scholarly journals Extinction reverses olfactory fear-conditioned increases in neuron number and glomerular size

2015 ◽  
Vol 112 (41) ◽  
pp. 12846-12851 ◽  
Author(s):  
Filomene G. Morrison ◽  
Brian G. Dias ◽  
Kerry J. Ressler
Keyword(s):  
Olfactory Bulb ◽  
Learning And Memory ◽  
Olfactory Epithelium ◽  
Olfactory System ◽  
Structural Changes ◽  
Freezing Behavior ◽  
Extinction Training ◽  
Odor Stimulus ◽  
Main Olfactory Epithelium ◽  
Odor Learning

Although much work has investigated the contribution of brain regions such as the amygdala, hippocampus, and prefrontal cortex to the processing of fear learning and memory, fewer studies have examined the role of sensory systems, in particular the olfactory system, in the detection and perception of cues involved in learning and memory. The primary sensory receptive field maps of the olfactory system are exquisitely organized and respond dynamically to cues in the environment, remaining plastic from development through adulthood. We have previously demonstrated that olfactory fear conditioning leads to increased odorant-specific receptor representation in the main olfactory epithelium and in glomeruli within the olfactory bulb. We now demonstrate that olfactory extinction training specific to the conditioned odor stimulus reverses the conditioning-associated freezing behavior and odor learning-induced structural changes in the olfactory epithelium and olfactory bulb in an odorant ligand-specific manner. These data suggest that learning-induced freezing behavior, structural alterations, and enhanced neural sensory representation can be reversed in adult mice following extinction training.

scholarly journals A Near Complete Zonal Map of Mouse Olfactory Receptors

2017 ◽  
Author(s):  
Longzhi Tan ◽  
X. Sunney Xie
Keyword(s):  
Olfactory Epithelium ◽  
Olfactory System ◽  
Olfactory Receptors ◽  
Mrna Abundance ◽  
Topological Map ◽  
Main Olfactory Epithelium ◽  
Regulated Expression ◽  
Or Genes

AbstractIn the mouse olfactory system, spatially regulated expression of > 1,000 olfactory receptors (ORs) ― a phenomenon termed “zones” ― forms a topological map in the main olfactory epithelium (MOE). However, the zones of most ORs are currently unknown. By sequencing mRNA of 12 isolated MOE pieces, we mapped out zonal information for 1,033 OR genes with an estimated accuracy of 0.3 zones, covering 81% of all intact OR genes and 99.4% of total OR mRNA abundance. Zones tend to vary gradually along chromosomes. We further identified putative non-OR genes that may exhibit zonal expression.

scholarly journals Olfactory subsystems associated with the necklace glomeruli in rodents

2020 ◽  
Author(s):  
Arthur D. Zimmerman ◽  
Steven Munger
Keyword(s):  
Olfactory Bulb ◽  
Olfactory Epithelium ◽  
Main Olfactory Bulb ◽  
Chemosensory Neurons ◽  
Main Olfactory Epithelium ◽  
Immunohistochemical Markers ◽  
Grueneberg Ganglion ◽  
Afferent Inputs ◽  
Necklace Glomeruli

The necklace glomeruli are a loosely defined group of glomeruli encircling the caudal main olfactory bulb in rodents. Initially defined by the expression of various immunohistochemical markers, they are now better understood in the context of the specialized chemosensory neurons of the main olfactory epithelium and Grueneberg ganglion that innervate them. It has become clear that the necklace region of the rodent main olfactory bulb is composed of multiple distinct groups of glomeruli, defined at least in part by their afferent inputs. In this review, we will explore the necklace glomeruli and the chemosensory neurons that innervate them.

scholarly journals Region Specific Amyloid-β Accumulation in Olfactory Sensory Neurons Influences Ecto-Ventral Olfactory Dysfunction in 5xFAD Mice

2020 ◽  
Author(s):  
Gowoon Son ◽  
Seung-Jun Yoo ◽  
Shinwoo Kang ◽  
Ameer Rasheed ◽  
Da Hae Jung ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Sensory Neurons ◽  
Olfactory Epithelium ◽  
Olfactory System ◽  
Amyloid Β ◽  
Olfactory Dysfunction ◽  
Olfactory Sensory Neurons ◽  
Basal Cells ◽  
Irreversible Damage ◽  
5Xfad Mouse

Abstract Background: Hyposmia in Alzheimer’s disease (AD) is a typical early symptom according to numerous previous clinical studies. Although the causes of damage have been proposed in every olfactory system including olfactory epithelium, olfactory bulb and olfactory cortex, the main causes of AD- related hyposmia are largely unknown. Methods: We here focused on peripheral olfactory sensory neurons (OSNs) and delved deeper into the direct relationship between pathophysiological and behavioral results using odorants. We also histologically confirmed the pathological changes in three-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 anatomical plane. Results: We observed the odorant group, which 5xFAD mouse could not detect, also neither did physiologically activate the OSNs that propagate to the ventral olfactory bulb. Interestingly, the amount of accumulated amyloid-β (Aβ) was high in the ecto-ventrally located OSNs that showed reduced responses to odorants. We also observed irreversible damage to the ecto-region of the olfactory epithelium by measuring 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 the AD-related hyposmia, a characteristic of early AD.

