Department of Anatomy, Faculty of Medical and Health Sciences, University of Auckland, PB 92019 Auckland, New Zealand.
J Comp Neurol. 2010 Jun 1;518(11):2149-67. doi: 10.1002/cne.22325.
Sequential to companion articles that report the projections of the cochlear nucleus angularis (NA) and the third-order nucleus laminaris (NL) to the central nucleus of the inferior colliculus (MLd) and to the superior olive (OS) and lateral lemniscal nuclei (LLV, LLI, and LLD) (Krützfeldt et al., J Comp Neurol, this issue), we here describe the projections of the latter group of nuclei using standard tract-tracing methods. OS projects on LLV and both have further ascending projections on LLI, LLD, and MLd. LLV also provides auditory input to the song system, via nucleus uvaeformis, and to the thalamo-telencephalic auditory system, via nucleus ovoidalis (Ov), thus bypassing MLd. The two divisions of LLD (LLDa and LLDp) project across the midline via the commissure of Probst each to innervate the homologous contralateral nucleus and MLd. Both, particularly LLDp, also project on Ov. Injections in LLD and LLV resulted in anterograde labeling of caudal nucleus basorostralis (Bas) in the frontal telencephalon, but retrograde tracing so far suggests that only LLI is a real source of this projection (Wild and Farabaugh [1996] J Comp Neurol 365:306-328). OS and LLV also have descending projections on the ipsilateral NA, NM, and NL, and LLV also projects on OS. The ascending inputs to MLd and more rostral nuclei may contribute importantly to mechanisms of auditory pattern (song) recognition. Consistent with previous studies, some of the descending projections may be inhibitory.
继报道耳蜗核角状部（NA）和第三级核板层状部（NL）投射到下丘中央核（MLd）和上橄榄核（OS）和外侧丘系核（LLV、 LLI 和 LLD）的相关文章之后（Krützfeldt 等人，J Comp Neurol，本期），我们使用标准追踪方法描述了后一组核的投射。OS 投射到 LLV，两者都有进一步的上行投射到 LLI、LLD 和 MLd。LLV 还通过穹窿状核（uveaformis nucleus）向 song 系统提供听觉输入，并通过卵形核（ovoidalis nucleus，Ov）向丘脑-端脑听觉系统提供听觉输入，从而绕过 MLd。LLD 的两个分支（LLDa 和 LLDp）通过 Probst 联合中线投射，各自投射到同侧的核和 MLd。两者，特别是 LLDp，也投射到 Ov。LLD 和 LLV 的注射导致额端脑腹侧的基底前脑核（basorostralis nucleus，Bas）的顺行标记，但逆行追踪目前表明，只有 LLI 是这个投射的真正来源（Wild 和 Farabaugh [1996] J Comp Neurol 365:306-328）。OS 和 LLV 也对同侧的 NA、NM 和 NL 有下行投射，LLV 也对 OS 有投射。MLd 和更靠前的核的上行输入可能对听觉模式（song）识别的机制有重要贡献。与先前的研究一致，一些下行投射可能具有抑制作用。
