China
Africa
Explore chapters and articles related to this topic
Spinal Cord and Reflexes
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
Another ascending tract is the spinotectal tract, or the spinomesencephalic tract, that originates in the anterolateral parts of the spinal cord and terminates in the inferior and superior colliculi (Section 12.2.4.2). It is believed to be involved in inhibiting or controlling pain sensations. The spinothalamic tract, the spinoreticular tract, and the spinotectal tract constitute what is designated as the anterolateral system that carries information from the skin to the thalamus.
Central Modulation of Pain
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
A third prominent ascending pathway that is involved in pain transmission is the spinomesencephalic tract (SMT). It originates in laminae I and IV–VI of the spinal dorsal horn, decussates and travels in the VLF to the mesencephalon (midbrain). These cells project to several nuclei in the midbrain, including the PAG, cuneiform nucleus, red nucleus, superior colliculus, pretectal nuclei, and Edinger–Westphal nucleus. The spinomesencephalic tract is somatotopically organized, with projections from caudal body regions terminating in the caudal midbrain and projections from rostral body regions terminating in more rostral regions of the midbrain. The sites of termination of this tract suggest that it may be involved in affective motor, autonomic, and anti-nociceptive responses to noxious input, such as orienting, quiescence, defence and confrontation.
Anatomy and Physiology of Pain: The Central and Peripheral Nervous Systems
Published in Gary W. Jay, Chronic Pain, 2007
The spinoreticular tract and the spinomesencephalic tract are also found in the anterolateral quadrant of the spinal cord, along with the STT. Both tracts are involved with the autonomic reflex responses to pain as well as the behavioral and motivational aspects of pain.
Pro-nociceptive pain modulation profile in patients with acute and chronic shoulder pain: a hypothesis-generating topical review
Published in Physical Therapy Reviews, 2021
Rani Othman, Nicola Swain, Steve Tumilty, Prasath Jayakaran, Ramakrishnan Mani
Descending control mechanisms that influence the neuronal activity of the dorsal horn arises from several supra-spinal sites [61]. In particular, periaqueductal grey matter and nuclei of the rostral ventral medulla are the key midbrain structures that are interconnected with the higher brain centres and limbic areas, and they receive direct inputs from the spinomesencephalic tract [52, 59, 61, 62]. The periaqueductal grey matter project to rostral ventral medulla, which projects onto the dorsal horn of the spinal cord [61]. The descending facilitatory or inhibitory control mechanisms of the periaqueductal grey matter and rostral ventral medulla are mainly coordinated by the activities of the higher brain centres [52, 62]. One aspect of descending control is associated with diffuse noxious inhibitory controls [59, 61]. Diffuse noxious inhibitory controls is a phenomenon that refers to a reduction in the nociceptive inputs produced by supra-spinally generated inhibition of wide dynamic range neurons and nociceptive-specific neurons in the dorsal horn of the spinal cord [63–65]. On the contrary, it is also evident that periaqueductal grey matter and rostral ventral medulla projections can facilitate nociceptive inputs at the dorsal horn of the spinal cord [52, 61]. Evidence suggests that descending facilitation of spinal nociception is a major contributor to the development of central sensitization, a key contributing mechanism linked to the chronic pain experience [52, 61].
Pain management in multiple myeloma
Published in Expert Review of Quality of Life in Cancer Care, 2018
Fibers belonging to the spinomesencephalic tract play an important role in pain control. The complexity of analgesia system is the reason why pain tolerance threshold is extremely variable [14]. Cancer pain should be considered a special category of pain with its peculiarities and incompletely understood etiology [15]. Pathophysiology of cancer pain involves both inflammatory and neuropathic mechanisms [16]. Malignant cells secrete a lot of algogenic mediators responsible for perineural invasion, together with microenvironment inflammation culminating to tissues damage and hyperalgesia [17]. These substances influence responsiveness to opioids by reducing expression of μ opioid receptors on dorsal root ganglia. Furthermore, the activation of N-methyl-D-aspartate (NMDA) receptors by algogenic mediators may reduce response to morphine [18,19].
Cannabinoid Receptor Type 1 and Its Role as an Analgesic: An Opioid Alternative?
Published in Journal of Dual Diagnosis, 2020
Amber L. Milligan, Thomas A. Szabo-Pardi, Michael D. Burton
The central nervous system tract postulated to be responsible for the affective components of pain is the spinomesencephalic tract, which connects spinal neurons of the dorsal horn at laminae I and V to the PAG. The PAG then projects to both the amygdala (after synapsing to the parabrachial nucleus) and the RVM. These regions process the painful stimuli, alerting of potentially harmful scenarios but also pain compensation and suppression, likely via projections from the RVM back to nociceptive fibers in the dorsal horn. There are high concentrations of CB1R in both of these nuclei, suggesting a potential role of cannabinoid modulation of this system.