Comparative analysis of Olfactory bulb RNA obtained from control and odor stimulated mice
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE221772 | GEO | 2024/01/05
REPOSITORIES: GEO
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Project description:Comparative analysis of Olfactory bulb RNA obtained from control and odor stimulated mice
| PRJNA915984 | ENA
Project description:The olfactory bulb (OB) is a critical component of mammalian olfactory neuroanatomy. Beyond being the first and sole relay station for olfactory information to the rest of the brain, it also contains elaborate stereotypical circuitry that is considered essential for olfaction. Indeed, substantial lesions of the OB in rodents lead to anosmia. Here, we examined the circuitry that underlies olfaction in a mouse model with severe developmental degeneration of the OB. These mice could perform odor-guided tasks and even responded normally to innate olfactory cues. Despite the near total loss of the OB, piriform cortex in these mice responded to odors normally and its neural activity sufficed to decode odor identity. We found that sensory neurons expressthe full repertoire of olfactory receptors and their axons project primarily to the rudiments of the OB, but also ectopically, to olfactory cortical regions. Within the OB, the number of principal neurons was greatly reduced and the morphology of their dendrites was abnormal, extending over large regions within the OB. Glomerular organization was totally lost in the severe cases of OB degeneration and altered in the more conserved OBs, and the transcriptional profile of the glomerular layer was highly inflammatory. This study shows that olfactory functionality can be preserved despite reduced and aberrant circuitry that is missing many of the elements that are believed to be essential for olfaction, and may explain reported retention of olfaction in humans with degenerated OBs
2023-09-04 | GSE241951 | GEO
Project description:The aim of this study was to use global gene expression profiling to define intrinsic molecular differences that distinguish olfactory ensheathing cells from mucosa (OM-OECs) from olfactory ensheathing cells from olfactory bulb (OB-OECs). 10,000 OECs from olfactory mucosa (OM) or olfactory bulb (OB) were isolated from 4 rats.
2009-12-02 | GSE19250 | GEO
Project description:Habituation and dishabituation modulate the neural resources and behavioral significance allocated to incoming stimuli across the sensory systems. We characterize these processes in the mouse olfactory bulb (OB) and uncover a role for OB acetylcholine (ACh) in physiological and behavioral olfactory dishabituation. We use calcium imaging in both awake and anesthetized mice to determine the time course and magnitude of OB glomerular habituation during a prolonged odor presentation. In addition, we develop a novel behavioral investigation paradigm to determine how prolonged odor input affects odor salience. We find that manipulating OB ACh release during prolonged odor presentations using electrical or optogenetic stimulation rapidly modulates habituated glomerular odor responses and odor salience, causing mice to suddenly investigate a previously ignored odor. To demonstrate the ethological validity of this effect, we show that changing the visual context can lead to dishabituation of odor investigation behavior, which is blocked by cholinergic antagonists in the OB.
| S-EPMC5951802 | biostudies-other
Project description:Olfactory dysfunction is among the earliest features of Alzheimer´s disease (AD). Although neuropathological abnormalities have been detected in the olfactory bulb (OB), little is known about its dynamic biology. Here, OB- proteome analysis was performed across different AD stages using a label-free approach.
2018-01-16 | PXD005319 | Pride
Project description:Whether 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.
| S-EPMC7873110 | biostudies-literature
Project description:The olfactory bulb (OB) is the first site of synaptic odor information processing, yet a wealth of contextual and learned information has been described in its activity. To investigate the mechanistic basis of contextual modulation, we use whole-cell recordings to measure odor responses across rapid learning episodes in identified mitral/tufted cells (MTCs). Across these learning episodes, diverse response changes occur already during the first sniff cycle. Motivated mice develop active sniffing strategies across learning that robustly correspond to the odor response changes, resulting in enhanced odor representation. Evoking fast sniffing in different behavioral states demonstrates that response changes during active sampling exceed those predicted from feedforward input alone. Finally, response changes are highly correlated in tufted cells, but not mitral cells, indicating there are cell-type-specific effects on odor representation during active sampling. Altogether, we show that active sampling is strongly associated with enhanced OB responsiveness on rapid timescales.
