reticular formation

noun

: a mass of nerve cells and fibers situated primarily in the brain stem that plays an important role in controlling autonomic functions (such as respiration), reflexive movement, posture and balance, and consciousness and the sleep-wake cycle

Examples of reticular formation in a Sentence

Recent Examples on the Web
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The neural circuitry involved in a hiccup episode includes the vagus nerve, the phrenic nerve, the medulla oblongata and the hypothalamic reticular formation. Scott Travers, Forbes.com, 22 Apr. 2026

Word History

First Known Use

1887, in the meaning defined above

Time Traveler
The first known use of reticular formation was in 1887

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Cite this Entry

“Reticular formation.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/reticular%20formation. Accessed 20 May. 2026.

Medical Definition

reticular formation

noun
: a mass of nerve cells and fibers situated primarily in the brain stem and functioning upon stimulation especially in arousal of the organism

called also reticular substance

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