Definition of "mesencephalon" []

• The midbrain. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "It has also been understood for some time that the functions of these and several other primary reflex centers are integrated in the mesencephalon, that is, the grey matter, grouped in several nuclei, which is located below the hemispheres of the cerebrum, in immediate proximity to the hypophysis, which exercises a regulating influence on a great many vegetative functions."
• "For reasons of its own, evolution allowed mammalian energy to hold sway, and the recently developed human midbrain or mesencephalon, which had folded over the old diencephalon, could be accurately labeled a mammal brain."
• "A broad layer of nerve-containing grey matter found bilaterally throughout the mesencephalon, or upper brain stem."