midbrain

noun

mid·​brain ˈmid-ˌbrān How to pronounce midbrain (audio)
: 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 There are three basic units of an vertebrate brain–the midbrain, forebrain, and the hindbrain. Laura Baisas, Popular Science, 22 Feb. 2024 Deep within the brain—in the areas of the hypothalamus, midbrain and hindbrain—the range of cell types is much greater than in the evolutionarily younger cerebral cortex. Karin Schlott, Scientific American, 18 Dec. 2023 In a study first published in the July edition of the journal Annals of Neurology, scientists used these synthetic mini brains to mimic the activity of a regular, human midbrain, which is critical to muscle movement and visual and auditory processing affected by Parkinson's disease. Sy Mukherjee, Fortune, 8 Sep. 2021 Now the midbrain becomes active, orchestrating a powerful, quick response: fight or flight. Carl Zimmer, Discover Magazine, 19 Aug. 2014 Otsuna explains that this dorsal view of a 5-day-old zebrafish head shows tissue stained in blue, including the eyes, olfactory pits, forebrain, and midbrain. Discover Magazine, 12 Oct. 2010 The amygdala, in the midbrain, is important for processing emotions. Anna Tan, Forbes, 14 Feb. 2023 In swarming locusts, the midbrain grew more than the optic lobes. Andrew Moseman, Discover Magazine, 26 May 2010 For a looming stimulus, a nucleus of nerve cells in the midbrain called the optic tectum has served as the prime threat detector since the early days of vertebrate evolution. Tom Siegfried, Smithsonian Magazine, 4 Jan. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'midbrain.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1864, in the meaning defined above

Time Traveler
The first known use of midbrain was in 1864

Dictionary Entries Near midbrain

Cite this Entry

“Midbrain.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/midbrain. Accessed 26 Feb. 2024.

Kids Definition

midbrain

noun
mid·​brain ˈmid-ˌbrān How to pronounce midbrain (audio)
: 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 How to pronounce midbrain (audio)
: 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

More from Merriam-Webster on midbrain

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