Projections from auditory cortex to cochlear nucleus: A comparative analysis of rat and mouse
Article first published online: 20 MAR 2006
Copyright © 2006 Wiley-Liss, Inc.
The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology
Special Issue: Structure and Function in the Auditory System: From Cochlea to Cortex
Volume 288A, Issue 4, pages 397–408, April 2006
How to Cite
Meltzer, N. E. and Ryugo, D. K. (2006), Projections from auditory cortex to cochlear nucleus: A comparative analysis of rat and mouse. Anat. Rec., 288A: 397–408. doi: 10.1002/ar.a.20300
- Issue published online: 23 MAR 2006
- Article first published online: 20 MAR 2006
- Manuscript Received: 29 DEC 2005
- Manuscript Accepted: 29 DEC 2005
- National Institutes of Health. Grant Numbers: RO1 DC04395, T32 DC00027
- cochlear nucleus;
- granule cell
Mammalian hearing is a complex special sense that involves detection, localization, and identification of the auditory stimulus. The cerebral cortex may subserve higher auditory processes by providing direct modulatory cortical projections to the auditory brainstem. To support the hypothesis that corticofugal projections are a conserved feature in the mammalian brain, this article reviews features of the rat corticofugal pathway and presents new data supporting the presence of similar projections in the mouse. The mouse auditory cortex was localized with electrophysiological recording and neuronal tracers were injected into AI. The cochlear nucleus was dissected and examined for terminal fibers by light and electron microscopy. Bouton endings were found bilaterally forming synapses with dendrites of granule cells of the cochlear nucleus. This report provides evidence for direct auditory cortex projections to the cochlear nucleus in the mouse. The distribution of projections to the granule cell domain and the synapses onto granule cell dendrites are consistent with what has been reported for rats and guinea pigs. These findings suggest a general plan for corticofugal modulation of ascending auditory information in mammals. Corticobulbar inputs to the auditory brainstem likely provided a survival advantage by improving sound detection and identification, thus allowing the development of complex social behaviors and the navigation of varied environments. Anat Rec Part A, 2006. © 2006 Wiley-Liss, Inc.