Copyright © American Speech-Language-Hearing Association From: Cross-Modal Interactions of Auditory and Somatic Inputs in the Brainstem and Midbrain and Their Imbalance in Tinnitus and Deafness Am J Audiol. 2008;17(2):S193-S209. doi:10.1044/1059-0889(2008/07-0045) Legend: Spinal trigeminal nucleus, dorsal column, and lateral reticular formation project to the cochlear nucleus (CN). (A)–(G) Retrograde labeling in the brainstem after an injection of biotinylated dextran amine into the CN. (A) Photomicrograph of the injection site. The injection site is virtually restricted to granule cell domain of the PVCN. (B)–(D) Drawings of 1-mm transverse sections across the medulla. Each dot represents one labeled neuron. The labeled neurons are located primarily in the ipsilateral Sp5I and Sp5C. Very few labeled cells, if any, are located in the subnucleus gelatinosus (D). Labeled neurons are also found in the medullar reticular formation (RVL and LPGi; C), inferior olive (IO; C), and dorsal column nuclei (Gr and Cu; D). Projection neurons in Sp5 have either polygonal or elongated somata (E). Projection neurons in dorsal column nuclei and reticular formation are multipolar (F and G). (H) Terminal labeling in the CN after placement of an anterograde tracer into Sp5I. Most Sp5 fibers enter the CN via the DAS/IAS and terminate primarily in the granule cell domain (gray-shaded) but also in deep DCN. Each dot represents one to three labeled terminal endings. Scale bars = 25 μm (E–G). DAS = dorsal acoustic striae; GCD = granule cell domain; IAS = intermediate acoustic striae; IO = inferior olive; LPGi = lateral paragigantocellular reticular nucleus; PVCN = posteroventral cochlear nucleus; RVL = rostral ventrolateral reticular formation. (Adapted with permission from Shore & Zhou, 2006.) Date of download: 12/24/2017 Copyright © American Speech-Language-Hearing Association