tectum

The tectum (Latin: roof) is a region of the brain, specifically the dorsal part of the mesencephalon (midbrain).It is derived in embryonic development from the alar plate of the neural tube. In adult humans it is present only in the mesencephalon as the inferior and the superior colliculi. The superior colliculus is involved in preliminary visual processing and control of eye movements. In non-mammalian vertebrates it serves as the main visual area of the brain, functionally analogous to the visual areas of the cerebral cortex in mammals.The inferior colliculus is involved in auditory processing. It receives input from various brain stem nuclei and projects to the medial geniculate nucleus of the thalamus, which relays auditory information to the primary auditory cortex.
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Tectum /tec·tum/ a rooflike structure. tectum of mesencephalon , tectum of midbrain the dorsal portion of the midbrain. tec·tum n. pl. [more]Tectum - Community and Resources

N
roof; ceiling; house