express a dominant negative Cx43 protein, Cx43/β-gal, in mature ORNs to inactivate gap junctions and hemichannels composed of Cx43 or other structurally related connexins. Characterization of OlfDNCX revealed that Cx43/β-gal was exclusively expressed in areas where mature ORNs resided. Real time quantitative PCR indicated that cellular machineries of OlfDNCX were normal in comparison to WT. Electroolfactogram recordings showed decreased olfactory responses to octaldehyde, heptaldehyde and acetyl acetate in OlfDNCX compared to WT. Octaldehyde-elicited glomerular activity in the olfactory bulb, measured according to odor-elicited c-fos mRNA upregulation in juxtaglomerular cells, was confined to smaller areas of the glomerular layer in OlfDNCX compared to WT. In WT mice, octaldehyde sensitive neurons exhibited reduced response magnitudes after application of gap junction uncoupling reagents and the effects were specific to subsets of neurons. Conclusions My study has demonstrated that altered assembly of Cx43 or structurally related connexins in ORNs modulates olfactory responses and changes olfactory activation maps in the olfactory bulb. Furthermore, pharmacologically uncoupling of gap junctions reduces olfactory activity in subsets of ORNs. These data suggest that gap junctional communication or hemichannel activity plays a critical role in maintaining olfactory

  1. Olfactory Environment Design for Human Spaceflight

    NASA Astrophysics Data System (ADS)

    Welch, C. S.; Holland, F. J.

    2002-01-01

    Smell is usually deemed the least important of the five senses. To contradict this assertion, however, there is no shortage of scientific literature which concludes that olfaction is of very great significance to humans. Odours have been shown to have a variety of effects on humans, and are capable of changing both behaviour and cognitive processing in ways that we are frequently completely unconscious of. Examples of this include alertness, alteration of mood, capacity for ideation and intellectual performance. To date, the design of human spacecraft has concentrated on making their olfactory environments, where possible, `odour neutral' - that is ensuring that all unpleasant and/or offensive odours are removed. Here it suggested that spacecraft (and other extraterrestrial facilities for human inhabitation) might benefit from having their olfactory environments designed to be `odour positive', that is to use odours and olfaction for the positive benefit of their residents. This paper presents a summary of current olfactory research and considers both its positive and negative implications for humans in space. It then discusses `odour positive' design of spacecraft olfactory environments and the possible benefits accruing from this approach before examining its implications for the architecture of spacecraft environmental control systems.

  2. Neuropeptide Y-like immunoreactive neurons in the human olfactory bulb.

    PubMed

    Ohm, T G; Braak, E; Probst, A; Weindl, A

    1988-06-01

    Neuropeptide Y-like (NPY) immunoreactivity was localized in the adult human olfactory bulb by the unlabeled antibody enzyme (peroxidase anti-peroxidase; PAP) technique in vibratome sections. The majority of NPY-immunoreactive somata was localized in the white matter surrounding the anterior olfactory nucleus. Immunoreactive neurons were less numerous within the anterior olfactory nucleus and within the olfactory bulb layers. NPY-immunoreactive fibres were present in the white matter, the anterior olfactory nucleus, and in the olfactory bulb layers. Fibres within the white matter were generally aligned in a straight path parallel to the long axis of the olfactory bulb and tract. Fibres within the anterior olfactory nucleus showed no clear orientation and displayed numerous branching points. Coiled plexus of NPY-immunoreactive fibres were present in the glomerular layer of the olfactory bulb. Additional characteristics of the NPY-immunoreactive neurons were studied after decolouring the chromogen and restaining the sections with aldehydefuchsin to demonstrate the presence of lipofuscin granules and also with gallocyanin chrome alum to stain the Nissl substance. This analysis showed that the neurons belong to the class of non-pigmented nerve cells. PMID:3251589

  3. Dendritic Organization of Olfactory Inputs to Medial Amygdala Neurons.

    PubMed

    Keshavarzi, Sepideh; Power, John M; Albers, Eva H H; Sullivan, Robert K S; Sah, Pankaj

    2015-09-23

    The medial amygdala (MeA) is a central hub in the olfactory neural network. It receives vomeronasal information directly from the accessory olfactory bulb (AOB) and main olfactory information largely via odor-processing regions such as the olfactory cortical amygdala (CoA). How these inputs are processed by MeA neurons is poorly understood. Using the GAD67-GFP mouse, we show that MeA principal neurons receive convergent AOB and CoA inputs. Somatically recorded AOB synaptic inputs had slower kinetics than CoA inputs, suggesting that they are electrotonically more distant. Field potential recording, pharmacological manipulation, and Ca(2+) imaging revealed that AOB synapses are confined to distal dendrites and segregated from the proximally located CoA synapses. Moreover, unsynchronized AOB inputs had significantly broader temporal summation that was dependent on the activation of NMDA receptors. These findings show that MeA principal neurons process main and accessory olfactory inputs differentially in distinct dendritic compartments. Significance statement: In most vertebrates, olfactory cues are processed by two largely segregated neural pathways, the main and accessory olfactory systems, which are specialized to detect odors and nonvolatile chemosignals, respectively. Information from these two pathways ultimately converges at higher brain regions, one of the major hubs being the medial amygdala. Little is known about how olfactory inputs are processed by medial amygdala neurons. This study shows that individual principal neurons in this region receive input from both pathways and that these synapses are spatially segregated on their dendritic tree. We provide evidence suggesting that this dendritic segregation leads to distinct input integration and impact on neuronal output; hence, dendritic mechanisms control olfactory processing in the amygdala. PMID:26400933

  4. Enhanced trapping of stable flies via olfactory and visual cues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adult stable flies are highly attracted to the so-called Alsynite cylinder trap; however this trap is expensive. Here we report the development of a cheaper and better white panel trap with options of adding visual and olfactory stimuli for enhanced stable fly trapping. The white panel trap attracte...

  5. Functional Evidence of Multidrug Resistance Transporters (MDR) in Rodent Olfactory Epithelium

    PubMed Central

    Molinas, Adrien; Sicard, Gilles; Jakob, Ingrid

    2012-01-01

    Background P-glycoprotein (Pgp) and multidrug resistance-associated protein (MRP1) are membrane transporter proteins which function as efflux pumps at cell membranes and are considered to exert a protective function against the entry of xenobiotics. While evidence for Pgp and MRP transporter activity is reported for olfactory tissue, their possible interaction and participation in the olfactory response has not been investigated. Principal Findings Functional activity of putative MDR transporters was assessed by means of the fluorometric calcein acetoxymethyl ester (calcein-AM) accumulation assay on acute rat and mouse olfactory tissue slices. Calcein-AM uptake was measured as fluorescence intensity changes in the presence of Pgp or MRP specific inhibitors. Epifluorescence microscopy measured time course analysis in the olfactory epithelium revealed significant inhibitor-dependent calcein uptake in the presence of each of the selected inhibitors. Furthermore, intracellular calcein accumulation in olfactory receptor neurons was also significantly increased in the presence of either one of the Pgp or MRP inhibitors. The presence of Pgp or MRP1 encoding genes in the olfactory mucosa of rat and mouse was confirmed by RT-PCR with appropriate pairs of species-specific primers. Both transporters were expressed in both newborn and adult olfactory mucosa of both species. To assess a possible involvement of MDR transporters in the olfactory response, we examined the electrophysiological response to odorants in the presence of the selected MDR inhibitors by recording electroolfactograms (EOG). In both animal species, MRPs inhibitors induced a marked reduction of the EOG magnitude, while Pgp inhibitors had only a minor or no measurable effect. Conclusions The findings suggest that both Pgp and MRP transporters are functional in the olfactory mucosa and in olfactory receptor neurons. Pgp and MRPs may be cellular constituents of olfactory receptor neurons and represent potential

  6. Re-establishment of olfactory and taste functions

    PubMed Central

    Welge-Lüssen, Antje

    2005-01-01

    The incidence of olfactory disorders is appoximately 1-2% and they can seriously impact on the quality of life. Quantitative disorders (hyposmia, anosmia) are distinguished from qualitative disorders (parosmia, phantosmia). Olfactory disorders are classified according to the etiology and therapy is planned according to the underlying pathophysiology. In ENT patients olfactory disorders caused by sinonasal diseases are the most common ones, followed by postviral disorders. Therapy consists of topical and systemic steroids, whereas systemic application seems to be of greater value. It is very difficult to predict the improvement of olfactory function using surgery, moreover, the long term - success in surgery is questionable. Isolated taste disorders are rare and in most often caused by underlying diseases or side effects of medications. A meticulous history is necessary and helps to choose effective treatment. In selected cases zinc might be useful. PMID:22073054

  7. Olfactory deprivation increases dopamine D2 receptor density in the rat olfactory bulb

    SciTech Connect

    Guthrie, K.M.; Pullara, J.M.; Marshall, J.F.; Leon, M. )

    1991-05-01

    Unilateral olfactory deprivation during postnatal development results in significant anatomical and neurochemical changes in the deprived olfactory bulb. Perhaps the most dramatic neurochemical change is the loss of dopaminergic expression by neurons of the glomerular region. The authors describe here the effects of early olfactory deprivation on other elements of the bulb dopaminergic system, namely the dopamine receptors of the olfactory bulb. Rat pups had a single naris occluded on postnatal day 2 (PN2). On PN20 or PN60, animals were sacrificed and the bulbs were examined for catecholamine levels or D2 and D1 dopamine receptor binding. Receptor densities were quantified by in vitro autoradiography using the tritiated antagonists spiperone (D2) and SCH23390 (D1). Dopamine uptake sites were similarly examined using tritiated mazindol. No significant specific labeling of D1 or mazindol sites was observed in the olfactory bulbs of control or experimental animals at either age. Normal animals displayed prominent labeling of D2 sites in the glomerular and nerve layers. After 60 days of deprivation, deprived bulbs exhibited an average increase in D2 receptor density of 32%. As determined by Scatchard analysis, the mean values for Kd and Bmax were 0.134 nM and 293 fmol/mg protein in normal bulbs, and 0.136 nM and 403 fmol/mg protein in deprived bulbs. The results suggest that, as in the neostriatum, dopamine depletion in the olfactory bulb leads to an upregulation of D2 receptor sites. This change may represent an attempt by the system to adapt neurochemically to reduced dopaminergic activity and thereby maintain bulb function.

  8. Olfactory Stimuli Increase Presence in Virtual Environments

    PubMed Central

    Munyan, Benson G.; Neer, Sandra M.; Beidel, Deborah C.; Jentsch, Florian

    2016-01-01

    Background Exposure therapy (EXP) is the most empirically supported treatment for anxiety and trauma-related disorders. EXP consists of repeated exposure to a feared object or situation in the absence of the feared outcome in order to extinguish associated anxiety. Key to the success of EXP is the need to present the feared object/event/situation in as much detail and utilizing as many sensory modalities as possible, in order to augment the sense of presence during exposure sessions. Various technologies used to augment the exposure therapy process by presenting multi-sensory cues (e.g., sights, smells, sounds). Studies have shown that scents can elicit emotionally charged memories, but no prior research has examined the effect of olfactory stimuli upon the patient’s sense of presence during simulated exposure tasks. Methods 60 adult participants navigated a mildly anxiety-producing virtual environment (VE) similar to those used in the treatment of anxiety disorders. Participants had no autobiographical memory associated with the VE. State anxiety, Presence ratings, and electrodermal (EDA) activity were collected throughout the experiment. Results Utilizing a Bonferroni corrected Linear Mixed Model, our results showed statistically significant relationships between olfactory stimuli and presence as assessed by both the Igroup Presence Questionnaire (IPQ: R2 = 0.85, (F(3,52) = 6.625, p = 0.0007) and a single item visual-analogue scale (R2 = 0.85, (F(3,52) = 5.382, p = 0.0027). State anxiety was unaffected by the presence or absence of olfactory cues. EDA was unaffected by experimental condition. Conclusion Olfactory stimuli increase presence in virtual environments that approximate those typical in exposure therapy, but did not increase EDA. Additionally, once administered, the removal of scents resulted in a disproportionate decrease in presence. Implications for incorporating the use of scents to increase the efficacy of exposure therapy is discussed. PMID

  9. The loss of scents: do defects in olfactory sensory neuron development underlie human disease?

    PubMed

    Whitlock, Kathleen E

    2015-06-01

    The olfactory system is a fascinating and beguiling sensory system: olfactory sensory neurons detect odors underlying behaviors essential for mate choice, food selection, and escape from predators, among others. These sensory neurons are unique in that they have dendrites contacting the outside world, yet their first synapse lies in the central nervous system. The information entering the central nervous system is used to create odor memories that play a profound role in recognition of individuals, places, and appropriate foods. Here, the structure of the olfactory epithelium is given as an overview to discuss the origin of the olfactory placode, the plasticity of the olfactory sensory neurons, and finally the origins of the gonadotropin-releasing hormone neuroendocrine cells. For the purposes of this review, the development of the peripheral sensory system will be analyzed, incorporating recently published studies highlighting the potential novelties in development mechanisms. Specifically, an emerging model where the olfactory epithelium and olfactory bulb develop simultaneously from a continuous neurectoderm patterned at the end of gastrulation, and the multiple origins of the gonadotropin-releasing hormone neuroendocrine cells associated with the olfactory sensory system development will be presented. Advances in the understanding of the basic mechanisms underlying olfactory sensory system development allows for a more thorough understanding of the potential causes of human disease. PMID:26111003

  10. Mechanisms of regulation of olfactory transduction and adaptation in the olfactory cilium.

    PubMed

    Antunes, Gabriela; Sebastião, Ana Maria; Simoes de Souza, Fabio Marques

    2014-01-01

    Olfactory adaptation is a fundamental process for the functioning of the olfactory system, but the underlying mechanisms regulating its occurrence in intact olfactory sensory neurons (OSNs) are not fully understood. In this work, we have combined stochastic computational modeling and a systematic pharmacological study of different signaling pathways to investigate their impact during short-term adaptation (STA). We used odorant stimulation and electroolfactogram (EOG) recordings of the olfactory epithelium treated with pharmacological blockers to study the molecular mechanisms regulating the occurrence of adaptation in OSNs. EOG responses to paired-pulses of odorants showed that inhibition of phosphodiesterases (PDEs) and phosphatases enhanced the levels of STA in the olfactory epithelium, and this effect was mimicked by blocking vesicle exocytosis and reduced by blocking cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) and vesicle endocytosis. These results suggest that G-coupled receptors (GPCRs) cycling is involved with the occurrence of STA. To gain insights on the dynamical aspects of this process, we developed a stochastic computational model. The model consists of the olfactory transduction currents mediated by the cyclic nucleotide gated (CNG) channels and calcium ion (Ca(2+))-activated chloride (CAC) channels, and the dynamics of their respective ligands, cAMP and Ca(2+), and it simulates the EOG results obtained under different experimental conditions through changes in the amplitude and duration of cAMP and Ca(2+) response, two second messengers implicated with STA occurrence. The model reproduced the experimental data for each pharmacological treatment and provided a mechanistic explanation for the action of GPCR cycling in the levels of second messengers modulating the levels of STA. All together, these experimental and theoretical results indicate the existence of a mechanism of regulation of STA by signaling pathways that control

  11. Mechanisms of Regulation of Olfactory Transduction and Adaptation in the Olfactory Cilium

    PubMed Central

    Antunes, Gabriela; Sebastião, Ana Maria; Simoes de Souza, Fabio Marques

    2014-01-01

    Olfactory adaptation is a fundamental process for the functioning of the olfactory system, but the underlying mechanisms regulating its occurrence in intact olfactory sensory neurons (OSNs) are not fully understood. In this work, we have combined stochastic computational modeling and a systematic pharmacological study of different signaling pathways to investigate their impact during short-term adaptation (STA). We used odorant stimulation and electroolfactogram (EOG) recordings of the olfactory epithelium treated with pharmacological blockers to study the molecular mechanisms regulating the occurrence of adaptation in OSNs. EOG responses to paired-pulses of odorants showed that inhibition of phosphodiesterases (PDEs) and phosphatases enhanced the levels of STA in the olfactory epithelium, and this effect was mimicked by blocking vesicle exocytosis and reduced by blocking cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) and vesicle endocytosis. These results suggest that G-coupled receptors (GPCRs) cycling is involved with the occurrence of STA. To gain insights on the dynamical aspects of this process, we developed a stochastic computational model. The model consists of the olfactory transduction currents mediated by the cyclic nucleotide gated (CNG) channels and calcium ion (Ca2+)-activated chloride (CAC) channels, and the dynamics of their respective ligands, cAMP and Ca2+, and it simulates the EOG results obtained under different experimental conditions through changes in the amplitude and duration of cAMP and Ca2+ response, two second messengers implicated with STA occurrence. The model reproduced the experimental data for each pharmacological treatment and provided a mechanistic explanation for the action of GPCR cycling in the levels of second messengers modulating the levels of STA. All together, these experimental and theoretical results indicate the existence of a mechanism of regulation of STA by signaling pathways that control GPCR

  12. The Arlington Adult Learning System (AALS) Curriculum: A Transitional ESL Curriculum for Adults.

    ERIC Educational Resources Information Center

    Arlington County Public Schools, VA. REEP, Arlington Education and Employment Program.

    The English-as-a-Second-Language (ESL) curriculum of the Arlington (Virginia) Adult Learning System (AALS) is presented. AALS is a consortium in which an adult education provider (the public school system) coordinates efforts of its own organization with a community-based organization, a vocational institute, and a university to transition…

  13. From the Cover: Odor maps in the olfactory cortex

    NASA Astrophysics Data System (ADS)

    Zou, Zhihua; Li, Fusheng; Buck, Linda B.

    2005-05-01

    In the olfactory system, environmental chemicals are deconstructed into neural signals and then reconstructed to form odor perceptions. Much has been learned about odor coding in the olfactory epithelium and bulb, but little is known about how odors are subsequently encoded in the cortex to yield diverse perceptions. Here, we report that the representation of odors by fixed glomeruli in the olfactory bulb is transformed in the cortex into highly distributed and multiplexed odor maps. In the mouse olfactory cortex, individual odorants are represented by subsets of sparsely distributed neurons. Different odorants elicit distinct, but partially overlapping, patterns that are strikingly similar among individuals. With increases in odorant concentration, the representations expand spatially and include additional cortical neurons. Structurally related odorants have highly related representations, suggesting an underlying logic to the mapping of odor identities in the cortex. odorant receptor | smell

  14. The muted sense: neurocognitive limitations of olfactory language

    PubMed Central

    Olofsson, Jonas K.; Gottfried, Jay A.

    2015-01-01

    Most people find it profoundly difficult to name familiar smells. This difficulty persists even though perceptual odor processing and visual object naming are unimpaired, implying deficient sensory-specific interactions with the language system. In this article, we synthesize recent behavioral and neuroimaging data to develop a biologically informed framework for olfactory lexical processing in the human brain. Our central premise is that the difficulty in naming common objects through olfactory (compared to visual) stimulation is the end result of cumulative effects occurring at three successive stages of the olfactory language pathway: object perception, lexical-semantic integration, and verbalization. Understanding the neurocognitive mechanisms by which the language network interacts with olfaction can yield unique insights into the elusive nature of olfactory naming. PMID:25979848

  15. Unravelling the Olfactory Sense: From the Gene to Odor Perception.

    PubMed

    Silva Teixeira, Carla S; Cerqueira, Nuno M F S A; Silva Ferreira, António C

    2016-02-01

    Although neglected by science for a long time, the olfactory sense is now the focus of a panoply of studies that bring new insights and raises interesting questions regarding its functioning. The importance in the clarification of this process is of interest for science, but also motivated by the food and perfume industries boosted by a consumer society with increasingly demands for higher quality standards. In this review, a general overview of the state of art of science regarding the olfactory sense is presented with the main focus on the peripheral olfactory system. Special emphasis will be given to the deorphanization of the olfactory receptors (ORs), a critical issue because the specificity and functional properties of about 90% of human ORs remain unknown mainly due to the difficulties associated with the functional expression of ORs in high yields. PMID:26688501

  16. The muted sense: neurocognitive limitations of olfactory language.

    PubMed

    Olofsson, Jonas K; Gottfried, Jay A

    2015-06-01

    Most people find it profoundly difficult to name familiar smells. This difficulty persists even when perceptual odor processing and visual object naming are unimpaired, implying deficient sensory-specific interactions with the language system. Here we synthesize recent behavioral and neuroimaging data to develop a biologically informed framework for olfactory lexical processing in the human brain. Our central premise is that the difficulty in naming common objects through olfactory (compared with visual) stimulation is the end result of cumulative effects occurring at three successive stages of the olfactory language pathway: object perception, lexical-semantic integration, and verbalization. Understanding the neurocognitive mechanisms by which the language network interacts with olfaction can yield unique insights into the elusive nature of olfactory naming. PMID:25979848

  17. Calcium and olfactory transduction.

    PubMed

    Winegar, B D; Rosick, E R; Schafer, R

    1988-01-01

    1. Inorganic cations, organic calcium antagonists, and calmodulin antagonists were applied to olfactory epithelia of frogs (Rana pipiens) while recording electroolfactogram (EOG) responses. 2. Inorganic cations inhibited EOGs in a rank order, reflecting their calcium channel blocking potency: La3+ greater than Zn2+ greater than Cd2+ greater than Al3+ greater than Ca2+ greater than Sr2+ greater than Co2+ greater than Ba2+ greater than Mg2+. Barium ion significantly enhanced EOGs immediately following application. 3. Diltiazem and verapamil produced dose-dependent EOG inhibition. 4. Calmodulin antagonists inhibited EOGs without correlation to their anti-calmodulin potency. PMID:2904344

  18. The locust olfactory system as a case study for modeling dynamics of neurobiological networks: from discrete time neurons to continuous time neurons.

