scholarly journals Interpreting the Spatial-Temporal Structure of Turbulent Chemical Plumes Utilized in Odor Tracking by Lobsters

Fluids ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 82
Author(s):  
Kyle W. Leathers ◽  
Brenden T. Michaelis ◽  
Matthew A. Reidenbach
Keyword(s):  
Spatial Information ◽  
Temporal Structure ◽  
Spiny Lobster ◽  
Search Time ◽  
The Body ◽  
Olfactory Receptor Neurons ◽  
Olfactory Systems ◽  
Receptor Neurons ◽  
Information Problem ◽  
Odor Signal

Olfactory systems in animals play a major role in finding food and mates, avoiding predators, and communication. Chemical tracking in odorant plumes has typically been considered a spatial information problem where individuals navigate towards higher concentration. Recent research involving chemosensory neurons in the spiny lobster, Panulirus argus, show they possess rhythmically active or ‘bursting’ olfactory receptor neurons that respond to the intermittency in the odor signal. This suggests a possible, previously unexplored olfactory search strategy that enables lobsters to utilize the temporal variability within a turbulent plume to track the source. This study utilized computational fluid dynamics to simulate the turbulent dispersal of odorants and assess a number of search strategies thought to aid lobsters. These strategies include quantification of concentration magnitude using chemosensory antennules and leg chemosensors, simultaneous sampling of water velocities using antennule mechanosensors, and utilization of antennules to quantify intermittency of the odorant plume. Results show that lobsters can utilize intermittency in the odorant signal to track an odorant plume faster and with greater success in finding the source than utilizing concentration alone. However, the additional use of lobster leg chemosensors reduced search time compared to both antennule intermittency and concentration strategies alone by providing spatially separated odorant sensors along the body.

scholarly journals Differential effects of adaptation on odor discrimination

2018 ◽  
Vol 120 (1) ◽  
pp. 171-185 ◽  
Author(s):  
Seth Haney ◽  
Debajit Saha ◽  
Baranidharan Raman ◽  
Maxim Bazhenov
Keyword(s):  
Olfactory Receptor ◽  
Olfactory Receptor Neurons ◽  
Neural Responses ◽  
Complex Environments ◽  
Peripheral Neurons ◽  
Neural Representations ◽  
Complex Stimuli ◽  
Olfactory Systems ◽  
Receptor Neurons ◽  
Distinguishing Features

Adaptation of neural responses is ubiquitous in sensory systems and can potentially facilitate many important computational functions. Here we examined this issue with a well-constrained computational model of the early olfactory circuits. In the insect olfactory system, the responses of olfactory receptor neurons (ORNs) on the antennae adapt over time. We found that strong adaptation of sensory input is important for rapidly detecting a fresher stimulus encountered in the presence of other background cues and for faithfully representing its identity. However, when the overlapping odorants were chemically similar, we found that adaptation could alter the representation of these odorants to emphasize only distinguishing features. This work demonstrates novel roles for peripheral neurons during olfactory processing in complex environments. NEW & NOTEWORTHY Olfactory systems face the problem of distinguishing salient information from a complex olfactory environment. The neural representations of specific odor sources should be consistent regardless of the background. How are olfactory representations robust to varying environmental interference? We show that in locusts the extraction of salient information begins in the periphery. Olfactory receptor neurons adapt in response to odorants. Adaptation can provide a computational mechanism allowing novel odorant components to be highlighted during complex stimuli.

scholarly journals Stimulus-selective lateral signaling between olfactory afferents enables parallel encoding of distinct CO2 dynamics

2020 ◽  
Author(s):  
Dhruv Zocchi ◽  
Elizabeth J. Hong
Keyword(s):  
Sensory Processing ◽  
Neurotransmitter Release ◽  
Odorant Receptor ◽  
Temporal Structure ◽  
Olfactory Receptor Neurons ◽  
Lateral Interactions ◽  
Presynaptic Release ◽  
Receptor Neurons ◽  
Parallel Encoding ◽  
Co2 Dynamics

