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1
Fleischmann, Alexander. „Circuits neuronaux et comportement. Analyse génétique de traitement olfactif et fonction“. L’annuaire du Collège de France, Nr. 112 (01.04.2013): 894–95. http://dx.doi.org/10.4000/annuaire-cdf.1088.
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Melcher, Christoph, Ruediger Bader und Michael J. Pankratz. „Amino acids, taste circuits, and feeding behavior in Drosophila: towards understanding the psychology of feeding in flies and man“. Journal of Endocrinology 192, Nr. 3 (März 2007): 467–72. http://dx.doi.org/10.1677/joe-06-0066.
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Feeding can be regulated by a variety of external sensory stimuli such as olfaction and gustation, as well as by systemic internal signals of feeding status and metabolic needs. Faced with a major health epidemic in eating-related conditions, such as obesity and diabetes, there is an ever increasing need to dissect and understand the complex regulatory network underlying the multiple aspects of feeding behavior. In this minireview, we highlight the use of Drosophila in studying the neural circuits that control the feeding behavior in response to external and internal signals. In particular, we outline the work on the neuroanatomical and functional characterization of the newly identified hugin neuronal circuit. We focus on the pivotal role of the central nervous system in integrating external and internal feeding-relevant information, thus enabling the organism to make one of the most basic decisions – to eat or not to eat.
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Carey, Ryan M., William Erik Sherwood, Michael T. Shipley, Alla Borisyuk und Matt Wachowiak. „Role of intraglomerular circuits in shaping temporally structured responses to naturalistic inhalation-driven sensory input to the olfactory bulb“. Journal of Neurophysiology 113, Nr. 9 (Mai 2015): 3112–29. http://dx.doi.org/10.1152/jn.00394.2014.
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Olfaction in mammals is a dynamic process driven by the inhalation of air through the nasal cavity. Inhalation determines the temporal structure of sensory neuron responses and shapes the neural dynamics underlying central olfactory processing. Inhalation-linked bursts of activity among olfactory bulb (OB) output neurons [mitral/tufted cells (MCs)] are temporally transformed relative to those of sensory neurons. We investigated how OB circuits shape inhalation-driven dynamics in MCs using a modeling approach that was highly constrained by experimental results. First, we constructed models of canonical OB circuits that included mono- and disynaptic feedforward excitation, recurrent inhibition and feedforward inhibition of the MC. We then used experimental data to drive inputs to the models and to tune parameters; inputs were derived from sensory neuron responses during natural odorant sampling (sniffing) in awake rats, and model output was compared with recordings of MC responses to odorants sampled with the same sniff waveforms. This approach allowed us to identify OB circuit features underlying the temporal transformation of sensory inputs into inhalation-linked patterns of MC spike output. We found that realistic input-output transformations can be achieved independently by multiple circuits, including feedforward inhibition with slow onset and decay kinetics and parallel feedforward MC excitation mediated by external tufted cells. We also found that recurrent and feedforward inhibition had differential impacts on MC firing rates and on inhalation-linked response dynamics. These results highlight the importance of investigating neural circuits in a naturalistic context and provide a framework for further explorations of signal processing by OB networks.
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Koickal, Thomas Jacob, Alister Hamilton, Su Lim Tan, James A. Covington, Julian W. Gardner und Tim C. Pearce. „Analog VLSI Circuit Implementation of an Adaptive Neuromorphic Olfaction Chip“. IEEE Transactions on Circuits and Systems I: Regular Papers 54, Nr. 1 (Januar 2007): 60–73. http://dx.doi.org/10.1109/tcsi.2006.888677.
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Jeong, Yun-Mi, Tae-Ik Choi, Kyu-Seok Hwang, Jeong-Soo Lee, Robert Gerlai und Cheol-Hee Kim. „Optogenetic Manipulation of Olfactory Responses in Transgenic Zebrafish: A Neurobiological and Behavioral Study“. International Journal of Molecular Sciences 22, Nr. 13 (03.07.2021): 7191. http://dx.doi.org/10.3390/ijms22137191.
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Olfaction is an important neural system for survival and fundamental behaviors such as predator avoidance, food finding, memory formation, reproduction, and social communication. However, the neural circuits and pathways associated with the olfactory system in various behaviors are not fully understood. Recent advances in optogenetics, high-resolution in vivo imaging, and reconstructions of neuronal circuits have created new opportunities to understand such neural circuits. Here, we generated a transgenic zebrafish to manipulate olfactory signal optically, expressing the Channelrhodopsin (ChR2) under the control of the olfactory specific promoter, omp. We observed light-induced neuronal activity of olfactory system in the transgenic fish by examining c-fos expression, and a calcium indicator suggesting that blue light stimulation caused activation of olfactory neurons in a non-invasive manner. To examine whether the photo-activation of olfactory sensory neurons affect behavior of zebrafish larvae, we devised a behavioral choice paradigm and tested how zebrafish larvae choose between two conflicting sensory cues, an aversive odor or the naturally preferred phototaxis. We found that when the conflicting cues (the preferred light and aversive odor) were presented together simultaneously, zebrafish larvae swam away from the aversive odor. However, the transgenic fish with photo-activation were insensitive to the aversive odor and exhibited olfactory desensitization upon optical stimulation of ChR2. These results show that an aversive olfactory stimulus can override phototaxis, and that olfaction is important in decision making in zebrafish. This new transgenic model will be useful for the analysis of olfaction related behaviors and for the dissection of underlying neural circuits.
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Wu, Jing, Penglai Liu, Fengjiao Chen, Lingying Ge, Yifan Lu und Anan Li. „Excitability of Neural Activity is Enhanced, but Neural Discrimination of Odors is Slightly Decreased, in the Olfactory Bulb of Fasted Mice“. Genes 11, Nr. 4 (16.04.2020): 433. http://dx.doi.org/10.3390/genes11040433.
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Olfaction and satiety status influence each other: cues from the olfactory system modulate eating behavior, and satiety affects olfactory abilities. However, the neural mechanisms governing the interactions between olfaction and satiety are unknown. Here, we investigate how an animal’s nutritional state modulates neural activity and odor representation in the mitral/tufted cells of the olfactory bulb, a key olfactory center that plays important roles in odor processing and representation. At the single-cell level, we found that the spontaneous firing rate of mitral/tufted cells and the number of cells showing an excitatory response both increased when mice were in a fasted state. However, the neural discrimination of odors slightly decreased. Although ongoing baseline and odor-evoked beta oscillations in the local field potential in the olfactory bulb were unchanged with fasting, the amplitude of odor-evoked gamma oscillations significantly decreased in a fasted state. These neural changes in the olfactory bulb were independent of the sniffing pattern, since both sniffing frequency and mean inhalation duration did not change with fasting. These results provide new information toward understanding the neural circuit mechanisms by which olfaction is modulated by nutritional status.
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Paoli, Marco, und Giovanni C. Galizia. „Olfactory coding in honeybees“. Cell and Tissue Research 383, Nr. 1 (Januar 2021): 35–58. http://dx.doi.org/10.1007/s00441-020-03385-5.
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Abstract With less than a million neurons, the western honeybee Apis mellifera is capable of complex olfactory behaviors and provides an ideal model for investigating the neurophysiology of the olfactory circuit and the basis of olfactory perception and learning. Here, we review the most fundamental aspects of honeybee’s olfaction: first, we discuss which odorants dominate its environment, and how bees use them to communicate and regulate colony homeostasis; then, we describe the neuroanatomy and the neurophysiology of the olfactory circuit; finally, we explore the cellular and molecular mechanisms leading to olfactory memory formation. The vastity of histological, neurophysiological, and behavioral data collected during the last century, together with new technological advancements, including genetic tools, confirm the honeybee as an attractive research model for understanding olfactory coding and learning.
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Groschner, Lukas N., und Gero Miesenböck. „Mechanisms of Sensory Discrimination: Insights from Drosophila Olfaction“. Annual Review of Biophysics 48, Nr. 1 (06.05.2019): 209–29. http://dx.doi.org/10.1146/annurev-biophys-052118-115655.
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All an animal can do to infer the state of its environment is to observe the sensory-evoked activity of its own neurons. These inferences about the presence, quality, or similarity of objects are probabilistic and inform behavioral decisions that are often made in close to real time. Neural systems employ several strategies to facilitate sensory discrimination: Biophysical mechanisms separate the neuronal response distributions in coding space, compress their variances, and combine information from sequential observations. We review how these strategies are implemented in the olfactory system of the fruit fly. The emerging principles of odor discrimination likely apply to other neural circuits of similar architecture.
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Bolding, Kevin A., und Kevin M. Franks. „Recurrent cortical circuits implement concentration-invariant odor coding“. Science 361, Nr. 6407 (13.09.2018): eaat6904. http://dx.doi.org/10.1126/science.aat6904.
