Inhibitory NPY Neurons Provide a Large and Heterotopic Commissural Projection in the Inferior Colliculus.

Autor:	Anair JD; Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States., Silveira MA; Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States., Mirjalili P; Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States., Beebe NL; Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States., Schofield BR; Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States., Roberts MT; Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States.
Jazyk:	angličtina
Zdroj:	Frontiers in neural circuits [Front Neural Circuits] 2022 May 26; Vol. 16, pp. 871924. Date of Electronic Publication: 2022 May 26 (Print Publication: 2022).
DOI:	10.3389/fncir.2022.871924
Abstrakt:	Located in the midbrain, the inferior colliculus (IC) plays an essential role in many auditory computations, including speech processing and sound localization. The right and left sides of the IC are interconnected by a dense fiber tract, the commissure of the IC (CoIC), that provides each IC with one of its largest sources of input (i.e., the contralateral IC). Despite its prominence, the CoIC remains poorly understood. Previous studies using anterograde and retrograde tract-tracing showed that IC commissural projections are predominately homotopic and tonotopic, targeting mirror-image locations in the same frequency region in the contralateral IC. However, it is unknown whether specific classes of neurons, particularly inhibitory neurons which constitute ~10%-40% of the commissural projection, follow this pattern. We, therefore, examined the commissural projections of Neuropeptide Y (NPY) neurons, the first molecularly identifiable class of GABAergic neurons in the IC. Using retrograde tracing with Retrobeads (RB) in NPY-hrGFP mice of both sexes, we found that NPY neurons comprise ~11% of the commissural projection. Moreover, focal injections of Retrobeads showed that NPY neurons in the central nucleus of the IC exhibit a more divergent and heterotopic commissural projection pattern than non-NPY neurons. Thus, commissural NPY neurons are positioned to provide lateral inhibition to the contralateral IC. Through this circuit, sounds that drive activity in limited regions on one side of the IC likely suppress activity across a broader region in the contralateral IC. Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. (Copyright © 2022 Anair, Silveira, Mirjalili, Beebe, Schofield and Roberts.)
Databáze:	MEDLINE
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