    PubMed

    Quenet, B; Horcholle-Bossavit, G

    2007-11-01

    Both chaotic and periodic activities are observed in networks of the central nervous systems. We choose the locust olfactory system as a good case study to analyze the relationships between networks' structure and the types of dynamics involved in coding mechanisms. In our modeling approach, we first build a fully connected recurrent network of synchronously updated McCulloch and Pitts neurons (MC-P type). In order to measure the use of the temporal dimension in the complex spatio-temporal patterns produced by the networks, we have defined an index the Normalized Euclidian Distance NED. We find that for appropriate parameters of input and connectivity, when adding some strong connections to the initial random synaptic matrices, it was easy to get the emergence of both robust oscillations and distributed synchrony in the spatiotemporal patterns. Then, in order to validate the MC-P model as a tool for analysis for network properties, we examine the dynamic behavior of networks of continuous time model neuron (Izhikevitch Integrate and Fire model -IFI-), implementing the same network characteristics. In both models, similarly to biological PN, the activity of excitatory neurons are phase-locked to different cycles of oscillations which remind the ones of the local field potential (LFP), and nevertheless exhibit dynamic behavior complex enough to be the basis of spatio-temporal codes. PMID:18075120

  19. Rhodioloside ameliorates depressive behavior via up-regulation of monoaminergic system activity and anti-inflammatory effect in olfactory bulbectomized rats.

    PubMed

    Zhang, Xu; Du, Qianming; Liu, Chao; Yang, Yan; Wang, Jianing; Duan, Suqian; Duan, Junguo

    2016-07-01

    Rhodioloside, a major constituent from roots of Rhodiola rosea, has been previously confirmed to alleviate the hyperactivity in olfactory bulbectomized (OBX) rats exposed to the open field and to decrease the immobility time in the forced swimming test (FST) and tail suspension test (TST). However, its antidepressant effects and mechanisms remain unclear. This study aimed to evaluate the antidepressant effect and the potential mechanisms of rhodioloside in OBX rats. ELISA kits, HPLC-MS and western blot analysis were applied to explore the underlying antidepressant mechanisms of rhodioloside. Rhodioloside (20, 40mg/kg) significantly reversed OBX-induced reduction in sucrose consumption. It was also observed that administration of rhodioloside (20, 40mg/kg) decreased pro-inflammatory cytokines interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) levels and inhibits nuclear factor-kappa B (NF-κB) activation, as well as normalized the monoaminergic system changes in prefrontal cortex (PFC) of OBX rats. These results confirmed the antidepressant-like effect of rhodioloside, which might be primarily based on its up-regulation of the monoaminergic system activity and anti-inflammatory effect. PMID:27214337

  20. A Micro-Preconcentrator Combined Olfactory Sensing System with a Micromechanical Cantilever Sensor for Detecting 2,4-Dinitrotoluene Gas Vapor

    PubMed Central

    Chae, Myung-Sic; Kim, Jinsik; Yoo, Yong Kyoung; Kang, Ji Yoon; Lee, Jeong Hoon; Hwang, Kyo Seon

    2015-01-01

    Preventing unexpected explosive attacks and tracing explosion-related molecules require the development of highly sensitive gas-vapor detection systems. For that purpose, a micromechanical cantilever-based olfactory sensing system including a sample preconcentrator was developed to detect 2,4-dinitrotoluene (2,4-DNT), which is a well-known by-product of the explosive molecule trinitrotoluene (TNT) and exists in concentrations on the order of parts per billion in the atmosphere at room temperature. A peptide receptor (His-Pro-Asn-Phe-Ser-Lys-Tyr-Ile-Leu-His-Gln-Arg) that has high binding affinity for 2,4-DNT was immobilized on the surface of the cantilever sensors to detect 2,4-DNT vapor for highly selective detection. A micro-preconcentrator (µPC) was developed using Tenax-TA adsorbent to produce higher concentrations of 2,4-DNT molecules. The preconcentration was achieved via adsorption and thermal desorption phenomena occurring between target molecules and the adsorbent. The µPC directly integrated with a cantilever sensor and enhanced the sensitivity of the cantilever sensor as a pretreatment tool for the target vapor. The response was rapidly saturated within 5 min and sustained for more than 10 min when the concentrated vapor was introduced. By calculating preconcentration factor values, we verified that the cantilever sensor provides up to an eightfold improvement in sensing performance. PMID:26213944

  1. Diverse Representations of Olfactory Information in Centrifugal Feedback Projections

    PubMed Central

    Osakada, Fumitaka; Tarabrina, Anna; Kizer, Erin; Callaway, Edward M.; Gage, Fred H.; Sejnowski, Terrence J.

    2016-01-01

    Although feedback or centrifugal projections from higher processing centers of the brain to peripheral regions have long been known to play essential functional roles, the anatomical organization of these connections remains largely unknown. Using a virus-based retrograde labeling strategy and 3D whole-brain reconstruction methods, we mapped the spatial organization of centrifugal projections from two olfactory cortical areas, the anterior olfactory nucleus (AON) and the piriform cortex, to the granule cell layer of the main olfactory bulb in the mouse. Both regions are major recipients of information from the bulb and are the largest sources of feedback to the bulb, collectively constituting circuits essential for olfactory coding and olfactory behavior. We found that, although ipsilateral inputs from the AON were uniformly distributed, feedback from the contralateral AON had a strong ventral bias. In addition, we observed that centrifugally projecting neurons were spatially clustered in the piriform cortex, in contrast to the distributed feedforward axonal inputs that these cells receive from the principal neurons of the bulb. Therefore, information carried from the bulb to higher processing structures by anatomically stereotypic projections is likely relayed back to the bulb by organizationally distinct feedback projections that may reflect different coding strategies and therefore different functional roles. SIGNIFICANCE STATEMENT Principles of anatomical organization, sometimes instantiated as “maps” in the mammalian brain, have provided key insights into the structure and function of circuits in sensory systems. Generally, these characterizations focus on projections from early sensory processing areas to higher processing structures despite considerable evidence that feedback or centrifugal projections often constitute major conduits of information flow. Our results identify structure in the organization of centrifugal feedback projections to the

  2. Evidence for a Peripheral Olfactory Memory in Imprinted Salmon

    NASA Astrophysics Data System (ADS)

    Nevitt, Gabrielle A.; Dittman, Andrew H.; Quinn, Thomas P.; Moody, William J., Jr.

    1994-05-01

    The remarkable homing ability of salmon relies on olfactory cues, but its cellular basis is unknown. To test the role of peripheral olfactory receptors in odorant memory retention, we imprinted coho salmon (Oncorhynchus kisutch) to micromolar concentrations of phenyl ethyl alcohol during parr-smolt transformation. The following year, we measured phenyl ethyl alcohol responses in the peripheral receptor cells using patch clamp. Cells from imprinted fish showed increased sensitivity to phenyl ethyl alcohol compared either to cells from naive fish or to sensitivity to another behaviorally important odorant (L-serine). Field experiments verified an increased behavioral preference for phenyl ethyl alcohol by imprinted salmon as adults. Thus, some component of the imprinted olfactory homestream memory appears to be retained peripherally.

  3. Training Delivery Systems for Adult Learners. A Bibliography.

    ERIC Educational Resources Information Center

    Florida State Univ., Tallahassee. Center for Instructional Development and Services.

    This bibliography focuses on the training needs of adults and the incorporation of the most effective training delivery systems for adults into job training programs. It includes citations exploring current training practices, methods, and philosophies in both the private sector and the educational system; how each system can learn from the…

  4. Alteration of the stability of Bag-1 protein in the control of olfactory neuronal apoptosis.

    PubMed

    Sourisseau, T; Desbois, C; Debure, L; Bowtell, D D; Cato, A C; Schneikert, J; Moyse, E; Michel, D

    2001-04-01

    Normal apoptosis occurs continuously in the olfactory neuroepithelium of adult vertebrates, making it a useful model for studying neuronal apoptosis. Here we demonstrate that overexpression of the anti-apoptotic Bag-1 gene in olfactory neuronal cells confers a strong resistance to apoptosis. Conversely decreased levels of Bag-1 were found to precede a massive wave of olfactory neuronal apoptosis triggered by synaptic target ablation. We show that the decrease is brought about by ubiquitination and subsequent degradation of the Bag-1 protein. The ring finger protein Siah-2 is a likely candidate for the ubiquitination reaction since Siah-2 mRNA accumulated in lesioned olfactory neuroepithelium and overexpression of Siah-2 stimulated Bag-1 ubiquitination and degradation in transient expression assays. These results together identify destabilization of Bag-1 as a necessary step in olfactory neuronal apoptosis. PMID:11257006

  5. The nasal cavity of the sheep and its olfactory sensory epithelium.

    PubMed

    Barrios, Arthur William; Sanchez Quinteiro, Pablo; Salazar, Ignacio

    2014-12-01

    Macro and microdissection methods, conventional histology and immunohistochemical procedures were used to investigate the nasal cavity and turbinate complex in fetal and adult sheep, with special attention to the ethmoturbinates, the vestibular mucosa, and the septal mucosa posterior to the vomeronasal organ. The ectoturbinates, which are variable in number and size, emerge and develop later than the endoturbinates. The olfactory sensory epithelium is composed of basal cells, neurons, and sustentacular cells organized in strata, but numerous different types are distinguishable on the basis of their thickness and other properties; all variants are present on the more developed turbinates, endoturbinates II and III. Mature neurons and olfactory nerve bundles express olfactory marker protein. We found no structure with the characteristics that in mouse define the septal organ or the ganglion of Grüneberg. Our results thus suggest that in sheep olfactory sensory neurons are exclusively concentrated in the main olfactory epithelium and (to a lesser extent) in the vomeronasal organ. PMID:25213000

  6. Multidimensional representation of odors in the human olfactory cortex.

    PubMed

    Fournel, A; Ferdenzi, C; Sezille, C; Rouby, C; Bensafi, M

    2016-06-01

    What is known as an odor object is an integrated representation constructed from physical features, and perceptual attributes mainly mediated by the olfactory and trigeminal systems. The aim of the present study was to comprehend how this multidimensional representation is organized, by deciphering how similarities in the physical, olfactory and trigeminal perceptual spaces of odors are represented in the human brain. To achieve this aim, we combined psychophysics, functional MRI and multivariate representational similarity analysis. Participants were asked to smell odors diffused by an fMRI-compatible olfactometer and to rate each smell along olfactory dimensions (pleasantness, intensity, familiarity and edibility) and trigeminal dimensions (irritation, coolness, warmth and pain). An event-related design was implemented, presenting different odorants. Results revealed that (i) pairwise odorant similarities in anterior piriform cortex (PC) activity correlated with pairwise odorant similarities in chemical properties (P < 0.005), (ii) similarities in posterior PC activity correlated with similarities in olfactory perceptual properties (P <0.01), and (iii) similarities in amygdala activity correlated with similarities in trigeminal perceptual properties (P < 0.01). These findings provide new evidence that extraction of physical, olfactory and trigeminal features is based on specific fine processing of similarities between odorous stimuli in a distributed manner in the olfactory system. Hum Brain Mapp 37:2161-2172, 2016. © 2016 Wiley Periodicals, Inc. PMID:26991044

  7. Direct transport of inhaled xylene and its metabolites from the olfactory mucosa to the glomeruli of the olfactory bulbs

    SciTech Connect

    Lewis, J.L.; Dahl, A.R.; Kracko, D.A.

    1994-11-01

    The olfactory epithelium is a unique tissue in that single receptor neurons have dendrites in contact with the external environment at the nasal airway, and axon terminals that penetrate the cribriform plate and synapse in the olfactory bulb. The Central Nervous System (CNS) is protected from systematically circulating toxicants by a blood-brain barrier primarily composed of tight junctions between endothelial cells in cerebral vessels and a high metabolic capacity within these cells. No such barrier has yet been defined to protect the CNS from inhaled toxicants. Because all inhalants do not seem to access the CNS directly, a nose-brain barrier seems plausible. The purpose of the work described here is to determine whether or not a nose-brain barrier exists and to define its components. Although such a barrier is likely to be multi-faceted, the present work focuses only on the importance of gross histologic and metabolic characteristics of the olfactory epithelium in olfactory transport.

  8. Odors Discrimination by Olfactory Epithelium Biosensor

    NASA Astrophysics Data System (ADS)

    Liu, Qingjun; Hu, Ning; Ye, Weiwei; Zhang, Fenni; Wang, Hua; Wang, Ping

    2011-09-01

    Humans are exploring the bionic biological olfaction to sense the various trace components of gas or liquid in many fields. For achieving the goal, we endeavor to establish a bioelectronic nose system for odor detection by combining intact bioactive function units with sensors. The bioelectronic nose is based on the olfactory epithelium of rat and microelectrode array (MEA). The olfactory epithelium biosensor generates extracellular potentials in presence of odor, and presents obvious specificity under different odors condition. The odor response signals can be distinguished with each other effectively by signal sorting. On basis of bioactive MEA hybrid system and the improved signal processing analysis, the bioelectronic nose will realize odor discrimination by the specific feature of signals response to various odors.

  9. Sharp wave-associated synchronized inputs from the piriform cortex activate olfactory tubercle neurons during slow-wave sleep

    PubMed Central

    Narikiyo, Kimiya; Manabe, Hiroyuki

    2013-01-01

    During slow-wave sleep, anterior piriform cortex neurons show highly synchronized discharges that accompany olfactory cortex sharp waves (OC-SPWs). The OC-SPW-related synchronized activity of anterior piriform cortex neurons travel down to the olfactory bulb and is thought to be involved in the reorganization of bulbar neuronal circuitry. However, influences of the OC-SPW-related activity on other regions of the central olfactory system are still unknown. Olfactory tubercle is an area of OC and part of ventral striatum that plays a key role in reward-directed motivational behaviors. In this study, we show that in freely behaving rats, olfactory tubercle receives OC-SPW-associated synchronized inputs during slow-wave sleep. Local field potentials in the olfactory tubercle showed SPW-like activities that were in synchrony with OC-SPWs. Single-unit recordings showed that a subpopulation of olfactory tubercle neurons discharged in synchrony with OC-SPWs. Furthermore, correlation analysis of spike activity of anterior piriform cortex and olfactory tubercle neurons revealed that the discharges of anterior piriform cortex neurons tended to precede those of olfactory tubercle neurons. Current source density analysis in urethane-anesthetized rats indicated that the current sink of the OC-SPW-associated input was located in layer III of the olfactory tubercle. These results indicate that OC-SPW-associated synchronized discharges of piriform cortex neurons travel to the deep layer of the olfactory tubercle and drive discharges of olfactory tubercle neurons. The entrainment of olfactory tubercle neurons in the OC-SPWs suggests that OC-SPWs coordinate reorganization of neuronal circuitry across wide areas of the central olfactory system including olfactory tubercle during slow-wave sleep. PMID:24108798

  10. Classifying continuous, real-time e-nose sensor data using a bio-inspired spiking network modelled on the insect olfactory system.

    PubMed

    Diamond, A; Schmuker, M; Berna, A Z; Trowell, S; Nowotny, Thomas

    2016-04-01

    In many application domains, conventional e-noses are frequently outperformed in both speed and accuracy by their biological counterparts. Exploring potential bio-inspired improvements, we note a number of neuronal network models have demonstrated some success in classifying static datasets by abstracting the insect olfactory system. However, these designs remain largely unproven in practical settings, where sensor data is real-time, continuous, potentially noisy, lacks a precise onset signal and accurate classification requires the inclusion of temporal aspects into the feature set. This investigation therefore seeks to inform and develop the potential and suitability of biomimetic classifiers for use with typical real-world sensor data. Taking a generic classifier design inspired by the inhibition and competition in the insect antennal lobe, we apply it to identifying 20 individual chemical odours from the timeseries of responses of metal oxide sensors. We show that four out of twelve available sensors and the first 30 s (10%) of the sensors' continuous response are sufficient to deliver 92% accurate classification without access to an odour onset signal. In contrast to previous approaches, once training is complete, sensor signals can be fed continuously into the classifier without requiring discretization. We conclude that for continuous data there may be a conceptual advantage in using spiking networks, in particular where time is an essential component of computation. Classification was achieved in real time using a GPU-accelerated spiking neural network simulator developed in our group. PMID:26891474

  11. The Olfactory Transcriptomes of Mice

    PubMed Central

    Ibarra-Soria, Ximena; Levitin, Maria O.; Saraiva, Luis R.; Logan, Darren W.

    2014-01-01

    The olfactory (OR) and vomeronasal receptor (VR) repertoires are collectively encoded by 1700 genes and pseudogenes in the mouse genome. Most OR and VR genes were identified by comparative genomic techniques and therefore, in many of those cases, only their protein coding sequences are defined. Some also lack experimental support, due in part to the similarity between them and their monogenic, cell-specific expression in olfactory tissues. Here we use deep RNA sequencing, expression microarray and quantitative RT-PCR in both the vomeronasal organ and whole olfactory mucosa to quantify their full transcriptomes in multiple male and female mice. We find evidence of expression for all VR, and almost all OR genes that are annotated as functional in the reference genome, and use the data to generate over 1100 new, multi-exonic, significantly extended receptor gene annotations. We find that OR and VR genes are neither equally nor randomly expressed, but have reproducible distributions of abundance in both tissues. The olfactory transcriptomes are only minimally different between males and females, suggesting altered gene expression at the periphery is unlikely to underpin the striking sexual dimorphism in olfactory-mediated behavior. Finally, we present evidence that hundreds of novel, putatively protein-coding genes are expressed in these highly specialized olfactory tissues, and carry out a proof-of-principle validation. Taken together, these data provide a comprehensive, quantitative catalog of the genes that mediate olfactory perception and pheromone-evoked behavior at the periphery. PMID:25187969

  12. The olfactory transcriptomes of mice.

    PubMed

    Ibarra-Soria, Ximena; Levitin, Maria O; Saraiva, Luis R; Logan, Darren W

    2014-09-01

    The olfactory (OR) and vomeronasal receptor (VR) repertoires are collectively encoded by 1700 genes and pseudogenes in the mouse genome. Most OR and VR genes were identified by comparative genomic techniques and therefore, in many of those cases, only their protein coding sequences are defined. Some also lack experimental support, due in part to the similarity between them and their monogenic, cell-specific expression in olfactory tissues. Here we use deep RNA sequencing, expression microarray and quantitative RT-PCR in both the vomeronasal organ and whole olfactory mucosa to quantify their full transcriptomes in multiple male and female mice. We find evidence of expression for all VR, and almost all OR genes that are annotated as functional in the reference genome, and use the data to generate over 1100 new, multi-exonic, significantly extended receptor gene annotations. We find that OR and VR genes are neither equally nor randomly expressed, but have reproducible distributions of abundance in both tissues. The olfactory transcriptomes are only minimally different between males and females, suggesting altered gene expression at the periphery is unlikely to underpin the striking sexual dimorphism in olfactory-mediated behavior. Finally, we present evidence that hundreds of novel, putatively protein-coding genes are expressed in these highly specialized olfactory tissues, and carry out a proof-of-principle validation. Taken together, these data provide a comprehensive, quantitative catalog of the genes that mediate olfactory perception and pheromone-evoked behavior at the periphery. PMID:25187969

  13. Expressions of the multidrug resistance-related proteins in the rat olfactory epithelium: a possible role in the phase III xenobiotic metabolizing function.

    PubMed

    Kudo, Hideaki; Doi, Yoshiaki; Fujimoto, Sunao

    2010-01-01

    The xenobiotic metabolizing system is considered to play important roles in the olfaction by the chemical homeostasis. Several phase I and phase II xenobiotic metabolizing enzymes are expressed in the olfactory epithelium in vertebrates. Multidrug resistance-related proteins (MRPs) are the phase III xenobiotic metabolizing pumps that eliminate some conjugated ligands from cells. However, the MRP-expressions in the olfactory epithelium have not been confirmed in the mammals. We investigated gene and protein expressions of MRP type 1 (MRP1) and type 2 (MRP2) isoforms in the adult rat olfactory epithelium in order to clarify the existence of phase III xenobiotic metabolizing pumps in the olfactory organs. Expressions of MRP1 mRNA were detected in the nasal cavity by reverse transcriptase polymerase chain reaction (RT-PCR). The nucleoside sequence of the RT-PCR products were completely identical to that found in other organs of rat. On the contrary, the analysis did not detect expressions of MRP2 mRNA in the nasal cavity. By in situ hybridization using a digoxigenin-labeled MRP1 cRNA probe, signals for MRP1 mRNA were observed preferentially in the perinuclear regions of supporting cells. However, the respiratory epithelial cells did not show the signals for MRP1 mRNA. By immunohistochemistry using a specific antibody to MRP1, MRP1-immunoreactivities were seen mainly on the supporting cells. These findings suggest that MRP1 is involved in olfaction as a part of the "olfactory signal termination" by the chemical homeostasis in the "perireceptor events" of the olfactory epithelium. PMID:19879335

  14. Variation in complex olfactory stimuli and its influence on odour recognition.

    PubMed Central

    Wrigh, Geraldine A.; Smith, Brian H.

    2004-01-01

    Natural olfactory stimuli are often complex and highly variable. The olfactory systems of animals are likely to have evolved to use specific features of olfactory stimuli for identification and discrimination. Here, we train honeybees to learn chemically defined odorant mixtures that systematically vary from trial to trial and then examine how they generalize to each odorant present in the mixture. An odorant that was present at a constant concentration in a mixture becomes more representative of the mixture than other variable odorants. We also show that both variation and intensity of a complex olfactory stimulus affect the rate of generalization by honeybees to subsequent olfactory stimuli. These results have implications for the way that all animals perceive and attend to features of olfactory stimuli. PMID:15058390

  15. Beta and gamma oscillatory activities associated with olfactory memory tasks: different rhythms for different functional networks?

