Pain pathway: an overview

Authors: Rachel Ann Joseph, Vijaylaxmi Ann Madalli, Kirty R Nandimath

DOI: 10.18231/j.ijohd.12772.1758537791

Keywords: Pain pathways, nociception, spinothalamic tract, descending inhibition, chronic pain, pain modulation, pain perception

Abstract: Pain is a complex sensory and emotional experience that plays a crucial protective role by signalling potential injury or harm. Derived from the Latin poena (punishment) and Greek poine (price paid, penalty), pain involves both sensory and emotional components, which are influenced by psychological factors such as fear, anxiety, and past experiences. This paper provides an overview of the anatomical and physiological mechanisms underlying pain processing, with a focus on the ascending and descending pain pathways. The ascending pathways, including the spinothalamic tract (STT) and trigeminal pathway, transmit nociceptive signals from peripheral tissues to the brain, where pain is perceived and localized. The descending pathways, originating from brain regions like the periaqueductal gray (PAG) and nucleus raphe magnus (NRM), modulate pain by inhibiting or facilitating nociceptive input at the spinal cord level. Key mechanisms such as Diffuse Noxious Inhibitory Control (DNIC), endogenous anti-nociception, and stress-induced analgesia (SIA) contribute to pain modulation. Furthermore, dysfunctions in these pathways can lead to chronic pain conditions, often characterized by central sensitization and failure of inhibitory control. Understanding these pain mechanisms, both in terms of physiology and psychological factors, is essential for developing effective pain management strategies and improving patient care. This review underscores the need for a holistic approach to pain, considering both the neurobiological and psychosocial aspects to enhance therapeutic outcomes.