| S-EPMC6030445 | biostudies-literature
Project description:Odors are initially represented in the olfactory bulb (OB) by patterns of sensory input across the array of glomeruli. Although activated glomeruli are often widely distributed, glomeruli responding to stimuli sharing molecular features tend to be loosely clustered and thus establish a fractured chemotopic map. Neuronal circuits in the OB transform glomerular patterns of sensory input into spatiotemporal patterns of output activity and thereby extract information about a stimulus. It is, however, unknown whether the chemotopic spatial organization of glomerular inputs is maintained during these computations. To explore this issue, we measured spatiotemporal patterns of odor-evoked activity across thousands of individual neurons in the zebrafish OB by temporally deconvolved two-photon Ca(2+) imaging. Mitral cells and interneurons were distinguished by transgenic markers and exhibited different response selectivities. Shortly after response onset, activity patterns exhibited foci of activity associated with certain chemical features throughout all layers. During the subsequent few hundred milliseconds, however, MC activity was locally sparsened within the initial foci in an odor-specific manner. As a consequence, chemotopic maps disappeared and activity patterns became more informative about precise odor identity. Hence, chemotopic maps of glomerular input activity are initially transmitted to OB outputs, but not maintained during pattern processing. Nevertheless, transient chemotopic maps may support neuronal computations by establishing important synaptic interactions within the circuit. These results provide insights into the functional topology of neural activity patterns and its potential role in circuit function.
| S-EPMC1904499 | biostudies-literature
Project description:Cellular heterogeneity within the mammalian brain poses a challenge towards understanding its complex functions. Within the olfactory bulb (OB), odor information is processed by subtypes of inhibitory interneurons whose heterogeneity and functionality is influenced by ongoing adult neurogenesis. To investigate this cellular heterogeneity, and to better understand the developmental programs of adult-born neurons, we utilized single cell RNA sequencing and computational modeling to reveal diverse and transcriptionally distinct neuronal and non-neuronal cell types. We also analyzed molecular changes during adult-born interneuron maturation, and uncovered developmental programs within their gene expression profiles. Finally, we discovered that distinct neuronal subtypes are differentially affected by sensory experience. Together, these data provide a transcriptome-based foundation for investigating subtype-specific neuronal function in the OB, charting the molecular profiles that arise during the maturation and integration of adult-born neurons, and documenting activity-dependent changes in the cellular composition of the olfactory system.
2018-12-04 | GSE121891 | GEO
Project description:The glomerular layer of the olfactory bulb (OB) receives heavy cholinergic input from the horizontal limb of the diagonal band of Broca (HDB) and expresses both muscarinic and nicotinic acetylcholine (ACh) receptors. However, the effects of ACh on OB glomerular odor responses remain unknown. Using calcium imaging in transgenic mice expressing the calcium indicator GCaMP2 in the mitral/tufted cells, we investigated the effect of ACh on the glomerular responses to increasing odor concentrations. Using HDB electrical stimulation and in vivo pharmacology, we find that increased OB ACh leads to dynamic, activity-dependent bi-directional modulation of glomerular odor response due to the combinatorial effects of both muscarinic and nicotinic activation. Using pharmacological manipulation to reveal the individual receptor type contributions, we find that m2 muscarinic receptor activation increases glomerular sensitivity to weak odor input whereas nicotinic receptor activation decreases sensitivity to strong input. Overall, we found that ACh in the OB increases glomerular sensitivity to odors and decreases activation thresholds. This effect, along with the decreased responses to strong odor input, reduces the response intensity range of individual glomeruli to increasing concentration making them more similar across the entire concentration range. As a result, odor representations are more similar as concentration increases.
| S-EPMC4863144 | biostudies-other