Encyclopedia of Child Behavior and Development

2011 Edition
| Editors: Sam Goldstein, Jack A. Naglieri

Reticular Activating System

  • Edalmarys SantosEmail author
  • Chad A. Noggle
Reference work entry
DOI: https://doi.org/10.1007/978-0-387-79061-9_2426



The RAS refers to a network of nerves and connections that originate in the superior portion of the brainstem which together serve the purpose of modulating attention and arousal [3].


The RAS, also known as the reticular formation, refers to a network of nuclei and fibers that extend throughout the central portion of the brainstem from the medulla to the midbrain [1, 2]. While the RAS is described as the primary source/ site of brain activation (e.g. [4]), this is just one portion of the functional role the RAS plays. The superior portion of the RAS, which is based in the upper pons and extends into the midbrain, regulates arousal level and consciousness [1]. In contrast, the inferior portion of the RAS, which lies in the lower pons and medulla, tends to be primarily involved in motor and autonomic function [1].

Due to its direct and indirect connections throughout the system, lesions of the RAS...

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    Kolb, B., & Whishaw, I. Q. (2003). Fundamentals of Human Neuropsychology (5th ed.). New York: Worth Publishers.Google Scholar
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    Loring, D. W. (1999). INS Dictionary of Neuropsychology. New York: Oxford University Press.Google Scholar
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    Zillmer, E. A., & Spiers, M. V. (2001). Principles of Neuropsychology. Belmont, CA: Wadsworth/Thomson Learning.Google Scholar

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  1. 1.Department of PsychologyMiddle Tennessee State UniversityMurfreesboroUSA
  2. 2.Department of PsychiatrySIU School of MedicineSpringfieldUSA