The understanding of pain and its underlying mechanisms remains a highly active research area. The trigeminal nerve system – the face’s sensation nerve – is one of the most complex cranial nerve systems of the human body. Research on it has vastly grown in recent years, but thorough reviews on the normal physiology of the trigeminal sensory system are lacking. Researchers from Leuven University present a recent overview of the current and evolving landscape.
Scientists are starting to understand how peripheral pain perception works (pain coming from the body’s trunk and extremities) and how these pain signals are being interpreted or sometimes misinterpreted at the level of our brain.
Pain signals that come from the face or intra-orally are conveyed through an anatomic and physiological entirely different system: the trigeminal sensory system. The trigeminal nerve functions both as the chief nerve of sensation for the face and as the motor nerve controlling the chewing muscles. This nerve and its branches are indispensable for sensitivity, speaking, eating, kissing and tasting.
Problems with the sensory part of the trigeminal nerve may result in pain or loss of sensation in the face. As these vital functions make up who we are, the trigeminal system is very well represented in the brain cortex.
This broad representation, its extensive and specialised innervation and multiple cross connections makes it one of the most complex cranial nerves of the human body.
Before understanding how this system can malfunction, we must understand the normal, non-pathological, functioning of this specialised sensory cascade.
In their study published in Reviews in the Neurosciences, researchers from the Catholic University of Leuven in Belgium give an overview of the most recent advances in trigeminal functioning at the level of embryology, anatomy and physiology.
Moreover, they briefly describe latest discoveries on how pain is perceived through the trigeminal sensory system. To take you on this path, the authors start at the different sensors of the trigeminal system lying in the skin and oral mucosa. They then move along its trajectory towards the trigeminal ganglion, being the first crossroad further towards the trigeminal nuclei at the spine from where it projects to the thalamus and cerebral cortex.
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