title: Pyramidal cells in primary auditory cortex project to cochlear nucleus in rat.
abstract: Recent work has demonstrated that the auditory cortex in rat sends direct projections to the auditory nuclei of the brainstem, including the cochlear nucleus and superior olive. To determine the cortical origin of the projections to cochlear nucleus, Fast Blue, a retrograde fluorescent tracer, was injected into the cochlear nucleus. Labeled cells in the forebrain were then studied with light microscopy and mapped. The projection was found to originate from large pyramidal neurons in layer V of primary auditory cortex. The projection was predominantly ipsilateral, and no labeled neurons were found in other cortical areas. These data imply that primary auditory cortex exerts influence over ascending auditory information at the earliest stages of the central auditory system.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Weedman
authors.forename: D K
authors.initials: DK
authors.lastname: Ryugo
mesh_terms: D000578:Amidines; D000818:Animals; D001303:Auditory Cortex / Q000166:cytology / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D017626:Cochlear Nucleus / Q000502:physiology*; D008297:Male; D009412:Nerve Fibers / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D016548:Prosencephalon / Q000166:cytology; D017966:Pyramidal Cells / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000578:Amidines; C031455:diamidino compound 253-50