Transmission of Pain Signals by the Brain at the Spinal Level

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Transmission of Pain Signals by the Brain at the Spinal Level Pain has been defined by Coates & Hindle as an unpleasant emotional and sensory experience which signals a potential or actual damage to tissues (2011, p. 213). Pain is a common human experience and can emanate from injury and illness. There are two main types of pain; acute pain is short-lived, lasting for minutes or several days and its onset often takes place rapidly. It results from the activation of pain nerve endings or nociceptors either by internal or external pain stimuli. On the other hand chronic pain is continuous and sometimes recurrent and can last for weeks, months or even years. Chronic pain is usually not located at or related to the tissue undergoing trauma (Draper & Knight, 2007, p. 104). Various theories have been proposed to explain the mechanism underlying the transmission and perception of pain. These include the specificity theory which maintains that specific fibers and pain receptors are activated by injury after which the pain signals are projected via the spinal pathway to an area in the brain that interprets the pain. In this regard, the specificity theory virtually equates the peripheral injury with the psychological experience caused by the pain (Anderson, 2004, p. 355). However, this theory has been found to harbor several limitations as research about pain has intensified with time. In light of this, the gate theory that was proposed by Melzack and Wall has had a major contribution to the understanding of pain transmission and perception (Pain Game Part 2, 2011). Research has demonstrated that pain is affected by psychological and physiological factors which helps to explain the mechanism underlying inhibition and/or facilitaion of pai... ... middle of paper ... ...t has been noted that the gate control theory proposed by Melzack and Wall in 1965 formed the foundation of understanding the process of pain signal transmission. The dorsal horn of the spinal cord is the region of the CNS that controls the passage of pain signals by means of opening and/or closing the gate. Pain can only be perceived if reaches the brain. Events that cause excitation such pain signals and the release of excitatory or facilitatory chemicals cause the gate to open whereas inhibitory events such as competing nerve impulses caused by rubbing trigger closure of the gate. The gate can also be closed due to descending inhibition enhanced by relaxation or the use of pain-relieving medication such as morphine. The brain stem is responsible for controlling the transmission of pain signals via the ascending and descending pain pathways.
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