GABAergic and non-GABAergic projections to the superior colliculus from the auditory brainstem.

Title

GABAergic and non-GABAergic projections to the superior colliculus from the auditory brainstem.

Creator

Mellott Jeffrey G; Beebe Nichole L; Schofield Brett R

Publisher

Brain structure & function

Date

2018
2018-05

Description

The superior colliculus (SC) contains an auditory space map that is shaped by projections from several subcortical auditory nuclei. Both GABAergic (inhibitory) and excitatory cells contribute to these inputs, but there are contradictory reports regarding the sources of these inputs. We used retrograde tracing techniques in guinea pigs to identify cells in the auditory brainstem that project to the SC. We combined retrograde tracing with immunohistochemistry for glutamic acid decarboxylase (GAD) to identify putative GABAergic cells that participate in this pathway. Following a tracer injection in the SC, the nucleus of the brachium of the inferior colliculus (NBIC) contained the most labeled cells, followed by the inferior colliculus (IC). Smaller populations were observed in the sagulum, paralemniscal area, periolivary nuclei and ventrolateral tegmental nucleus. Overall, only 10% of the retrogradely labeled cells were GAD immunopositive. The presumptive inhibitory cells were observed in the NBIC, IC, superior paraolivary nucleus, sagulum and paralemniscal area. We conclude that the guinea pig SC receives input from a diverse set of auditory brainstem nuclei, some of which provide GABAergic input. These diverse origins of input to the SC likely represent a variety of functions. Inputs from the NBIC and IC likely provide spatial information for guiding orienting behaviors. Inputs from subcollicular nuclei are less likely to provide spatial information; rather, they may provide a shorter route for auditory information to reach the SC, and could generate avoidance or escape responses to an external threat.

Subject

Animals; Attention; Auditory Pathways/*physiology; Avoidance behavior; Brain Mapping; Escape; Female; Fluorescent Dyes/metabolism; Functional Laterality; GABAergic Neurons/*physiology; Glutamate Decarboxylase/*metabolism; Guinea Pigs; Inferior colliculus; Inhibition; Male; Nitric Oxide Synthase/metabolism; Nucleus of the brachium of the inferior colliculus; Orienting; Superior Colliculi/*cytology

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).

Pages

1923–1936

Issue

4

Volume

223

Citation

Mellott Jeffrey G; Beebe Nichole L; Schofield Brett R, “GABAergic and non-GABAergic projections to the superior colliculus from the auditory brainstem.,” NEOMED Bibliography Database, accessed July 24, 2021, https://neomed.omeka.net/items/show/3186.

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