scholarly journals Transduction in Drosophila olfactory receptor neurons is invariant to air speed

2012 ◽  
Vol 108 (7) ◽  
pp. 2051-2059 ◽  
Author(s):  
Yi Zhou ◽  
Rachel I. Wilson
Keyword(s):  
Olfactory Receptor ◽  
Air Flow ◽  
Full Range ◽  
Olfactory Receptor Neurons ◽  
Odor Concentration ◽  
Terrestrial Vertebrates ◽  
Receptor Neurons ◽  
Air Speed ◽  
Olfactory Organs

In the vertebrate nose, increasing air speed tends to increase the magnitude of odor-evoked activity in olfactory receptor neurons (ORNs), given constant odor concentration and duration. It is often assumed that the same is true of insect olfactory organs, but this has not been directly tested. In this study, we examined the effect of air speed on ORN responses in Drosophila melanogaster. We constructed an odor delivery device that allowed us to independently vary concentration and air speed, and we used a fast photoionization detector to precisely measure the actual odor concentration at the antenna while simultaneously recording spikes from ORNs in vivo. Our results demonstrate that Drosophila ORN odor responses are invariant to air speed, as long as odor concentration is kept constant. This finding was true across a >100-fold range of air speeds. Because odor hydrophobicity has been proposed to affect the air speed dependence of olfactory transduction, we tested a >1,000-fold range of hydrophobicity values and found that ORN responses are invariant to air speed across this full range. These results have implications for the mechanisms of odor delivery to Drosophila ORNs. Our findings are also significant because flies have a limited ability to control air flow across their antennae, unlike terrestrial vertebrates, which can control air flow within their nasal cavity. Thus, for the fly, invariance to air speed may be adaptive because it confers robustness to changing wind conditions.

In Vivo Responses of Single Olfactory Receptor Neurons of Channel Catfish to Binary Mixtures of Amino Acids

1997 ◽  
Vol 77 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Jiesheng Kang ◽  
John Caprio
Keyword(s):  
Amino Acids ◽  
Binary Mixtures ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Olfactory Receptor ◽  
Olfactory Receptor Neurons ◽  
Electrophysiological Response ◽  
Receptor Neurons ◽  
First Time

Kang, Jiesheng and John Caprio. In vivo response of single olfactory receptor neurons of channel catfish to binary mixtures of amino acids. J. Neurophysiol. 77: 1–8, 1997. For the first time in any vertebrate, in vivo responses of single olfactory receptor neurons to odorant mixtures were studied quantitatively. Extracellular electrophysiological response of 54 single olfactory receptor neurons from 23 channel catfish, Ictalurus punctatus, to binary mixtures of amino acids and to their components were recorded simultaneously with the electroolfactogram (EOG). For 57% (73 of 128) of the tests, no significant change (N) from spontaneous activity occurred. Responses to the remaining 55 tests of binary mixtures were excitatory (E; 13%) or suppressive (S; 30%). No response type was associated with any specific mixture across the neurons sampled. Eighty-six percent of the responses of catfish olfactory receptor neurons to binary mixtures were classifed similar to at least one of the component responses, a percentage comparable (i.e., 89%) with that observed for single olfactory bulb neurons in the same species to equivalent binary mixtures. The responses of single olfactory receptor neurons to component-similar binary mixtures (i.e., component responses were both E, both S, and both N, respectively) were generally (80% of 59 tests) classified similar to the responses to the components. For E+N and S+N binary mixtures, the N component often (66% of 58 tests) reduced or concealed (i.e., “masked”) the excitatory and suppressive responses, respectively. For the majority (6 of 11 tests) of E+S binary mixtures, null activity resulted. Responses to the remaining five tests were either excitatory ( n = 3) or suppressive ( n = 2).

Relation between stimulus and response in frog olfactory receptor neurons in vivo

2003 ◽  
Vol 18 (5) ◽  
pp. 1135-1154 ◽  
Author(s):  
Jean-Pierre Rospars ◽  
Petr Lansky ◽  
Andre Duchamp ◽  
Patricia Duchamp-Viret
Keyword(s):  
Olfactory Receptor ◽  
Olfactory Receptor Neurons ◽  
Receptor Neurons

In vivo responses of single olfactory receptor neurons in the channel catfish, Ictalurus punctatus

1995 ◽  
Vol 73 (1) ◽  
pp. 172-177 ◽  
Author(s):  
J. Kang ◽  
J. Caprio
Keyword(s):  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Olfactory Receptor ◽  
Action Potentials ◽  
Olfactory Receptor Neurons ◽  
Receptor Neurons ◽  
Spontaneous Frequency ◽  
Excitatory Responses ◽  
First Time

