TOPOGRAPHY OF PROJECTIONS FROM THE AUDITORY-CORTEX TO THE INFERIOR COLLICULUS IN THE RAT
TOPOGRAPHY OF PROJECTIONS FROM THE AUDITORY-CORTEX TO THE INFERIOR COLLICULUS IN THE RAT
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DOI：
10.1002/cne.903040108
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发表时间：
1991-02-01
影响因子：
2.5
通讯作者：
OSTWALD, J
中科院分区：
文献类型：
--
作者：
HERBERT, H;ASCHOFF, A;OSTWALD, J
我们利用麦芽凝集素-辣根过氧化物酶的逆行和顺行运输方法，观察了大鼠下丘(IC)从听觉和邻近皮质区域向下丘(IC)下行投射的组织。根据得到的皮层逆行标记神经元的模式，定义了不同的皮质区域和区域。在此基础上，分别勾画出初级听区(TE1)的腹尾部(TE2)和腹侧部(TE3)两个次生区。初级听区被细分为后听区(Te1.p)、内听区(Te1.m)和前听区(Tel.a)。此外，我们还勾画了一个位于听区顶部的区域，该区域包括一部分次级体感皮质和一条环绕听区背侧的背侧带。结果表明：1)中脑(DC2，DC3)背侧皮质的第2层和第3层分别由初级听域(Te1.p和Te1.a投射到DC2，Te1.m投射到DC2，Te1.m投射到DC3)支配，Te1.m内的细胞按从尾端到喙的顺序排列，投射到DC3的相应部位，从背外侧到腹内侧；2)IC的纤维细胞被膜，包括IC的背侧和外皮质的第1层，接受来自次级听区TE2的输入；3)IC的外皮质的第2层和第3层只接受初级和次级听觉皮质的弱神经支配；4)丘间区接受次级听区Te3、次级体感皮质和背带的主要输入；5)IC的中央核完全不接受颞叶皮质的输入。这些通路可能调节下丘不同功能回路的听觉处理。
We examined the organization of descending projections from auditory and adjacent cortical areas to the inferior colliculus (IC) in the rat by using the retrograde and anterograde transport of wheat germ agglutinin-horseradish peroxidase.Small tracer injections were placed into cytologically defined subnuclei of the IC. On the basis of the resulting pattern of retrogradely labeled neurons in the cortex, different cortical areas and fields were defined. Two secondary areas located ventrocaudally (Te2) and ventrally (Te3) to the primary auditory area (Te1) were delineated. The primary auditory area was subdivided into a posterior (Te1.p), a medial (Te1.m), and an anterior (Tel.a) auditory field. In addition, we outlined an area located rostrally to the auditory areas comprising a part of the secondary somatosensory cortex, as well as a dorsal belt surrounding dorsally the auditory areas.The following basic patterns of corticocollicular projections are revealed: 1) layers 2 and 3 of the dorsal cortex of the IC (DC2, DC3) are differentially innervated by the primary auditory fields (Te1.p and Te1.a project bilaterally to DC2, while Te1.m projects bilaterally and in topographical order to DC3); cells in Te1.m, arranged in caudal to rostral sequence, project to corresponding loci in DC3 arranged from dorsolateral to ventromedial; 2) the fibrocellular capsule of the IC, comprising layer 1 of the dorsal and external cortex of the IC, receives input from the secondary auditory area Te2; 3) layers 2 and 3 of the external cortex of the IC are only weakly innevated by the primary and secondary auditory cortex; 4) the intercollicular zone receives its major input from the secondary auditory area Te3, the secondary somatosensory cortex, and the dorsal belt; and 5) finally, the central nucleus of the IC receives no input from the temporal cortex at all.Our results demonstrate that the corticocollicular projections are highly organized. These pathways may modulate auditory processing in different functional circuits of the inferior colliculus.