Olivocochlear neurons in the brainstem of the mouse

Campbell, Jeffrey P.; Henson, Miriam M.

doi:10.1016/0378-5955(88)90124-4

Cited by 72 publications

(61 citation statements)

References 9 publications

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“…2B). MOC neurons have large somata and were located in the ventral nucleus of the trapezoid body (VNTB), as described previously by retrograde labeling studies in other strains of mice (Campbell and Henson 1988;Brown and Levine 2008) and rat (Vetter et al 1991;Vetter and Mugnaini 1992). Their distribution in all strains extends a considerable distance in the rostro-caudal direction, beginning somewhat caudal to the lateral superior olivary nucleus (LSO) and extending rostrally to the caudal part of the ventral nucleus of the lateral lemniscus.…”

Section: Oc Somatamentioning

confidence: 54%

Olivocochlear Neuron Central Anatomy Is Normal in α9 Knockout Mice

Brown

Vetter

2008

JARO

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Olivocochlear (OC) neurons were studied in a transgenic mouse with deletion of the α9 nicotinic acetylcholine receptor subunit. In this α9 knockout mouse, the peripheral effects of OC stimulation are lacking and the peripheral terminals of OC neurons under outer hair cells have abnormal morphology. To account for this mouse's apparently normal hearing, it has been proposed to have central compensation via collateral branches to the cochlear nucleus. We tested this idea by staining OC neurons for acetylcholinesterase and examining their morphology in knockout mice, wild-type mice of the same background strain, and CBA/CaJ mice. Knockout mice had normal OC systems in terms of numbers of OC neurons, dendritic patterns, and numbers of branches to the cochlear nucleus. The branch terminations were mainly to edge regions and to a lesser extent the core of the cochlear nucleus, and were similar among the strains in terms of the distribution and staining density. These data demonstrate that there are no obvious changes in the central morphology of the OC neurons in α9 knockout mice and make less attractive the idea that there is central compensation for deletion of the peripheral receptor in these mice.

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Section: Oc Somatamentioning

confidence: 54%

Olivocochlear Neuron Central Anatomy Is Normal in α9 Knockout Mice

Brown

Vetter

2008

JARO

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“…Interest in this species also arises because its short life span renders it attractive for studies of the effects of aging (e.g., Zettel et al, 2007). Yet there has been only one previous study of the central distribution of OC neurons (Campbell and Henson, 1988) and the strain of mouse used was not identified. Work on the cochlear terminations of OC neurons in CBA/CaJ mice shows a typical mammalian plan with some exceptions (Maison et al, 2003).…”

Section: Published In Final Edited Form Asmentioning

confidence: 99%

“…Two major groups of AChE-stained neurons were separated according to location. The first group was composed of large neurons located in the ventral nucleus of the trapezoid body (VNTB), which we presume to be Medial (M) OC neurons as described previously in mouse (Osen et al, 1984;Campbell and Henson, 1988). The second group was composed of smaller neurons presumed to be Lateral (L) OC neurons located within LSO (LOC intrinsic neurons).…”

Section: Distribution and Number Of Oc Neuronsmentioning

confidence: 99%

“…Our results demonstrate that MOC neurons in mouse are mainly located in a single nucleus, a plan observed in many species. This group extends the full rostro/ caudal extent of the VNTB and is most numerous rostrally (Campbell and Henson, 1988). Using either AChE stains or FG labeling, the per-cochlea number of MOC neurons in VNTB averages about 170, and, for DPO neurons, averages about a dozen.…”

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confidence: 99%

“…The right panels are an atlas from a different animal showing AChE-stained neurons, which presumably project to either the left or right cochleas. Both techniques show that MOC neurons are located mainly in the VNTB throughout its entire rostro-caudal extent, from the caudal-most point near the facial motor nucleus to the rostral most point near the beginning of the ventral nucleus of the lateral lemniscus (Campbell and Henson, 1988). FG labeling indicates that the neurons projecting to the left cochlea are bilaterally distributed in both the VNTB and DPO, but that there are more of them on the right side of the brain, the side opposite to the injected cochlea.…”

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confidence: 99%

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Dendrites of medial olivocochlear neurons in mouse

