midbrain

noun

mid·​brain ˈmid-ˌbrān 

: the middle of the three primary divisions of the developing vertebrate brain or the corresponding part of the adult brain between the forebrain and hindbrain that includes the tectum, tegmentum, and substantia nigra

called also mesencephalon

see brain illustration

Examples of midbrain in a Sentence

Recent Examples on the Web

Each has a spinal cord, which controls reflex behaviors; a brain stem, which controls autonomic behaviors such as breathing and heart rate; and a midbrain, which controls emotions and basic behaviors. —IEEE Spectrum, 2 June 2017

And because the growth was in his midbrain stem, there was no way to remove the tumor, said his mom, Huifan Chan. —Jason Mastrodonato, The Mercury News, 10 Aug. 2024

Dopamine neurons receive inputs from a large swath of the brain: your sensory, motor, and limbic systems all send information to the midbrain. —Celia Ford, Vox, 22 May 2024

Parallel research into Parkinson’s disease led to a breakthrough: Neurologists realized the disease’s characteristic tremors and muscle stiffness were tied to the loss of dopamine-producing cells in a part of the midbrain that controls movement. —Celia Ford, Vox, 22 May 2024

Word History

First Known Use

1864, in the meaning defined above

Kids Definition

midbrain

noun

mid·​brain ˈmid-ˌbrān 

: the middle division of the three primary divisions of the developing brain of a vertebrate animal or the parts of the adult brain that develop from it that contains the optic lobes and is situated between the forebrain and the hindbrain

Medical Definition

midbrain

noun

mid·​brain ˈmid-ˌbrān 

: the middle division of the three primary divisions of the developing vertebrate brain or the corresponding part of the adult brain that includes a ventral part containing the cerebral peduncles and a dorsal tectum containing the corpora quadrigemina and that surrounds the aqueduct of Sylvius connecting the third and fourth ventricles

called also mesencephalon