Cholinergic projections from the pedunculopontine tegmental nucleus contact excitatory and inhibitory neurons in the inferior colliculus

Title

Cholinergic projections from the pedunculopontine tegmental nucleus contact excitatory and inhibitory neurons in the inferior colliculus

Creator

Noftz WA; Beebe NL; Mellott JG; Schofield BR

Publisher

Frontiers in Neural Circuits

Date

2020
2020-07-16

Description

The inferior colliculus processes nearly all ascending auditory information. Most collicular cells respond to sound, and for a majority of these cells, the responses can be modulated by acetylcholine (ACh). The cholinergic effects are varied and, for the most part, the underlying mechanisms are unknown. The major source of cholinergic input to the inferior colliculus is the pedunculopontine tegmental nucleus (PPT), part of the pontomesencephalic tegmentum known for projections to the thalamus and roles in arousal and the sleep-wake cycle. Characterization of PPT inputs to the inferior colliculus has been complicated by the mixed neurotransmitter population within the PPT. Using selective viral-tract tracing techniques in a ChAT-Cre Long Evans rat, the present study characterizes the distribution and targets of cholinergic projections from PPT to the inferior colliculus. Following the deposit of viral vector in one PPT, cholinergic axons studded with boutons were present bilaterally in the inferior colliculus, with the greater density of axons and boutons ipsilateral to the injection site. On both sides, cholinergic axons were present throughout the inferior colliculus, distributing boutons to the central nucleus, lateral cortex, and dorsal cortex. In each inferior colliculus (IC) subdivision, the cholinergic PPT axons appear to contact both GABAergic and glutamatergic neurons. These findings suggest cholinergic projections from the PPT have a widespread influence over the IC, likely affecting many aspects of midbrain auditory processing. Moreover, the effects are likely to be mediated by direct cholinergic actions on both excitatory and inhibitory circuits in the inferior colliculus.

Subject

rat; acetylcholine; auditory; brain-stem; plasticity; cells; modulation; neuromodulation; pathways; midbrain; hearing; arousal; acetylcholine-receptors; auditory input; choline acetyltransferase; gabaergic neurons; viral tracing; volume transmission; viral tracing

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

43

Volume

14

NEOMED College

NEOMED College of Medicine

NEOMED Department

Department of Anatomy & Neurobiology
NEOMED Postdoc Publications

Update Year & Number

August 2020 List

Citation

Noftz WA; Beebe NL; Mellott JG; Schofield BR, “Cholinergic projections from the pedunculopontine tegmental nucleus contact excitatory and inhibitory neurons in the inferior colliculus,” NEOMED Bibliography Database, accessed June 15, 2021, https://neomed.omeka.net/items/show/11207.

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