posterior quadrigeminal body -->
inferior colliculus
The ovoid, paired, inferior eminence of the laminae of mesencephalic tectum; it receives the lateral lemniscus and projects by way of the brachium of inferior colliculus to the medial geniculate body of the thalamus, and is thus an essential way-station in the central auditory pathway.
Synonym: colliculus inferior, corpus quadrigeminum posterius, inferior nasal colliculus, posterior quadrigeminal body.
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Structure of the Corpora Quadrigemina.—The inferior colliculus (colliculus inferior; inferior quadrigeminal body; postgemina) consists of a compact nucleus of gray substance containing large and small multipolar nerve cells, and more or less completely surrounded by white fibers derived from the lateral lemniscus. Most of these fibers end in the gray nucleus of the same side, but some cross the middle line and end in that of the opposite side. From the cells of the gray nucleus, fibers are prolonged through the inferior brachium into the tegmentum of the cerebral peduncle, and are carried to the thalamus and the cortex of the temporal lobe; other fibers cross the middle line and end in the opposite colliculus.
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