Why there is a pain modulation in the level of spinal cord?

Why there is a pain modulation in the level of spinal cord?

The modulation of pain by electrical brain stimulation results from the activation of descending inhibitory fibers, which modulate (block) the input and output of laminae I, II, V and VII neurons. The route from the PAG to the spinal cord is not direct.

What part of the brain is important for pain modulation?

Descending pain modulation involves multiple brain sites and pathways ranging from the cerebral cortex to caudal medulla. The most well characterized pathway involves a circuitry linking the midbrain periaqueductal gray, rostral ventromedial medulla (RVM) and the spinal cord.

Which brain regions sends projections to the spinal cord for pain modulation?

The dorsal reticular nucleus (DRt) receives nociceptive inputs from spinal projections and communicates with the PAG and RVM as well as the thalamus and amygdala and sends pain modulatory projections to the spinal cord (131–133).

What does the raphe nuclei do in the spinal cord?

Projections from the raphe nuclei also terminate in the dorsal horn of spinal gray matter where they regulate the release of enkephalins, which inhibit pain sensation. The raphe nuclei provide feedback to the suprachiasmatic nuclei (SCN), thus contributing in circadian rhythms in animals.

What is the raphe magnus nucleus?

The nucleus raphe magnus (NRM) is a structure in the rostral ventral medulla that is a major site in the endogenous pain inhibitory system that receives projections from the PAG. The raphe magnus nucleus (RMg) is located in the caudal pons and the most rostral portion of the medulla ( Fig. 12.3 ).

Where do the caudal raphe nuclei project?

Overall, the caudal raphe nuclei, including the nucleus raphe magnus, nucleus raphe pallidus and nucleus raphe obscurus, all project towards the spinal cord and brain stem.

How does the SCN transmit information to the raphe nuclei?

The SCN transmits to the raphe nuclei via the dorsomedial hypothalamic nucleus altering serotonin levels for sleep/wake states. The raphe nuclei will then transmit feedback to the SCN about the animal’s vigilance and levels of alertness.