Reticular formation : a network system of brain

The term "reticular formation" was coined in the late 19th century, coinciding with Ramon y Cajal's "neuron doctrine".1 Reticulum means a "netlike structure", which is what the reticular formation appears to be at first glance. It has been described as being either too complex to study or an undifferentiated part of the brain with no organization at all. This chaotic, loose and intricate form of organization is what has turned off many researchers from looking farther into this mysterious area of the brain which seems to be at the crux of our basic neurological and behavioural functions.2 Reticular formation is a diffuse, interconnected network of neurons with complex dendritic and axonal processes and occupies the core of the brainstem, from the lower border of medulla (myelencephalon) to upper border of midbrain (mesencephalon). It receives collaterals from multiple somatic sensory ascending pathways, trigeminal, olfactory, auditory & visual systems and plays a role in consciousness, alertness, attention, behaviour, sleep & wakefulness, muscle tone, body posture and reflex mechanism.3 This network has two components - Ascending and Descending. Reticular Activating System (RAS) is the name given to its ascending connections to cerebral cortex through thalamus which is concerned with conciousness, arousal, attention and motivation in mammals and the other component that is descending which affect autonomic nervous system and motor system.--p. 143