1. We report for the first time in any teleost, a quantitative in vivo study of recordings from single olfactory receptor neurons (ORNs) in the channel catfish, Ictalurus punctatus, with odorant stimuli. 2. Responses of 69 spontaneously active single ORNs were recorded simultaneously with the electroolfactogram (EOG). Recording times ranged from 10 to 72 min per receptor cell with an average of 24 +/- 15 (SD) min/cell. The averaged spontaneous frequency ranged from < 1 to 12 action potentials/s with a mean frequency of 4.7 +/- 2.5 action potentials/s. 3. Catfish ORNs responded to the odorant stimuli (amino acids, bile salts, and ATP) with either an excitation or suppression of the background neural activity. Suppressive responses were encountered more frequently than excitatory responses, suggesting that suppressive responses also play an important role in olfactory coding. 4. Excitatory and suppressive responses to the different odorants were elicited from the same ORN, suggesting that different olfactory receptor molecules and different transduction pathways exist in the same ORN.

scholarly journals Concentration-Invariant Odor Representation in the Olfactory System by Presynaptic Inhibition

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Danke Zhang ◽  
Yuanqing Li ◽  
Si Wu
Keyword(s):  
Olfactory Receptor ◽  
Olfactory System ◽  
Olfactory Receptor Neurons ◽  
Projection Neurons ◽  
Invariant Representation ◽  
Odor Concentration ◽  
Presynaptic Site ◽  
Divisive Normalization ◽  
Receptor Neurons ◽  
Parameter Condition

The present study investigates a network model for implementing concentration-invariant representation for odors in the olfactory system. The network consists of olfactory receptor neurons, projection neurons, and inhibitory local neurons. Receptor neurons send excitatory inputs to projection neurons, which are modulated by the inhibitory inputs from local neurons. The modulation occurs at the presynaptic site from a receptor neuron to a projection one, leading to the operation of divisive normalization. The responses of local interneurons are determined by the total activities of olfactory receptor neurons. We find that with a proper parameter condition, the responses of projection neurons become effectively independent of the odor concentration. Simulation results confirm our theoretical analysis.

scholarly journals Comparison of the Nasal Olfactory Organs of Various Species of Lizardfishes (Teleostei: Aulopiformes: Synodontidae) with Additional Remarks on the Brain

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
L. Fishelson ◽  
D. Golani ◽  
B. Galil ◽  
M. Goren
Keyword(s):  
Olfactory Epithelium ◽  
Olfactory Receptor ◽  
Olfactory Receptor Neurons ◽  
Adult Fish ◽  
Supporting Cells ◽  
Receptor Neurons ◽  
Olfactory Organs ◽  
Species Specific ◽  
The Brain

The olfactory organs of lizardfishes (Synodontidae) are situated in two capsules connected to the outside by incurrent and excurrent openings. The olfactory epithelium is in form of petal rosettes each composed of lamellae and a rephe, and bear olfactory receptor neurons, supporting cells and cells with kinocillia. The dimension of rosettes and lamellae, as well as the number of lamellae, increase with growth of the fish; until in adult fish these parameters remaine constant, species specific. In adultSynodusspp. andTrachinocephalus myopsthe rosettes are 3.5–4.0 mm long, with 5–8 lamellae, whereas inSauridaspp. they are 8.0 mm and possess up tp 22 lamellae. The number of ORN ranges from 2,600 on the smaller lamellae to 20,000 on the largest ones. The number of ORN/m of olfactory is ca. 30,000 inSauridaspp. Thus the rosettes ofS. macrolepiswith 20 lamellae possess a total of ca. 170,000 ORN, whereas those ofSy. variegatusandT. myopswith the average of six lamellae possess only ca. 50,000–65,000 ORN. The olfactory nerves lead from the rosettes to the olfactory balbs situated on the olfactory lobes. The differences among the species in olfactory organs are discussed in correlation with their distribution.

scholarly journals Calcium-activated chloride channels clamp odor-evoked spike activity in olfactory receptor neurons

2018 ◽  
Author(s):  
Joseph D. Zak ◽  
Julien Grimaud ◽  
Rong-Chang Li ◽  
Chih-Chun Lin ◽  
Venkatesh N. Murthy
Keyword(s):  
Olfactory Receptor ◽  
Chloride Channels ◽  
Feedback Mechanism ◽  
Olfactory Receptor Neurons ◽  
Odor Source ◽  
Wild Type ◽  
Behavioral Deficits ◽  
Receptor Neurons

AbstractThe calcium-activated chloride channel anoctamin-2 (Ano2) is thought to amplify transduction currents in ORNs, a hypothesis supported by previous studies in dissociated neurons from Ano2-/- mice. Paradoxically, despite a reduction in transduction currents in Ano2-/- ORNs, their spike output for odor stimuli may be higher. We examined the role of Ano2 in ORNs in their native environment in freely breathing mice by imaging activity in ORN axons as they arrive in the olfactory bulb glomeruli. Odor-evoked responses in ORN axons of Ano2-/- mice were consistently larger for a variety of odorants and concentrations. In an open arena, Ano2-/- mice took longer to approach a localized odor source than wild-type mice, revealing clear olfactory behavioral deficits. Our studies provide the first in vivo evidence toward an alternative role for Ano2 in the olfactory transduction cascade, where it may serve as a feedback mechanism to clamp ORN spike output.

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.

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