    PubMed Central

    Martin, Claire; Ravel, Nadine

    2014-01-01

    Olfactory processing in behaving animals, even at early stages, is inextricable from top down influences associated with odor perception. The anatomy of the olfactory network (olfactory bulb, piriform, and entorhinal cortices) and its unique direct access to the limbic system makes it particularly attractive to study how sensory processing could be modulated by learning and memory. Moreover, olfactory structures have been early reported to exhibit oscillatory population activities easy to capture through local field potential recordings. An attractive hypothesis is that neuronal oscillations would serve to “bind” distant structures to reach a unified and coherent perception. In relation to this hypothesis, we will assess the functional relevance of different types of oscillatory activity observed in the olfactory system of behaving animals. This review will focus primarily on two types of oscillatory activities: beta (15–40 Hz) and gamma (60–100 Hz). While gamma oscillations are dominant in the olfactory system in the absence of odorant, both beta and gamma rhythms have been reported to be modulated depending on the nature of the olfactory task. Studies from the authors of the present review and other groups brought evidence for a link between these oscillations and behavioral changes induced by olfactory learning. However, differences in studies led to divergent interpretations concerning the respective role of these oscillations in olfactory processing. Based on a critical reexamination of those data, we propose hypotheses on the functional involvement of beta and gamma oscillations for odor perception and memory. PMID:25002840

  16. Analysis of the goldfish Carassius auratus olfactory epithelium transcriptome reveals the presence of numerous non-olfactory GPCR and putative receptors for progestin pheromones

    PubMed Central

    Kolmakov, Nikolay N; Kube, Michael; Reinhardt, Richard; Canario, Adelino VM

    2008-01-01

    Background The goldfish (Carassius auratus) uses steroids and prostaglandins as pheromone cues at different stages of the reproductive cycle to facilitate spawning synchronization. Steroid progestin pheromone binding has been detected in goldfish olfactory membranes but the receptors responsible for this specific binding remain unknown. In order to shed some light on the olfactory epithelium transcriptome and search for possible receptor candidates a large set of EST from this tissue were analysed and compared to and combined with a similar zebrafish (Danio rerio) resource. Results We generated 4,797 high quality sequences from a normalized cDNA library of the goldfish olfactory epithelium, which were clustered in 3,879 unique sequences, grouped in 668 contigs and 3,211 singletons. BLASTX searches produced 3,243 significant (E-value < e-10) hits and Gene Ontology (GO) analysis annotated a further 1,223 of these genes (37.7%). Comparative analysis with zebrafish olfactory epithelium ESTs revealed 1,088 identical unigenes. The transcriptome size of both species was estimated at about 16,400 unigenes, based on the proportion of genes identified involved in Glucose Metabolic Process. Of 124 G-protein coupled receptors identified in the olfactory epithelium of both species, 56 were olfactory receptors. Beta and gamma membrane progestin receptors were also isolated by subcloning of RT-PCR products from both species and an olfactory epithelium specific splice form identified. Conclusion The high similarity between the goldfish and zebrafish olfactory systems allowed the creation of a 'cyprinid' olfactory epithelium library estimated to represent circa 70% of the transcriptome. These results are an important resource for the identification of components of signalling pathways involved in olfaction as well as putative targets for pharmacological and histochemical studies. The possible function of the receptors identified in the olfactory system is described. Moreover, the

  17. Circadian regulation of insect olfactory learning.

    PubMed

    Decker, Susan; McConnaughey, Shannon; Page, Terry L

    2007-10-01

    Olfactory learning in insects has been used extensively for studies on the neurobiology, genetics, and molecular biology of learning and memory. We show here that the ability of the cockroach Leucophaea maderae to acquire olfactory memories is regulated by the circadian system. We investigated the effect of training and testing at different circadian phases on performance in an odor-discrimination test administered 30 min after training (short-term memory) or 48 h after training (long-term memory). When odor preference was tested by allowing animals to choose between two odors (peppermint and vanilla), untrained cockroaches showed a clear preference for vanilla at all circadian phases, indicating that there was no circadian modulation of initial odor preference or ability to discriminate between odors. After differential conditioning, in which peppermint odor was associated with a positive unconditioned stimulus of sucrose solution and vanilla odor was associated with a negative unconditioned stimulus of saline solution, cockroaches conditioned in the early subjective night showed a strong preference for peppermint and retained the memory for at least 2 days. Animals trained and tested at other circadian phases showed significant deficits in performance for both short- and long-term memory. Performance depended on the circadian time (CT) of training, not the CT of testing, and results indicate that memory acquisition rather than retention or recall is modulated by the circadian system. The data suggest that the circadian system can have profound effects on olfactory learning in insects. PMID:17893338

  18. Illuminating odors: when optogenetics brings to light unexpected olfactory abilities

    PubMed Central

    Grimaud, Julien

    2016-01-01

    For hundreds of years, the sense of smell has generated great interest in the world literature, oenologists, and perfume makers but less of scientists. Only recently this sensory modality has gained new attraction in neuroscience when original tools issued from physiology, anatomy, or molecular biology were available to decipher how the brain makes sense of olfactory cues. However, this move was promptly dampened by the difficulties of developing quantitative approaches to study the relationship between the physical characteristics of stimuli and the sensations they create. An upswing of olfactory investigations occurred when genetic tools could be used in combination with devices borrowed from the physics of light (a hybrid technique called optogenetics) to scrutinize the olfactory system and to provide greater physiological precision for studying olfactory-driven behaviors. This review aims to present the most recent studies that have used light to activate components of the olfactory pathway, such as olfactory receptor neurons, or neurons located further downstream, while leaving intact others brain circuits. With the use of optogenetics to unravel the mystery of olfaction, scientists have begun to disentangle how the brain makes sense of smells. In this review, we shall discuss how the brain recognizes odors, how it memorizes them, and how animals make decisions based on odorants they are capable of sensing. Although this review deals with olfaction, the role of light will be central throughout. PMID:27194792

  19. Illuminating odors: when optogenetics brings to light unexpected olfactory abilities.

    PubMed

    Grimaud, Julien; Lledo, Pierre-Marie

    2016-06-01

    For hundreds of years, the sense of smell has generated great interest in the world literature, oenologists, and perfume makers but less of scientists. Only recently this sensory modality has gained new attraction in neuroscience when original tools issued from physiology, anatomy, or molecular biology were available to decipher how the brain makes sense of olfactory cues. However, this move was promptly dampened by the difficulties of developing quantitative approaches to study the relationship between the physical characteristics of stimuli and the sensations they create. An upswing of olfactory investigations occurred when genetic tools could be used in combination with devices borrowed from the physics of light (a hybrid technique called optogenetics) to scrutinize the olfactory system and to provide greater physiological precision for studying olfactory-driven behaviors. This review aims to present the most recent studies that have used light to activate components of the olfactory pathway, such as olfactory receptor neurons, or neurons located further downstream, while leaving intact others brain circuits. With the use of optogenetics to unravel the mystery of olfaction, scientists have begun to disentangle how the brain makes sense of smells. In this review, we shall discuss how the brain recognizes odors, how it memorizes them, and how animals make decisions based on odorants they are capable of sensing. Although this review deals with olfaction, the role of light will be central throughout. PMID:27194792

  20. Intracellular trafficking of a tagged and functional mammalian olfactory receptor.

    PubMed

    Ivic, Lidija; Zhang, Cen; Zhang, Xinmin; Yoon, Sung Ok; Firestein, Stuart

    2002-01-01

    Tagged G-protein-coupled receptors (GPCRs) have been used to facilitate intracellular visualization of these receptors. We have used a combination of adenoviral vector gene transfer and tagged olfactory receptors to help visualize mammalian olfactory receptor proteins in the normal olfactory epithelium of rats, and in cell culture. Three recombinant adenoviral vectors were generated carrying variously tagged versions of rat olfactory receptor I7. The constructs include an N-terminal Flag epitope tag (Flag:I7), enhanced green fluorescent protein (EGFP) fusion protein (EGFP:I7), and a C-terminal EGFP fusion (I7:EGFP). These receptor constructs were assayed in rat olfactory sensory neurons (OSNs) and in a heterologous system (HEK 293 cell line) for protein localization and functional expression. Functional expression of the tagged receptor proteins was tested by electroolfactogram (EOG) recordings in the infected rat olfactory epithelium, and by calcium imaging in single cells. Our results demonstrate that the I7:EGFP fusion protein and Flag:I7 are functionally expressed in OSNs while the EGFP:I7 fusion is not, probably due to inappropriate processing of the protein in the cells. These data suggest that a small epitope tag (Flag) at the N-terminus, or EGFP located at the C-terminus of the receptor, does not affect ligand binding or downstream signaling. In addition, both functional fusion proteins (Flag:I7 and I7:EGFP) are properly targeted to the plasma membrane of HEK 293 cells. PMID:11748633

  1. Glomerular interactions in olfactory processing channels of the antennal lobes

    PubMed Central

    Heinbockel, Thomas; Shields, Vonnie D. C.; Reisenman, Carolina E.

    2014-01-01

    An open question in olfactory coding is the extent of interglomerular connectivity: do olfactory glomeruli and their neurons regulate the odorant responses of neurons innervating other glomeruli? In the olfactory system of the moth Manduca sexta, the response properties of different types of antennal olfactory receptor cells are known. Likewise, a subset of antennal lobe glomeruli has been functionally characterized and the olfactory tuning of their innervating neurons identified. This provides a unique opportunity to determine functional interactions between glomeruli of known input, specifically, (1) glomeruli processing plant odors and (2) glomeruli activated by antennal stimulation with pheromone components of conspecific females. Several studies describe reciprocal inhibitory effects between different types of pheromone-responsive projection neurons suggesting lateral inhibitory interactions between pheromone component-selective glomerular neural circuits. Furthermore, antennal lobe projection neurons that respond to host plant volatiles and innervate single, ordinary glomeruli are inhibited during antennal stimulation with the female’s sex pheromone. The studies demonstrate the existence of lateral inhibitory effects in response to behaviorally significant odorant stimuli and irrespective of glomerular location in the antennal lobe. Inhibitory interactions are present within and between olfactory subsystems (pheromonal and non-pheromonal subsystems), potentially to enhance contrast and strengthen odorant discrimination. PMID:23893248

  2. Differential Muscarinic Modulation in the Olfactory Bulb

    PubMed Central

    Smith, Richard S.; Hu, Ruilong; DeSouza, Andre; Eberly, Christian L.; Krahe, Krista; Chan, Wilson

    2015-01-01

    modulation differentially regulates two parallel circuits that process chemosensory information, the accessory and main olfactory bulb (AOB and MOB, respectively). These circuits consist of remarkably similar synaptic arrangement and neuronal types, yet cholinergic regulation produced strikingly opposing effects in output and intrinsic neurons. Despite these differences, the chemogenetic reduction of cholinergic activity in freely behaving animals disrupted odor discrimination of simple odors, and the investigation of social odors associated with behaviors signaled by the Vomeronasal system. PMID:26224860

  3. Ultrastructural analysis of olfactory ensheathing cells derived from olfactory bulb and nerve of neonatal and juvenile rats.

    PubMed

    Gómez, Rosa M; Ghotme, Kemel; Botero, Lucía; Bernal, Jaime E; Pérez, Rosalía; Barreto, George E; Bustos, Rosa Helena

    2016-02-01

    Olfactory nerve derived and olfactory bulb derived olfactory ensheathing cells (OECs) have the ability to promote axonal regeneration and remyelination, both of which are essential in a successful cell transplant. Thus, morphological identification of OECs is a key aspect to develop an applicable cell therapy for injuries to the nervous system. However, there is no clear definition regarding which developmental stage or anatomical origin of OECs is more adequate for neural repair. In the present study, an ultrastructural comparison was made between OECs recovered from primary cultures of olfactory nerve and bulb in two developmental stages. The most notorious difference between cells obtained from olfactory nerve and bulb was the presence of indented nuclei in bulb derived OECs, suggesting a greater ability for possible chemotaxis. In neonatal OECs abundant mitochondria, lipid vacuoles, and smooth endoplasmic reticulum were detected, suggesting an active lipid metabolism, probably involved in synthesis of myelin. Our results suggest that neonatal OECs obtained from olfactory bulb have microscopic properties that could make them more suitable for neural repair. PMID:26254553

  4. Adenovirus-mediated WGA gene delivery for transsynaptic labeling of mouse olfactory pathways.

    PubMed

    Kinoshita, Nanako; Mizuno, Takeo; Yoshihara, Yoshihiro

    2002-03-01

    Detailed knowledge of neuronal connectivity patterns is indispensable for studies of various aspects of brain functions. We previously established a genetic strategy for visualization of multisynaptic neural pathways by expressing wheat germ agglutinin (WGA) transgene under the control of neuron type-specific promoter elements in transgenic mice and Drosophila. In this paper, we have developed a WGA-expressing recombinant adenoviral vector system and applied it for analysis of the olfactory system. When the WGA-expressing adenovirus was infused into a mouse nostril, various types of cells throughout the olfactory epithelium were infected and expressed WGA protein robustly. WGA transgene products in the olfactory sensory neurons were anterogradely transported along their axons to the olfactory bulb and transsynaptically transferred in glomeruli to dendrites of the second-order neurons, mitral and tufted cells. WGA protein was further conveyed via the lateral olfactory tract to the olfactory cortical areas including the anterior olfactory nucleus, olfactory tubercle, piriform cortex and lateral entorhinal cortex. In addition, transsynaptic retrograde labeling was observed in cholinergic neurons in the horizontal limb of diagonal band, serotonergic neurons in the median raphe nucleus, and noradrenergic neurons in the locus coeruleus, all of which project centrifugal fibers to the olfactory bulb. Thus, the WGA-expressing adenovirus is a useful and powerful tool for tracing neural pathways and could be used in animals that are not amenable to the transgenic technology. PMID:11923184

  5. Olfactory lateralization in homing pigeons: a GPS study on birds released with unilateral olfactory inputs.

    PubMed

    Gagliardo, Anna; Filannino, Caterina; Ioalè, Paolo; Pecchia, Tommaso; Wikelski, Martin; Vallortigara, Giorgio

    2011-02-15

    A large body of evidence has shown that pigeons rely on an olfactory-based navigational map when homing from unfamiliar locations. Previous studies on pigeons released with one nostril occluded highlighted an asymmetry in favour of the right nostril, particularly concerning the initial orientation performance of naïve birds. Nevertheless, all pigeons experiencing only unilateral olfactory input showed impaired homing, regardless of the side of the occluded nostril. So far this phenomenon has been documented only by observing the birds' vanishing bearings. In the present work we recorded the flight tracks of pigeons with previous homing experience equipped with a GPS data logger and released from an unfamiliar location with the right or the left nostril occluded. The analysis of the tracks revealed that the flight path of the birds with the right nostril occluded was more tortuous than that of unmanipulated controls. Moreover, the pigeons smelling with the left nostril interrupted their journey significantly more frequently and displayed more exploratory activity than the control birds, e.g. during flights around a stopover site. These data suggest a more important involvement of the right olfactory system in processing the olfactory information needed for the operation of the navigational map. PMID:21270307

  6. Functional neuroanatomy of Drosophila olfactory memory formation

    PubMed Central

    Guven-Ozkan, Tugba

    2014-01-01

    New approaches, techniques and tools invented over the last decade and a half have revolutionized the functional dissection of neural circuitry underlying Drosophila learning. The new methodologies have been used aggressively by researchers attempting to answer three critical questions about olfactory memories formed with appetitive and aversive reinforcers: (1) Which neurons within the olfactory nervous system mediate the acquisition of memory? (2) What is the complete neural circuitry extending from the site(s) of acquisition to the site(s) controlling memory expression? (3) How is information processed across this circuit to consolidate early-forming, disruptable memories to stable, late memories? Much progress has been made and a few strong conclusions have emerged: (1) Acquisition occurs at multiple sites within the olfactory nervous system but is mediated predominantly by the γ mushroom body neurons. (2) The expression of long-term memory is completely dependent on the synaptic output of α/β mushroom body neurons. (3) Consolidation occurs, in part, through circuit interactions between mushroom body and dorsal paired medial neurons. Despite this progress, a complete and unified model that details the pathway from acquisition to memory expression remains elusive. PMID:25225297

  7. Functional neuroanatomy of Drosophila olfactory memory formation.

    PubMed

    Guven-Ozkan, Tugba; Davis, Ronald L

    2014-10-01

    New approaches, techniques and tools invented over the last decade and a half have revolutionized the functional dissection of neural circuitry underlying Drosophila learning. The new methodologies have been used aggressively by researchers attempting to answer three critical questions about olfactory memories formed with appetitive and aversive reinforcers: (1) Which neurons within the olfactory nervous system mediate the acquisition of memory? (2) What is the complete neural circuitry extending from the site(s) of acquisition to the site(s) controlling memory expression? (3) How is information processed across this circuit to consolidate early-forming, disruptable memories to stable, late memories? Much progress has been made and a few strong conclusions have emerged: (1) Acquisition occurs at multiple sites within the olfactory nervous system but is mediated predominantly by the γ mushroom body neurons. (2) The expression of long-term memory is completely dependent on the synaptic output of α/β mushroom body neurons. (3) Consolidation occurs, in part, through circuit interactions between mushroom body and dorsal paired medial neurons. Despite this progress, a complete and unified model that details the pathway from acquisition to memory expression remains elusive. PMID:25225297

  8. Profound Olfactory Dysfunction in Myasthenia Gravis

    PubMed Central

    Leon-Sarmiento, Fidias E.; Bayona, Edgardo A.; Bayona-Prieto, Jaime; Osman, Allen; Doty, Richard L.

    2012-01-01

    In this study we demonstrate that myasthenia gravis, an autoimmune disease strongly identified with deficient acetylcholine receptor transmission at the post-synaptic neuromuscular junction, is accompanied by a profound loss of olfactory function. Twenty-seven MG patients, 27 matched healthy controls, and 11 patients with polymiositis, a disease with peripheral neuromuscular symptoms analogous to myasthenia gravis with no known central nervous system involvement, were tested. All were administered the University of Pennsylvania Smell Identification Test (UPSIT) and the Picture Identification Test (PIT), a test analogous in content and form to the UPSIT designed to control for non-olfactory cognitive confounds. The UPSIT scores of the myasthenia gravis patients were markedly lower than those of the age- and sex-matched normal controls [respective means (SDs) = 20.15 (6.40) & 35.67 (4.95); p<0.0001], as well as those of the polymiositis patients who scored slightly below the normal range [33.30 (1.42); p<0.0001]. The latter finding, along with direct monitoring of the inhalation of the patients during testing, implies that the MG-related olfactory deficit is unlikely due to difficulties sniffing, per se. All PIT scores were within or near the normal range, although subtle deficits were apparent in both the MG and PM patients, conceivably reflecting influences of mild cognitive impairment. No relationships between performance on the UPSIT and thymectomy, time since diagnosis, type of treatment regimen, or the presence or absence of serum anti-nicotinic or muscarinic antibodies were apparent. Our findings suggest that MG influences olfactory function to the same degree as observed in a number of neurodegenerative diseases in which central nervous system cholinergic dysfunction has been documented. PMID:23082113

  9. Assessment of olfactory function.

    PubMed

    Hummel, Thomas; Welge-Lüessen, Antje

    2006-01-01

    Numerous techniques are available for the investigation of chemosensory functions in humans. They include psychophysical measures of chemosensory function, e.g. odor identification, odor discrimination, odor thresholds, odor memory, and retronasal perception of odors. In order to assess changes related to the patients' quality of life or effects of qualitative olfactory dysfunction, questionnaires are being used. Measures relying to a lesser degree on the subjects' cooperation are e.g. chemosensory event-related potentials, odor-induced changes of the EEG, the electroolfactogram, imaging techniques, or measures of respiration. In a clinical context, however, psychophysical techniques are most frequently used, e.g. tests for odor identification, and odor thresholds. Interpretation of results from these measures is frequently supported by the assessment of chemosensory event-related potentials. Other techniques await further standardization before they will become useful in a clinical context. PMID:16733334

  10. Olfactory receptor signaling.

    PubMed

    Antunes, Gabriela; Simoes de Souza, Fabio Marques

    2016-01-01

    The guanine nucleotide protein (G protein)-coupled receptors (GPCRs) superfamily represents the largest class of membrane protein in the human genome. More than a half of all GPCRs are dedicated to interact with odorants and are termed odorant-receptors (ORs). Linda Buck and Richard Axel, the Nobel Prize laureates in physiology or medicine in 2004, first cloned and characterized the gene family that encode ORs, establishing the foundations to the understanding of the molecular basis for odor recognition. In the last decades, a lot of progress has been done to unravel the functioning of the sense of smell. This chapter gives a general overview of the topic of olfactory receptor signaling and reviews recent advances in this field. PMID:26928542

  11. Detection of alpha-L fucose containing carbohydrates in mouse immature olfactory neurons.

    PubMed

    Ducray, A; Propper, A; Kastner, A

    1999-10-15

    The cellular location of alpha-L fucose was studied in mice olfactory epithelium (OE) using the Ulex europaeus agglutinin-I (UEA-I) and Tetragonolobus purpureas agglutinin (TPA). In adult mice, UEA-I and TPA revealed a layer of cells that mostly correspond to immature olfactory neurons. Moreover, autoradiographic studies after 3H-T incorporation showed that UEA-I cell labelling occurred during the week following the division of neural cell precursors. In newborn animals, active neurogenesis process is associated with a higher number of UEA-I labelled cells. Olfactory neurogenesis may thus involve a transient event of protein fucosylation, preceding axonal growth. PMID:10530509

  12. Sniffing out the contributions of the olfactory tubercle to the sense of smell: hedonics, sensory integration, and more?

    PubMed Central

    Wesson, Daniel W.; Wilson, Donald A.