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Animals rely on olfaction to find food, attract mates, and avoid predators. To support these behaviors, they must be able to identify odors across different odorant concentrations. The neural circuit operations that implement this concentration invariance remain unclear. We found that despite concentration-dependence in the olfactory bulb (OB), representations of odor identity were preserved downstream, in the piriform cortex (PCx). The OB cells responding earliest after inhalation drove robust responses in sparse subsets of PCx neurons. Recurrent collateral connections broadcast their activation across the PCx, recruiting global feedback inhibition that rapidly truncated and suppressed cortical activity for the remainder of the sniff, discounting the impact of slower, concentration-dependent OB inputs. Eliminating recurrent collateral output amplified PCx odor responses rendered the cortex steeply concentration-dependent and abolished concentration-invariant identity decoding.
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Terral, Geoffrey, Giovanni Marsicano, Pedro Grandes und Edgar Soria-Gómez. „Cannabinoid Control of Olfactory Processes: The Where Matters“. Genes 11, Nr. 4 (16.04.2020): 431. http://dx.doi.org/10.3390/genes11040431.
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Olfaction has a direct influence on behavior and cognitive processes. There are different neuromodulatory systems in olfactory circuits that control the sensory information flowing through the rest of the brain. The presence of the cannabinoid type-1 (CB1) receptor, (the main cannabinoid receptor in the brain), has been shown for more than 20 years in different brain olfactory areas. However, only over the last decade have we started to know the specific cellular mechanisms that link cannabinoid signaling to olfactory processing and the control of behavior. In this review, we aim to summarize and discuss our current knowledge about the presence of CB1 receptors, and the function of the endocannabinoid system in the regulation of different olfactory brain circuits and related behaviors.
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Kermen, Florence, Nathalie Mandairon und Laura Chalençon. „Odor hedonics coding in the vertebrate olfactory bulb“. Cell and Tissue Research 383, Nr. 1 (Januar 2021): 485–93. http://dx.doi.org/10.1007/s00441-020-03372-w.
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AbstractWhether an odorant is perceived as pleasant or unpleasant (hedonic value) governs a range of crucial behaviors: foraging, escaping danger, and social interaction. Despite its importance in olfactory perception, little is known regarding how odor hedonics is represented and encoded in the brain. Here, we review recent findings describing how odorant hedonic value is represented in the first olfaction processing center, the olfactory bulb. We discuss how olfactory bulb circuits might contribute to the coding of innate and learned odorant hedonics in addition to the odorant’s physicochemical properties.
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Jafari, Shadi, und Mattias Alenius. „Odor response adaptation in Drosophila—a continuous individualization process“. Cell and Tissue Research 383, Nr. 1 (Januar 2021): 143–48. http://dx.doi.org/10.1007/s00441-020-03384-6.
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AbstractOlfactory perception is very individualized in humans and also inDrosophila. The process that individualize olfaction is adaptation that across multiple time scales and mechanisms shape perception and olfactory-guided behaviors. Olfactory adaptation occurs both in the central nervous system and in the periphery. Central adaptation occurs at the level of the circuits that process olfactory inputs from the periphery where it can integrate inputs from other senses, metabolic states, and stress. We will here focus on the periphery and how the fast, slow, and persistent (lifelong) adaptation mechanisms in the olfactory sensory neurons individualize theDrosophilaolfactory system.
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Weiss, Lukas, Ivan Manzini und Thomas Hassenklöver. „Olfaction across the water–air interface in anuran amphibians“. Cell and Tissue Research 383, Nr. 1 (Januar 2021): 301–25. http://dx.doi.org/10.1007/s00441-020-03377-5.
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AbstractExtant anuran amphibians originate from an evolutionary intersection eventually leading to fully terrestrial tetrapods. In many ways, they have to deal with exposure to both terrestrial and aquatic environments: (i) phylogenetically, as derivatives of the first tetrapod group that conquered the terrestrial environment in evolution; (ii) ontogenetically, with a development that includes aquatic and terrestrial stages connected via metamorphic remodeling; and (iii) individually, with common changes in habitat during the life cycle. Our knowledge about the structural organization and function of the amphibian olfactory system and its relevance still lags behind findings on mammals. It is a formidable challenge to reveal underlying general principles of circuity-related, cellular, and molecular properties that are beneficial for an optimized sense of smell in water and air. Recent findings in structural organization coupled with behavioral observations could help to understand the importance of the sense of smell in this evolutionarily important animal group. We describe the structure of the peripheral olfactory organ, the olfactory bulb, and higher olfactory centers on a tissue, cellular, and molecular levels. Differences and similarities between the olfactory systems of anurans and other vertebrates are reviewed. Special emphasis lies on adaptations that are connected to the distinct demands of olfaction in water and air environment. These particular adaptations are discussed in light of evolutionary trends, ontogenetic development, and ecological demands.
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Mallick, Ahana, Andrew M. Dacks und Quentin Gaudry. „Olfactory Critical Periods: How Odor Exposure Shapes the Developing Brain in Mice and Flies“. Biology 13, Nr. 2 (02.02.2024): 94. http://dx.doi.org/10.3390/biology13020094.
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Neural networks have an extensive ability to change in response to environmental stimuli. This flexibility peaks during restricted windows of time early in life called critical periods. The ubiquitous occurrence of this form of plasticity across sensory modalities and phyla speaks to the importance of critical periods for proper neural development and function. Extensive investigation into visual critical periods has advanced our knowledge of the molecular events and key processes that underlie the impact of early-life experience on neuronal plasticity. However, despite the importance of olfaction for the overall survival of an organism, the cellular and molecular basis of olfactory critical periods have not garnered extensive study compared to visual critical periods. Recent work providing a comprehensive mapping of the highly organized olfactory neuropil and its development has in turn attracted a growing interest in how these circuits undergo plasticity during critical periods. Here, we perform a comparative review of olfactory critical periods in fruit flies and mice to provide novel insight into the importance of early odor exposure in shaping neural circuits and highlighting mechanisms found across sensory modalities.
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Bathellier, Brice, Samuel Lagier, Philippe Faure und Pierre-Marie Lledo. „Circuit Properties Generating Gamma Oscillations in a Network Model of the Olfactory Bulb“. Journal of Neurophysiology 95, Nr. 4 (April 2006): 2678–91. http://dx.doi.org/10.1152/jn.01141.2005.
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The study of the neural basis of olfaction is important both for understanding the sense of smell and for understanding the mechanisms of neural computation. In the olfactory bulb (OB), the spatial patterning of both sensory inputs and synaptic interactions is crucial for processing odor information, although this patterning alone is not sufficient. Recent studies have suggested that representations of odor may already be distributed and dynamic in the first olfactory relay. The growing evidence demonstrating a functional role for the temporal structure of bulbar neuronal activity supports this assumption. However, the detailed mechanisms underlying this temporal structure have never been thoroughly studied. Our study focused on gamma (40–100 Hz) network oscillations in the mammalian OB, which is a form of temporal patterning in bulbar activity elicited by olfactory stimuli. We used computational modeling combined with electrophysiological recordings to investigate the basic synaptic organization necessary and sufficient to generate sustained gamma rhythms. We found that features of gamma oscillations obtained in vitro were identical to those of a model based on lateral inhibition as the coupling modality (i.e., low irregular firing rate and high oscillation stability). In contrast, they differed substantially from those of a model based on lateral excitatory coupling (i.e., high regular firing rate and instable oscillations). Therefore we could precisely tune the oscillation frequency by changing the kinetics of inhibitory events supporting the lateral inhibition. Moreover, gradually decreasing GABAergic synaptic transmission decreased the degree of relay neuron synchronization in response to sensory inputs, both theoretically and experimentally. Thus we have shown that lateral inhibition provides a mechanism by which the dynamic processing of odor information might be finely tuned within the OB circuit.
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King, Bruce M. „Amygdaloid lesion-induced obesity: relation to sexual behavior, olfaction, and the ventromedial hypothalamus“. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 291, Nr. 5 (November 2006): R1201—R1214. http://dx.doi.org/10.1152/ajpregu.00199.2006.
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Lesions of the amygdala have long been known to produce hyperphagia and obesity in cats, dogs, and monkeys, but only recently have studies with rats determined that the effective site is the posterodorsal amygdala (PDA)—the posterodorsal medial amygdaloid nucleus and the intra-amygdaloid bed nucleus of the stria terminalis. There is a sex difference; female rats with PDA lesions display greater weight gain than male rats. In the brains of female rats with obesity-inducing PDA lesions, there is a dense pattern of axonal degeneration in the capsule of the ventromedial hypothalamus (VMH) and other targets of the stria terminalis. Transections of the dorsal component of the stria terminalis also result in hyperphagia and obesity in female rats. Similar to rats with VMH lesions, rats with PDA lesions are hyperinsulinemic during food restriction and greatly prefer high-carbohydrate diets. The PDA is also a critical site for some aspects of rodent sexual behavior, particularly those that depend on olfaction, and the pattern of degeneration observed after obesity-inducing PDA lesions is remarkably parallel to the circuit that has been proposed to mediate sexual behavior. Medial amygdaloid lesions disrupt the normal feeding pattern and result in impaired responses to caloric challenges, and there is evidence that these behavioral changes are also due to a disruption of olfactory input. With its input from the olfactory bulbs and connections to the VMH, the PDA may be a nodal point at which olfactory and neuroendocrine stimuli are integrated to affect feeding behavior.
