Map-independent representation of an aggression-promoting social cue in the main olfactory pathway

While the olfactory system is required for proper social behaviors, the molecular basis for how social cues are detected via the main olfactory pathway of mammals is not well-characterized. Trimethylamine is a volatile, sex-specific odor found in adult male mouse urine that selectively activates main olfactory sensory neurons that express trace amine-associated receptor 5 (TAAR5). Here we show that trimethylamine, acting via TAAR5, elicits state-dependent attraction or aversion in male mice and drives inter-male aggression. Genetic knockout of TAAR5 significantly reduces aggression-related behaviors, while adding trimethylamine augments aggressive behavior towards juvenile males. We further show that transgenic expression of TAAR5 specifically in olfactory sensory neurons rescues aggressive behaviors in knockout mice, despite extensive remapping of TAAR5 projections to the olfactory bulb. Our results identify a specific main olfactory input that detects a prominent male-specific odor to induce inter-male aggression in a mammalian species and reveal that apparently innate behavioral responses are independent of patterned glomerular input to the olfactory bulb.

Download Full-text

Regulation by Protein Kinase A Switching of Axonal Pathfinding of Zebrafish Olfactory Sensory Neurons through the Olfactory Placode–Olfactory Bulb Boundary

Journal of Neuroscience ◽

10.1523/jneurosci.22-12-04964.2002 ◽

2002 ◽

Vol 22 (12) ◽

pp. 4964-4972 ◽

Cited By ~ 26

Author(s):

Tomoyuki Yoshida ◽

Aya Ito ◽

Naoto Matsuda ◽

Masayoshi Mishina

Keyword(s):

Protein Kinase ◽

Olfactory Bulb ◽

Protein Kinase A ◽

Sensory Neurons ◽

Olfactory Sensory Neurons ◽

Axonal Pathfinding ◽

Olfactory Placode ◽

Kinase A

Download Full-text

Region-specific amyloid-β accumulation in the olfactory system influences olfactory sensory neuronal dysfunction in 5xFAD mice

Alzheimer s Research & Therapy ◽

10.1186/s13195-020-00730-2 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Gowoon Son ◽

Seung-Jun Yoo ◽

Shinwoo Kang ◽

Ameer Rasheed ◽

Da Hae Jung ◽

...

Keyword(s):

Olfactory Bulb ◽

Sensory Neurons ◽

Olfactory System ◽

Amyloid Β ◽

Olfactory Sensory Neurons ◽

Basal Cells ◽

Irreversible Damage ◽

5Xfad Mouse ◽

Peripheral Areas ◽

5Xfad Mice

Abstract Background Hyposmia in Alzheimer’s disease (AD) is a typical early symptom according to numerous previous clinical studies. Although amyloid-β (Aβ), which is one of the toxic factors upregulated early in AD, has been identified in many studies, even in the peripheral areas of the olfactory system, the pathology involving olfactory sensory neurons (OSNs) remains poorly understood. Methods Here, we focused on peripheral olfactory sensory neurons (OSNs) and delved deeper into the direct relationship between pathophysiological and behavioral results using odorants. We also confirmed histologically the pathological changes in 3-month-old 5xFAD mouse models, which recapitulates AD pathology. We introduced a numeric scale histologically to compare physiological phenomenon and local tissue lesions regardless of the anatomical plane. Results We observed the odorant group that the 5xFAD mice showed reduced responses to odorants. These also did not physiologically activate OSNs that propagate their axons to the ventral olfactory bulb. Interestingly, the amount of accumulated amyloid-β (Aβ) was high in the OSNs located in the olfactory epithelial ectoturbinate and the ventral olfactory bulb glomeruli. We also observed irreversible damage to the ectoturbinate of the olfactory epithelium by measuring the impaired neuronal turnover ratio from the basal cells to the matured OSNs. Conclusions Our results showed that partial and asymmetrical accumulation of Aβ coincided with physiologically and structurally damaged areas in the peripheral olfactory system, which evoked hyporeactivity to some odorants. Taken together, partial olfactory dysfunction closely associated with peripheral OSN’s loss could be a leading cause of AD-related hyposmia, a characteristic of early AD.

Download Full-text

Cortical Processing of Odorants

Oxford Research Encyclopedia of Neuroscience ◽

10.1093/acrefore/9780190264086.013.96 ◽

2017 ◽

Author(s):

Yaniv Cohen ◽

Emmanuelle Courtiol ◽

Regina M. Sullivan ◽

Donald A. Wilson

Keyword(s):

Olfactory Bulb ◽

Sensory Neurons ◽

Perceptual Experience ◽

Spatial Organization ◽

Piriform Cortex ◽

Olfactory Sensory Neurons ◽

Anterior Olfactory Nucleus ◽

Molecular Features ◽

Cortical Nucleus ◽

Local Circuitry

Odorants, inhaled through the nose or exhaled from the mouth through the nose, bind to receptors on olfactory sensory neurons. Olfactory sensory neurons project in a highly stereotyped fashion into the forebrain to a structure called the olfactory bulb, where odorant-specific spatial patterns of neural activity are evoked. These patterns appear to reflect the molecular features of the inhaled stimulus. The olfactory bulb, in turn, projects to the olfactory cortex, which is composed of multiple sub-units including the anterior olfactory nucleus, the olfactory tubercle, the cortical nucleus of the amygdala, the anterior and posterior piriform cortex, and the lateral entorhinal cortex. Due to differences in olfactory bulb inputs, local circuitry and other factors, each of these cortical sub-regions appears to contribute to different aspects of the overall odor percept. For example, there appears to be some spatial organization of olfactory bulb inputs to the cortical nucleus of the amygdala, and this region may be involved in the expression of innate odor hedonic preferences. In contrast, the olfactory bulb projection to the piriform cortex is highly distributed and not spatially organized, allowing the piriform to function as a combinatorial, associative array, producing the emergence of experience-dependent odor-objects (e.g., strawberry) from the molecular features extracted in the periphery. Thus, the full perceptual experience of an odor requires involvement of a large, highly dynamic cortical network.

