scholarly journals Antagonistic odor interactions in olfactory sensory neurons are widespread in freely breathing mice

2019 ◽  
Author(s):  
Joseph D. Zak ◽  
Gautam Reddy ◽  
Massimo Vergassola ◽  
Venkatesh N. Murthy
Keyword(s):  
Sensory Neurons ◽  
Information Loss ◽  
Complex Mixtures ◽  
Olfactory Sensory Neurons ◽  
Neural Responses ◽  
Axon Terminals ◽  
Odor Mixture ◽  
Ligand Interactions ◽  
Odor Mixtures ◽  
Antagonistic Interactions

AbstractOdor landscapes contain complex blends of discrete molecules that each activate unique, overlapping populations of olfactory sensory neurons (OSNs). Despite the presence of hundreds of OSN subtypes in many animals, the overlapping nature of odor inputs may lead to saturation of neural responses at the early stages of stimulus encoding. Information loss due to saturation could be mitigated by normalizing mechanisms such as antagonism at the level of receptor-ligand interactions, whose existence and prevalence remains uncertain. By imaging OSN axon terminals in olfactory bulb glomeruli as well as OSN cell bodies within the olfactory epithelium in freely breathing mice, we found widespread antagonistic interactions in binary odor mixtures. In complex mixtures of up to 12 odorants, antagonistic interactions became stronger and more prevalent with increasing mixture complexity. Therefore, antagonism is a remarkably common feature of odor mixture encoding in olfactory sensory neurons and helps in normalizing activity to reduce saturation.

scholarly journals Widespread inhibition, antagonism, and synergy in mouse olfactory sensory neurons in vivo

2019 ◽  
Author(s):  
Shigenori Inagaki ◽  
Ryo Iwata ◽  
Masakazu Iwamoto ◽  
Takeshi Imai
Keyword(s):  
Sensory Neurons ◽  
Calcium Imaging ◽  
Odorant Receptor ◽  
Sensory Information ◽  
Olfactory Sensory Neurons ◽  
Axon Terminals ◽  
Two Photon ◽  
Odor Mixtures ◽  
The Brain

SUMMARYSensory information is selectively or non-selectively inhibited and enhanced in the brain, but it remains unclear whether this occurs commonly at the peripheral stage. Here, we performed two-photon calcium imaging of mouse olfactory sensory neurons (OSNs) in vivo and found that odors produce not only excitatory but also inhibitory responses at their axon terminals. The inhibitory responses remained in mutant mice, in which all possible sources of presynaptic lateral inhibition were eliminated. Direct imaging of the olfactory epithelium revealed widespread inhibitory responses at OSN somata. The inhibition was in part due to inverse agonism toward the odorant receptor. We also found that responses to odor mixtures are often suppressed or enhanced in OSNs: Antagonism was dominant at higher odor concentrations, whereas synergy was more prominent at lower odor concentrations. Thus, odor responses are extensively tuned by inhibition, antagonism, and synergy, at the early peripheral stage, contributing to robust odor representations.

scholarly journals Widespread receptor-driven modulation in peripheral olfactory coding

Science ◽  
2020 ◽  
Vol 368 (6487) ◽  
pp. eaaz5390 ◽  
Author(s):  
Lu Xu ◽  
Wenze Li ◽  
Venkatakaushik Voleti ◽  
Dong-Jing Zou ◽  
Elizabeth M. C. Hillman ◽  
...  
Keyword(s):  
Sensory Neurons ◽  
Olfactory System ◽  
Complex Mixtures ◽  
High Throughput Analysis ◽  
Intact Mouse ◽  
Olfactory Responses ◽  
Cell Responses ◽  
Large Numbers ◽  
Single Cell Responses ◽  
Odor Mixtures

Olfactory responses to single odors have been well characterized but in reality we are continually presented with complex mixtures of odors. We performed high-throughput analysis of single-cell responses to odor blends using Swept Confocally Aligned Planar Excitation (SCAPE) microscopy of intact mouse olfactory epithelium, imaging ~10,000 olfactory sensory neurons in parallel. In large numbers of responding cells, mixtures of odors did not elicit a simple sum of the responses to individual components of the blend. Instead, many neurons exhibited either antagonism or enhancement of their response in the presence of another odor. All eight odors tested acted as both agonists and antagonists at different receptors. We propose that this peripheral modulation of responses increases the capacity of the olfactory system to distinguish complex odor mixtures.

Odorant Receptors in the Formation of the Olfactory Bulb Circuitry

Physiology ◽  
2012 ◽  
Vol 27 (4) ◽  
pp. 200-212 ◽  
Author(s):  
Claudia Lodovichi ◽  
Leonardo Belluscio
Keyword(s):  
Olfactory Bulb ◽  
Axon Guidance ◽  
Sensory Neurons ◽  
Odorant Receptors ◽  
Olfactory Sensory Neurons ◽  
Neural Connectivity ◽  
Axon Terminals ◽  
Primary Function

In mammals, smell is mediated by odorant receptors expressed by sensory neurons in the nose. These specialized receptors are found both on olfactory sensory neurons' cilia and axon terminals. Although the primary function of ciliary odorant receptors is to detect odorants, their axonal role remains unclear but is thought to involve axon guidance. This review discusses findings that show axonal odorant receptors are indeed functional and capable of modulating neural connectivity.

scholarly journals Predicting the response of olfactory sensory neurons to odor mixtures from single odor response

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Addolorata Marasco ◽  
Alessandro De Paris ◽  
Michele Migliore
Keyword(s):  
Sensory Neurons ◽  
Olfactory Sensory Neurons ◽  
Odor Mixtures

scholarly journals Widespread Receptor Driven Modulation in Peripheral Olfactory Coding

2019 ◽  
Author(s):  
Lu Xu ◽  
Wenze Li ◽  
Venkatakaushik Voleti ◽  
Elizabeth M. C. Hillman ◽  
Stuart Firestein
Keyword(s):  
Sensory Neurons ◽  
Olfactory System ◽  
Olfactory Sensory Neurons ◽  
Sensory Receptors ◽  
Intact Mouse ◽  
Coding Strategies ◽  
Odor Compounds ◽  
Odor Mixtures ◽  
The Individual ◽  
Combinatorial Code

AbstractWe utilized swept confocally aligned planar excitation (SCAPE) microscopy to measure odor-driven activity simultaneously in many (>10,000) olfactory sensory neurons distributed over large areas of intact mouse olfactory epithelium. This approach allowed us to investigate the responses to mixtures or blends of odors and their components, a more realistic stimulus than monomolecular odors. In up to 38% of responding cells, responses to a mixture of odors were different - absent, smaller or larger - than what would be expected from the sum of the individual components. Further investigation revealed instances of both antagonism and allosteric enhancement in the primary olfactory sensory neurons. All 10 of the odor compounds tested were found to act as both agonists and antagonists at different receptors. We present a hypothetical scheme for how modulation at the peripheral receptors increases the capability of the olfactory system to recognize patterns of complex odor mixtures. The widespread modulation of primary sensory receptors argues against a simple combinatorial code and should motivate a search for alternative coding strategies.

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