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Mast, Thomas Gerald, Kelsey Zuk, Andrew Rinke, Khaleel Quasem, Bradley Savard, Charles Brobbey, Jacob Reiss und Michael Dryden. „Temporary Anosmia in Mice Following Nasal Lavage With Dilute Detergent Solution“. Chemical Senses 44, Nr. 8 (31.07.2019): 639–48. http://dx.doi.org/10.1093/chemse/bjz047.
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AbstractOlfactory sensory deprivation induces anosmia and reduces tyrosine hydroxylase and dopamine levels in the olfactory bulb. The behavioral consequences specific to the loss of olfactory bulb dopamine are difficult to determine because sensory deprivation protocols are either confounded by side effects or leave the animal anosmic. A new method to both induce sensory deprivation and to measure the behavioral and circuit consequences is needed. We developed a novel, recoverable anosmia protocol using nasal lavage with a dilute detergent solution. Detergent treatment did not damage the olfactory epithelium as measured by scanning electron microscopy, alcian blue histology, and acetylated tubulin immunohistochemistry. One treatment-induced anosmia that lasted 24 to 48 h. Three treatments over 5 days reduced olfactory bulb tyrosine hydroxylase and dopamine levels indicating that anosmia persists between treatments. Importantly, even with multiple treatments, olfactory ability recovered within 48 h. This is the first report of a sensory deprivation protocol that induces recoverable anosmia and can be paired with biochemical, histological, and behavioral investigations of olfaction.
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Arifani, Tania. „Overview of Anatomy and Physiology of Gustatory and Olfactory System“. Sriwijaya Journal of Otorhinolaryngology 1, Nr. 2 (22.12.2023): 36–39. http://dx.doi.org/10.59345/sjorl.v1i2.93.
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The olfactory system is involved in detecting potential threats in the environment, generating sensations of enjoyment, facilitating proper nourishment, impacting sexual behavior, and regulating mood. Concurrently, the human taste system identifies hydrophilic molecules dissolved in saliva. The purpose of this review was to offer a thorough depiction of the human gustatory and olfactory systems. The various regions of the brain and the taste pathways transmit and receive information through distinct mechanisms. The taste circuits and various regions of the brain interconnect bidirectionally. The peripheral subdivision of the olfactory system consists of the olfactory epithelium and nerve fascicles. On the other hand, the central subdivision includes the olfactory bulb and its links to the central nervous system. Olfactory dysfunction (smell) and gustatory dysfunction (taste) can manifest independently or together. The robust correlation between olfaction and gustation engenders a gustatory feeling. Disruption of a feeling can alter the sense of flavor. Human olfactory and taste senses become less sensitive as they age.
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Zhou, Fu-Wen, Zuo-Yi Shao, Michael T. Shipley und Adam C. Puche. „Short-term plasticity in glomerular inhibitory circuits shapes olfactory bulb output“. Journal of Neurophysiology 123, Nr. 3 (01.03.2020): 1120–32. http://dx.doi.org/10.1152/jn.00628.2019.
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Short-term plasticity is a fundamental synaptic property thought to underlie memory and neural processing. The glomerular microcircuit comprises complex excitatory and inhibitory interactions and transmits olfactory nerve signals to the excitatory output neurons, mitral/tufted cells (M/TCs). The major glomerular inhibitory interneurons, short axon cells (SACs) and periglomerular cells (PGCs), both provide feedforward and feedback inhibition to M/TCs and have reciprocal inhibitory synapses between each other. Olfactory input is episodically driven by sniffing. We hypothesized that frequency-dependent short-term plasticity within these inhibitory circuits could influence signals sent to higher-order olfactory networks. To assess short-term plasticity in glomerular circuits and MC outputs, we virally delivered channelrhodopsin-2 (ChR2) in glutamic acid decarboxylase-65 promotor (GAD2-cre) or tyrosine hydroxylase promoter (TH-cre) mice and selectively activated one of these two populations while recording from cells of the other population or from MCs. Selective activation of TH-ChR2-expressing SACs inhibited all recorded GAD2-green fluorescent protein(GFP)-expressing presumptive PGC cells, and activation of GAD2-ChR2 cells inhibited TH-GFP-expressing SACs, indicating reciprocal inhibitory connections. SAC synaptic inhibition of GAD2-expressing cells was significantly facilitated at 5–10 Hz activation frequencies. In contrast, GAD2-ChR2 cell inhibition of TH-expressing cells was activation-frequency independent. Both SAC and PGC inhibition of MCs also exhibited short-term plasticity, pronounced in the 5–20 Hz range corresponding to investigative sniffing frequency ranges. In paired SAC and olfactory nerve electrical stimulations, the SAC to MC synapse was able to markedly suppress MC spiking. These data suggest that short-term plasticity across investigative sniffing ranges may differentially regulate intra- and interglomerular inhibitory circuits to dynamically shape glomerular output signals to downstream targets. NEW & NOTEWORTHY Short-term plasticity is a fundamental synaptic property that modulates synaptic strength based on preceding activity of the synapse. In rodent olfaction, sensory input arrives episodically driven by sniffing rates ranging from quiescent respiration (1–2 Hz) through to investigative sniffing (5–10 Hz). Here we show that glomerular inhibitory networks are exquisitely sensitive to input frequencies and exhibit plasticity proportional to investigative sniffing frequencies. This indicates that olfactory glomerular circuits are dynamically modulated by episodic sniffing input.
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Su, Yaozong, Bo Zhang und Xuenong Xu. „Chemosensory systems in predatory mites: from ecology to genome“. Systematic and Applied Acarology 26, Nr. 5 (05.05.2021): 852–65. http://dx.doi.org/10.11158/saa.26.5.3.
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The reception of chemical cues in the environment is essential for the survival of almost all organisms, including phytoseiid mites. Compared with the progress made in the field of insect olfaction, the understanding of how predatory mites perceive chemical compounds and react to their surroundings is merely fragmentarily documented in past decades. In this review, we provide a guide in the field from chemoecology of herbivore-induced plant volatiles (HIPVs) as early as 1980s to the advances made in comparative genomics of predatory mites in 2019. We present from three aspects, i.e., chemosensory-guided feeding behavior, sensory structures and chemoreceptors predicted from genomes. The molecular principles of chemosensory system remain exciting areas for future research, since insights into the mechanisms underlying the sensing of chemical signals will not only contribute to a better understanding of predator behavior and physiology but may also open new avenues for the development of more specific and sustainable approaches to control pests by manipulating behaviors in predators. We then suggest three directions for future research: 1) chemoreceptor gene identification and function verification; 2) neural response circuit to stimuli and 3) application of chemoperception on feeding behavior. The potential methods and techniques are provided as well.
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Smeets, Paul A. M., Lisette Charbonnier, Floor van Meer, Laura N. van der Laan und Maartje S. Spetter. „Food-induced brain responses and eating behaviour“. Proceedings of the Nutrition Society 71, Nr. 4 (29.08.2012): 511–20. http://dx.doi.org/10.1017/s0029665112000808.
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The brain governs food intake behaviour by integrating many different internal and external state and trait-related signals. Understanding how the decisions to start and to stop eating are made is crucial to our understanding of (maladaptive patterns of) eating behaviour. Here, we aim to (1) review the current state of the field of ‘nutritional neuroscience’ with a focus on the interplay between food-induced brain responses and eating behaviour and (2) highlight research needs and techniques that could be used to address these. The brain responses associated with sensory stimulation (sight, olfaction and taste), gastric distension, gut hormone administration and food consumption are the subject of increasing investigation. Nevertheless, only few studies have examined relations between brain responses and eating behaviour. However, the neural circuits underlying eating behaviour are to a large extent generic, including reward, self-control, learning and decision-making circuitry. These limbic and prefrontal circuits interact with the hypothalamus, a key homeostatic area. Target areas for further elucidating the regulation of food intake are: (eating) habit and food preference formation and modification, the neural correlates of self-control, nutrient sensing and dietary learning, and the regulation of body adiposity. Moreover, to foster significant progress, data from multiple studies need to be integrated. This requires standardisation of (neuroimaging) measures, data sharing and the application and development of existing advanced analysis and modelling techniques to nutritional neuroscience data. In the next 20 years, nutritional neuroscience will have to prove its potential for providing insights that can be used to tackle detrimental eating behaviour.