    2010-01-01

    Since its designation in 1896 as a putative olfactory structure, the olfactory tubercle has received little attention in terms of elucidating its role in the processing and perception of odors. Instead, research on the olfactory tubercle has mostly focused on its relationship with the reward system. Here we provide a comprehensive review of research on the olfactory tubercle – with an emphasis on the likely role of this region in olfactory processing and its contributions to perception. Further, we propose several testable hypotheses regarding the likely involvement of the olfactory tubercle in both basic (odor detection, discrimination, parallel processing of olfactory information) and higher-order (social odor processing, hedonics, multi-modal integration) functions. Together, the information within this review highlights an understudied yet potentially critical component in central odor processing. PMID:20800615

  13. Transformation of the Adult Education System in Slovakia

    NASA Astrophysics Data System (ADS)

    Švec, Štefan

    1998-07-01

    This article examines trends in adult education in Slovakia since it became a separate republic in 1993. Economic and social transformations during this period have led to a re-thinking of the adult education system. The author describes four basic modalities for providing adult education in Slovakia: (1) schools and colleges; (2) cultural centres and similar institutions; (3) institutions for vocational training; (4) voluntary organizations such as trade unions, political parties and ethnic minority groups.

  14. Lesion of the Olfactory Epithelium Accelerates Prion Neuroinvasion and Disease Onset when Prion Replication Is Restricted to Neurons

    PubMed Central

    Crowell, Jenna; Wiley, James A.; Bessen, Richard A.

    2015-01-01

    Natural prion diseases of ruminants are moderately contagious and while the gastrointestinal tract is the primary site of prion agent entry, other mucosae may be entry sites in a subset of infections. In the current study we examined prion neuroinvasion and disease induction following disruption of the olfactory epithelium in the nasal mucosa since this site contains environmentally exposed olfactory sensory neurons that project directly into the central nervous system. Here we provide evidence for accelerated prion neuroinvasion and clinical onset from the olfactory mucosa after disruption and regeneration of the olfactory epithelium and when prion replication is restricted to neurons. In transgenic mice with neuron restricted replication of prions, there was a reduction in survival when the olfactory epithelium was disrupted prior to intranasal inoculation and there was >25% decrease in the prion incubation period. In a second model, the neurotropic DY strain of transmissible mink encephalopathy was not pathogenic in hamsters by the nasal route, but 50% of animals exhibited brain infection and/or disease when the olfactory epithelium was disrupted prior to intranasal inoculation. A time course analysis of prion deposition in the brain following loss of the olfactory epithelium in models of neuron-restricted prion replication suggests that neuroinvasion from the olfactory mucosa is via the olfactory nerve or brain stem associated cranial nerves. We propose that induction of neurogenesis after damage to the olfactory epithelium can lead to prion infection of immature olfactory sensory neurons and accelerate prion spread to the brain. PMID:25822718

  15. Sensitization of olfactory guanylyl cyclase to a specific imprinted odorant in coho salmon.

    PubMed

    Dittman, A H; Quinn, T P; Nevitt, G A; Hacker, B; Storm, D R

    1997-08-01

    The role of cGMP in olfactory signaling is not fully understood, but it is believed to play a modulatory role in intracellular signaling in vertebrate olfactory receptor neurons (ORNs). Here, we present evidence that cGMP in ORNs may play an important role in recognition of biologically relevant odors and olfactory learning. Specifically, we investigated the cellular mechanisms underlying olfactory imprinting in salmon. Salmon learn odors associated with their natal site as juveniles and later use these odors to guide their homing migration. This imprinting is believed to involve sensitization of the peripheral olfactory system to specific homestream odorants. We imprinted juvenile salmon to the odorant beta-phenylethyl alcohol (PEA) and examined the sensitivity of olfactory adenylyl and guanylyl cyclases to PEA during development. Stimulation of guanylyl cyclase activity by PEA was significantly greater in olfactory cilia isolated from PEA-imprinted salmon compared with PEA-naive fish only at the time of the homing migration, 2 years after PEA exposure. These results suggest that sensitization of olfactory guanylyl cyclase may play an important role in olfactory imprinting by salmon. PMID:9292727

  16. Evolutionary Genomics of Genes Involved in Olfactory Behavior in the Drosophila melanogaster Species Group

    PubMed Central

    Lavagnino, Nicolás; Serra, François; Arbiza, Leonardo; Dopazo, Hernán; Hasson, Esteban

    2012-01-01

    Previous comparative genomic studies of genes involved in olfactory behavior in Drosophila focused only on particular gene families such as odorant receptor and/or odorant binding proteins. However, olfactory behavior has a complex genetic architecture that is orchestrated by many interacting genes. In this paper, we present a comparative genomic study of olfactory behavior in Drosophila including an extended set of genes known to affect olfactory behavior. We took advantage of the recent burst of whole genome sequences and the development of powerful statistical tools to analyze genomic data and test evolutionary and functional hypotheses of olfactory genes in the six species of the Drosophila melanogaster species group for which whole genome sequences are available. Our study reveals widespread purifying selection and limited incidence of positive selection on olfactory genes. We show that the pace of evolution of olfactory genes is mostly independent of the life cycle stage, and of the number of life cycle stages, in which they participate in olfaction. However, we detected a relationship between evolutionary rates and the position that the gene products occupy in the olfactory system, genes occupying central positions tend to be more constrained than peripheral genes. Finally, we demonstrate that specialization to one host does not seem to be associated with bursts of adaptive evolution in olfactory genes in D. sechellia and D. erecta, the two specialists species analyzed, but rather different lineages have idiosyncratic evolutionary histories in which both historical and ecological factors have been involved. PMID:22346339

  17. Neurally Encoding Time for Olfactory Navigation

    PubMed Central

    Park, In Jun; Hein, Andrew M.; Bobkov, Yuriy V.; Reidenbach, Matthew A.; Ache, Barry W.; Principe, Jose C.

    2016-01-01

    Accurately encoding time is one of the fundamental challenges faced by the nervous system in mediating behavior. We recently reported that some animals have a specialized population of rhythmically active neurons in their olfactory organs with the potential to peripherally encode temporal information about odor encounters. If these neurons do indeed encode the timing of odor arrivals, it should be possible to demonstrate that this capacity has some functional significance. Here we show how this sensory input can profoundly influence an animal’s ability to locate the source of odor cues in realistic turbulent environments—a common task faced by species that rely on olfactory cues for navigation. Using detailed data from a turbulent plume created in the laboratory, we reconstruct the spatiotemporal behavior of a real odor field. We use recurrence theory to show that information about position relative to the source of the odor plume is embedded in the timing between odor pulses. Then, using a parameterized computational model, we show how an animal can use populations of rhythmically active neurons to capture and encode this temporal information in real time, and use it to efficiently navigate to an odor source. Our results demonstrate that the capacity to accurately encode temporal information about sensory cues may be crucial for efficient olfactory navigation. More generally, our results suggest a mechanism for extracting and encoding temporal information from the sensory environment that could have broad utility for neural information processing. PMID:26730727

  18. Olfactory conditioning in the zebrafish (Danio rerio).

    PubMed

    Braubach, Oliver R; Wood, Heather-Dawn; Gadbois, Simon; Fine, Alan; Croll, Roger P

    2009-03-01

    The zebrafish olfactory system is an attractive model for studying neural processing of chemosensory information. Here we characterize zebrafish olfactory behaviors and their modification through learning, using an apparatus consisting of a circular flow-through tank that allows controlled administration of odorants. When exposed to the amino acids l-alanine and l-valine, naive zebrafish responded with appetitive swimming behavior, which we measured as the number of >90 degrees turns made during 30s observation periods. Such appetitive responses were not observed when naive zebrafish were exposed to an unnatural odorant, phenylethyl alcohol (PEA). Repeated pairing of amino acids or PEA (conditioned stimuli, CS) with food flakes (unconditioned stimuli; UCS) increased odorant-evoked appetitive swimming behavior in all fish tested. The zebrafish also learned to restrict this behavior to the vicinity of a feeding ring, through which UCS were administered. When both nares were temporarily occluded, conditioned fish failed to respond to odorants, confirming that these behaviors were mediated by olfaction. These results represent the first demonstration of a classically conditioned appetitive response to a behaviorally neutral odorant in fish. Furthermore, they complement recent demonstrations of conditional place preferences in fish. By virtue of its robustness and simplicity, this method will be a useful tool for future research into the biological basis of olfactory learning in zebrafish. PMID:19056431

  19. Olfactory receptor patterning in a higher primate.

    PubMed

    Horowitz, Lisa F; Saraiva, Luis R; Kuang, Donghui; Yoon, Kyoung-hye; Buck, Linda B

    2014-09-10

    The mammalian olfactory system detects a plethora of environmental chemicals that are perceived as odors or stimulate instinctive behaviors. Studies using odorant receptor (OR) genes have provided insight into the molecular and organizational strategies underlying olfaction in mice. One important unanswered question, however, is whether these strategies are conserved in primates. To explore this question, we examined the macaque, a higher primate phylogenetically close to humans. Here we report that the organization of sensory inputs in the macaque nose resembles that in mouse in some respects, but not others. As in mouse, neurons with different ORs are interspersed in the macaque nose, and there are spatial zones that differ in their complement of ORs and extend axons to different domains in the olfactory bulb of the brain. However, whereas the mouse has multiple discrete band-like zones, the macaque appears to have only two broad zones. It is unclear whether the organization of OR inputs in a rodent/primate common ancestor degenerated in primates or, alternatively became more sophisticated in rodents. The mouse nose has an additional small family of chemosensory receptors, called trace amine-associated receptors (TAARs), which may detect social cues. Here we find that TAARs are also expressed in the macaque nose, suggesting that TAARs may also play a role in human olfactory perception. We further find that one human TAAR responds to rotten fish, suggesting a possible role as a sentinel to discourage ingestion of food harboring pathogenic microorganisms. PMID:25209267

  20. Neurally Encoding Time for Olfactory Navigation.

    PubMed

    Park, In Jun; Hein, Andrew M; Bobkov, Yuriy V; Reidenbach, Matthew A; Ache, Barry W; Principe, Jose C

    2016-01-01

    Accurately encoding time is one of the fundamental challenges faced by the nervous system in mediating behavior. We recently reported that some animals have a specialized population of rhythmically active neurons in their olfactory organs with the potential to peripherally encode temporal information about odor encounters. If these neurons do indeed encode the timing of odor arrivals, it should be possible to demonstrate that this capacity has some functional significance. Here we show how this sensory input can profoundly influence an animal's ability to locate the source of odor cues in realistic turbulent environments-a common task faced by species that rely on olfactory cues for navigation. Using detailed data from a turbulent plume created in the laboratory, we reconstruct the spatiotemporal behavior of a real odor field. We use recurrence theory to show that information about position relative to the source of the odor plume is embedded in the timing between odor pulses. Then, using a parameterized computational model, we show how an animal can use populations of rhythmically active neurons to capture and encode this temporal information in real time, and use it to efficiently navigate to an odor source. Our results demonstrate that the capacity to accurately encode temporal information about sensory cues may be crucial for efficient olfactory navigation. More generally, our results suggest a mechanism for extracting and encoding temporal information from the sensory environment that could have broad utility for neural information processing. PMID:26730727

  1. Olfactory Receptor Patterning in a Higher Primate

    PubMed Central

    Horowitz, Lisa F.; Saraiva, Luis R.; Kuang, Donghui; Yoon, Kyoung-hye

    2014-01-01

    The mammalian olfactory system detects a plethora of environmental chemicals that are perceived as odors or stimulate instinctive behaviors. Studies using odorant receptor (OR) genes have provided insight into the molecular and organizational strategies underlying olfaction in mice. One important unanswered question, however, is whether these strategies are conserved in primates. To explore this question, we examined the macaque, a higher primate phylogenetically close to humans. Here we report that the organization of sensory inputs in the macaque nose resembles that in mouse in some respects, but not others. As in mouse, neurons with different ORs are interspersed in the macaque nose, and there are spatial zones that differ in their complement of ORs and extend axons to different domains in the olfactory bulb of the brain. However, whereas the mouse has multiple discrete band-like zones, the macaque appears to have only two broad zones. It is unclear whether the organization of OR inputs in a rodent/primate common ancestor degenerated in primates or, alternatively became more sophisticated in rodents. The mouse nose has an additional small family of chemosensory receptors, called trace amine-associated receptors (TAARs), which may detect social cues. Here we find that TAARs are also expressed in the macaque nose, suggesting that TAARs may also play a role in human olfactory perception. We further find that one human TAAR responds to rotten fish, suggesting a possible role as a sentinel to discourage ingestion of food harboring pathogenic microorganisms. PMID:25209267

  2. In goldfish the discriminative ability for odours persists after reduction of the olfactory epithelium, and rapidly returns after olfactory nerve axotomy and crossing bulbs.

    PubMed

    Zippel, H P

    2000-09-29

    Goldfish are ideal vertebrates for the study of regeneration within the peripheral and the central olfactory system. The present behavioural investigations studied the effects of bilateral lesions on the animals' ability to qualitatively discriminate two amino acids (10(-6) M) and their performance in two more difficult tasks: (i) rewarded amino acid applied in a lower concentration, and (ii) rewarded stimulus contaminated. A 50 and 85% reduction of the olfactory epithelium resulted in no recordable behavioural deficit. After axotomy of olfactory nerves and lateral olfactory tractotomy, fishes were anosmic for seven to ten days. Following replacement of sensory cells in the epithelium, and after regeneration of olfactory tract fibres a full functional recovery i.e. a highly specific regeneration, was recorded. After three surgical modifications of the olfactory bulbs' position, (i) crossing olfactory tracts and bulbs, (ii) crossing tracts and turning bulbs, and (iii) turning bulbs upside down, a full functional recovery was recorded for amino-acid discrimination in a similar concentration. A permanent, and similar slight deficit was, however, found during application of different concentrations, and of contaminated stimuli when medial lateral halves of the bulb were in 'incorrect' position (i) and (ii), or olfactory bulbs were positioned in the vicinity of the contralateral epithelium (i) and (ii). PMID:11079402

  3. A TAP1 null mutation leads to an enlarged olfactory bulb and supernumerary, ectopic olfactory glomeruli

    PubMed Central

    Salcedo, Ernesto; Cruz, Nicole M.; Ly, Xuan; Welander, Beth A.; Hanson, Kyle; Kronberg, Eugene; Restrepo, Diego

    2013-01-01

    Major histocompatibility class I (MHCI) molecules are well known for their immunological role in mediating tissue graft rejection. Recently, these molecules were discovered to be expressed in distinct neuronal subclasses, dispelling the long-held tenet that the uninjured brain is immune-privileged. Here, we show that MHCI molecules are expressed in the main olfactory bulb (MOB) of adult animals. Furthermore, we find that mice with diminished levels of MHCI expression have enlarged MOBs containing an increased number of small, morphologically abnormal and ectopically located P2 glomeruli. These findings suggest that MHCI molecules may play an important role in the proper formation of glomeruli in the bulb. PMID:23697805

  4. SVZ-derived newly generated neurons populate several olfactory and limbic forebrain regions

    PubMed Central

    Shapiro, Lee A.; Ng, Kwan; Zhou, Qun-Yong; Ribak, Charles E.

    2009-01-01

    Neurogenesis persists in several regions of the adult mammalian brain. Although the hippocampus and olfactory bulb are most commonly studied in the context of adult neurogenesis, there is an increasing body of evidence in support of neurogenesis occurring outside of these two regions. The current study expands upon previous data by showing newborn neurons with a mature phenotype are located in several olfactory and limbic structures outside of the hippocampus and olfactory bulb, where we previously described DCX/BrdU immature neurons. Notably, newborn neurons with a mature neuronal phenotype are found in the olfactory tubercles, anterior olfactory nuclei, tenia tecta, islands of Calleja, amygdala and lateral entorhinal cortex. The appearance of newborn neurons with a mature phenotype in these regions suggests that these structures are destinations, and that newborn neurons are not simply passing through these structures. In light of the increasing body of evidence for neurogenesis in these, and other olfactory, limbic and striatal structures, we hypothesize that brain regions displaying adult neurogenesis are functionally linked. PMID:18849007

  5. Comparing Adult Learning Systems: An Emerging Political Economy

    ERIC Educational Resources Information Center

    Rees, Gareth

    2013-01-01

    Adult learning systems have come to be dominated by the view that the essential role of adult learning is to generate the high levels of skills deemed necessary for competitiveness and growth in the globalised economy. This 'education gospel' is underpinned by human capital theory (HCT) and its contemporary conceptualisation in terms of…

  6. Systemic vascular function is associated with muscular power in adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Age-associated loss of muscular strength and muscular power are critical determinants of loss of physical function and progression to disability in older adults. In this study, we examined the association of systemic vascular function and measures of muscle strength and power in older adults. Measu...

  7. Olfactory insights into sleep-dependent learning and memory.

    PubMed

    Shanahan, Laura K; Gottfried, Jay A

    2014-01-01

    Sleep is pervasive throughout most of the animal kingdom-even jellyfish and honeybees do it. Although the precise function of sleep remains elusive, research increasingly suggests that sleep plays a key role in memory consolidation. Newly formed memories are highly labile and susceptible to interference, and the sleep period offers an optimal window in which memories can be strengthened or modified. Interestingly, a small but growing research area has begun to explore the ability of odors to modulate memories during sleep. The unique anatomical organization of the olfactory system, including its intimate overlap with limbic systems mediating emotion and memory, and the lack of a requisite thalamic intermediary between the nasal periphery and olfactory cortex, suggests that odors may have privileged access to the brain during sleep. Indeed, it has become clear that the long-held assumption that odors have no impact on the sleeping brain is no longer tenable. Here, we summarize recent studies in both animal and human models showing that odor stimuli experienced in the waking state modulate olfactory cortical responses in sleep-like states, that delivery of odor contextual cues during sleep can enhance declarative memory and extinguish fear memory, and that olfactory associative learning can even be achieved entirely within sleep. Data reviewed here spotlight the emergence of a new research area that should hold far-reaching implications for future neuroscientific investigations of sleep, learning and memory, and olfactory system function. PMID:24767488

  8. Diabetes Impairs Wnt3 Protein-induced Neurogenesis in Olfactory Bulbs via Glutamate Transporter 1 Inhibition.

    PubMed

    Wakabayashi, Tamami; Hidaka, Ryo; Fujimaki, Shin; Asashima, Makoto; Kuwabara, Tomoko

    2016-07-15

    Diabetes is associated with impaired cognitive function. Streptozotocin (STZ)-induced diabetic rats exhibit a loss of neurogenesis and deficits in behavioral tasks involving spatial learning and memory; thus, impaired adult hippocampal neurogenesis may contribute to diabetes-associated cognitive deficits. Recent studies have demonstrated that adult neurogenesis generally occurs in the dentate gyrus of the hippocampus, the subventricular zone, and the olfactory bulbs (OB) and is defective in patients with diabetes. We hypothesized that OB neurogenesis and associated behaviors would be affected in diabetes. In this study, we show that inhibition of Wnt3-induced neurogenesis in the OB causes several behavioral deficits in STZ-induced diabetic rats, including impaired odor discrimination, cognitive dysfunction, and increased anxiety. Notably, the sodium- and chloride-dependent GABA transporters and excitatory amino acid transporters that localize to GABAergic and glutamatergic terminals decreased in the OB of diabetic rats. Moreover, GAT1 inhibitor administration also hindered Wnt3-induced neurogenesis in vitro Collectively, these data suggest that STZ-induced diabetes adversely affects OB neurogenesis via GABA and glutamate transporter systems, leading to functional impairments in olfactory performance. PMID:27226528

  9. SUGGESTIONS FOR COLLECTION AND REPORTING OF CHEMOSENSORY (OLFACTORY) EVENT-RELATED POTENTIALS

    EPA Science Inventory

    Chemosensory event-related potentials hold great promise for furthering understanding of the olfactory system and the processing of olfactory information. ollection of this type of data has been difficult and suggestions are presented to aid investigators new to this field. ugges...

  10. OLFACTORY TOXICITY OF B,B'-IMINODIPROPIONITRILE (IDPN) IN THE RAT

    EPA Science Inventory

    Following a pilot study which revealed olfactory epithelial degeneration induced by iminodipropionitrile (IDPN), dose-response and time course analyses were undertaken to further characterize the effects of IDPN on the olfactory system. Male Long-Evans rats received 25-400 mg/kg ...

  11. A 3'UTR pumilio-binding element directs translational activation in olfactory sensory neurons.

    PubMed

    Kaye, Julia A; Rose, Natalie C; Goldsworthy, Brett; Goga, Andrei; L'Etoile, Noelle D

    2009-01-15

    Prolonged stimulation leads to specific and stable changes in an animal's behavior. In interneurons, this plasticity requires spatial and temporal control of neuronal protein synthesis. Whether such translational control occurs in sensory neurons is not known. Adaptation of the AWC olfactory sensory neurons of C. elegans requires the cGMP-dependent protein kinase EGL-4. Here, we show that the RNA-binding PUF protein FBF-1 is required in the adult AWC for adaptation. In the odor-adapted animal, it increases translation via binding to the egl-4 3' UTR. Further, the PUF protein may localize translation near the sensory cilia and cell body. Although the RNA-binding PUF proteins have been shown to promote plasticity in development by temporally and spatially repressing translation, this work reveals that in the adult nervous system, they can work in a different way to promote experience-dependent plasticity by activating translation in response to environmental stimulation. PMID:19146813

  12. Early Olfactory Processing in Drosophila: Mechanisms and Principles

    PubMed Central

    Wilson, Rachel I.