Brown

Levine

2008

Neuroscience

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Stains for acetylcholinesterase (AChE) and retrograde labeling with Fluorogold (FG) were used to study olivocochlear neurons and their dendritic patterns in mice. The two methods gave similar results for location and number of somata. The total number of medial olivocochlear (MOC) neurons in the ventral nucleus of the trapezoid body (VNTB) is about 170 per side. An additional dozen large olivocochlear neurons are located in the dorsal periolivary nucleus (DPO). Dendrites of all of these neurons are long and extend in all directions from the cell bodies, a pattern that contrasts with the sharp frequency tuning of their responses. For VNTB neurons, there were greater numbers of dendrites directed medially than laterally and those directed medially were longer (on average, 25-50% longer). Dendrite extensions were most pronounced for neurons located in the rostral portion of the VNTB. When each dendrite from a single neuron was represented as a vector, and all the vectors summed, the result was also skewed toward the medial direction. DPO neurons, however, had more symmetric dendrites that projected into more dorsal parts of the trapezoid body, suggesting that this small group of olivocochlear neurons has very different physiological properties. Dendrites of both types of neurons were somewhat elongated rostrally, about 20% longer than those directed caudally. These results can be interpreted as extensions of dendrites of olivocochlear neurons toward their synaptic inputs: medially to meet crossing fibers from the cochlear nucleus that are part of the MOC reflex pathway, and rostrally to meet descending inputs from higher centers. Keywords superior olive; cochlear nucleus; efferent; descending pathway; auditory reflex Dendrites represent an important site for neurons to receive synaptic input. As such, dendrite corientation and pattern can shape a neuron's response properties. For example, octopus cells of the posteroventral cochlear nucleus have long dendrites oriented perpendicular to the incoming auditory nerve fibers (Osen, 1969;Brawer et al., 1974). This orientation allows them to receive input from auditory-nerve fibers that are tuned to a range of frequencies. Octopus cells, which have an onset pattern of discharge in response to a tone burst (Rouiller and Ryugo, 1983; Rhode et al., 1983), are often tuned more broadly than their inputs (Godfrey et al., *Corresponding Author. Tel: (617) 573-3875; fax (617) . Address: Eaton-Peabody Laboratory, Massachusetts Eye & Ear Infirmary, 243 Charles St., Boston, MA 02114. Email address: Chris_Brown@meei.harvard.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal ...

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Synaptic input to cochlear nucleus dendrites that receive medial olivocochlear synapses

1996

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Axons of olivocochlear neurons originate in the superior olivary complex and project to the cochlea. Along their course, medial olivocochlear axons give off branches to the cochlear nucleus. We labeled these branches with horseradish peroxidase and used electron microscopy to determine their target dendrites. Target dendrites were of two classes: "large" dendrites and "varicose" dendrites. Using serial sections, we reconstructed the dendrites and, in addition to the labeled olivocochlear input, we determined the synaptic profile of unlabeled inputs onto the dendrites. We classified the terminals on the basis of the shape and size of their synaptic vesicles. On large dendrites, the predominant type of unlabeled terminal had small round (SmRnd) vesicles. These terminals are likely to be excitatory, and some of them may originate from unlabeled medial olivocochlear branches. On varicose dendrites, the predominant type of terminal had pleomorphic vesicles. These terminals are likely to be inhibitory. They may be from descending inputs that arise in higher centers. A final type of terminal onto large dendrites exhibited signs of neuronal degeneration, possibly because the cell body of origin was damaged during the injection procedure. These terminals often had long, perforated synaptic densities and may originate from type II primary afferents. Thus, medial olivocochlear efferents and type II afferents, which both contact outer hair cells in the periphery, appear to synapse onto the same targets in the cochlear nucleus. In contrast, where examined, the target dendrites did not receive terminals with large vesicles from afferents that contact inner hair cells. Thus, target neurons appear to function in a neural circuit associated more closely with outer than with inner hair cells.

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Olivocochlear neurons in the brainstem of the mouse

Cited by 72 publications

References 9 publications

Olivocochlear Neuron Central Anatomy Is Normal in α9 Knockout Mice

Olivocochlear Neuron Central Anatomy Is Normal in α9 Knockout Mice

Dendrites of medial olivocochlear neurons in mouse

Synaptic input to cochlear nucleus dendrites that receive medial olivocochlear synapses

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