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Wettschureck, Nina, Alexandra Moers, Tuula Hamalainen, Thomas Lemberger, Günther Schütz und Stefan Offermanns. „Heterotrimeric G Proteins of the Gq/11 Family Are Crucial for the Induction of Maternal Behavior in Mice“. Molecular and Cellular Biology 24, Nr. 18 (15.09.2004): 8048–54. http://dx.doi.org/10.1128/mcb.24.18.8048-8054.2004.
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ABSTRACT Heterotrimeric G proteins of the Gq/11 family transduce signals from a variety of neurotransmitter receptors and have therefore been implicated in several functions of the central nervous system. To investigate the potential role of Gq/11 signaling in behavior, we generated mice which lack the α-subunits of the two main members of the Gq/11 family, Gαq and Gα11, selectively in the forebrain. We show here that forebrain Gαq/11-deficient females do not display any maternal behavior such as nest building, pup retrieving, crouching, or nursing. However, olfaction, motor behavior and mammary gland function are normal in forebrain Gαq/11-deficient females. We used c-fos immunohistochemistry to investigate pup-induced neuronal activation in different forebrain regions and found a significant reduction in the medial preoptic area, the bed nucleus of stria terminalis, and the lateral septum both in postpartum females and in virgin females after foster pup exposure. Pituitary function, especially prolactin release, was normal in forebrain Gαq/11-deficient females, and activation of oxytocin receptor-positive neurons in the hypothalamus did not differ between genotypes. Our findings show that Gq/11 signaling is indispensable to the neuronal circuit that connects the perception of pup-related stimuli to the initiation of maternal behavior and that this defect cannot be attributed to either reduced systemic prolactin levels or impaired activation of oxytocin receptor-positive neurons of the hypothalamus.
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Sakayori, Nobuyuki, Ryuichi Kimura und Noriko Osumi. „Impact of Lipid Nutrition on Neural Stem/Progenitor Cells“. Stem Cells International 2013 (2013): 1–12. http://dx.doi.org/10.1155/2013/973508.
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The neural system originates from neural stem/progenitor cells (NSPCs). Embryonic NSPCs first proliferate to increase their numbers and then produce neurons and glial cells that compose the complex neural circuits in the brain. New neurons are continually produced even after birth from adult NSPCs in the inner wall of the lateral ventricle and in the hippocampal dentate gyrus. These adult-born neurons are involved in various brain functions, including olfaction-related functions, learning and memory, pattern separation, and mood control. NSPCs are regulated by various intrinsic and extrinsic factors. Diet is one of such important extrinsic factors. Of dietary nutrients, lipids are important because they constitute the cell membrane, are a source of energy, and function as signaling molecules. Metabolites of some lipids can be strong lipid mediators that also regulate various biological activities. Recent findings have revealed that lipids are important regulators of both embryonic and adult NSPCs. We and other groups have shown that lipid signals including fat, fatty acids, their metabolites and intracellular carriers, cholesterol, and vitamins affect proliferation and differentiation of embryonic and adult NSPCs. A better understanding of the NSPCs regulation by lipids may provide important insight into the neural development and brain function.
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Harvey, John, und Thomas Heinbockel. „Neuromodulation of Synaptic Transmission in the Main Olfactory Bulb“. International Journal of Environmental Research and Public Health 15, Nr. 10 (08.10.2018): 2194. http://dx.doi.org/10.3390/ijerph15102194.
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A major step in our understanding of brain function is to determine how neural circuits are altered in their function by signaling molecules or neuromodulators. Neuromodulation is the neurochemical process that modifies the computations performed by a neuron or network based on changing the functional needs or behavioral state of the subject. These modulations have the effect of altering the responsivity to synaptic inputs. Early sensory processing areas, such as the main olfactory bulb, provide an accessible window for investigating how neuromodulation regulates the functional states of neural networks and influences how we process sensory information. Olfaction is an attractive model system in this regard because of its relative simplicity and because it links primary olfactory sensory neurons to higher olfactory and associational networks. Likewise, centrifugal fibers from higher order brain centers target neurons in the main olfactory bulb to regulate synaptic processing. The neuromodulatory systems that provide regulatory inputs and play important roles in olfactory sensory processing and behaviors include the endocannabinoid system, the dopaminergic system, the cholinergic system, the noradrenergic system and the serotonergic system. Here, we present a brief survey of neuromodulation of olfactory signals in the main olfactory bulb with an emphasis on the endocannabinoid system.
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Shimada, Kunio. „Correlations among Firing Rates of Tactile, Thermal, Gustatory, Olfactory, and Auditory Sensations Mimicked by Artificial Hybrid Fluid (HF) Rubber Mechanoreceptors“. Sensors 23, Nr. 10 (09.05.2023): 4593. http://dx.doi.org/10.3390/s23104593.
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In order to advance the development of sensors fabricated with monofunctional sensation systems capable of a versatile response to tactile, thermal, gustatory, olfactory, and auditory sensations, mechanoreceptors fabricated as a single platform with an electric circuit require investigation. In addition, it is essential to resolve the complicated structure of the sensor. In order to realize the single platform, our proposed hybrid fluid (HF) rubber mechanoreceptors of free nerve endings, Merkel cells, Krause end bulbs, Meissner corpuscles, Ruffini endings, and Pacinian corpuscles mimicking the bio-inspired five senses are useful enough to facilitate the fabrication process for the resolution of the complicated structure. This study used electrochemical impedance spectroscopy (EIS) to elucidate the intrinsic structure of the single platform and the physical mechanisms of the firing rate such as slow adaption (SA) and fast adaption (FA), which were induced from the structure and involved the capacitance, inductance, reactance, etc. of the HF rubber mechanoreceptors. In addition, the relations among the firing rates of the various sensations were clarified. The adaption of the firing rate in the thermal sensation is the opposite of that in the tactile sensation. The firing rates in the gustation, olfaction, and auditory sensations at frequencies of less than 1 kHz have the same adaption as in the tactile sensation. The present findings are useful not only in the field of neurophysiology, to research the biochemical reactions of neurons and brain perceptions of stimuli, but also in the field of sensors, to advance salient developments in sensors mimicking bio-inspired sensations.
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Quet, Etienne, Jean-Christophe Cassel, Brigitte Cosquer, Marine Galloux, Anne Pereira De Vasconcelos und Aline Stéphan. „Ventral midline thalamus is not necessary for systemic consolidation of a social memory in the rat“. Brain and Neuroscience Advances 4 (Januar 2020): 239821282093973. http://dx.doi.org/10.1177/2398212820939738.
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According to the standard theory of memory consolidation, recent memories are stored in the hippocampus before their transfer to cortical modules, a process called systemic consolidation. The ventral midline thalamus (reuniens and rhomboid nuclei, ReRh) takes part in this transfer as its lesion disrupts systemic consolidation of spatial and contextual fear memories. Here, we wondered whether ReRh lesions would also affect the systemic consolidation of another type of memory, namely an olfaction-based social memory. To address this question we focused on social transmission of food preference. Adult Long-Evans rats were subjected to N-methyl-d-aspartate-induced, fibre-sparing lesions of the ReRh nuclei or to a sham-operation, and subsequently trained in a social transmission of food preference paradigm. Retrieval was tested on the next day (recent memory, nSham = 10, nReRh = 12) or after a 25-day delay (remote memory, nSham = 10, nReRh = 10). All rats, whether sham-operated or subjected to ReRh lesions, learned and remembered the task normally, whatever the delay. Compared to our former results on spatial and contextual fear memories (Ali et al., 2017; Klein et al., 2019; Loureiro et al., 2012; Quet et al., 2020), the present findings indicate that the ReRh nuclei might not be part of a generic, systemic consolidation mechanism processing all kinds of memories in order to make them persistent. The difference between social transmission of food preference and spatial or contextual fear memories could be explained by the fact that social transmission of food preference is not hippocampus-dependent and that the persistence of social transmission of food preference memory relies on different circuits.
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Li, Wen, und Donald A. Wilson. „Threat Memory in the Sensory Cortex: Insights from Olfaction“. Neuroscientist, 26.01.2023, 107385842211489. http://dx.doi.org/10.1177/10738584221148994.
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The amygdala has long held the center seat in the neural basis of threat conditioning. However, a rapidly growing literature has elucidated extra-amygdala circuits in this process, highlighting the sensory cortex for its critical role in the mnemonic aspect of the process. While this literature is largely focused on the auditory system, substantial human and rodent findings on the olfactory system have emerged. The unique nature of the olfactory neuroanatomy and its intimate association with emotion compels a review of this recent literature to illuminate its special contribution to threat memory. Here, integrating recent evidence in humans and animal models, we posit that the olfactory (piriform) cortex is a primary and necessary component of the distributed threat memory network, supporting mnemonic ensemble coding of acquired threat. We further highlight the basic circuit architecture of the piriform cortex characterized by distributed, auto-associative connections, which is prime for highly efficient content-addressable memory computing to support threat memory. Given the primordial role of the piriform cortex in cortical evolution and its simple, well-defined circuits, we propose that olfaction can be a model system for understanding (transmodal) sensory cortical mechanisms underlying threat memory.
