n. A part of the brain located rostral to the pons and caudal to the thalamus and the basal ganglia, composed of the tectum (dorsal portion) and the tegmentum (ventral portion).
the GNU version of the Collaborative International Dictionary of English
n. The middle segment of the brain; the mesencephalon. See brain.
The Century Dictionary and Cyclopedia
n. The mesencephalon. See cuts under encephalon.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. the middle portion of the brain
Word Usage
"Strong responses to near-wins were detected in the midbrain, which is packed with dopamine-releasing brain cells and is an area associated with addiction."