    2014-01-01

    In the olfactory system of Drosophila melanogaster, it is relatively straightforward to make in vivo measurements of activity in neurons corresponding to targeted processing. This, together with the numerical simplicity of the Drosophila olfactory system, has produced rapid gains in our understanding of Drosophila olfaction. This review summarizes the neurophysiology of the first two layers of this system: the peripheral olfactory receptor neurons and their postsynaptic targets in the antennal lobe. We now understand in some detail the cellular and synaptic mechanisms that shape odor representations in these neurons. Together, these mechanisms imply that interesting neural adaptations to environmental statistics have occurred and place some fundamental constraints on early sensory processing that pose challenges for higher brain regions. These findings suggest some general principles with broad relevance to early sensory processing in other modalities. PMID:23841839

  13. Using insect electroantennogram sensors on autonomous robots for olfactory searches.

    PubMed

    Martinez, Dominique; Arhidi, Lotfi; Demondion, Elodie; Masson, Jean-Baptiste; Lucas, Philippe

    2014-01-01

    Robots designed to track chemical leaks in hazardous industrial facilities or explosive traces in landmine fields face the same problem as insects foraging for food or searching for mates: the olfactory search is constrained by the physics of turbulent transport. The concentration landscape of wind borne odors is discontinuous and consists of sporadically located patches. A pre-requisite to olfactory search is that intermittent odor patches are detected. Because of its high speed and sensitivity, the olfactory organ of insects provides a unique opportunity for detection. Insect antennae have been used in the past to detect not only sex pheromones but also chemicals that are relevant to humans, e.g., volatile compounds emanating from cancer cells or toxic and illicit substances. We describe here a protocol for using insect antennae on autonomous robots and present a proof of concept for tracking odor plumes to their source. The global response of olfactory neurons is recorded in situ in the form of electroantennograms (EAGs). Our experimental design, based on a whole insect preparation, allows stable recordings within a working day. In comparison, EAGs on excised antennae have a lifetime of 2 hr. A custom hardware/software interface was developed between the EAG electrodes and a robot. The measurement system resolves individual odor patches up to 10 Hz, which exceeds the time scale of artificial chemical sensors. The efficiency of EAG sensors for olfactory searches is further demonstrated in driving the robot toward a source of pheromone. By using identical olfactory stimuli and sensors as in real animals, our robotic platform provides a direct means for testing biological hypotheses about olfactory coding and search strategies. It may also prove beneficial for detecting other odorants of interests by combining EAGs from different insect species in a bioelectronic nose configuration or using nanostructured gas sensors that mimic insect antennae. PMID:25145980

  14. Using Insect Electroantennogram Sensors on Autonomous Robots for Olfactory Searches

    PubMed Central

    Martinez, Dominique; Arhidi, Lotfi; Demondion, Elodie; Masson, Jean-Baptiste; Lucas, Philippe

    2014-01-01

    Robots designed to track chemical leaks in hazardous industrial facilities1 or explosive traces in landmine fields2 face the same problem as insects foraging for food or searching for mates3: the olfactory search is constrained by the physics of turbulent transport4. The concentration landscape of wind borne odors is discontinuous and consists of sporadically located patches. A pre-requisite to olfactory search is that intermittent odor patches are detected. Because of its high speed and sensitivity5-6, the olfactory organ of insects provides a unique opportunity for detection. Insect antennae have been used in the past to detect not only sex pheromones7 but also chemicals that are relevant to humans, e.g., volatile compounds emanating from cancer cells8 or toxic and illicit substances9-11. We describe here a protocol for using insect antennae on autonomous robots and present a proof of concept for tracking odor plumes to their source. The global response of olfactory neurons is recorded in situ in the form of electroantennograms (EAGs). Our experimental design, based on a whole insect preparation, allows stable recordings within a working day. In comparison, EAGs on excised antennae have a lifetime of 2 hr. A custom hardware/software interface was developed between the EAG electrodes and a robot. The measurement system resolves individual odor patches up to 10 Hz, which exceeds the time scale of artificial chemical sensors12. The efficiency of EAG sensors for olfactory searches is further demonstrated in driving the robot toward a source of pheromone. By using identical olfactory stimuli and sensors as in real animals, our robotic platform provides a direct means for testing biological hypotheses about olfactory coding and search strategies13. It may also prove beneficial for detecting other odorants of interests by combining EAGs from different insect species in a bioelectronic nose configuration14 or using nanostructured gas sensors that mimic insect antennae15

  15. Functional representation of olfactory impairment in early Alzheimer's disease.

    PubMed

    Förster, Stefan; Vaitl, Andreas; Teipel, Stefan J; Yakushev, Igor; Mustafa, Mona; la Fougère, Christian; Rominger, Axel; Cumming, Paul; Bartenstein, Peter; Hampel, Harald; Hummel, Thomas; Buerger, Katharina; Hundt, Walter; Steinbach, Silke

    2010-01-01

    We used [18F]fluorodeoxyglucose (FDG) PET analysis to determine performance in different olfactory domains of patients with early AD compared to cognitively healthy subjects, and to map the functional metabolic representation of olfactory impairment in the patient sample. A cohort of patients with early AD (n=24), consisting of 6 subjects with incipient AD and 18 subjects with mild AD, and a control group of 28 age-matched non-demented individuals were assembled. Patients and controls were tested for olfactory performance using the "Sniffin' Sticks" test battery [odor identification (ID), discrimination (DIS) and threshold (THR)], while patients additionally underwent resting state FDG-PET. Voxel-wise PET results in the patients were correlated with olfaction scores using the general linear model in SPM5. Patients with early AD showed significantly reduced function in all three olfactory subdomains compared to controls. After controlling for effects due to patients' age, gender, cognitive status, and treating scores in the two other olfactory subdomains as nuisance variables, ID scores correlated with normalized FDG uptake in clusters with peaks in the right superior parietal lobule, fusiform gyrus, inferior frontal gyrus, and precuneus, while DIS scores correlated with a single cluster in the left postcentral cortex, and THR scores correlated with clusters in the right thalamus and cerebellum. The subtests employed in the "Sniffin' Sticks" test battery are complementary indicators of different aspects of olfactory dysfunction in early AD, and support the theory of a parallel organized olfactory system, revealed by FDG-PET correlation analysis. PMID:20847402

  16. Neural representations of novel objects associated with olfactory experience.

    PubMed

    Ghio, Marta; Schulze, Patrick; Suchan, Boris; Bellebaum, Christian

    2016-07-15

    Object conceptual knowledge comprises information related to several motor and sensory modalities (e.g. for tools, how they look like, how to manipulate them). Whether and to which extent conceptual object knowledge is represented in the same sensory and motor systems recruited during object-specific learning experience is still a controversial question. A direct approach to assess the experience-dependence of conceptual object representations is based on training with novel objects. The present study extended previous research, which focused mainly on the role of manipulation experience for tool-like stimuli, by considering sensory experience only. Specifically, we examined the impact of experience in the non-dominant olfactory modality on the neural representation of novel objects. Sixteen healthy participants visually explored a set of novel objects during the training phase while for each object an odor (e.g., peppermint) was presented (olfactory-visual training). As control conditions, a second set of objects was only visually explored (visual-only training), and a third set was not part of the training. In a post-training fMRI session, participants performed an old/new task with pictures of objects associated with olfactory-visual and visual-only training (old) and no training objects (new). Although we did not find any evidence of activations in primary olfactory areas, the processing of olfactory-visual versus visual-only training objects elicited greater activation in the right anterior hippocampus, a region included in the extended olfactory network. This finding is discussed in terms of different functional roles of the hippocampus in olfactory processes. PMID:27083305

  17. Adult Roles & Functions. Objective Based Evaluation System.

    ERIC Educational Resources Information Center

    West Virginia State Vocational Curriculum Lab., Cedar Lakes.

    This book of objective-based test items is designed to be used with the Adult Roles and Functions curriculum for a non-laboratory home economic course for grades eleven and twelve. It contains item banks for each cognitive objective in the curriculum. In addition, there is a form for the table of specifications to be developed for each unit. This…

  18. Neurotrophins are not required for normal embryonic development of olfactory neurons.

    PubMed

    Nef, S; Lush, M E; Shipman, T E; Parada, L F

    2001-06-01

    Neurons of the vertebrate olfactory epithelium (OE) regenerate continuously throughout life. The capacity of these neurons to regenerate and make new and precise synaptic connections in the olfactory bulb provides a useful model to study factors that may control or mediate neuronal regeneration. Expression and in vitro studies have suggested potential roles for the neurotrophins in the olfactory system. To directly examine whether neurotrophins are required for olfactory neuron development, we characterized in vivo the role of the neurotrophins in the primary olfactory system. For this, we generated mutant mice for TrkA, TrkB, TrkC, and also for BDNF and NT3 together with P2-IRES-tau-LacZ trangenic mice. Histochemical staining for beta-galactosidase at birth allowed in vivo analysis of the P2 subpopulation of olfactory neurons as well as their projections to the olfactory bulb. Our data indicate that Trk signaling is not required for normal embryonic development of the olfactory system. PMID:11356021

  19. Experience Modifies Olfactory Acuity: Acetylcholine-Dependent Learning Decreases Behavioral Generalization between Similar Odorants

    PubMed Central

    Fletcher, Max L.; Wilson, Donald A.

    2008-01-01

    Perceptual learning has been demonstrated in several thalamocortical sensory systems wherein experience enhances sensory acuity for trained stimuli. This perceptual learning is believed to be dependent on changes in sensory cortical receptive fields. Sensory experience and learning also modifies receptive fields and neural response patterns in the mammalian olfactory system; however, to date there has been little reported evidence of learned changes in behavioral olfactory acuity. The present report used a bradycardial orienting response and cross-habituation paradigm that allowed assessment of behavioral discrimination of nearly novel odorants, and then used the same paradigm to examine odorant discrimination after associative olfactory conditioning with similar or dissimilar odorants. The results demonstrate that associative conditioning can enhance olfactory acuity for odors that are the same as or similar to the learned odorant, but not for odors dissimilar to the learned odorant. Furthermore, scopolamine injected before associative conditioning can block the acquisition of this learned enhancement in olfactory acuity. These results could have important implications for mechanisms of olfactory perception and memory, as well as for correlating behavioral olfactory acuity with observed spatial representations of odorant features in the olfactory system. PMID:11784813

  20. [Olfactory sensory perception].

    PubMed

    Fuentes, Aler; Fresno, María Javiera; Santander, Hugo; Valenzuela, Saúl; Gutiérrez, Mario Felipe; Miralles, Rodolfo

    2011-03-01

    The five senses have had a fundamental importance for survival and socialization of human beings. From an evolutionary point of view the sense of smell is the oldest. This sense has a strong representation within the genome, allowing the existence of many types of receptors that allow us to capture multiple volatile odor producing molecules, sending electrical signals to higher centers to report the outside world. Several cortical areas are activated in the brain, which are interconnected to form an extensive and complex neural network, linking for example, areas involved with memory and emotions, thus giving this sense of perceptual richness. While the concept of flavor is largely related to the sense of taste, smell provides the necessary integration with the rest of the senses and higher functions. Fully understanding the sense of smell is relevant to health professionals. Knowing the characteristics of the receptors, the transduction processes and convergence of information in the higher centers involved, we can properly detect olfactory disorders in our patients. PMID:21879170

  1. Integration of Visual and Olfactory Cues in Host Plant Identification by the Asian Longhorned Beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae).

    PubMed

    Yv, Fei L; Hai, Xiaoxia; Wang, Zhigang; Yan, Aihua; Liu, Bingxiang; Bi, Yongguo

    2015-01-01

    Some insects use host and mate cues, including odor, color, and shape, to locate and recognize their preferred hosts and mates. Previous research has shown that the Asian longicorn beetle, Anoplophora glabripennis (Motschulsky), uses olfactory cues to locate host plants and differentiate them from non-host plants. However, whether A. glabripennis adults use visual cues or a combination of visual and olfactory cues remains unclear. In this study, we tested the host location and recognition behavior in A. glabripennis, which infests a number of hardwood species and causes considerable economic losses in North America, Europe and Asia. We determined the relative importance of visual and olfactory cues from Acer negundo in host plant location and recognition, as well as in the discrimination of non-host plants (Sabina chinensis and Pinus bungeana), by female and male A. glabripennis. Visual and olfactory cues from the host plants (A. negundo), alone and combined, attracted significantly more females and males than equivalent cues from non-host plants (S. chinensis and P. bungeana). Furthermore, the combination of visual and olfactory cues of host plants attracted more adults than either cue alone, and visual cues alone attracted significantly more adults than olfactory cues alone. This finding suggests that adult A. glabripennis has an innate preference for the visual and/or olfactory cues of its host plants (A. negundo) over those of the non-host plant and visual cues are initially more important than olfactory cues for orientation; furthermore, this finding also suggests that adults integrate visual and olfactory cues to find their host plants. Our results indicate that different modalities of host plant cues should be considered together to understand fully the communication between host plants and Asian longhorned beetles. PMID:26556100

  2. Integration of Visual and Olfactory Cues in Host Plant Identification by the Asian Longhorned Beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae)

    PubMed Central

    L.Yv, Fei; Hai, Xiaoxia; Wang, Zhigang; Yan, Aihua; Liu, Bingxiang; Bi, Yongguo

    2015-01-01

    Some insects use host and mate cues, including odor, color, and shape, to locate and recognize their preferred hosts and mates. Previous research has shown that the Asian longicorn beetle, Anoplophora glabripennis (Motschulsky), uses olfactory cues to locate host plants and differentiate them from non-host plants. However, whether A. glabripennis adults use visual cues or a combination of visual and olfactory cues remains unclear. In this study, we tested the host location and recognition behavior in A. glabripennis, which infests a number of hardwood species and causes considerable economic losses in North America, Europe and Asia. We determined the relative importance of visual and olfactory cues from Acer negundo in host plant location and recognition, as well as in the discrimination of non-host plants (Sabina chinensis and Pinus bungeana), by female and male A. glabripennis. Visual and olfactory cues from the host plants (A. negundo), alone and combined, attracted significantly more females and males than equivalent cues from non-host plants (S. chinensis and P. bungeana). Furthermore, the combination of visual and olfactory cues of host plants attracted more adults than either cue alone, and visual cues alone attracted significantly more adults than olfactory cues alone. This finding suggests that adult A. glabripennis has an innate preference for the visual and/or olfactory cues of its host plants (A. negundo) over those of the non-host plant and visual cues are initially more important than olfactory cues for orientation; furthermore, this finding also suggests that adults integrate visual and olfactory cues to find their host plants. Our results indicate that different modalities of host plant cues should be considered together to understand fully the communication between host plants and Asian longhorned beetles. PMID:26556100

  3. Magnetite-Based Magnetoreceptor Cells in the Olfactory Organ of Rainbow Trout and Zebrafish

    NASA Astrophysics Data System (ADS)

    Kirschvink, J. L.; Cadiou, H.; Dixson, A. D.; Eder, S.; Kobayashi, A.; McNaughton, P. A.; Muhamad, A. N.; Raub, T. D.; Walker, M. M.; Winklhofer, M.; Yuen, B. B.

    2011-12-01

    Many vertebrate and invertebrate animals have a geomagnetic sensory system, but the biophysics and anatomy of how magnetic stimuli are transduced to the nervous system is a challenging problem. Previous work in our laboratories identified single-domain magnetite chains in olfactory epithelium in cells proximal to the ros V nerve, which, in rainbow trout, responds to magnetic fields. Our objectives are to characterize these magnetite-containing cells and determine whether they form part of the mechanism of magnetic field transduction in teleost fishes, as a model for other Vertebrates. Using a combination of reflection mode confocal microscopy and a Prussian Blue technique modified to stain specifically for magnetite, our Auckland group estimated that both juvenile rainbow trout (ca. 7 cm total length) olfactory rosettes have ~200 magnetite-containing cells. The magnetite present in two types of cells within the olfactory epithelium appears to be arranged in intracellular chains. All of our groups (Munich, Auckland, Cambridge and Caltech) have obtained different types of structural evidence that magnetite chains closely associate with the plasma membrane in the cells, even in disaggregated tissues. In addition, our Cambridge group used Ca2+ imaging to demonstrate a clear response by individual magnetite-containing cells to a step change in the intensity of the external magnetic field and a slow change in Ca2+ activity when the external magnetic field was cancelled. In the teleost, zebrafish (Danio rerio), a small (~4 cm adult length in captivity) genetic and developmental biology model organism, our Caltech group detected ferromagnetic material throughout the body, but concentrated in the rostral trunk, using NRM and IRM scans of whole adults. Our analysis suggests greater than one million, 80-100 nm crystals, with Lowrie-Fuller curves strongly consistent with single-domain magnetite in 100-100,000 magnetocytes. Ferromagentic resonance (FMR) spectra show crystals

  4. Somatostatin-14-like immunoreactive neurons and fibres in the human olfactory bulb.

    PubMed

    Ohm, T G; Braak, E; Probst, A

    1988-01-01

    This study describes the morphological features and the distribution pattern of neurons in the human olfactory bulb which are immunoreactive for an antiserum against the neuropeptide somatostatin-14. Immunoreactive nerve cell bodies were mainly found in the white matter surrounding the cell clusters of the anterior olfactory nucleus. Some immunoreactive neurons were also found scattered throughout the anterior olfactory nucleus and the deeper parts of the inner granule cell layer. Only a few immunoreactive neurons were localized in the glomerular layer and the outer granule cell layer. Immunoreactive fibres were found in all layers of the olfactory bulb. In addition, an impressive number of coiled and kinked immunoreactive fibres were localized within the anterior olfactory nucleus forming a dense plexus. Accumulations of twisted and coiled branches of immunoreactive fibres were rarely found either surrounding or within the olfactory glomerula. The characteristics of somatostatin-14 immunoreactive neurons as seen in the combined pigment-Nissl preparation were studied after decolourizing the chromogen and restaining the preparations with aldehydefuchsin in order to demonstrate the lipofuscin pigment and gallocyanin chrome alum for Nissl material. About 90% of the immunoreactive neurons studied in this manner turned out to be devoid of lipofuscin granules. The remaining 10% displayed different patterns of pigmentation. These findings suggest the presence of different types of somatostatin-14-like immunoreactive neurons in the olfactory bulb of the human adult. PMID:2906788

  5. Illustrated Review of the Ventral Striatum's Olfactory Tubercle.

    PubMed

    Xiong, Angeline; Wesson, Daniel W

    2016-09-01

    Modern neuroscience often relies upon artistic renderings to illustrate key aspects of anatomy. These renderings can be in 2 or even 3 dimensions. Three-dimensional renderings are especially helpful in conceptualizing highly complex aspects of neuroanatomy which otherwise are not visually apparent in 2 dimensions or even intact biological samples themselves. Here, we provide 3 dimensional renderings of the gross- and cellular-anatomy of the rodent olfactory tubercle. Based upon standing literature and detailed investigations into rat brain specimens, we created biologically inspired illustrations of the olfactory tubercle in 3 dimensions as well as its connectivity with olfactory bulb projection neurons, the piriform cortex association fiber system, and ventral pallidum medium spiny neurons. Together, we intend for these illustrations to serve as a resource to the neuroscience community in conceptualizing and discussing this highly complex and interconnected brain system with established roles in sensory processing and motivated behaviors. PMID:27340137

  6. Genetic tracing reveals a stereotyped sensory map in the olfactory cortex

    NASA Astrophysics Data System (ADS)

    Zou, Zhihua; Horowitz, Lisa F.; Montmayeur, Jean-Pierre; Snapper, Scott; Buck, Linda B.

    2001-11-01

    The olfactory system translates myriad chemical structures into diverse odour perceptions. To gain insight into how this is accomplished, we prepared mice that coexpressed a transneuronal tracer with only one of about 1,000 different odorant receptors. The tracer travelled from nasal neurons expressing that receptor to the olfactory bulb and then to the olfactory cortex, allowing visualization of cortical neurons that receive input from a particular odorant receptor. These studies revealed a stereotyped sensory map in the olfactory cortex in which signals from a particular receptor are targeted to specific clusters of neurons. Inputs from different receptors overlap spatially and could be combined in single neurons, potentially allowing for an integration of the components of an odorant's combinatorial receptor code. Signals from the same receptor are targeted to multiple olfactory cortical areas, permitting the parallel, and perhaps differential, processing of inputs from a single receptor before delivery to the neocortex and limbic system.

  7. A neural network model for olfactory glomerular activity prediction

    NASA Astrophysics Data System (ADS)

    Soh, Zu; Tsuji, Toshio; Takiguchi, Noboru; Ohtake, Hisao

    2012-12-01

    Recently, the importance of odors and methods for their evaluation have seen increased emphasis, especially in the fragrance and food industries. Although odors can be characterized by their odorant components, their chemical information cannot be directly related to the flavors we perceive. Biological research has revealed that neuronal activity related to glomeruli (which form part of the olfactory system) is closely connected to odor qualities. Here we report on a neural network model of the olfactory system that can predict glomerular activity from odorant molecule structures. We also report on the learning and prediction ability of the proposed model.

  8. Identification and Comparison of Candidate Olfactory Genes in the Olfactory and Non-Olfactory Organs of Elm Pest Ambrostoma quadriimpressum (Coleoptera: Chrysomelidae) Based on Transcriptome Analysis

    PubMed Central

    Wang, Yinliang; Chen, Qi; Zhao, Hanbo; Ren, Bingzhong

    2016-01-01

    The leaf beetle Ambrostoma quadriimpressum (Coleoptera: Chrysomelidae) is a predominant forest pest that causes substantial damage to the lumber industry and city management. However, no effective and environmentally friendly chemical method has been discovered to control this pest. Until recently, the molecular basis of the olfactory system in A. quadriimpressum was completely unknown. In this study, antennae and leg transcriptomes were analyzed and compared using deep sequencing data to identify the olfactory genes in A. quadriimpressum. Moreover, the expression profiles of both male and female candidate olfactory genes were analyzed and validated by bioinformatics, motif analysis, homology analysis, semi-quantitative RT-PCR and RT-qPCR experiments in antennal and non-olfactory organs to explore the candidate olfactory genes that might play key roles in the life cycle of A. quadriimpressum. As a result, approximately 102.9 million and 97.3 million clean reads were obtained from the libraries created from the antennas and legs, respectively. Annotation led to 34344 Unigenes, which were matched to known proteins. Annotation data revealed that the number of genes in antenna with binding functions and receptor activity was greater than that of legs. Furthermore, many pathway genes were differentially expressed in the two organs. Sixteen candidate odorant binding proteins (OBPs), 10 chemosensory proteins (CSPs), 34 odorant receptors (ORs), 20 inotropic receptors [1] and 2 sensory neuron membrane proteins (SNMPs) and their isoforms were identified. Additionally, 15 OBPs, 9 CSPs, 18 ORs, 6 IRs and 2 SNMPs were predicted to be complete ORFs. Using RT-PCR, RT-qPCR and homology analysis, AquaOBP1/2/4/7/C1/C6, AquaCSP3/9, AquaOR8/9/10/14/15/18/20/26/29/33, AquaIR8a/13/25a showed olfactory-specific expression, indicating that these genes might play a key role in olfaction-related behaviors in A. quadriimpressum such as foraging and seeking. AquaOBP4/C5, AquaOBP4/C5, AquaCSP7

  9. Identification and Comparison of Candidate Olfactory Genes in the Olfactory and Non-Olfactory Organs of Elm Pest Ambrostoma quadriimpressum (Coleoptera: Chrysomelidae) Based on Transcriptome Analysis.