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Lazar, Aurel A., Tingkai Liu, Mehmet Kerem Turkcan und Yiyin Zhou. „Accelerating with FlyBrainLab the discovery of the functional logic of the Drosophila brain in the connectomic and synaptomic era“. eLife 10 (22.02.2021). http://dx.doi.org/10.7554/elife.62362.
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In recent years, a wealth of Drosophila neuroscience data have become available including cell type and connectome/synaptome datasets for both the larva and adult fly. To facilitate integration across data modalities and to accelerate the understanding of the functional logic of the fruit fly brain, we have developed FlyBrainLab, a unique open-source computing platform that integrates 3D exploration and visualization of diverse datasets with interactive exploration of the functional logic of modeled executable brain circuits. FlyBrainLab’s User Interface, Utilities Libraries and Circuit Libraries bring together neuroanatomical, neurogenetic and electrophysiological datasets with computational models of different researchers for validation and comparison within the same platform. Seeking to transcend the limitations of the connectome/synaptome, FlyBrainLab also provides libraries for molecular transduction arising in sensory coding in vision/olfaction. Together with sensory neuron activity data, these libraries serve as entry points for the exploration, analysis, comparison, and evaluation of circuit functions of the fruit fly brain.
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Adden, Andrea, Terrence C. Stewart, Barbara Webb und Stanley Heinze. „A Neural Model for Insect Steering Applied to Olfaction and Path Integration“. Neural Computation, 09.09.2022, 1–27. http://dx.doi.org/10.1162/neco_a_01540.
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Abstract Many animal behaviors require orientation and steering with respect to the environment. For insects, a key brain area involved in spatial orientation and navigation is the central complex. Activity in this neural circuit has been shown to track the insect's current heading relative to its environment and has also been proposed to be the substrate of path integration. However, it remains unclear how the output of the central complex is integrated into motor commands. Central complex output neurons project to the lateral accessory lobes (LAL), from which descending neurons project to thoracic motor centers. Here, we present a computational model of a simple neural network that has been described anatomically and physiologically in the LALs of male silkworm moths, in the context of odor-mediated steering. We present and analyze two versions of this network, one rate based and one based on spiking neurons. The modeled network consists of an inhibitory local interneuron and a bistable descending neuron (flip-flop) that both receive input in the LAL. The flip-flop neuron projects onto neck motor neurons to induce steering. We show that this simple computational model not only replicates the basic parameters of male silkworm moth behavior in a simulated odor plume but can also take input from a computational model of path integration in the central complex and use it to steer back to a point of origin. Furthermore, we find that increasing the level of detail within the model improves the realism of the model's behavior, leading to the emergence of looping behavior as an orientation strategy. Our results suggest that descending neurons originating in the LALs, such as flip-flop neurons, are sufficient to mediate multiple steering behaviors. This study is therefore a first step to close the gap between orientation circuits in the central complex and downstream motor centers.
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Kim, Soohwan, Sandeepan Mukherjee, Jordi Fonollosa und David L. Hu. „Canine-inspired Unidirectional Flows for Improving Memory Effects in Machine Olfaction“. Integrative And Comparative Biology, 25.04.2023. http://dx.doi.org/10.1093/icb/icad016.
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Abstract In a dog's nose, air flows unidirectionally from the nostrils’ inlet to its outlet. Previous simulations showed that unidirectional flow through a dog's complex nasal passageways creates stagnant zones of trapped air. We hypothesize that these zones give the dog a “physical memory” which it may use to compare recent odors to past ones. In this study, we conducted experiments with our previously built Gaseous Recognition Oscillatory Machine Integrating Technology (GROMIT) and perform corresponding simulations in two dimensions. We compared three settings: a control setting that mimics the bidirectional flow of the human nose, a short-circuit setting where odors exit before reaching the sensors, and a unidirectional configuration using a dedicated inlet and outlet that most mimics the dog's nose. After exposure to odors, the sensors in the unidirectional setting showed the slowest return to their baseline level, indicative of memory effects. Simulations showed that both short-circuit and unidirectional flows created trapped recirculation zones which slows the release of odors from the chamber. In the future, the memory effects such as the ones found here may improve the sensitivity and utility of electronic noses.
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Pardasani, Meenakshi, Anantha Maharasi Ramakrishnan, Sarang Mahajan, Meher Kantroo, Eleanor McGowan, Susobhan Das, Priyadharshini Srikanth, Sanyukta Pandey und Nixon M. Abraham. „Perceptual learning deficits mediated by somatostatin releasing inhibitory interneurons of olfactory bulb in an early life stress mouse model“. Molecular Psychiatry, 19.09.2023. http://dx.doi.org/10.1038/s41380-023-02244-3.
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AbstractEarly life adversity (ELA) causes aberrant functioning of neural circuits affecting the health of an individual. While ELA-induced behavioural disorders resulting from sensory and cognitive disabilities can be assessed clinically, the neural mechanisms need to be probed using animal models by employing multi-pronged experimental approaches. As ELA can alter sensory perception, we investigated the effect of early weaning on murine olfaction. By implementing go/no-go odour discrimination paradigm, we observed olfactory learning and memory impairments in early life stressed (ELS) male mice. As olfactory bulb (OB) circuitry plays a critical role in odour learning, we studied the plausible changes in the OB of ELS mice. Lowered c-Fos activity in the external plexiform layer and a reduction in the number of dendritic processes of somatostatin-releasing, GABAergic interneurons (SOM-INs) in the ELS mice led us to hypothesise the underlying circuit. We recorded reduced synaptic inhibitory feedback on mitral/tufted (M/T) cells, in the OB slices from ELS mice, explaining the learning deficiency caused by compromised refinement of OB output. The reduction in synaptic inhibition was nullified by the photo-activation of ChR2-expressing SOM-INs in ELS mice. The role of SOM-INs was revealed by learning-dependent refinement of Ca2+dynamics quantified by GCaMP6f signals, which was absent in ELS mice. Further, the causal role of SOM-INs involving circuitry was investigated by optogenetic modulation during the odour discrimination learning. Photo-activating these neurons rescued the ELA-induced learning deficits. Conversely, photo-inhibition caused learning deficiency in control animals, while it completely abolished the learning in ELS mice, confirming the adverse effects mediated by SOM-INs. Our results thus establish the role of specific inhibitory circuit in pre-cortical sensory area in orchestrating ELA-dependent changes.
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Takesono, Aya, Paula Schirrmacher, Aaron Scott, Jon M. Green, Okhyun Lee, Matthew J. Winter, Tetsuhiro Kudoh und Charles R. Tyler. „Estrogens regulate early embryonic development of the olfactory sensory system via estrogen-responsive glia“. Development 149, Nr. 1 (01.01.2022). http://dx.doi.org/10.1242/dev.199860.
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ABSTRACT Estrogens are well-known to regulate development of sexual dimorphism of the brain; however, their role in embryonic brain development prior to sex-differentiation is unclear. Using estrogen biosensor zebrafish models, we found that estrogen activity in the embryonic brain occurs from early neurogenesis specifically in a type of glia in the olfactory bulb (OB), which we name estrogen-responsive olfactory bulb (EROB) cells. In response to estrogen, EROB cells overlay the outermost layer of the OB and interact tightly with olfactory sensory neurons at the olfactory glomeruli. Inhibiting estrogen activity using an estrogen receptor antagonist, ICI182,780 (ICI), and/or EROB cell ablation impedes olfactory glomerular development, including the topological organisation of olfactory glomeruli and inhibitory synaptogenesis in the OB. Furthermore, activation of estrogen signalling inhibits both intrinsic and olfaction-dependent neuronal activity in the OB, whereas ICI or EROB cell ablation results in the opposite effect on neuronal excitability. Altering the estrogen signalling disrupts olfaction-mediated behaviour in later larval stage. We propose that estrogens act on glia to regulate development of OB circuits, thereby modulating the local excitability in the OB and olfaction-mediated behaviour.
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Silvas-Baltazar, Monserrat, Grecia López-Oropeza, Pilar Durán und Alonso Martínez-Canabal. „Olfactory neurogenesis and its role in fear memory modulation“. Frontiers in Behavioral Neuroscience 17 (28.09.2023). http://dx.doi.org/10.3389/fnbeh.2023.1278324.
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Olfaction is a critical sense that allows animals to navigate and understand their environment. In mammals, the critical brain structure to receive and process olfactory information is the olfactory bulb, a structure characterized by a laminated pattern with different types of neurons, some of which project to distant telencephalic structures, like the piriform cortex, the amygdala, and the hippocampal formation. Therefore, the olfactory bulb is the first structure of a complex cognitive network that relates olfaction to different types of memory, including episodic memories. The olfactory bulb continuously adds inhibitory newborn neurons throughout life; these cells locate both in the granule and glomerular layers and integrate into the olfactory circuits, inhibiting projection neurons. However, the roles of these cells modulating olfactory memories are unclear, particularly their role in fear memories. We consider that olfactory neurogenesis might modulate olfactory fear memories by a plastic process occurring in the olfactory bulb.