Download Full-text

Severe Acute Respiratory Syndrome Coronavirus 2 Infects and Damages the Mature and Immature Olfactory Sensory Neurons of Hamsters

Clinical Infectious Diseases ◽

10.1093/cid/ciaa995 ◽

2020 ◽

Cited By ~ 11

Author(s):

Anna Jinxia Zhang ◽

Andrew Chak-Yiu Lee ◽

Hin Chu ◽

Jasper Fuk-Woo Chan ◽

Zhimeng Fan ◽

...

Keyword(s):

Severe Acute Respiratory Syndrome ◽

Olfactory Bulb ◽

Sensory Neurons ◽

Young Patients ◽

Olfactory Dysfunction ◽

Olfactory Sensory Neurons ◽

Specific Class ◽

Olfactory Neurons ◽

Viral Antigens ◽

Sustentacular Cells

Abstract Background Coronavirus disease 2019 (COVID-19) is primarily an acute respiratory tract infection. Distinctively, a substantial proportion of COVID-19 patients develop olfactory dysfunction. Especially in young patients, loss of smell can be the first or only symptom. The roles of inflammatory obstruction of the olfactory clefts, inflammatory cytokines affecting olfactory neuronal function, destruction of olfactory neurons or their supporting cells, and direct invasion of olfactory bulbs in causing olfactory dysfunction are uncertain. Methods We investigated the location for the pathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from the olfactory epithelium (OE) to the olfactory bulb in golden Syrian hamsters. Results After intranasal inoculation with SARS-CoV-2, inflammatory cell infiltration and proinflammatory cytokine/chemokine responses were detected in the nasal turbinate tissues. The responses peaked between 2 and 4 days postinfection, with the highest viral load detected at day 2 postinfection. In addition to the pseudo-columnar ciliated respiratory epithelial cells, SARS-CoV-2 viral antigens were also detected in the mature olfactory sensory neurons labeled by olfactory marker protein, in the less mature olfactory neurons labeled by neuron-specific class III β-tubulin at the more basal position, and in the sustentacular cells, resulting in apoptosis and severe destruction of the OE. During the entire course of infection, SARS-CoV-2 viral antigens were not detected in the olfactory bulb. Conclusions In addition to acute inflammation at the OE, infection of mature and immature olfactory neurons and the supporting sustentacular cells by SARS-CoV-2 may contribute to the unique olfactory dysfunction related to COVID-19, which is not reported with SARS-CoV-2.

Download Full-text

Thallium-201 Imaging in Intact Olfactory Sensory Neurons with Reduced Pre-Synaptic Inhibition In Vivo

Molecular Neurobiology ◽

10.1007/s12035-020-02078-y ◽

2020 ◽

Vol 57 (12) ◽

pp. 4989-4999

Author(s):

Hideaki Shiga ◽

Hiroshi Wakabayashi ◽

Kohshin Washiyama ◽

Tomohiro Noguchi ◽

Tomo Hiromasa ◽

...

Keyword(s):

Olfactory Bulb ◽

Sensory Neurons ◽

Action Potentials ◽

Migration Rate ◽

Intranasal Administration ◽

Thallium 201 ◽

Nasal Administration ◽

Olfactory Sensory Neurons ◽

Synaptic Inhibition

Abstract In this study, we determined whether the 201Tl (thallium-201)-based olfactory imaging is affected if olfactory sensory neurons received reduced pre-synaptic inhibition signals from dopaminergic interneurons in the olfactory bulb in vivo. The thallium-201 migration rate to the olfactory bulb and the number of action potentials of olfactory sensory neurons were assessed 3 h following left side nasal administration of rotenone, a mitochondrial respiratory chain complex I inhibitor that decreases the number of dopaminergic interneurons without damaging the olfactory sensory neurons in the olfactory bulb, in mice (6–7 animals per group). The migration rate of thallium-201 to the olfactory bulb was significantly increased following intranasal administration of thallium-201 and rotenone (10 μg rotenone, p = 0.0012; 20 μg rotenone, p = 0.0012), compared with that in control mice. The number of action potentials was significantly reduced in the olfactory sensory neurons in the rotenone treated side of 20 μg rotenone-treated mice, compared with that in control mice (p = 0.0029). The migration rate of thallium-201 to the olfactory bulb assessed with SPECT-CT was significantly increased in rats 24 h after the left intranasal administration of thallium-201 and 100 μg rotenone, compared with that in control rats (p = 0.008, 5 rats per group). Our results suggest that thallium-201 migration to the olfactory bulb is increased in intact olfactory sensory neurons with reduced pre-synaptic inhibition from dopaminergic interneurons in olfactory bulb glomeruli.

Download Full-text

Odorant Receptors in the Formation of the Olfactory Bulb Circuitry

Physiology ◽

10.1152/physiol.00015.2012 ◽

2012 ◽

Vol 27 (4) ◽

pp. 200-212 ◽

Cited By ~ 14

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.

Download Full-text