The reticular formation of the brain stem is a reticular formation, a set of nerve structures located in the central departments (optic tubercles , middle and medulla oblongata). The neurons that make it up differ in size, axon length, and structure. Their dense interweaving is noted.
Reticular formation functions
The formation is associated with the cerebellum, spinal cord, cortex in the cerebral hemispheres, and the limbic (providing the most important reactions in the body) system. In the field of reticular formation, ascending (afferent) and descending (efferent) impulses interact. Pulses can also circulate through closed neural circuits. In this case, a constant stimulation of neurons in the reticular formation at a certain level is ensured. As a result, a certain readiness for the activity of different departments of the central nervous system is ensured. The degree of excitation of the mesh formation is regulated by the cortex of the hemispheres.
The reticular formation includes areas that can have a facilitating or inhibitory effect on spinal motor reactions.
For the first time, a relationship between spinal reflexes and irritation of various sections of the reticular formation was revealed by I.M.Sechenov. Subsequently, the American neurophysiologist Magone, with the assistance of employees, clearly illustrated Sechenov's observation.
So, with electric stimulation of the medial region in anesthetized monkeys and cats, there was a complete cessation of movements, both reflex and stimulated motor zones of the cerebral cortex. Moreover, all the inhibitory phenomena that provokes the reticular formation, subjected to irritation, are bilateral in nature.
When exposed to the lateral zone of the reticular formation along the periphery, which has an inhibitory effect on the area, a facilitating effect on the spinal motor activity is revealed.
The reticular formation is capable of affecting various spinal formations.
It should be noted that the net formation zone, which has a facilitating effect on motor activity, spreads anteriorly. Thus, it covers not only the region of the medulla oblongata, but also the midbrain and the pons.
Net formation can affect muscle tone. This provision was discovered by R. Granite. The Swedish neurophysiologist has shown that the reticular formation affects the activity of gamma-motor neurons. Their axons pass through the so-called “intrafusar” muscle fibers and play an important role in the regulation of phase movements and body postures.
Different areas of the reticular formation are capable of exerting exciting effects of a generalized nature on the cerebral cortex, involving all its areas.
Maintaining the activity of net formation and sensitivity to various chemical elements circulating in the blood is carried out by means of humoral factors (carbon dioxide, catecholamines, etc.). This, in turn, contributes to the inclusion of the reticular formation in the regulation of individual autonomic functions.
It should be noted that the study of the relationship of reticular formation with other subcortical structures, its properties, made it possible to clarify the mechanisms of the neurophysiological nature of individual states (pain, wakefulness, sleep, active attention, emotional and motivational states, and others). The use of drugs in research allows you to identify methods of treatment of certain pathologies of the central nervous system, determine a new approach to certain medical problems.