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Kuruppath, Praveen, Lin Xue, Frederic Pouille, Shelly T. Jones und Nathan E. Schoppa. „Hyperexcitability in the olfactory bulb and impaired fine odor discrimination in theFmr1KO mouse model of fragile X syndrome“. Journal of Neuroscience, 03.10.2023, JN—RM—0584–23. http://dx.doi.org/10.1523/jneurosci.0584-23.2023.
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Fragile X syndrome (FXS) is the single most common monogenetic cause of autism spectrum disorders in humans. FXS is caused by loss of expression of the Fragile X mental retardation protein (FMRP), an mRNA-binding protein encoded on the X chromosome involved in suppressing protein translation. Sensory processing deficits have been a major focus of studies of FXS in both humans and rodent models of FXS, but olfactory deficits remain poorly understood. Here we conducted experiments in wild-type andFmr1KO (Fmr1-/y) mice (males)that lack expression of the gene encoding FMRP to assess olfactory circuit and behavioral abnormalities. In patch-clamp recordings conducted in slices of the olfactory bulb, output mitral cells (MCs) inFmr1KO mice displayed greatly enhanced excitation under baseline conditions, as evidenced by a much higher rate of occurrence of spontaneous network-level events known as long-lasting depolarizations (LLDs). The higher probability of spontaneous LLDs, which appeared to be due to a decrease in GABAergic synaptic inhibition in glomeruli leading to more feedforward excitation, caused a reduction in the reliability of stimulation-evoked responses in MCs. In addition, in a go/no-go operant discrimination paradigm, we found thatFmr1KO mice displayed impaired discrimination of odors in difficult tasks that involved odor mixtures but not altered discrimination of monomolecular odors. We suggest that theFmr1KO-induced reduction in MC response reliability is one plausible mechanism for the impaired fine odor discrimination.Significance StatementFragile X syndrome (FXS) in humans is associated with a range of debilitating deficits including aberrant sensory processing. One sensory system that has received comparatively little attention in studies in animal models of FXS is olfaction. Here, we report the first comprehensive physiological analysis of circuit defects in the olfactory bulb in the commonly-usedFmr1knockout (KO) mouse model of FXS. Our studies indicate thatFmr1KO alters the local excitation/inhibition balance in the bulb – similar to whatFmr1KO does in other brain circuits – but through a novel mechanism that involves enhanced feedforward excitation. Furthermore,Fmr1KO mice display behavioral impairments in fine odor discrimination, an effect that may be explained by changes in neural response reliability.
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Hussain, Ashiq, Atefeh Pooryasin, Mo Zhang, Laura F. Loschek, Marco La Fortezza, Anja B. Friedrich, Catherine-Marie Blais et al. „Inhibition of oxidative stress in cholinergic projection neurons fully rescues aging-associated olfactory circuit degeneration in Drosophila“. eLife 7 (18.01.2018). http://dx.doi.org/10.7554/elife.32018.
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Loss of the sense of smell is among the first signs of natural aging and neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Cellular and molecular mechanisms promoting this smell loss are not understood. Here, we show that Drosophila melanogaster also loses olfaction before vision with age. Within the olfactory circuit, cholinergic projection neurons show a reduced odor response accompanied by a defect in axonal integrity and reduction in synaptic marker proteins. Using behavioral functional screening, we pinpoint that expression of the mitochondrial reactive oxygen scavenger SOD2 in cholinergic projection neurons is necessary and sufficient to prevent smell degeneration in aging flies. Together, our data suggest that oxidative stress induced axonal degeneration in a single class of neurons drives the functional decline of an entire neural network and the behavior it controls. Given the important role of the cholinergic system in neurodegeneration, the fly olfactory system could be a useful model for the identification of drug targets.
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De Beukelaer, Sophie, A. A. Sokolov und R. M. Müri. „Case report: “Proust phenomenon” after right posterior cerebral artery occlusion“. Frontiers in Neurology 14 (13.07.2023). http://dx.doi.org/10.3389/fneur.2023.1183265.
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Odors evoking vivid and intensely felt autobiographical memories are known as the “Proust phenomenon,” delineating the particularity of olfaction in being more effective with eliciting emotional memories than other sensory modalities. The phenomenon has been described extensively in healthy participants as well as in patients during pre-epilepsy surgery evaluation after focal stimulation of the amygdalae and post-traumatic stress disorder (PTSD). In this study, we provide the inaugural description of aversive odor-evoked autobiographical memories after stroke in the right hippocampal, parahippocampal, and thalamic nuclei. As potential underlying neural signatures of the phenomenon, we discuss the disinhibition of limbic circuits and impaired communication between the major networks, such as saliency, central executive, and default mode network.
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Zhao, Xin-Cheng, Bente G. Berg und Guirong Wang. „Editorial: Recent advances in insect olfaction: characterization of neural circuits from sensory input to motor output“. Frontiers in Cellular Neuroscience 17 (05.09.2023). http://dx.doi.org/10.3389/fncel.2023.1282499.
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Huang, Li, Francesca Hardyman, Megan Edwards und Elisa Galliano. „Deprivation-induced plasticity in the early central circuits of the rodent visual, auditory, and olfactory systems“. eneuro, 09.01.2024, ENEURO.0435–23.2023. http://dx.doi.org/10.1523/eneuro.0435-23.2023.
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Activity-dependent neuronal plasticity is crucial for animals to adapt to dynamic sensory environments. Traditionally, it has been investigated using deprivation approaches in animal models primarily in sensory cortices. Nevertheless, emerging evidence emphasizes its significance in sensory organs and in sub-cortical regions where cranial nerves relay information to the brain. Additionally, critical questions started to arise. Do different sensory modalities share common cellular mechanisms for deprivation-induced plasticity at these central entry-points? Does the deprivation duration correlate with specific plasticity mechanisms?This study systematically reviews and meta-analyses research papers that investigated visual, auditory, or olfactory deprivation in rodents of both sexes. It examines the consequences of sensory deprivation in homologous regions at the first central synapse following cranial nerve transmission (vision-lateral geniculate nucleus and superior colliculus; audition-ventral and dorsal cochlear nucleus; olfaction-olfactory bulb). The systematic search yielded 91 papers (39 vision, 22 audition, 30 olfaction), revealing substantial heterogeneity in publication trends, experimental methods, measures of plasticity, and reporting across the sensory modalities. Despite these differences, commonalities emerged when correlating plasticity mechanisms with the duration of sensory deprivation. Short-term deprivation (up to 1 day) reduced activity and increased disinhibition, medium-term deprivation (1 day to a week) involved glial changes and synaptic remodelling, and long-term deprivation (over a week) primarily led to structural alterations.These findings underscore the importance of standardizing methodologies and reporting practices. Additionally, they highlight the value of cross-modals synthesis for understanding how the nervous system, including peripheral, pre-cortical, and cortical areas, respond to and compensate for sensory inputs loss.Significance StatementThis study addresses the critical issue of sensory loss and its impact on the brain's adaptability, shedding light on how different sensory systems respond to loss of inputs from the environment. While past research has primarily explored early-life sensory deprivation, this study focuses on the effects of sensory loss in post-weaning rodents. By systematically reviewing 91 research articles, the findings reveal distinct responses based on the duration of sensory deprivation. This research not only enhances our understanding of brain plasticity but also has broad implications for translational applications, particularly in cross-modal plasticity, offering valuable insights into neuroscientific research and potential clinical interventions.
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Rihani, Karen, und Silke Sachse. „Shedding Light on Inter-Individual Variability of Olfactory Circuits in Drosophila“. Frontiers in Behavioral Neuroscience 16 (25.04.2022). http://dx.doi.org/10.3389/fnbeh.2022.835680.
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Inter-individual differences in behavioral responses, anatomy or functional properties of neuronal populations of animals having the same genotype were for a long time disregarded. The majority of behavioral studies were conducted at a group level, and usually the mean behavior of all individuals was considered. Similarly, in neurophysiological studies, data were pooled and normalized from several individuals. This approach is mostly suited to map and characterize stereotyped neuronal properties between individuals, but lacks the ability to depict inter-individual variability regarding neuronal wiring or physiological characteristics. Recent studies have shown that behavioral biases and preferences to olfactory stimuli can vary significantly among individuals of the same genotype. The origin and the benefit of these diverse “personalities” is still unclear and needs to be further investigated. A perspective taken into account the inter-individual differences is needed to explore the cellular mechanisms underlying this phenomenon. This review focuses on olfaction in the vinegar fly Drosophila melanogaster and summarizes previous and recent studies on odor-guided behavior and the underlying olfactory circuits in the light of inter-individual variability. We address the morphological and physiological variabilities present at each layer of the olfactory circuitry and attempt to link them to individual olfactory behavior. Additionally, we discuss the factors that might influence individuality with regard to olfactory perception.