    PubMed

    Wang, Yinliang; Chen, Qi; Zhao, Hanbo; Ren, Bingzhong

    2016-01-01

    The leaf beetle Ambrostoma quadriimpressum (Coleoptera: Chrysomelidae) is a predominant forest pest that causes substantial damage to the lumber industry and city management. However, no effective and environmentally friendly chemical method has been discovered to control this pest. Until recently, the molecular basis of the olfactory system in A. quadriimpressum was completely unknown. In this study, antennae and leg transcriptomes were analyzed and compared using deep sequencing data to identify the olfactory genes in A. quadriimpressum. Moreover, the expression profiles of both male and female candidate olfactory genes were analyzed and validated by bioinformatics, motif analysis, homology analysis, semi-quantitative RT-PCR and RT-qPCR experiments in antennal and non-olfactory organs to explore the candidate olfactory genes that might play key roles in the life cycle of A. quadriimpressum. As a result, approximately 102.9 million and 97.3 million clean reads were obtained from the libraries created from the antennas and legs, respectively. Annotation led to 34344 Unigenes, which were matched to known proteins. Annotation data revealed that the number of genes in antenna with binding functions and receptor activity was greater than that of legs. Furthermore, many pathway genes were differentially expressed in the two organs. Sixteen candidate odorant binding proteins (OBPs), 10 chemosensory proteins (CSPs), 34 odorant receptors (ORs), 20 inotropic receptors [1] and 2 sensory neuron membrane proteins (SNMPs) and their isoforms were identified. Additionally, 15 OBPs, 9 CSPs, 18 ORs, 6 IRs and 2 SNMPs were predicted to be complete ORFs. Using RT-PCR, RT-qPCR and homology analysis, AquaOBP1/2/4/7/C1/C6, AquaCSP3/9, AquaOR8/9/10/14/15/18/20/26/29/33, AquaIR8a/13/25a showed olfactory-specific expression, indicating that these genes might play a key role in olfaction-related behaviors in A. quadriimpressum such as foraging and seeking. AquaOBP4/C5, AquaOBP4/C5, AquaCSP7

  10. Assessing olfactory performance in a New World primate, Saimiri sciureus.

    PubMed

    Laska, M; Hudson, R

    1993-01-01

    Using a task designed to simulate olfactory-guided foraging behavior, this study demonstrates for the first time that olfactory performance can be reliably assessed in squirrel monkeys. Small flip-top vials were fixed in random order to the arms of a climbing frame and equipped with odorized strips signalling either that they contained a peanut food reward (S+) or that they did not (S-), and three adult female monkeys were allowed 1 min to harvest as many baited nuts from this tree as possible. Given five 1-min trials per day, animals took between 15 and 25 days to reach the criterion of 80% correct choices, could readily transfer to new S+ or S- stimuli, and could remember the task even after a 1-month break. The precision and consistency of the monkeys' performance in tests of discrimination ability and sensitivity demonstrate the suitability of this paradigm for assessing olfactory function, and a first test of human subjects using the same cups and odorants showed that it may also be used to directly compare olfactory performance in human and nonhuman primates. PMID:8434074

  11. Olfactory morphology and physiology of elasmobranchs.

    PubMed

    Meredith, Tricia L; Kajiura, Stephen M

    2010-10-15

    Elasmobranch fishes are thought to possess greater olfactory sensitivities than teleost fishes due in part to the large amount of epithelial surface area that comprises their olfactory organs; however, direct evidence correlating the size of the olfactory organ to olfactory sensitivity is lacking. This study examined the olfactory morphology and physiology of five distantly related elasmobranch species. Specifically, we quantified the number of lamellae and lamellar surface area (as if it were a flat sheet, not considering secondary lamellae) that comprise their olfactory organs. We also calculated the olfactory thresholds and relative effectiveness of amino acid odorants for each species. The olfactory organs varied in both the number of lamellae and lamellar surface area, which may be related to their general habitat, but neither correlated with olfactory threshold. Thresholds to amino acid odorants, major olfactory stimuli of all fishes, ranged from 10⁻⁹·⁰ to 10⁻⁶·⁹ mol l⁻¹, which indicates that these elasmobranch species demonstrate comparable thresholds with teleosts. In addition, the relative effectiveness of amino acid stimuli to the olfactory organ of elasmobranchs is similar to that previously described in teleosts with neutral amino acids eliciting significantly greater responses than others. Collectively, these results indicate parallels in olfactory physiology between these two groups of fishes. PMID:20889825

  12. Olfactory dysfunction in patients with multiple sclerosis.

    PubMed

    Li, Li-Min; Yang, Li-Na; Zhang, Lin-Jie; Fu, Ying; Li, Ting; Qi, Yuan; Wang, Jing; Zhang, Da-Qi; Zhang, Ningnannan; Liu, Jingchun; Yang, Li

    2016-06-15

    Association of changes in olfactory-related structures with olfactory function in patients with multiple sclerosis (MS) is not well understood. We used a T&T olfactometer test kit to evaluate olfactory function in 26 patients with MS and 26 age- and sex-matched healthy controls (HC). Then, Brain MRI were performed and olfactory-related structures were analyzed in these subjects. Olfactory detection and recognition threshold were significantly higher in the MS group, interestingly olfactory recognition threshold positively correlated with expanded disability status scale scores in these patients. Olfactory bulb (OB) volume reduced in patients with olfactory dysfunction (ODF). At the same time, reductions in gray matter (GM) volume were observed in the parahippocampal gyrus (PCG), amygdala, piriform cortex, and inferior frontal gyrus in patients with MS compared to HC. Atrophy of the PCG was more obvious in patients with ODF than patients without ODF and the PCG volume correlated with the olfactory recognition threshold, while no difference was found in fractional anisotropy values of tract-based spatial statistics analysis in the two groups. Olfactory function in patients with MS tends to become gradually more impaired with disability aggravation. Decreases in the volume of the OB and olfactory-related GM might provide valuable information about disease status in patients with MS with olfactory impairment. PMID:27206870

  13. Sniffing and Oxytocin: Effects on Olfactory Memories.

    PubMed

    Stoop, Ron

    2016-05-01

    In this issue of Neuron, Oettl et al. (2016) show how oxytocin can boost processing of olfactory information in female rats by a top-downregulation from the anterior olfactory nucleus onto the main olfactory bulb. As a result, interactions with juvenile conspecifics receive more attention and are longer memorized. PMID:27151635

  14. Olfactory sensitivity to bile acids in salmonid fishes.

    PubMed

    Døving, K B; Selset, R; Thommesen, G

    1980-02-01

    Monopolar DC-recordings were made simultaneously from two positions on the olfactory bulb of chars (Salmo alpinus L.) and graylings (Thymallus thymallu L.) using bile acids and amino acids as olfactory stimulants. The bile acids induced responses with characteristic spatial differences from those of the amino acids. The distribution of responses to bile acids indicated a neuronal activity in the medial part of the bulb. In contrast, amino acids elicit responses in the lateral part of the bulb. Taurine conjugated bile acids were up to 1 000 times more potent as olfactory stimuli than methionine. The results suggest that olfactory receptors are of two types, one responding to bile acids, the other to amino acids. 3 -alpha-hydroxysteroids are released from the fish into the water in quantities that suffice for detection by their olfactory system. The odorant potency of the bile acids, their evolutionary history and variability, together with their renowned adherent properties made them interesting candidates for specific signals in the acquatic environment. PMID:7376910

  15. Muscarinic ACh Receptors Contribute to Aversive Olfactory Learning in Drosophila

    PubMed Central

    Silva, Bryon; Molina-Fernández, Claudia; Ugalde, María Beatriz; Tognarelli, Eduardo I.; Angel, Cristian; Campusano, Jorge M.

    2015-01-01

    The most studied form of associative learning in Drosophila consists in pairing an odorant, the conditioned stimulus (CS), with an unconditioned stimulus (US). The timely arrival of the CS and US information to a specific Drosophila brain association region, the mushroom bodies (MB), can induce new olfactory memories. Thus, the MB is considered a coincidence detector. It has been shown that olfactory information is conveyed to the MB through cholinergic inputs that activate acetylcholine (ACh) receptors, while the US is encoded by biogenic amine (BA) systems. In recent years, we have advanced our understanding on the specific neural BA pathways and receptors involved in olfactory learning and memory. However, little information exists on the contribution of cholinergic receptors to this process. Here we evaluate for the first time the proposition that, as in mammals, muscarinic ACh receptors (mAChRs) contribute to memory formation in Drosophila. Our results show that pharmacological and genetic blockade of mAChRs in MB disrupts olfactory aversive memory in larvae. This effect is not explained by an alteration in the ability of animals to respond to odorants or to execute motor programs. These results show that mAChRs in MB contribute to generating olfactory memories in Drosophila. PMID:26380118

  16. Disruption of Olfactory Receptor Neuron Patterning in Scutoid mutant Drosophila

    PubMed Central

    Tom, W.; de Bruyne, M.; Haehnel, M.; Carlson, J. R.; Ray, A.

    2010-01-01

    Olfactory neurons show an extreme diversity of cell types with each cell usually expressing one member from a large family of 60 Odorant receptor (Or)genes in Drosophila. Little is known about the developmental processes and transcription factors that generate this stereotyped pattern of cellular diversity. Here we investigate the molecular and cellular basis of defects in olfactory system function in an unusual dominant mutant, Scutoid. We show that the defects map to olfactory neurons innervating a specific morphological class of sensilla on the antenna, large basiconics. Molecular analysis indicates defects in neurons expressing specific classes of receptor genes that map to large basiconic sensilla. Previous studies have shown that in Scutoid mutants the coding region of the transcriptional repressor snail is translocated near the no-ocelli promoter, leading to misexpression of snail in the developing eye-antenna disc. We show that ectopic expression of snail in developing olfactory neurons leads to severe defects in neurons of the antennal large basiconics supporting the model that the dominant olfactory phenotype in Scutoid is caused by misexpression of snail. PMID:20875862

  17. Olfactory marker protein: turnover and transport in normal and regenerating neurons

    SciTech Connect

    Kream, R.M.; Margolis, F.L.

    1984-03-01

    A 19,000-dalton acidic protein designated olfactory marker protein (OMP) is a cell-specific marker of mature olfactory chemosensory neurons. Intranasal irrigation of mouse olfactory epithelium with (/sup 35/S)methionine labeled OMP to high specific activity. Turnover and transport characteristics of /sup 35/S-labeled OMP were compared to those of /sup 35/S-labeled global cytosol protein in groups of young, adult, and Triton-treated adult mice. The latter contained primarily large numbers of regenerating olfactory neurons. In olfactory epithelium of young and Triton-treated mice, the specific activity of OMP was three times that of global cytosol protein, whereas in adults the two measures were equal. In all three groups, however, the rate of degradation of OMP was roughly equal to that of cytosol protein (T1/2 . 5 to 6 days). By contrast, differences in T1/2 for OMP decline in the bulb of adult, young, and Triton-treated adult mice were highly significant (T1/2's of 9.3, 6.1, and 4 to 5 days, respectively; p . 0.001). The specific activity of (35S)methionine incorporated in OMP exceeded that of the free amino acid 5-fold, indicating minimal precursor reutilization during the course of our experiments. Turnover data indicate that increased isotope incorporation into OMP in the epithelium is matched by an accelerated rate of degradation in the bulb. This may be correlated with the physiological state or developmental age of the primary neurons since in young and Triton-treated adult mice, rapidly maturing ''young'' olfactory neurons represent a larger proportion of the total population than in adults. Thus, OMP behaves as a typical, relatively slowly transported soluble protein (v . 2 to 4 mm/day, slow component b).

  18. The Role of Dopamine in Drosophila Larval Classical Olfactory Conditioning

    PubMed Central

    Han, Kyung-An; Stocker, Reinhard F.; Thum, Andreas S.

    2009-01-01

    Learning and memory is not an attribute of higher animals. Even Drosophila larvae are able to form and recall an association of a given odor with an aversive or appetitive gustatory reinforcer. As the Drosophila larva has turned into a particularly simple model for studying odor processing, a detailed neuronal and functional map of the olfactory pathway is available up to the third order neurons in the mushroom bodies. At this point, a convergence of olfactory processing and gustatory reinforcement is suggested to underlie associative memory formation. The dopaminergic system was shown to be involved in mammalian and insect olfactory conditioning. To analyze the anatomy and function of the larval dopaminergic system, we first characterize dopaminergic neurons immunohistochemically up to the single cell level and subsequent test for the effects of distortions in the dopamine system upon aversive (odor-salt) as well as appetitive (odor-sugar) associative learning. Single cell analysis suggests that dopaminergic neurons do not directly connect gustatory input in the larval suboesophageal ganglion to olfactory information in the mushroom bodies. However, a number of dopaminergic neurons innervate different regions of the brain, including protocerebra, mushroom bodies and suboesophageal ganglion. We found that dopamine receptors are highly enriched in the mushroom bodies and that aversive and appetitive olfactory learning is strongly impaired in dopamine receptor mutants. Genetically interfering with dopaminergic signaling supports this finding, although our data do not exclude on naïve odor and sugar preferences of the larvae. Our data suggest that dopaminergic neurons provide input to different brain regions including protocerebra, suboesophageal ganglion and mushroom bodies by more than one route. We therefore propose that different types of dopaminergic neurons might be involved in different types of signaling necessary for aversive and appetitive olfactory memory

  19. The Olfactory Bulb: An Immunosensory Effector Organ during Neurotropic Viral Infections.

    PubMed

    Durrant, Douglas M; Ghosh, Soumitra; Klein, Robyn S

    2016-04-20

    In 1935, the olfactory route was hypothesized to be a portal for virus entry into the central nervous system (CNS). This hypothesis was based on experiments in which nasophayngeal infection with poliovirus in monkeys was prevented from spreading to their CNS via transection of olfactory tracts between the olfactory neuroepithelium (ONE) of the nasal cavity and the olfactory bulb (OB). Since then, numerous neurotropic viruses have been observed to enter the CNS via retrograde transport along axons of olfactory sensory neurons whose cell bodies reside in the ONE. Importantly, this route of infection can occur even after subcutaneous inoculation of arboviruses that can cause encephalitis in humans. While the olfactory route is now accepted as an important pathway for viral entry into the CNS, it is unclear whether it provides a way for infection to spread to other brain regions. More recently, studies of antiviral innate and adaptive immune responses within the olfactory bulb suggest it provides early virologic control. Here we will review the data demonstrating that neurotropic viruses gain access to the CNS initially via the olfactory route with emphasis on findings that suggest the OB is a critical immunosensory effector organ that effectively clears virus. PMID:27058872

  20. Calcium-activated chloride currents in olfactory sensory neurons from mice lacking bestrophin-2

    PubMed Central

    Pifferi, Simone; Dibattista, Michele; Sagheddu, Claudia; Boccaccio, Anna; Al Qteishat, Ahmed; Ghirardi, Filippo; Tirindelli, Roberto; Menini, Anna

    2009-01-01

    Olfactory sensory neurons use a chloride-based signal amplification mechanism to detect odorants. The binding of odorants to receptors in the cilia of olfactory sensory neurons activates a transduction cascade that involves the opening of cyclic nucleotide-gated channels and the entry of Ca2+ into the cilia. Ca2+ activates a Cl− current that produces an efflux of Cl− ions and amplifies the depolarization. The molecular identity of Ca2+-activated Cl− channels is still elusive, although some bestrophins have been shown to function as Ca2+-activated Cl− channels when expressed in heterologous systems. In the olfactory epithelium, bestrophin-2 (Best2) has been indicated as a candidate for being a molecular component of the olfactory Ca2+-activated Cl− channel. In this study, we have analysed mice lacking Best2. We compared the electrophysiological responses of the olfactory epithelium to odorant stimulation, as well as the properties of Ca2+-activated Cl− currents in wild-type (WT) and knockout (KO) mice for Best2. Our results confirm that Best2 is expressed in the cilia of olfactory sensory neurons, while odorant responses and Ca2+-activated Cl− currents were not significantly different between WT and KO mice. Thus, Best2 does not appear to be the main molecular component of the olfactory channel. Further studies are required to determine the function of Best2 in the cilia of olfactory sensory neurons. PMID:19622610

  1. Gene expression and specificity in the mature zone of the lobster olfactory organ.

    PubMed

    Stepanyan, Ruben; Day, Kristen; Urban, Jason; Hardin, Debra L; Shetty, Ranjit S; Derby, Charles D; Ache, Barry W; McClintock, Timothy S

    2006-04-13

    The lobster olfactory organ is an important model for investigating many aspects of the olfactory system. To facilitate study of the molecular basis of olfaction in lobsters, we made a subtracted cDNA library from the mature zone of the olfactory organ of Homarus americanus, the American lobster. Sequencing of the 5'-end of 5,184 cDNA clones produced 2,389 distinct high-quality sequences consisting of 1,944 singlets and 445 contigs. Matches to known sequences corresponded with the types of cells present in the olfactory organ, including specific markers of olfactory sensory neurons, auxiliary cells, secretory cells of the aesthetasc tegumental gland, and epithelial cells. The wealth of neuronal mRNAs represented among the sequences reflected the preponderance of neurons in the tissue. The sequences identified candidate genes responsible for known functions and suggested new functions not previously recognized in the olfactory organ. A cDNA microarray was designed and tested by assessing mRNA abundance differences between two of the lobster's major chemosensory structures: the mature zone of the olfactory organ and the dactyl of the walking legs, a taste organ. The 115 differences detected again emphasized the abundance of neurons in the olfactory organ, especially a cluster of mRNAs encoding cytoskeletal-associated proteins and cell adhesion molecules such as 14-3-3zeta, actins, tubulins, trophinin, Fax, Yel077cp, suppressor of profilin 2, and gelsolin. PMID:16614458

  2. A Novel Neural Substrate for the Transformation of Olfactory Inputs into Motor Output

    PubMed Central

    Derjean, Dominique; Moussaddy, Aimen; Atallah, Elias; St-Pierre, Melissa; Auclair, François; Chang, Steven; Ren, Xiang; Zielinski, Barbara; Dubuc, Réjean

    2010-01-01

    It is widely recognized that animals respond to odors by generating or modulating specific motor behaviors. These reactions are important for daily activities, reproduction, and survival. In the sea lamprey, mating occurs after ovulated females are attracted to spawning sites by male sex pheromones. The ubiquity and reliability of olfactory-motor behavioral responses in vertebrates suggest tight coupling between the olfactory system and brain areas controlling movements. However, the circuitry and the underlying cellular neural mechanisms remain largely unknown. Using lamprey brain preparations, and electrophysiology, calcium imaging, and tract tracing experiments, we describe the neural substrate responsible for transforming an olfactory input into a locomotor output. We found that olfactory stimulation with naturally occurring odors and pheromones induced large excitatory responses in reticulospinal cells, the command neurons for locomotion. We have also identified the anatomy and physiology of this circuit. The olfactory input was relayed in the medial part of the olfactory bulb, in the posterior tuberculum, in the mesencephalic locomotor region, to finally reach reticulospinal cells in the hindbrain. Activation of this olfactory-motor pathway generated rhythmic ventral root discharges and swimming movements. Our study bridges the gap between behavior and cellular neural mechanisms in vertebrates, identifying a specific subsystem within the CNS, dedicated to producing motor responses to olfactory inputs. PMID:21203583

  3. A novel neural substrate for the transformation of olfactory inputs into motor output.

    PubMed

    Derjean, Dominique; Moussaddy, Aimen; Atallah, Elias; St-Pierre, Melissa; Auclair, François; Chang, Steven; Ren, Xiang; Zielinski, Barbara; Dubuc, Réjean

    2010-01-01

    It is widely recognized that animals respond to odors by generating or modulating specific motor behaviors. These reactions are important for daily activities, reproduction, and survival. In the sea lamprey, mating occurs after ovulated females are attracted to spawning sites by male sex pheromones. The ubiquity and reliability of olfactory-motor behavioral responses in vertebrates suggest tight coupling between the olfactory system and brain areas controlling movements. However, the circuitry and the underlying cellular neural mechanisms remain largely unknown. Using lamprey brain preparations, and electrophysiology, calcium imaging, and tract tracing experiments, we describe the neural substrate responsible for transforming an olfactory input into a locomotor output. We found that olfactory stimulation with naturally occurring odors and pheromones induced large excitatory responses in reticulospinal cells, the command neurons for locomotion. We have also identified the anatomy and physiology of this circuit. The olfactory input was relayed in the medial part of the olfactory bulb, in the posterior tuberculum, in the mesencephalic locomotor region, to finally reach reticulospinal cells in the hindbrain. Activation of this olfactory-motor pathway generated rhythmic ventral root discharges and swimming movements. Our study bridges the gap between behavior and cellular neural mechanisms in vertebrates, identifying a specific subsystem within the CNS, dedicated to producing motor responses to olfactory inputs. PMID:21203583