AbstractAn important problem in sensory processing is how lateral interactions that mediate the integration of information across sensory channels function with respect to their stimulus tunings. We demonstrate a novel form of stimulus-selective crosstalk between olfactory channels that occurs between primary olfactory receptor neurons (ORNs). Neurotransmitter release from ORNs can be driven by two distinct sources of excitation, feedforward activity derived from the odorant receptor and lateral input originating from specific subsets of other ORNs. Consequently, levels of presynaptic release can become dissociated from firing rate. Stimulus-selective lateral signaling results in the distributed representation of CO2, a behaviorally important environmental cue that elicits spiking in only a single ORN class, across multiple olfactory channels. Different CO2-responsive channels preferentially transmit distinct stimulus dynamics, thereby expanding the coding bandwidth for CO2. These results generalize to additional odors and olfactory channels, revealing a subnetwork of lateral interactions between ORNs that reshape the spatial and temporal structure of odor representations in a stimulus-specific manner.One Sentence SummaryA novel subnetwork of stimulus-selective lateral interactions between primary olfactory sensory neurons enables new sensory computations.

scholarly journals An update on anatomy and function of the teleost olfactory system

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7808 ◽  
Author(s):  
Jesús Olivares ◽  
Oliver Schmachtenberg
Keyword(s):  
Olfactory System ◽  
Olfactory Receptor Neurons ◽  
Odorant Receptors ◽  
Odor Coding ◽  
Animal Group ◽  
Different Types ◽  
Olfactory Systems ◽  
Receptor Neurons ◽  
Olfactory Organs ◽  
And Function

About half of all extant vertebrates are teleost fishes. Although our knowledge about anatomy and function of their olfactory systems still lags behind that of mammals, recent advances in cellular and molecular biology have provided us with a wealth of novel information about the sense of smell in this important animal group. Its paired olfactory organs contain up to five types of olfactory receptor neurons expressing OR, TAAR, VR1- and VR2-class odorant receptors associated with individual transduction machineries. The different types of receptor neurons are preferentially tuned towards particular classes of odorants, that are associated with specific behaviors, such as feeding, mating or migration. We discuss the connections of the receptor neurons in the olfactory bulb, the differences in bulbar circuitry compared to mammals, and the characteristics of second order projections to telencephalic olfactory areas, considering the everted ontogeny of the teleost telencephalon. The review concludes with a brief overview of current theories about odor coding and the prominent neural oscillations observed in the teleost olfactory system.

scholarly journals Olfactory coding in the turbulent realm

2017 ◽  
Author(s):  
Vincent Jacob ◽  
Christelle Monsempès ◽  
Jean-Pierre Rospars ◽  
Jean-Baptiste Masson ◽  
Philippe Lucas
Keyword(s):  
White Noise ◽  
Firing Rate ◽  
Olfactory Receptor ◽  
Olfactory System ◽  
Time Course ◽  
Temporal Structure ◽  
Olfactory Receptor Neurons ◽  
Odor Source ◽  
Long Distance ◽  
Receptor Neurons

AbstractLong-distance olfactory search behaviors depend on odor detection dynamics. Due to turbulence, olfactory signals travel as bursts of variable concentration and spacing and are characterized by long-tail distributions of odor/no-odor events, challenging the computing capacities of olfactory systems. How animals encode complex olfactory scenes to track the plume far from the source remains unclear. Here we focus on the coding of the plume temporal dynamics in moths. We compare responses of olfactory receptor neurons (ORNs) and antennal lobe projection neurons (PNs) to sequences of pheromone stimuli either with white-noise patterns or with realistic turbulent temporal structures simulating a large range of distances (8 to 64 m) from the odor source. For the first time, we analyze what information is extracted by the olfactory system at large distances from the source. Neuronal responses are analyzed using linear–nonlinear models fitted with white-noise stimuli and used for predicting responses to turbulent stimuli. We found that neuronal firing rate is less correlated with the dynamic odor time course when distance to the source increases because of improper coding during long odor and no-odor events that characterize large distances. Rapid adaptation during long puffs does not preclude however the detection of puff transitions in PNs. Individual PNs but not individual ORNs encode the onset and offset of odor puffs for any temporal structure of stimuli. A higher spontaneous firing rate coupled to an inhibition phase at the end of PN responses contributes to this coding property. This allows PNs to decode the temporal structure of the odor plume at any distance to the source, an essential piece of information moths can use in their tracking behavior.Author SummaryLong-distance olfactory search is a difficult task because atmospheric turbulence erases global gradients and makes the plume discontinuous. The dynamics of odor detections is the sole information about the position of the source. Male moths successfully track female pheromone plumes at large distances. Here we show that the moth olfactory system encodes olfactory scenes simulating variable distances from the odor source by characterizing puff onsets and offsets. A single projection neuron is sufficient to provide an accurate representation of the dynamic pheromone time course at any distance to the source while this information seems to be encoded at the population level in olfactory receptor neurons.

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