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Zhang, Zhijian, Qing Liu, Pengjie Wen, Jiaozhen Zhang, Xiaoping Rao, Ziming Zhou, Hongruo Zhang et al. „Activation of the dopaminergic pathway from VTA to the medial olfactory tubercle generates odor-preference and reward“. eLife 6 (18.12.2017). http://dx.doi.org/10.7554/elife.25423.
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Odor-preferences are usually influenced by life experiences. However, the neural circuit mechanisms remain unclear. The medial olfactory tubercle (mOT) is involved in both reward and olfaction, whereas the ventral tegmental area (VTA) dopaminergic (DAergic) neurons are considered to be engaged in reward and motivation. Here, we found that the VTA (DAergic)-mOT pathway could be activated by different types of naturalistic rewards as well as odors in DAT-cre mice. Optogenetic activation of the VTA-mOT DAergic fibers was able to elicit preferences for space, location and neutral odor, while pharmacological blockade of the dopamine receptors in the mOT fully prevented the odor-preference formation. Furthermore, inactivation of the mOT-projecting VTA DAergic neurons eliminated the previously formed odor-preference and strongly affected the Go-no go learning efficiency. In summary, our results revealed that the VTA (DAergic)-mOT pathway mediates a variety of naturalistic reward processes and different types of preferences including odor-preference in mice.
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Craft, Michelle F., Andrea K. Barreiro, Shree Hari Gautam, Woodrow L. Shew und Cheng Ly. „Odor modality is transmitted to cortical brain regions from the olfactory bulb“. Journal of Neurophysiology, 04.10.2023. http://dx.doi.org/10.1152/jn.00101.2023.
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Odor perception is the impetus for important animal behaviors with two predominate modes of processing: odors pass through the front of the nose (orthonasal) while inhaling and sniffing, or through the rear (retronasal) during exhalation and while eating. Despite the importance of olfaction for an animal's well-being and that ortho and retro naturally occur, it is unknown how the modality (ortho versus retro) is even transmitted to cortical brain regions, which could significantly affect how odors are processed and perceived. Using multi-electrode array recordings in tracheotomized anesthetized rats, which decouples ortho-retro modality from breathing, we show that mitral cells in rat olfactory bulb can reliably and directly transmit ortho versus retronasal modality with ethyl butyrate, a common food odor. Drug manipulations affecting synaptic inhibition via GABAA lead to worse decoding of ortho versus retro, independent of whether overall inhibition increases or decreases, suggesting that the olfactory bulb circuit may naturally favor encoding this important aspect of odors. Detailed data analysis paired with a firing rate model that captures population trends in spiking statistics shows how this circuit can encode odor modality. We have not only demonstrated that ortho/retro information is encoded to downstream brain regions, but also use modeling to demonstrate a plausible mechanism for this encoding: due to synaptic adaptation, it is the slower time course of the retronasal stimulation that causes retronasal responses to be stronger and less sensitive to inhibitory drug manipulations than orthonasal responses.
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Bruce, Marissa L., Katharine D. Andrews, Elizabeth A. Lungwitz und William A. Truitt. „CHARACTERIZING THE ROLE OF ORBITOFRONTAL CORTEX IN SOCIAL MEMORY“. Proceedings of IMPRS 1, Nr. 1 (07.12.2018). http://dx.doi.org/10.18060/22667.
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Background and Hypothesis:
Social-enhanced safety learning is a psychosocial process used to reduce fear or anxiety by learning to discriminate fearful versus safe stimuli via a social safety cue. Learning to associate safety with a social cue requires intact social memory. Preliminary data in rats suggests inhibiting the orbitofrontal cortex (OFC) with pharmacologic agents impairs social memory. However, the specific mechanism by which OFC regulates social memory remains unknown. Because the OFC has broad functional implications including valuation, decision-making, social and emotional behaviors, olfaction, and non-social memory, we hypothesized that OFC inhibition was disrupting one of these specific processes, resulting in social memory impairment.
Experimental Design or Project Methods:
Cannulated adult male Sprague-Dawley rats were injected bilaterally in OFC with either saline vehicle, or 0.9 mM Muscimol, a GABAA agonist that transiently inhibits local neuronal activity. At 10 minutes post-injection, rats underwent behavior testing for either: social recognition, novel object recognition, social preference (innate gregariousness), or olfactory discrimination.
Results:
Rats receiving Muscimol injection, but not rats receiving vehicle injection, demonstrated statistically significant impairment of social recognition, observed as a failure to discriminate between two conspecifics. Alternatively, rats receiving Muscimol injection, but not rats receiving vehicle injection, did not demonstrate statistically significant impairment of novel object (non-social) recognition, innate gregariousness, or olfaction, which were all intact in vehicle injected rats.
Conclusion and Potential Impact:
These data suggest OFC may be part of a unique neural circuit specific to social memory. Delineating the circuitry of social memory from non-social memory offers exciting possibilities in the advancement of precision therapies.
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Jaime-Lara, Rosario B., Brianna E. Brooks, Carlotta Vizioli, Mari Chiles, Nafisa Nawal, Rodrigo S. E. Ortiz-Figueroa, Alicia A. Livinski et al. „A Systematic Review of the Biological Mediators of Fat-Taste and Smell“. Physiological Reviews, 15.09.2022. http://dx.doi.org/10.1152/physrev.00061.2021.
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Taste and smell play a key role in our ability to perceive foods. Overconsumption of highly palatable energy-dense foods can lead to increased caloric intake and obesity. Thus, there is growing interest in the study of the biological mediators of fat taste and associated olfaction as potential targets for pharmacologic and nutritional interventions in the context of obesity and health. The number of studies examining mechanisms underlying fat taste and smell has grown rapidly in the last five years. Therefore, the purpose of this systematic review is to summarize emerging evidence examining the biological mechanisms of fat taste and smell. A literature search was conducted of studies published in English between 2014 and 2021 in adult humans and animal models. Database searches were conducted using PubMed, EMBASE, Scopus and Web of Science for key terms including fat/lipid, taste, and olfaction. Initially, 4,062 articles were identified through database searches and a total of 84 relevant articles met inclusion and exclusion criteria and are included in this review. Existing literature suggests that there are several proteins integral to fat chemosensation, including CD36 and GPR120. This systematic review will discuss these proteins and the signal transduction pathways involved in fat detection. We also review neural circuits, key brain regions, ingestive cues, post-ingestive signals, and genetic polymorphism that play a role in fat perception and consumption. Lastly, we discuss the role of fat taste and smell in the context eating behavior and obesity.
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Brunert, Daniela, und Markus Rothermel. „Extrinsic neuromodulation in the rodent olfactory bulb“. Cell and Tissue Research, 23.12.2020. http://dx.doi.org/10.1007/s00441-020-03365-9.
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AbstractEvolutionarily, olfaction is one of the oldest senses and pivotal for an individual’s health and survival. The olfactory bulb (OB), as the first olfactory relay station in the brain, is known to heavily process sensory information. To adapt to an animal’s needs, OB activity can be influenced by many factors either from within (intrinsic neuromodulation) or outside (extrinsic neuromodulation) the OB which include neurotransmitters, neuromodulators, hormones, and neuropeptides. Extrinsic sources seem to be of special importance as the OB receives massive efferent input from numerous brain centers even outweighing the sensory input from the nose. Here, we review neuromodulatory processes in the rodent OB from such extrinsic sources. We will discuss extrinsic neuromodulation according to points of origin, receptors involved, affected circuits, and changes in behavior. In the end, we give a brief outlook on potential future directions in research on neuromodulation in the OB.
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Zhang, Xiaonan, und Quentin Gaudry. „Functional integration of a serotonergic neuron in the Drosophila antennal lobe“. eLife 5 (30.08.2016). http://dx.doi.org/10.7554/elife.16836.
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Serotonin plays a critical role in regulating many behaviors that rely on olfaction and recently there has been great effort in determining how this molecule functions in vivo. However, it remains unknown how serotonergic neurons that innervate the first olfactory relay respond to odor stimulation and how they integrate synaptically into local circuits. We examined the sole pair of serotonergic neurons that innervates the Drosophila antennal lobe (the first olfactory relay) to characterize their physiology, connectivity, and contribution to pheromone processing. We report that nearly all odors inhibit these cells, likely through connections made reciprocally within the antennal lobe. Pharmacological and immunohistochemical analyses reveal that these neurons likely release acetylcholine in addition to serotonin and that exogenous and endogenous serotonin have opposing effects on olfactory responses. Finally, we show that activation of the entire serotonergic network, as opposed to only activation of those fibers innervating the antennal lobe, may be required for persistent serotonergic modulation of pheromone responses in the antennal lobe.
