scholarly journals Ex Vivo Preparations of the Intact Vomeronasal Organ and Accessory Olfactory Bulb

10.3791/51813 ◽  
2014 ◽  
Author(s):  
Wayne I. Doyle ◽  
Gary F. Hammen ◽  
Julian P. Meeks
Keyword(s):  
Olfactory Bulb ◽  
Ex Vivo ◽  
Vomeronasal Organ ◽  
Accessory Olfactory Bulb

scholarly journals Paradoxically sparse chemosensory tuning in broadly-integrating external granule cells in the mouse accessory olfactory bulb

2019 ◽  
Author(s):  
Xingjian Zhang ◽  
Julian P. Meeks
Keyword(s):  
Patch Clamp ◽  
Olfactory Bulb ◽  
Olfactory System ◽  
Granule Cells ◽  
Ex Vivo ◽  
Accessory Olfactory Bulb ◽  
Main Olfactory Bulb ◽  
Patch Clamp Electrophysiology ◽  
Accessory Olfactory System ◽  
Critical Circuit

AbstractThe accessory olfactory bulb (AOB) is a critical circuit in the mouse accessory olfactory system (AOS), but AOB processing is poorly understood compared to the main olfactory bulb (MOB). We used 2-photon GCaMP6f Ca2+ imaging in an ex vivo preparation to study the chemosensory tuning of AOB external granule cells (EGCs), an interneuron population hypothesized to broadly integrate from mitral cells (MCs). We measured MC and EGC tuning to natural chemosignal blends and monomolecular ligands, finding that EGC tuning was far sparser than MC tuning. Simultaneous patch-clamp electrophysiology and Ca2+ imaging indicated that this was only partially explained by lower GCaMP6f-to-spiking ratios in EGCs compared to MCs. Ex vivo patch-clamp recordings revealed that EGC subthreshold responsivity was broad, but monomolecular ligand responses were insufficient to elicit spiking. These results indicate that EGC spiking is selectively engaged by chemosensory blends, suggesting different roles for EGCs than analogous interneurons in the MOB.

scholarly journals Heterogeneous effects of norepinephrine on spontaneous and stimulus-driven activity in the male accessory olfactory bulb

2017 ◽  
Vol 117 (3) ◽  
pp. 1342-1351 ◽  
Author(s):  
Wayne I. Doyle ◽  
Julian P. Meeks
Keyword(s):  
Information Processing ◽  
Olfactory Bulb ◽  
Spontaneous Activity ◽  
Behavioral Plasticity ◽  
Ex Vivo ◽  
Model Systems ◽  
Projection Neurons ◽  
Response Suppression ◽  
Accessory Olfactory Bulb ◽  
The Impact

Norepinephrine (NE) release has been linked to experience-dependent plasticity in many model systems and brain regions. Among these is the rodent accessory olfactory system (AOS), which is crucial for detecting and processing socially relevant environmental cues. The accessory olfactory bulb (AOB), the first site of chemosensory information processing in the AOS, receives dense centrifugal innervation by noradrenergic fibers originating in the locus coeruleus. Although NE release has been linked to behavioral plasticity through its actions in the AOB, the impacts of noradrenergic modulation on AOB information processing have not been thoroughly studied. We made extracellular single-unit recordings of AOB principal neurons in ex vivo preparations of the early AOS taken from adult male mice. We analyzed the impacts of bath-applied NE (10 μM) on spontaneous and stimulus-driven activity. In the presence of NE, we observed overall suppression of stimulus-driven neuronal activity with limited impact on spontaneous activity. NE-associated response suppression in the AOB came in two forms: one that was strong and immediate (21%) and one other that involved gradual, stimulus-dependent monotonic response suppression (47%). NE-associated changes in spontaneous activity were more modest, with an overall increase in spontaneous spike frequency observed in 25% of neurons. Neurons with increased spontaneous activity demonstrated a net decrease in chemosensory discriminability. These results reveal that noradrenergic signaling in the AOB causes cell-specific changes in chemosensory tuning, even among similar projection neurons. NEW & NOTEWORTHY Norepinephrine (NE) is released throughout the brain in many behavioral contexts, but its impacts on information processing are not well understood. We studied the impact of NE on chemosensory tuning in the mouse accessory olfactory bulb (AOB). Electrophysiological recordings from AOB neurons in ex vivo preparations revealed that NE, on balance, inhibited mitral cell responses to chemosensory cues. However, NE’s effects were heterogeneous, indicating that NE signaling reshapes AOB output in a cell- and stimulus-specific manner.

Female puberty acceleration by male odour in mice: neural pathway and behavioural consequences

2014 ◽  
Vol 42 (4) ◽  
pp. 878-881 ◽  
Author(s):  
Mélanie Jouhanneau ◽  
Laura A. Szymanski ◽  
Matthieu Keller
Keyword(s):  
Olfactory Bulb ◽  
Vomeronasal Organ ◽  
Medial Amygdala ◽  
Accessory Olfactory Bulb ◽  
Vaginal Opening ◽  
Uterine Weight ◽  
Vomeronasal System ◽  
Neural Pathway ◽  
Early Puberty ◽  
Puberty Onset

In female mice, exposure to male chemosignals results in early puberty onset characterized by advanced vaginal opening and higher uterine weight. Evidence suggests that the male chemosignals responsible for acceleration of female puberty are androgen-dependent, but not all of the compounds that contribute to puberty acceleration have been identified. The male chemosignals are primarily detected and processed by the vomeronasal system including the vomeronasal organ, the accessory olfactory bulb and the medial amygdala. By contrast, the mechanism by which this olfactory information is integrated in the hypothalamus is poorly understood. In this context, the recent identification of the neuropeptide kisspeptin as a gatekeeper of puberty onset may provide a good candidate neuropeptide system for the transmission of chemosensory information to the gonadotrope axis.

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