  4. Decoding of Context-Dependent Olfactory Behavior in Drosophila.

    PubMed

    Badel, Laurent; Ohta, Kazumi; Tsuchimoto, Yoshiko; Kazama, Hokto

    2016-07-01

    Odor information is encoded in the activity of a population of glomeruli in the primary olfactory center. However, how this information is decoded in the brain remains elusive. Here, we address this question in Drosophila by combining neuronal imaging and tracking of innate behavioral responses. We find that the behavior is accurately predicted by a model summing normalized glomerular responses, in which each glomerulus contributes a specific, small amount to odor preference. This model is further supported by targeted manipulations of glomerular input, which biased the behavior. Additionally, we observe that relative odor preference changes and can even switch depending on the context, an effect correctly predicted by our normalization model. Our results indicate that olfactory information is decoded from the pooled activity of a glomerular repertoire and demonstrate the ability of the olfactory system to adapt to the statistics of its environment. PMID:27321924

  5. Behavioural responses to olfactory cues in carrion crows.

    PubMed

    Wascher, Claudia A F; Heiss, Rebecca S; Baglione, Vittorio; Canestrari, Daniela

    2015-02-01

    Until recently, the use of olfactory signals in birds has been largely ignored, despite the fact that birds do possess a fully functioning olfactory system and have been shown to use odours in social and foraging tasks, predator detection and orientation. The present study investigates whether carrion crows (Corvus corone corone), a bird species living in complex social societies, respond behaviourally to olfactory cues of conspecifics. During our experiment, carrion crows were observed less often close to the conspecific scent compared to a control side. Because conspecific scent was extracted during handling, a stressful procedure for birds, we interpreted the general avoidance of the 'scent' side as disfavour against a stressed conspecific. However, males, unlike females, showed less avoidance towards the scent of a familiar individual compared to an unfamiliar one, which might reflect a stronger interest in the information conveyed and/or willingness to provide social support. PMID:25447513

  6. Using Single Sensillum Recording to Detect Olfactory Neuron Responses of Bed Bugs to Semiochemicals.

    PubMed

    Liu, Feng; Liu, Nannan

    2016-01-01

    The insect olfactory system plays an important role in detecting semiochemicals in the environment. In particular, the antennal sensilla which house single or multiple neurons inside, are considered to make the major contribution in responding to the chemical stimuli. By directly recording action potential in the olfactory sensillum after exposure to stimuli, single sensillum recording (SSR) technique provides a powerful approach for investigating the neural responses of insects to chemical stimuli. For the bed bug, which is a notorious human parasite, multiple types of olfactory sensillum have been characterized. In this study, we demonstrated neural responses of bed bug olfactory sensilla to two chemical stimuli and the dose-dependent responses to one of them using the SSR method. This approach enables researchers to conduct early screening for individual chemical stimuli on the bed bug olfactory sensilla, which would provide valuable information for the development of new bed bug attractants or repellents and benefits the bed bug control efforts. PMID:26862929

  7. Olfactory Basis of Homing Behavior in the Giant Garden Slug, Limax maximus

    PubMed Central

    Gelperin, Alan

    1974-01-01

    Time lapse photography of slugs living in an experimental enclosure shows that these animals can return to a homesite from over 90 cm by a direct route. Slime trail following and vision are not involved in this behavior. In the presence of a low velocity wind, homing occurs upwind. Surgical disconnection of the presumptive olfactory apparatus (digitate ganglion) from the central nervous system eliminates homing. Neurophysiological recordings from the receptor surface associated with the digitate ganglion and the olfactory nerve demonstrate the olfactory function of the digitate ganglion. The olfactory acuity and capacity for directed locomotion via olfactory cues are also relevant to studies of slug feeding behavior, ecology, and learning ability. Images PMID:16592149

  8. Expression and Localization of the Cell Adhesion Molecule SgIGSF during Regeneration of the Olfactory Epithelium in Mice

    PubMed Central

    Tsukioka, Fusae; Wakayama, Tomohiko; Tsukatani, Toshiaki; Miwa, Takaki; Furukawa, Mitsuru; Iseki, Shoichi

    2007-01-01

    Spermatogenic immunoglobulin superfamily (SgIGSF) is a cell adhesion molecule originally discovered in mouse testis. SgIGSF is expressed not only in spermatogenic cells but also in lung and liver epithelial cells and in neurons and glia of the central and peripheral nervous systems. In the present study, we examined the expression and localization of SgIGSF in mouse olfactory epithelium before and after transection of the olfactory nerves, by RT-PCR, Western blotting and immunohistochemistry. In normal olfactory mucosa, SgIGSF showed 100 kDa in molecular weight, which was identical with that in the lung but different from that in the brain. SgIGSF was expressed on the membrane of all olfactory, sustentacular and basal cells, but more abundantly in the apical portions of the olfactory epithelium where the dendrites of olfactory cells are in contact with sustentacular cells. After olfactory nerve transection, mature olfactory cells disappeared in 4 days but were regenerated around 7–15 days by proliferation and differentiation of basal cells into mature olfactory cells through the step of immature olfactory cells. During this period, both the mRNA and protein for SgIGSF showed a transient increase, with peak levels at 7 days and 11 days, respectively, after the transection. Immunohistochemistry showed that the enriched immunoreactivity for SgIGSF at 7–11 days was localized primarily to the membrane of immature olfactory cells. These results suggested that, during regeneration of the olfactory epithelium, the adhesion molecule SgIGSF plays physiological roles in differentiation, migration, and maturation of immature olfactory cells. PMID:17576432

  9. The adaptive significance of adult neurogenesis: an integrative approach

    PubMed Central

    Konefal, Sarah; Elliot, Mick; Crespi, Bernard

    2013-01-01

    Adult neurogenesis in mammals is predominantly restricted to two brain regions, the dentate gyrus (DG) of the hippocampus and the olfactory bulb (OB), suggesting that these two brain regions uniquely share functions that mediate its adaptive significance. Benefits of adult neurogenesis across these two regions appear to converge on increased neuronal and structural plasticity that subserves coding of novel, complex, and fine-grained information, usually with contextual components that include spatial positioning. By contrast, costs of adult neurogenesis appear to center on potential for dysregulation resulting in higher risk of brain cancer or psychological dysfunctions, but such costs have yet to be quantified directly. The three main hypotheses for the proximate functions and adaptive significance of adult neurogenesis, pattern separation, memory consolidation, and olfactory spatial, are not mutually exclusive and can be reconciled into a simple general model amenable to targeted experimental and comparative tests. Comparative analysis of brain region sizes across two major social-ecological groups of primates, gregarious (mainly diurnal haplorhines, visually-oriented, and in large social groups) and solitary (mainly noctural, territorial, and highly reliant on olfaction, as in most rodents) suggest that solitary species, but not gregarious species, show positive associations of population densities and home range sizes with sizes of both the hippocampus and OB, implicating their functions in social-territorial systems mediated by olfactory cues. Integrated analyses of the adaptive significance of adult neurogenesis will benefit from experimental studies motivated and structured by ecologically and socially relevant selective contexts. PMID:23882188

  10. Olfactory dysfunction in Alzheimer’s disease

    PubMed Central

    Zou, Yong-ming; Lu, Da; Liu, Li-ping; Zhang, Hui-hong; Zhou, Yu-ying

    2016-01-01

    Alzheimer’s disease (AD) is a common neurodegenerative disorder with the earliest clinical symptom of olfactory dysfunction, which is a potential clinical marker for AD severity and progression. However, many questions remain unanswered. This article reviews relevant research on olfactory dysfunction in AD and evaluates the predictive value of olfactory dysfunction for the epidemiological, pathophysiological, and clinical features of AD, as well as for the conversion of cognitive impairment to AD. We summarize problems of existing studies and provide a useful reference for further studies in AD olfactory dysfunction and for clinical applications of olfactory testing. PMID:27143888

  11. The Peripheral Olfactory Repertoire of the Lightbrown Apple Moth, Epiphyas postvittana

    PubMed Central

    Thrimawithana, Amali H.; Crowhurst, Ross N.; Newcomb, Richard D.

    2015-01-01

    The lightbrown apple moth, Epiphyas postvittana is an increasingly global pest of horticultural crops. Like other moths, E. postvittana relies on olfactory cues to locate mates and oviposition sites. To detect these cues, moths have evolved families of genes encoding elements of the peripheral olfactory reception system, including odor carriers, receptors and degrading enzymes. Here we undertake a transcriptomic approach to identify members of these families expressed in the adult antennae of E. postvittana, describing open reading frames encoding 34 odorant binding proteins, 13 chemosensory proteins, 70 odorant receptors, 19 ionotropic receptors, nine gustatory receptors, two sensory neuron membrane proteins, 27 carboxylesterases, 20 glutathione-S-transferases, 49 cytochrome p450s and 18 takeout proteins. For the odorant receptors, quantitative RT-PCR corroborated RNAseq count data on steady state transcript levels. Of the eight odorant receptors that group phylogenetically with pheromone receptors from other moths, two displayed significant male-biased expression patterns, one displayed significant female-biased expression pattern and five were expressed equally in the antennae of both sexes. In addition, we found two male-biased odorant receptors that did not group with previously described pheromone receptors. This suite of olfaction-related genes provides a substantial resource for the functional characterization of this signal transduction system and the development of odor-mediated control strategies for horticultural pests. PMID:26017144

  12. Neuropeptide receptors provide a signalling pathway for trigeminal modulation of olfactory transduction.

    PubMed

    Daiber, Philipp; Genovese, Federica; Schriever, Valentin A; Hummel, Thomas; Möhrlen, Frank; Frings, Stephan

    2013-02-01

    The mammalian olfactory epithelium contains olfactory receptor neurons and trigeminal sensory endings. The former mediate odor detection, the latter the detection of irritants. The two apparently parallel chemosensory systems are in reality interdependent in various well-documented ways. Psychophysical studies have shown that virtually all odorants can act as irritants, and that most irritants have an odor. Thus, the sensory perception of odorants and irritants is based on simultaneous input from the two systems. Moreover, functional interactions between the olfactory system and the trigeminal system exist on both peripheral and central levels. Here we examine the impact of trigeminal stimulation on the odor response of olfactory receptor neurons. Using an odorant with low trigeminal potency (phenylethyl alcohol) and a non-odorous irritant (CO(2) ), we have explored this interaction in psychophysical experiments with human subjects and in electroolfactogram (EOG) recordings from rats. We have demonstrated that simultaneous activation of the trigeminal system attenuates the perception of odor intensity and distorts the EOG response. On the molecular level, we have identified a route for this cross-modal interaction. The neuropeptide calcitonin-gene related peptide (CGRP), which is released from trigeminal sensory fibres upon irritant stimulation, inhibits the odor response of olfactory receptor neurons. CGRP receptors expressed by these neurons mediate this neuromodulatory effect. This study demonstrates a site of trigeminal-olfactory interaction in the periphery. It reveals a pathway for trigeminal impact on olfactory signal processing that influences odor perception. PMID:23205840

  13. Olfactory cues are subordinate to visual stimuli in a neotropical generalist weevil.

    PubMed

    Otálora-Luna, Fernando; Lapointe, Stephen L; Dickens, Joseph C

    2013-01-01

    The tropical root weevil Diaprepes abbreviatus is a major pest of multiple crops in the Caribbean Islands and has become a serious constraint to citrus production in the United States. Recent work has identified host and conspecific volatiles that mediate host- and mate-finding by D. abbreviatus. The interaction of light, color, and odors has not been studied in this species. The responses of male and female D. abbreviatus to narrow bandwidths of visible light emitted by LEDs offered alone and in combination with olfactory stimuli were studied in a specially-designed multiple choice arena combined with a locomotion compensator. Weevils were more attracted to wavelengths close to green and yellow compared with blue or ultraviolet, but preferred red and darkness over green. Additionally, dim green light was preferred over brighter green. Adult weevils were also attracted to the odor of its citrus host + conspecifics. However, the attractiveness of citrus + conspecific odors disappeared in the presence of a green light. Photic stimulation induced males but not females to increase their speed. In the presence of light emitted by LEDs, turning speed decreased and path straightness increased, indicating that weevils tended to walk less tortuously. Diaprepes abbreviatus showed a hierarchy between chemo- and photo-taxis in the series of experiments presented herein, where the presence of the green light abolished upwind anemotaxis elicited by the pheromone + host plant odor. Insight into the strong responses to visual stimuli of chemically stimulated insects may be provided when the amount of information supplied by vision and olfaction is compared, as the information transmission capacity of compound eyes is estimated to be several orders of magnitude higher compared with the olfactory system. Subordination of olfactory responses by photic stimuli should be considered in the design of strategies aimed at management of such insects. PMID:23341926

  14. Olfactory Cues Are Subordinate to Visual Stimuli in a Neotropical Generalist Weevil

    PubMed Central

    Otálora-Luna, Fernando; Lapointe, Stephen L.; Dickens, Joseph C.

    2013-01-01

    The tropical root weevil Diaprepes abbreviatus is a major pest of multiple crops in the Caribbean Islands and has become a serious constraint to citrus production in the United States. Recent work has identified host and conspecific volatiles that mediate host- and mate-finding by D. abbreviatus. The interaction of light, color, and odors has not been studied in this species. The responses of male and female D. abbreviatus to narrow bandwidths of visible light emitted by LEDs offered alone and in combination with olfactory stimuli were studied in a specially-designed multiple choice arena combined with a locomotion compensator. Weevils were more attracted to wavelengths close to green and yellow compared with blue or ultraviolet, but preferred red and darkness over green. Additionally, dim green light was preferred over brighter green. Adult weevils were also attracted to the odor of its citrus host + conspecifics. However, the attractiveness of citrus + conspecific odors disappeared in the presence of a green light. Photic stimulation induced males but not females to increase their speed. In the presence of light emitted by LEDs, turning speed decreased and path straightness increased, indicating that weevils tended to walk less tortuously. Diaprepes abbreviatus showed a hierarchy between chemo- and photo-taxis in the series of experiments presented herein, where the presence of the green light abolished upwind anemotaxis elicited by the pheromone + host plant odor. Insight into the strong responses to visual stimuli of chemically stimulated insects may be provided when the amount of information supplied by vision and olfaction is compared, as the information transmission capacity of compound eyes is estimated to be several orders of magnitude higher compared with the olfactory system. Subordination of olfactory responses by photic stimuli should be considered in the design of strategies aimed at management of such insects. PMID:23341926

  15. Mainstream cigarette smoke exposure alters cytochrome P4502G1 expression in F344 rat olfactory mucosa

    SciTech Connect

    Hotchkiss, J.A.; Nikula, K.J.; Lewis, J.L.; Finch, G.L.; Belinsky, S.A.; Dahl, A.R.

    1994-11-01

    Inhalation of mainstream cigarette smoke (MCS) by rats results in multifocal rhinitis, mucous hypersecretion, nasal epithelial hyperplasia and metaplasia, and focal olfactory mucosal atrophy. In humans, cigarette smoking causes long-term, dose-related alterations in olfactory function in both current and former smokers. An olfactory-specific cytochrome P450 has been identified in rabbits and rats. The presence of olfactory-specific P450s, as well as relatively high levels of other biotransformation enzymes, such as NADPH-cytochrome P450 reductase and UDP-glucuronosyl transferase, in the olfactory neuroepithelium suggest that these enzyme systems may play a role in olfaction. This hypothesis is strengthened by the observation that, in rats, the temporal gene activation of P4502G1 coincides with the postnatal increase in the sensitivity of olfactory response to odorants. The purpose of this investigation was to examine the effect of MCS exposure on P4502G1 protein expression.

  16. The olfactory receptor family album

    PubMed Central

    Crasto, Chiquito; Singer, Michael S; Shepherd, Gordon M

    2001-01-01

    Analysis of the human genome draft sequences has revealed a more complete portrait of the olfactory receptor gene repertoire in humans than was available previously. The new information provides a basis for deeper analysis of the functions of the receptors, and promises new insights into the evolutionary history of the family. PMID:11597337

  17. Development of the terminal nerve system in the shark Scyliorhinus canicula.

    PubMed

    Quintana-Urzainqui, Idoia; Anadón, Ramón; Candal, Eva; Rodríguez-Moldes, Isabel

    2014-01-01

    The nervus terminalis (or terminal nerve) system was discovered in an elasmobranch species more than a century ago. Over the past century, it has also been recognized in other vertebrate groups, from agnathans to mammals. However, its origin, functions or relationship with the olfactory system are still under debate. Despite the abundant literature about the nervus terminalis system in adult elasmobranchs, its development has been overlooked. Studies in other vertebrates have reported newly differentiated neurons of the terminal nerve system migrating from the olfactory epithelium to the telencephalon as part of a 'migratory mass' of cells associated with the olfactory nerve. Whether the same occurs in developing elasmobranchs (adults showing anatomically separated nervus terminalis and olfactory systems) has not yet been determined. In this work we characterized for the first time the development of the terminal nerve and ganglia in an elasmobranch, the lesser spotted dogfish (Scyliorhinus canicula), by means of tract-tracing techniques combined with immunohistochemical markers for the terminal nerve (such as FMRF-amide peptide), for the developing components of the olfactory system (Gα0 protein, GFAP, Pax6), and markers for early postmitotic neurons (HuC/D) and migrating immature neurons (DCX). We discriminated between embryonic olfactory and terminal nerve systems and determined that both components may share a common origin in the migratory mass. We also localized the exact point where they split off near the olfactory nerve-olfactory bulb junction. The study of the development of the terminal nerve system in a basal gnathostome contributes to the knowledge of the ancestral features of this system in vertebrates, shedding light on its evolution and highlighting the importance of elasmobranchs for developmental and evolutionary studies. PMID:25402659

  18. The sensory basis of olfactory search behavior in banded kokopu ( Galaxias fasciatus).

    PubMed

    Baker, Cindy F; Montgomery, John C; Dennis, Todd E

    2002-08-01

    The sensory basis of olfactory search behavior was investigated in the banded kokopu, Galaxias fasciatus, using a flow tank. In the presence of a 2 cm s(-1) current flow, banded kokopu use both water current and chemical information to locate a food odor source. The superficial neuromasts of the lateral line system mediate the rheotactic component of the odor search. A physical block of one olfactory nostril did not affect the olfactory search strategy employed by banded kokopu in still water or in the presence of a current flow. Thus, there is no evidence that banded kokopu perform a bilateral comparison of the olfactory stimulus during their odor search. Previously, olfaction and gustation have been the only sensory systems shown to directly mediate orientation and movement towards odor sources in fish. The use of hydrodynamic cues by fish in location of an olfactory source has been previously proposed, but without direct experimental identification of the sensory systems employed. This study identifies the contributing roles of both olfactory and hydrodynamic sensory systems to the olfactory search repertoire of fish. PMID:12209343

  19. Mechanisms of neuronal chloride accumulation in intact mouse olfactory epithelium

    PubMed Central

    Nickell, William T; Kleene, Nancy K; Kleene, Steven J

    2007-01-01

    When olfactory receptor neurons respond to odours, a depolarizing Cl− efflux is a substantial part of the response. This requires that the resting neuron accumulate Cl− against an electrochemical gradient. In isolated olfactory receptor neurons, the Na+–K+–2Cl− cotransporter NKCC1 is essential for Cl− accumulation. However, in intact epithelium, a robust electrical olfactory response persists in mice lacking NKCC1. This response is largely due to a neuronal Cl− efflux. It thus appears that NKCC1 is an important part of a more complex system of Cl− accumulation. To identify the remaining transport proteins, we first screened by RT-PCR for 21 Cl− transporters in mouse nasal tissue containing olfactory mucosa. For most of the Cl− transporters, the presence of mRNA was demonstrated. We also investigated the effects of pharmacological block or genetic ablation of Cl− transporters on the olfactory field potential, the electroolfactogram (EOG). Mice lacking the common Cl−/HCO3− exchanger AE2 had normal EOGs. Block of NKCC cotransport with bumetanide reduced the EOG in epithelia from wild-type mice but had no effect in mice lacking NKCC1. Hydrochlorothiazide, a blocker of the Na+–Cl− cotransporter, had only a small effect. DIDS, a blocker of some KCC cotransporters and Cl−/HCO3− exchangers, reduced the EOG in epithelia from both wild-type and NKCC1 knockout mice. A combination of bumetanide and DIDS decreased the response more than either drug alone. However, no combination of drugs completely abolished the Cl− component of the response. These results support the involvement of both NKCC1 and one or more DIDS-sensitive transporters in Cl− accumulation in olfactory receptor neurons. PMID:17656441

  20. Mechanisms of neuronal chloride accumulation in intact mouse olfactory epithelium.

    PubMed

    Nickell, William T; Kleene, Nancy K; Kleene, Steven J

    2007-09-15

    When olfactory receptor neurons respond to odours, a depolarizing Cl(-) efflux is a substantial part of the response. This requires that the resting neuron accumulate Cl(-) against an electrochemical gradient. In isolated olfactory receptor neurons, the Na(+)-K(+)-2Cl(-) cotransporter NKCC1 is essential for Cl(-) accumulation. However, in intact epithelium, a robust electrical olfactory response persists in mice lacking NKCC1. This response is largely due to a neuronal Cl(-) efflux. It thus appears that NKCC1 is an important part of a more complex system of Cl(-) accumulation. To identify the remaining transport proteins, we first screened by RT-PCR for 21 Cl(-) transporters in mouse nasal tissue containing olfactory mucosa. For most of the Cl(-) transporters, the presence of mRNA was demonstrated. We also investigated the effects of pharmacological block or genetic ablation of Cl(-) transporters on the olfactory field potential, the electroolfactogram (EOG). Mice lacking the common Cl(-)/HCO(3)(-) exchanger AE2 had normal EOGs. Block of NKCC cotransport with bumetanide reduced the EOG in epithelia from wild-type mice but had no effect in mice lacking NKCC1. Hydrochlorothiazide, a blocker of the Na(+)-Cl(-) cotransporter, had only a small effect. DIDS, a blocker of some KCC cotransporters and Cl(-)/HCO(3)(-) exchangers, reduced the EOG in epithelia from both wild-type and NKCC1 knockout mice. A combination of bumetanide and DIDS decreased the response more than either drug alone. However, no combination of drugs completely abolished the Cl(-) component of the response. These results support the involvement of both NKCC1 and one or more DIDS-sensitive transporters in Cl(-) accumulation in olfactory receptor neurons. PMID:17656441

  1. Exploring Motivational System Theory within the Context of Adult Education

    ERIC Educational Resources Information Center

    Hutto, Debra Jean

    2013-01-01

    Adult Basic Education (ABE) and the General Equivalency Diploma (GED) programs serve those students who, for whatever reason, have left the educational system without attaining a regular high school diploma. Because of the manner in which they may have left the school system, many have negative emotions and personal agency beliefs hindering their…

  2. SOVIET POLITICAL SCHOOLS, THE COMMUNIST PARTY ADULT INSTRUCTION SYSTEM.

    ERIC Educational Resources Information Center

    MICKIEWICZ, ELLEN PROPPER

    A STUDY WAS MADE OF SOVIET ADULT POLITICAL EDUCATION MAINLY AS IT APPLIES TO RUSSIAN URBAN AREAS, WHERE THE SYSTEM IS MOST HIGHLY DEVELOPED. THIS SYSTEM, AN AGENCY FOR TRANSMITTING POLITICAL DOCTRINE, FORMS A PART OF THE VAST NETWORK OF FORMAL POLITICAL COMMUNICATION, WHICH INCLUDES THE MASS MEDIA, AGITATION, AND COMMUNIST PARTY LEADERSHIP…

  3. Angiotensinergic involvement in olfactory function

    SciTech Connect

    Speth, R.C.; Parker, J.L.; Wright, J.W.; Harding, J.W.