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Chen, Fengjiao, Wei Liu, Penglai Liu, Zhen Wang, You Zhou, Xingyu Liu und Anan Li. „α-Synuclein aggregation in the olfactory bulb induces olfactory deficits by perturbing granule cells and granular–mitral synaptic transmission“. npj Parkinson's Disease 7, Nr. 1 (Dezember 2021). http://dx.doi.org/10.1038/s41531-021-00259-7.
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AbstractOlfactory dysfunction is an early pre-motor symptom of Parkinson’s disease (PD) but the neural mechanisms underlying this dysfunction remain largely unknown. Aggregation of α-synuclein is observed in the olfactory bulb (OB) during the early stages of PD, indicating a relationship between α-synuclein pathology and hyposmia. Here we investigate whether and how α-synuclein aggregates modulate neural activity in the OB at the single-cell and synaptic levels. We induced α-synuclein aggregation specifically in the OB via overexpression of double-mutant human α-synuclein by an adeno-associated viral (AAV) vector. We found that α-synuclein aggregation in the OB decreased the ability of mice to detect odors and to perceive attractive odors. The spontaneous activity and odor-evoked firing rates of single mitral/tufted cells (M/Ts) were increased by α-synuclein aggregates with the amplitude of odor-evoked high-gamma oscillations increased. Furthermore, the decreased activity in granule cells (GCs) and impaired inhibitory synaptic function were responsible for the observed hyperactivity of M/Ts induced by α-synuclein aggregates. These results provide direct evidences of the role of α-synuclein aggregates on PD-related olfactory dysfunction and reveal the neural circuit mechanisms by which olfaction is modulated by α-synuclein pathology.
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Shteyman, Gary, John Alan Davis und Julien Grimaud. „Lack of correlation between odor composition and neuron response in the olfactory cortex of mice“. Journal of Emerging Investigators, 2022. http://dx.doi.org/10.59720/21-135.
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In the mammalian brain, sensory circuits are usually organized in a topographical way, meaning that, for a given brain region, neighboring neurons respond to stimuli close to each other in their sensory space. Olfaction is a notable exception to this rule; projections to the olfactory system are sparse and dispersed, leading to no apparent topography. Here, we assessed the presence of a topographical map in the mouse olfactory cortex, using a previously generated online dataset of neuronal recordings. The dataset consisted of about 1,800 olfactory cortical neurons collected from 10 mice, stimulated with a panel of 15 odorants. If there is no odor topography in the olfactory cortex, there should be no correlation between the chemical composition of odorants and their evoked neuronal response. To test this hypothesis, we first calculated odor similarity between each pair of odorants, using their chemical traits. Then, for each odor pair, we computed the similarity between their evoked neuronal responses. Finally, we assessed the relationship between odor similarity and neuronal response similarity. We found little to no correlation between the two variables (R2 averaged across all mice tested: 0.015), which suggests the lack of topography in the murine olfactory cortex and opens new questions into what other variables might play a role in odorant distinction.
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Hanson, Elizabeth, Katie L. Brandel-Ankrapp und Benjamin R. Arenkiel. „Dynamic Cholinergic Tone in the Basal Forebrain Reflects Reward-Seeking and Reinforcement During Olfactory Behavior“. Frontiers in Cellular Neuroscience 15 (02.02.2021). http://dx.doi.org/10.3389/fncel.2021.635837.
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Sensory perception underlies how we internalize and interact with the external world. In order to adapt to changing circumstances and interpret signals in a variety of contexts, sensation needs to be reliable, but perception of sensory input needs to be flexible. An important mediator of this flexibility is top-down regulation from the cholinergic basal forebrain. Basal forebrain projection neurons serve as pacemakers and gatekeepers for downstream neural networks, modulating circuit activity across diverse neuronal populations. This top-down control is necessary for sensory cue detection, learning, and memory, and is disproportionately disrupted in neurodegenerative diseases associated with cognitive decline. Intriguingly, cholinergic signaling acts locally within the basal forebrain to sculpt the activity of basal forebrain output neurons. To determine how local cholinergic signaling impacts basal forebrain output pathways that participate in top-down regulation, we sought to define the dynamics of cholinergic signaling within the basal forebrain during motivated behavior and learning. Toward this, we utilized fiber photometry and the genetically encoded acetylcholine indicator GAChR2.0 to define temporal patterns of cholinergic signaling in the basal forebrain during olfactory-guided, motivated behaviors and learning. We show that cholinergic signaling reliably increased during reward seeking behaviors, but was strongly suppressed by reward delivery in a go/no-go olfactory-cued discrimination task. The observed transient reduction in cholinergic tone was mirrored by a suppression in basal forebrain GABAergic neuronal activity. Together, these findings suggest that cholinergic tone in the basal forebrain changes rapidly to reflect reward-seeking behavior and positive reinforcement and may impact downstream circuitry that modulates olfaction.
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Schenk, Jonathan E., und Quentin Gaudry. „Nonspiking Interneurons in theDrosophilaAntennal Lobe Exhibit Spatially Restricted Activity“. eneuro, 17.01.2023, ENEURO.0109–22.2022. http://dx.doi.org/10.1523/eneuro.0109-22.2022.
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Inhibitory interneurons are important for neuronal circuit function. They regulate sensory inputs and enhance output discriminability (Olsen et al., 2010; Olsen and Wilson, 2008; Root et al., 2008). Often, the identities of interneurons can be determined by location and morphology, which can have implications for their functions (Wachowiak and Shipley, 2006). While most interneurons fire traditional action potentials, many are nonspiking. These can be seen in insect olfaction (Husch et al., 2009; Laurent and Davidowitz, 1994; Tabuchi et al., 2015) and the vertebrate retina (Gleason et al., 1993). Here, we present the novel observation of nonspiking inhibitory interneurons in the antennal lobe (AL) of the adult fruit fly,Drosophila melanogaster. These neurons have a morphology where they innervate a patchwork of glomeruli. We used electrophysiology to determine if their nonspiking characteristic is due to a lack of sodium current. We then used immunohistochemsitry andin situhybridization to show this is likely achieved through translational regulation of the voltage gated sodium channel gene,para. Usingin vivocalcium imaging, we explored how these cells respond to odors, finding regional isolation in their responses' spatial patterns. Further, their response patterns were dependent on both odor identity and concentration. Thus, we surmise these neurons are electrotonically compartmentalized such that activation of the neurites in one region does not propagate across the whole antennal lobe. We propose these neurons may be the source of intraglomerular inhibition in the AL and may contribute to regulation of spontaneous activity within glomeruli.Significance StatementThese findings are a novel discovery of nonspiking interneurons specifically in the olfactory system of adultDrosophila melanogaster. The role of the nonspiking characteristic of similar interneurons in other species is not fully understood. Further, the sources of specific regulatory mechanisms such as intraglomerular inhibition in the fly are unclear. The characterization of nonspiking interneurons inDrosophilabegins to explain these mechanisms and provides an avenue for further study into the roles of similar cells across species.
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Browne, Tyler J., David I. Hughes, Christopher V. Dayas, Robert J. Callister und Brett A. Graham. „Projection Neuron Axon Collaterals in the Dorsal Horn: Placing a New Player in Spinal Cord Pain Processing“. Frontiers in Physiology 11 (21.12.2020). http://dx.doi.org/10.3389/fphys.2020.560802.
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The pain experience depends on the relay of nociceptive signals from the spinal cord dorsal horn to higher brain centers. This function is ultimately achieved by the output of a small population of highly specialized neurons called projection neurons (PNs). Like output neurons in other central nervous system (CNS) regions, PNs are invested with a substantial axon collateral system that ramifies extensively within local circuits. These axon collaterals are widely distributed within and between spinal cord segments. Anatomical data on PN axon collaterals have existed since the time of Cajal, however, their function in spinal pain signaling remains unclear and is absent from current models of spinal pain processing. Despite these omissions, some insight on the potential role of PN axon collaterals can be drawn from axon collateral systems of principal or output neurons in other CNS regions, such as the hippocampus, amygdala, olfactory cortex, and ventral horn of the spinal cord. The connectivity and actions of axon collaterals in these systems have been well-defined and used to confirm crucial roles in memory, fear, olfaction, and movement control, respectively. We review this information here and propose a framework for characterizing PN axon collateral function in the dorsal horn. We highlight that experimental approaches traditionally used to delineate axon collateral function in other CNS regions are not easily applied to PNs because of their scarcity relative to spinal interneurons (INs), and the lack of cellular organization in the dorsal horn. Finally, we emphasize how the rapid development of techniques such as viral expression of optogenetic or chemogenetic probes can overcome these challenges and allow characterization of PN axon collateral function. Obtaining detailed information of this type is a necessary first step for incorporation of PN collateral system function into models of spinal sensory processing.