scholarly journals Gonadotropin Releasing Hormone (GnRH) Modulates Odorant Responses in the Peripheral Olfactory System of Axolotls

2003 ◽  
Vol 90 (2) ◽  
pp. 731-738 ◽  
Author(s):  
Daesik Park ◽  
Heather L. Eisthen
Keyword(s):  
Glutamic Acid ◽  
Olfactory Epithelium ◽  
Olfactory System ◽  
Gonadotropin Releasing Hormone ◽  
Ambystoma Mexicanum ◽  
Stimulus Interval ◽  
Releasing Hormone ◽  
Main Olfactory Epithelium ◽  
Peripheral Olfactory System ◽  
Aquatic Salamanders

Peripheral signal modulation plays an important role in sensory processing. Activity in the vertebrate olfactory epithelium may be modulated by peptides released from the terminal nerve, such as gonadotropin releasing hormone (GnRH). Here, we demonstrate that GnRH modulates odorant responses in aquatic salamanders (axolotls, Ambystoma mexicanum). We recorded electrical field potentials (electro-olfactograms, or EOGs) in response to stimulation with four different amino acid odorants, l-lysine, l-methionine, l-cysteine, and l-glutamic acid. EOG responses were recorded from the main olfactory epithelium before, during, and after application of 10 μM GnRH. This protocol was repeated for a total of three trials with 60–80 min between trials. The effect of GnRH on EOG responses was broadly similar across odorants and across trials. In general, EOG responses were reduced to 79% of the initial magnitude during application of GnRH; in some trials in which glutamic acid served as the odorant, EOG responses were enhanced during the wash period. Although the 4-min inter-stimulus interval did not lead to adaptation of EOG responses during the first trial, we frequently observed evidence of adaptation during the second and third trials. In addition, we found that lower concentrations of GnRH produced a smaller effect. These results demonstrate that GnRH can modulate odorant responses in the peripheral olfactory system.

scholarly journals Accessory olfactory bulb function is modulated by input from the main olfactory epithelium

2010 ◽  
Vol 31 (6) ◽  
pp. 1108-1116 ◽  
Author(s):  
Burton Slotnick ◽  
Diego Restrepo ◽  
Heather Schellinck ◽  
Georgina Archbold ◽  
Stephen Price ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Olfactory Epithelium ◽  
Accessory Olfactory Bulb ◽  
Main Olfactory Epithelium

scholarly journals How keeping active pays off in the olfactory system

eLife ◽  
2012 ◽  
Vol 1 ◽  
Author(s):  
Kevin Monahan ◽  
Stavros Lomvardas
Keyword(s):  
Olfactory Epithelium ◽  
Olfactory System ◽  
Main Olfactory Epithelium

A protein that is found in the main olfactory epithelium of mice ensures that odour-sensing neurons that are active to have longer lifespans than those that are inactive.

scholarly journals Notch signaling determines cell-fate specification of the two main types of vomeronasal neurons of rodents.

2021 ◽  
Author(s):  
Raghu Ram Katreddi ◽  
Ed Zandro M Taroc ◽  
Sawyer M Hicks ◽  
Jennifer M Lin ◽  
Shuting Liu ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Cell Fate ◽  
Sensory Neurons ◽  
Sexual Behaviors ◽  
Olfactory System ◽  
Mammalian Species ◽  
Sequencing Data ◽  
Terrestrial Vertebrates ◽  
Main Olfactory Epithelium ◽  
Vomeronasal Receptors

The ability of terrestrial vertebrates to find food, mating partners and to avoid predators heavily relies on the detection of chemosensory information from the environment. The olfactory system of most vertebrate species comprises two distinct chemosensory systems usually referred to as the main and the accessory olfactory system. Olfactory sensory neurons of the main olfactory epithelium detect and transmit odor information to main olfactory bulb (MOB), while the chemosensory neurons of the vomeronasal organ detect semiochemicals responsible for social and sexual behaviors and transmit information to the accessory olfactory bulb (AOB). The vomeronasal sensory epithelium (VNE) of most mammalian species contains uniform vomeronasal (VN) system with vomeronasal sensory neurons (VSNs) expressing vomeronasal receptors of the V1R family. However, rodents and some marsupials have developed a more complex binary VN system, where VNO containing a second main type of VSNs expressing vomeronasal receptors of the V2R family is identified. In mice, V1R and V2R VSNs form from a common pool of progenitors but have distinct differentiation programs. As they mature, they segregate in different regions of the VNE and connect with different parts of the AOB. How these two main types of VSNs are formed has never been addressed. In this study, using single cell RNA sequencing data, we identified differential expression of Notch1 receptor and Dll4 ligand among the neuronal precursors at the VSN dichotomy. We further demonstrated with loss of function (LOF) and gain of function (GOF) studies that Dll4-Notch1 signaling plays a crucial role in triggering the binary dichotomy between the two main types of VSNs in mice.

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