The Functional Anatomy of the Reticular Formation

Book excerpt: The brainstem reticular formation is the archaic core of ascending and descending pathways connecting the brain with spinal cord. After the pioneer description of the activating role of the ascending reticular activating system by Moruzzi and Magoun in 1949, an increasing number of studies have contributed to disclose the multifaceted roles of this brain area. In fact, the brainstem reticular formation sub-serves a variety of brain activities such as the modulation of the sleep-waking cycle, the level of arousal and attention, the drive for novelty seeking behaviors and mood. Meanwhile, descending pathways play a key role in posture modulation, extrapyramidal movements, and autonomic functions such as breathing and blood pressure. Moreover, both descending and ascending fibers of the reticular formation are critical in gating the sensory inputs and play a critical role in pain modulation and gaze control. All these activities are impaired when a damage affects critical nuclei of the reticular formation. Remarkably, in neurodegenerative diseases involving reticular nuclei, the rich collaterals interconnecting reticular isodendritic neurons represent a gateway for disease spreading placing the role of the reticular nuclei as a pivot in a variety of brain disorders. The present Research Topic is an updated collection of recent studies, which contribute to define the systematic anatomy of the reticular formation, its physiological and pharmacological features, as well as its involvement in neurodegenerative disorders and neuroprotection.