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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 illustrationExamples 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
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
Dictionary Entries Near midbrain
Cite this Entry
“Midbrain.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/midbrain. Accessed 3 Jun. 2024.
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
More from Merriam-Webster on midbrain
Britannica.com: Encyclopedia article about midbrain
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