    1986-03-05

    The olfactory bulbs (OB) from Sprague-Dawley and Wistar-Kyoto rats were frozen and sectioned in a sagittal plane, 20 ..mu.. thick. Sections incubated with /sup 125/-Sar/sup 1/, Ile/sup 8/-AII indicated a high density of AII receptor binding sites in the external layers of the OB. Since the primary olfactory neurons synapse with the mitral cells in these layers, this suggests that AII may affect olfactory input to the OB. To test this hypothesis, male Sprague-Dawley rats, 9-12 weeks of age, n = 8, were administered 0.2 ml of 0.17 M ZnSO/sub 4/ into each nostril to lesion the primary olfactory neurons and their axon terminals in the OB. Rats treated with ZnSO/sub 4/ showed an impairment in their ability to find a buried food pellet, P = 0.041, Mann-Whitney test. Nine days post-treatment, the rats were sacrificed and AII receptors binding in homogenates of the OB was determined. There was a 23% increase (P < 0.05) in AII receptor density in the ZnSO/sub 4/ treated rat OB; it was correlated with the extent of the olfactory deficit, r/sub s/ = .91, Spearman Rank Order Test, P < .01. However, there was a 24% decrease in OB weight in the ZnSO/sub 4/ group, so the number of AII receptors per OB was unchanged. These data suggest that AII plays a role in olfaction. Localizing AII receptor changes within the OB by quantitative autoradiography will characterize the changes in AII receptor density caused by ZnSO/sub 4/.

  4. How much does nasal cavity morphology matter? Patterns and rates of olfactory airflow in phyllostomid bats

    PubMed Central

    Eiting, Thomas P.; Perot, J. Blair; Dumont, Elizabeth R.

    2015-01-01

    The morphology of the nasal cavity in mammals with a good sense of smell includes features that are thought to improve olfactory airflow, such as a dorsal conduit that delivers odours quickly to the olfactory mucosa, an enlarged olfactory recess at the back of the airway, and a clear separation of the olfactory and respiratory regions of the nose. The link between these features and having a good sense of smell has been established by functional examinations of a handful of distantly related mammalian species. In this paper, we provide the first detailed examination of olfactory airflow in a group of closely related species that nevertheless vary in their sense of smell. We study six species of phyllostomid bats that have different airway morphologies and foraging ecologies, which have been linked to differences in olfactory ability or reliance. We hypothesize that differences in morphology correlate with differences in the patterns and rates of airflow, which in turn are consistent with dietary differences. To compare species, we make qualitative and quantitative comparisons of the patterns and rates of airflow through the olfactory region during both inhalation and exhalation across the six species. Contrary to our expectations, we find no clear differences among species in either the patterns of airflow through the airway or in rates of flow through the olfactory region. By and large, olfactory airflow seems to be conserved across species, suggesting that morphological differences appear to be driven by other mechanical demands on the snout, such as breathing and feeding. Olfactory ability may depend on other aspects of the system, such as the neurobiological processing of odours that work within the existing morphology imposed by other functional demands on the nasal cavity. PMID:25520358

  5. How much does nasal cavity morphology matter? Patterns and rates of olfactory airflow in phyllostomid bats.

    PubMed

    Eiting, Thomas P; Perot, J Blair; Dumont, Elizabeth R

    2015-02-01

    The morphology of the nasal cavity in mammals with a good sense of smell includes features that are thought to improve olfactory airflow, such as a dorsal conduit that delivers odours quickly to the olfactory mucosa, an enlarged olfactory recess at the back of the airway, and a clear separation of the olfactory and respiratory regions of the nose. The link between these features and having a good sense of smell has been established by functional examinations of a handful of distantly related mammalian species. In this paper, we provide the first detailed examination of olfactory airflow in a group of closely related species that nevertheless vary in their sense of smell. We study six species of phyllostomid bats that have different airway morphologies and foraging ecologies, which have been linked to differences in olfactory ability or reliance. We hypothesize that differences in morphology correlate with differences in the patterns and rates of airflow, which in turn are consistent with dietary differences. To compare species, we make qualitative and quantitative comparisons of the patterns and rates of airflow through the olfactory region during both inhalation and exhalation across the six species. Contrary to our expectations, we find no clear differences among species in either the patterns of airflow through the airway or in rates of flow through the olfactory region. By and large, olfactory airflow seems to be conserved across species, suggesting that morphological differences appear to be driven by other mechanical demands on the snout, such as breathing and feeding. Olfactory ability may depend on other aspects of the system, such as the neurobiological processing of odours that work within the existing morphology imposed by other functional demands on the nasal cavity. PMID:25520358

  6. Distinct Neural Mechanisms Mediate Olfactory Memory Formation at Different Timescales

    ERIC Educational Resources Information Center

    McNamara, Ann Marie; Magidson, Phillip D.; Linster, Christiane; Wilson, Donald A.; Cleland, Thomas A.

    2008-01-01

    Habituation is one of the oldest forms of learning, broadly expressed across sensory systems and taxa. Here, we demonstrate that olfactory habituation induced at different timescales (comprising different odor exposure and intertrial interval durations) is mediated by different neural mechanisms. First, the persistence of habituation memory is…

  7. Homeobox Protein Hop Functions in the Adult Cardiac Conduction System

    PubMed Central

    Ismat, Fraz A.; Zhang, Maozhen; Kook, Hyun; Huang, Bin; Zhou, Rong; Ferrari, Victor A.; Epstein, Jonathan A.; Patel, Vickas V.

    2006-01-01

    Hop is an unusual homeobox gene expressed in the embryonic and adult heart. Hop acts downstream of Nkx2–5 during development, and Nkx2–5 mutations are associated with cardiac conduction system (CCS) defects. Inactivation of Hop in the mouse is lethal in half of the expected null embryos. Here, we show that Hop is expressed strongly in the adult CCS. Hop−/− adult mice display conduction defects below the atrioventricular node (AVN) as determined by invasive electrophysiological testing. These defects are associated with decreased expression of connexin40. Our results suggest that Hop functions in the adult CCS and demonstrate conservation of molecular hierarchies between embryonic myocardium and the specialized conduction tissue of the mature heart. PMID:15790958

  8. Is the age-related loss in olfactory sensitivity similar for light and heavy molecules?

    PubMed

    Sinding, Charlotte; Puschmann, Laura; Hummel, Thomas

    2014-06-01

    The process of aging affects olfaction quite early and can lead to a major handicap. One may ask whether olfactory loss is general or if it affects some odors more specifically? We investigated whether an age-related increase in olfactory threshold could be more or less specific to heavy or light molecules, based on the idea that these odors would bind differently to olfactory receptors. One group of 30 older subjects (50-70 years) and one group of 30 young adults (18-30 years) were tested for their threshold to 4 odors. Two odorants were light molecules (<150 g/mol) and the 2 others were heavy molecules (>150 g/mol). Both sets contained a single molecule and a binary mixture. Older subjects performed worse than young adults in an odor identification task, confirming a decline in the olfactory function. As a major result, young adults were as sensitive to light and heavy molecules; on the contrary, older subjects were less sensitive to heavy molecules (single molecule and binary mixture). The results suggest that older people present a heterogeneous olfactory loss more specific to heavier molecules. PMID:24803088

  9. Olfactory abnormalities in temporal lobe epilepsy.

    PubMed

    Desai, M; Agadi, J B; Karthik, N; Praveenkumar, S; Netto, A B

    2015-10-01

    We studied olfactory function in a cohort of 25 temporal lobe epilepsy (TLE) patients and 25 healthy controls. Our objectives were to measure olfactory acuity in patients with right, left or bilateral TLE and compare them with age and sex matched controls, and to correlate olfactory acuity with duration of seizure, baseline seizure control and the number of drugs used. Olfactory impairment is common in neurological disorders and dysfunction of the temporo-limbic neural substrates involved in olfactory perception is noted in TLE. We measured olfactory acuity in 25 patients with TLE, nine with right, 10 with left and six with bilateral temporal lobe seizure activity, and compared them to the controls. Odor identification was assessed using the University of Pennsylvania Smell Identification Test (UPSIT) which is a 40 item olfactory test used to diagnose olfactory deficits. Our results showed that patients with TLE exhibited significant impairment in UPSIT performance compared to the controls. There was no significant difference in scores between the right and left TLE patients. The severity of olfactory impairment did not correlate with the duration of seizures, baseline seizure control and number of drugs used. We concluded that significant olfactory impairment is seen in both right and left TLE patients, unrelated to the duration and baseline frequency of seizures or drugs used. PMID:26149406

  10. Systems Development in Adult Language Learning: A European Unit/Credit System for Modern Language Learning by Adults.

    ERIC Educational Resources Information Center

    Council for Cultural Cooperation, Strasbourg (France).

    The study prepares the ground for the introduction of a language learning system for adults. Part 1 presents a draft outline of such a system, in which the language material to be learned is organized into units and credits awarded on the completion of each unit. The content is defined with reference to the nature of the learners and their…

  11. Olfactory dysfunction, olfactory bulb pathology and urban air pollution

    PubMed Central

    Calderón-Garcidueñas, Lilian; Franco-Lira, Maricela; Henríquez-Roldán, Carlos; Osnaya, Norma; González-Maciel, Angelica; Reynoso-Robles, Rafael; Villarreal-Calderon, Rafael; Herritt, Lou; Brooks, Diane; Keefe, Sheyla; Palacios-Moreno, Juan; Villarreal-Calderon, Rodolfo; Torres-Jardón, Ricardo; Medina-Cortina, Humberto; Delgado-Chávez, Ricardo; Aiello-Mora, Mario; Maronpot, Robert R.; Doty, Richard L

    2010-01-01

    Mexico City (MC) residents are exposed to severe air pollution and exhibit olfactory bulb inflammation. We compared the olfactory function of individuals living under conditions of extreme air pollution to that of controls from a relatively clean environment and explore associations between olfaction scores, apolipoprotein E (APOE) status, and pollution exposure. The olfactory bulbs (OBs) of 35 MC and 9 controls 20.8 ± 8.5 y were assessed by light and electron microscopy. The University of Pennsylvania Smell Identification Test (UPSIT) was administered to 62 MC / 25 controls 21.2 ±2.7 y. MC subjects had significantly lower UPSIT scores: 34.24 ± 0.42 versus controls 35.76 ± 0.40, p=0.03. Olfaction deficits were present in 35.5% MC and 12% of controls. MC APOE ε 4 carriers failed 2.4 ± 0.54 items in the 10-item smell identification scale from the UPSIT related to Alzheimer's disease, while APOE 2/3 and 3/3 subjects failed 1.36 ± 0.16 items, p = 0.01. MC residents exhibited OB endothelial hyperplasia, neuronal accumulation of particles (2/35), and immunoreactivity to beta amyloid βA42 (29/35) and/or α-synuclein (4/35) in neurons, glial cells and/or blood vessels. Ultrafine particles were present in OBs endothelial cytoplasm and basement membranes. Control OBs were unremarkable. Air pollution exposure is associated with olfactory dysfunction and OB pathology, APOE 4 may confer greater susceptibility to such abnormalities, and ultrafine particles could play a key role in the OB pathology. This study contributes to our understanding of the influences of air pollution on olfaction and its potential contribution to neurodegeneration. PMID:19297138

  12. Voltage-dependent anion channel (VDAC-1) is required for olfactory sensing in Caenorhabditis elegans.

    PubMed

    Uozumi, Takayuki; Hamakawa, Masayuki; Deno, Yu-Ki; Nakajo, Nobushige; Hirotsu, Takaaki

    2015-10-01

    The Ras-MAP kinase signaling pathway plays important roles for the olfactory reception in olfactory neurons in Caenorhabditis elegans. However, given the absence of phosphorylation targets of MAPK in the olfactory neurons, the mechanism by which this pathway regulates olfactory function is unknown. Here, we used proteomic screening to identify the mitochondrial voltage-dependent anion channel VDAC-1 as a candidate target molecule of MAPK in the olfactory system of C. elegans. We found that Amphid Wing "C" (AWC) olfactory neuron-specific knockdown of vdac-1 caused severe defects in chemotaxis toward AWC-sensed odorants. We generated a new vdac-1 mutant using the CRISPR-Cas9 system, with this mutant also showing decreased chemotaxis toward odorants. This defect was rescued by AWC-specific expression of vdac-1, indicating that functions of VDAC-1 in AWC neurons are essential for normal olfactory reception in C. elegans. We observed that AWC-specific RNAi of vdac-1 reduced AWC calcium responses to odorant stimuli and caused a decrease in the quantity of mitochondria in the sensory cilia. Behavioral abnormalities in vdac-1 knockdown animals might therefore be due to reduction of AWC response, which might be caused by loss of mitochondria in the cilia. Here, we showed that the function of VDAC-1 is regulated by phosphorylation and identified Thr175 as the potential phosphorylation site of MAP kinase. PMID:26223767

  13. Multi-unit Recording Methods to Characterize Neural Activity in the Locust (Schistocerca Americana) Olfactory Circuits

    PubMed Central

    Saha, Debajit; Leong, Kevin; Katta, Nalin; Raman, Baranidharan

    2013-01-01

    Detection and interpretation of olfactory cues are critical for the survival of many organisms. Remarkably, species across phyla have strikingly similar olfactory systems suggesting that the biological approach to chemical sensing has been optimized over evolutionary time1. In the insect olfactory system, odorants are transduced by olfactory receptor neurons (ORN) in the antenna, which convert chemical stimuli into trains of action potentials. Sensory input from the ORNs is then relayed to the antennal lobe (AL; a structure analogous to the vertebrate olfactory bulb). In the AL, neural representations for odors take the form of spatiotemporal firing patterns distributed across ensembles of principal neurons (PNs; also referred to as projection neurons)2,3. The AL output is subsequently processed by Kenyon cells (KCs) in the downstream mushroom body (MB), a structure associated with olfactory memory and learning4,5. Here, we present electrophysiological recording techniques to monitor odor-evoked neural responses in these olfactory circuits. First, we present a single sensillum recording method to study odor-evoked responses at the level of populations of ORNs6,7. We discuss the use of saline filled sharpened glass pipettes as electrodes to extracellularly monitor ORN responses. Next, we present a method to extracellularly monitor PN responses using a commercial 16-channel electrode3. A similar approach using a custom-made 8-channel twisted wire tetrode is demonstrated for Kenyon cell recordings8. We provide details of our experimental setup and present representative recording traces for each of these techniques. PMID:23380828

  14. Insight of scent: experimental evidence of olfactory capabilities in the wandering albatross (Diomedea exulans).

    PubMed

    Mardon, J; Nesterova, A P; Traugott, J; Saunders, S M; Bonadonna, F

    2010-02-15

    Wandering albatrosses routinely forage over thousands of kilometres of open ocean, but the sensory mechanisms used in the food search itself have not been completely elucidated. Recent telemetry studies show that some spatial behaviours of the species are consistent with the 'multimodal foraging strategy' hypothesis which proposes that birds use a combination of olfactory and visual cues while foraging at sea. The 'multimodal foraging strategy' hypothesis, however, still suffers from a lack of experimental evidence, particularly regarding the olfactory capabilities of wandering albatrosses. As an initial step to test the hypothesis, we carried out behavioural experiments exploring the sensory capabilities of adult wandering albatrosses at a breeding colony. Three two-choice tests were designed to investigate the birds' response to olfactory and visual stimuli, individually or in combination. Perception of the different stimuli was assessed by comparing the amount of exploration directed towards an 'experimental' display or a 'control' display. Our results indicate that birds were able to perceive the three types of stimulus presented: olfactory, visual and combined. Moreover, olfactory and visual cues were found to have additional effects on the exploratory behaviours of males. This simple experimental demonstration of reasonable olfactory capabilities in the wandering albatross supports the 'multimodal foraging strategy' and is consistent with recent hypotheses of the evolutionary history of procellariiforms. PMID:20118306

  15. Morphological and electrophysiological examination of olfactory sensory neurons during the early developmental prolarval stage of the sea lamprey Petromyzon marinus L

    USGS Publications Warehouse

    Zielinski, B.S.; Fredricks, Keith; McDonald, R.; Zaidi, A.U.

    2005-01-01

    This study examined olfactory sensory neuron morphology and physiological responsiveness in newly hatched sea lamprey, Petromyzon marinus L. These prolarvae hatch shortly after neural tube formation, and stay within nests for approximately 18 days, before moving downstream to silty areas where they burrow, feed and pass to the larval stage. To explore the possibility that the olfactory system is functioning during this prolarval stage, morphological and physiological development of olfactory sensory neurons was examined. The nasal cavity contained an olfactory epithelium with ciliated olfactory sensory neurons. Axons formed aggregates in the basal portion of the olfactory epithelium and spanned the narrow distance between the olfactory epithelium and the brain. The presence of asymmetric synapses with agranular vesicles within fibers in the brain, adjacent to the olfactory epithelium suggests that there was synaptic connectivity between olfactory sensory axons and the brain. Neural recordings from the surface of the olfactory epithelium showed responses following the application of L-arginine, taurocholic acid, petromyzonol sulfate (a lamprey migratory pheromone), and water conditioned by conspecifics. These results suggest that lampreys may respond to olfactory sensory input during the prolarval stage. ?? 2006 Springer Science + Business Media, LLC.

  16. Olfactory input increases visual sensitivity in zebrafish: a possible function for the terminal nerve and dopaminergic interplexiform cells.

    PubMed

    Maaswinkel, Hans; Li, Lei

    2003-07-01

    Centrifugal innervation of the neural retina has been documented in many species. In zebrafish Danio rerio, the only so-far described centrifugal pathway originates from terminal nerve (TN) cell bodies that are located in the olfactory bulb. Most of the TN axons terminate in the forebrain and midbrain, but some project via the optic nerve to the neural retina, where they synapse onto dopaminergic interplexiform cells (DA-IPCs). While the anatomical pathway between the olfactory and visual organs has been described, it is unknown if and how olfactory signals influence visual system functions. We demonstrate here that olfactory input is involved in the modulation of visual sensitivity in zebrafish. As determined by a behavioral assay and by electroretinographic (ERG) recording, zebrafish visual sensitivity was increased upon presentation of amino acids as olfactory stimuli. This effect, however, was observed only in the early morning hours when zebrafish are least sensitive to light. The effect of olfactory input on vision was eliminated after lesion of the olfactory bulbs or after the destruction of DA-IPCs. Intraocular injections of a dopamine D(2) but not a D(1) receptor antagonist blocked the effect of olfactory input on visual sensitivity. Although we cannot exclude the involvement of other anatomical pathways, our data suggest that the TN and DA-IPCs are the prime candidates for olfactory modulation of visual sensitivity. PMID:12771169

  17. Olfactory memory in the old and very old: relations to episodic and semantic memory and APOE genotype.

    PubMed

    Larsson, Maria; Hedner, Margareta; Papenberg, Goran; Seubert, Janina; Bäckman, Lars; Laukka, Erika J

    2016-02-01

    The neuroanatomical organization that underlies olfactory memory is different from that of other memory types. The present work examines olfactory memory in an elderly population-based sample (Swedish National Study on Aging and Care in Kungsholmen) aged 60-100 years (n = 2280). We used structural equation modeling to investigate whether olfactory memory in old age is best conceptualized as a distinct category, differentiated from episodic and semantic memory. Further, potential olfactory dedifferentiation and genetic associations (APOE) to olfactory function in late senescence were investigated. Results are in support of a 3-factor solution where olfactory memory, as indexed by episodic odor recognition and odor identification, is modeled separately from episodic and semantic memory for visual and verbal information. Increasing age was associated with poorer olfactory memory performance, and observed age-related deficits were further exacerbated for carriers of the APOE ε4 allele; these effects tended to be larger for olfactory memory compared to episodic and semantic memory pertaining to other sensory systems (vision, auditory). Finally, stronger correlations between olfactory and episodic memory, indicating dedifferentiation, were observed in the older age groups. PMID:26827650

  18. Postnatal Experience Modulates Functional Properties of Mouse Olfactory Sensory Neurons

    PubMed Central

    He, Jiwei; Tian, Huikai; Lee, Anderson C.; Ma, Minghong

    2012-01-01

    Early experience considerably modulates the organization and function of all s