Multiple Sources of Cholinergic Input to the Superior Olivary Complex.

Title

Multiple Sources of Cholinergic Input to the Superior Olivary Complex.

Creator

Beebe NL; Zhang C; Burger RM; Schofield BR

Publisher

Frontiers in Neural Circuits

Date

2021
2021-07-15

Description

The superior olivary complex (SOC) is a major computation center in the brainstem auditory system. Despite previous reports of high expression levels of cholinergic receptors in the SOC, few studies have addressed the functional role of acetylcholine in the region. The source of the cholinergic innervation is unknown for all but one of the nuclei of the SOC, limiting our understanding of cholinergic modulation. The medial nucleus of the trapezoid body, a key inhibitory link in monaural and binaural circuits, receives cholinergic input from other SOC nuclei and also from the pontomesencephalic tegmentum. Here, we investigate whether these same regions are sources of cholinergic input to other SOC nuclei. We also investigate whether individual cholinergic cells can send collateral projections bilaterally (i.e., into both SOCs), as has been shown at other levels of the subcortical auditory system. We injected retrograde tract tracers into the SOC in gerbils, then identified retrogradely-labeled cells that were also immunolabeled for choline acetyltransferase, a marker for cholinergic cells. We found that both the SOC and the pontomesencephalic tegmentum (PMT) send cholinergic projections into the SOC, and these projections appear to innervate all major SOC nuclei. We also observed a small cholinergic projection into the SOC from the lateral paragigantocellular nucleus of the reticular formation. These various sources likely serve different functions; e.g., the PMT has been associated with things such as arousal and sensory gating whereas the SOC may provide feedback more closely tuned to specific auditory stimuli. Further, individual cholinergic neurons in each of these regions can send branching projections into both SOCs. Such projections present an opportunity for cholinergic modulation to be coordinated across the auditory brainstem. (Copyright © 2021 Beebe, Zhang, Burger and Schofield.)

Subject

acetylcholine; arousal; collateral; gerbil; hearing; modulation; plasticity; pontomesencephalic tegmentum

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Format

journalArticle

Search for Full-text

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Pages

715369

Volume

15

ISSN

1662-5110

NEOMED College

NEOMED College of Medicine

NEOMED Department

Department of Anatomy & Neurobiology

Update Year & Number

August 2021 List

Citation

Beebe NL; Zhang C; Burger RM; Schofield BR, “Multiple Sources of Cholinergic Input to the Superior Olivary Complex.,” NEOMED Bibliography Database, accessed December 5, 2021, https://neomed.omeka.net/items/show/11770.

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