In 1949 Moruzzi and Magoun first described the activating role of a wide area within the brainstem. They defined some physiological features of what they called the ascending reticular activating system, setting the scene for the discovery of the multifaceted roles of the reticular formation. In particular, beyond the original effects on behavioral arousal, a variety of effects is generated in the brain by the activation of these discrete nuclei population of the brainstem. In this way, physiological conditions such as the sleep-waking cycle, the level of arousal and attention, the drive for novelty seeking behaviors, the mood states and other brain activities were shown to depend on the ascending reticular formation. Meanwhile, it became more and more evident that an equal amount of processes is controlled by its descending pathways. More specifically, the reticular formation plays a key role in the modulation of posture, extrapyramidal movements, cardiovascular activity, breathing and a variety of harmonic variations in the sympathetic and parasympathetic systems which accompanies motor activity. The descending fibers of the reticular formation, as well as the ascending system, are critical in gating the sensory inputs and play a critical role in pain modulation, mainly by acting on the posterior horn of the spinal cord.

All these activities are impaired when a damage affects critical nuclei of the reticular formation. This may occur either suddenly, due to vascular disorders, or progressively, as it happens in neurodegenerative conditions. Interestingly, in this latter case the spreading of neurodegeneration has been attributed to the rich collaterals connecting various reticular nuclei, which are more and more involved in later stages of many neurodegenerative disorders.

During the last decades the anatomical counterparts of the reticular formation have been further investigated, even though a comprehensive description is still missing. Thus, the present research topic is designed to welcome contributions both defining the updated anatomy of the reticular formation and its physiological functions (sleep-wake cycle, EEG synchronization, postural control, etc.) as well as its involvement in a wide array of neuropsychiatric disorders (Parkinson and extrapyramidal disorders, epilepsy, sleep disorders, ADHD, degenerative dementia, neurovascular disorders, etc.).

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