scholarly journals Resolving different presynaptic activity patterns within single olfactory glomeruli of Xenopus laevis larvae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rodi Topci ◽  
Mihai Alevra ◽  
Erik H. U. Rauf ◽  
Daniëlle de Jong-Bolm
Keyword(s):  
Olfactory Receptor ◽  
Activity Patterns ◽  
Region Of Interest ◽  
Mitral Cell ◽  
Olfactory Receptor Neurons ◽  
Odor Stimulus ◽  
Calcium Activity ◽  
Axon Terminals ◽  
Olfactory Glomeruli ◽  
Receptor Neurons

AbstractOlfactory sensing is generally organized into groups of similarly sensing olfactory receptor neurons converging into their corresponding glomerulus, which is thought to behave as a uniform functional unit. It is however unclear to which degree axons within a glomerulus show identical activity, how many converge into a glomerulus, and to answer these questions, how it is possible to visually separate them in live imaging. Here we investigate activity of olfactory receptor neurons and their axon terminals throughout olfactory glomeruli using electrophysiological recordings and rapid 4D calcium imaging. While single olfactory receptor neurons responsive to the same odor stimulus show a diversity of responses in terms of sensitivity and spontaneous firing rate on the level of the somata, their pre-synaptic calcium activity in the glomerulus is homogeneous. In addition, we could not observe the correlated spontaneous calcium activity that is found on the post-synaptic side throughout mitral cell dendrites and has been used in activity correlation imaging. However, it is possible to induce spatio-temporal presynaptic response inhomogeneities by applying trains of olfactory stimuli with varying amino acid concentrations. Automated region-of-interest detection and correlation analysis then visually distinguishes at least two axon subgroups per glomerulus that differ in odor sensitivity.

Olfactory Representations by Drosophila Mushroom Body Neurons

2008 ◽  
Vol 99 (2) ◽  
pp. 734-746 ◽  
Author(s):  
Glenn C. Turner ◽  
Maxim Bazhenov ◽  
Gilles Laurent
Keyword(s):  
Olfactory Receptor ◽  
Mushroom Body ◽  
Temporal Integration ◽  
Activity Patterns ◽  
Olfactory Receptor Neurons ◽  
Projection Neurons ◽  
Contributing Factors ◽  
Receptor Neurons ◽  
Whole Cell Recordings

Learning and memory has been studied extensively in Drosophila using behavioral, molecular, and genetic approaches. These studies have identified the mushroom body as essential for the formation and retrieval of olfactory memories. We investigated odor responses of the principal neurons of the mushroom body, the Kenyon cells (KCs), in Drosophila using whole cell recordings in vivo. KC responses to odors were highly selective and, thus sparse, compared with those of their direct inputs, the antennal lobe projection neurons (PNs). We examined the mechanisms that might underlie this transformation and identified at least three contributing factors: excitatory synaptic potentials (from PNs) decay rapidly, curtailing temporal integration, PN convergence onto individual KCs is low (∼10 PNs per KC on average), and KC firing thresholds are high. Sparse activity is thought to be useful in structures involved in memory in part because sparseness tends to reduce representation overlaps. By comparing activity patterns evoked by the same odors across olfactory receptor neurons and across KCs, we show that representations of different odors do indeed become less correlated as they progress through the olfactory system.

scholarly journals Initial Characterization of a Subpopulation of Inherent Oscillatory Mammalian Olfactory Receptor Neurons

2019 ◽  
Vol 44 (8) ◽  
pp. 583-592 ◽  
Author(s):  
Kirill Ukhanov ◽  
Yuriy V Bobkov ◽  
Jeffrey R Martens ◽  
Barry W Ache
Keyword(s):  
Olfactory Receptor ◽  
Dynamic Properties ◽  
Rhythmic Activity ◽  
Olfactory Receptor Neurons ◽  
Odor Stimulus ◽  
Fundamental Feature ◽  
Published Evidence ◽  
Odor Plumes ◽  
Receptor Neurons

Abstract Published evidence suggests that inherent rhythmically active or “bursting” primary olfactory receptor neurons (bORNs) in crustaceans have the previously undescribed functional property of encoding olfactory information by having their rhythmicity entrained by the odor stimulus. In order to determine whether such bORN-based encoding is a fundamental feature of olfaction that extends beyond crustaceans, we patch-clamped bORN-like ORNs in mice, characterized their dynamic properties, and show they align with the dynamic properties of lobster bORNs. We then characterized bORN-like activity by imaging the olfactory epithelium of OMP-GCaMP6f mice. Next, we showed rhythmic activity is not dependent upon the endogenous OR by patching ORNs in OR/GFP mice. Lastly, we showed the properties of bORN-like ORNs characterized in mice generalize to rats. Our findings suggest encoding odor time should be viewed as a fundamental feature of olfaction with the potential to be used to navigate odor plumes in animals as diverse as crustaceans and mammals.

scholarly journals Calcium-stores mediate adaptation in axon terminals of Olfactory Receptor Neurons in Drosophila

2011 ◽  
Vol 12 (1) ◽  
pp. 105 ◽  
Author(s):  
Meena S Murmu ◽  
Jacques Stinnakre ◽  
Eléonore Réal ◽  
Jean-René Martin
Keyword(s):  
Olfactory Receptor ◽  
Olfactory Receptor Neurons ◽  
Calcium Stores ◽  
Axon Terminals ◽  
Receptor Neurons
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