Pain and the Brain: Chronic and Neuropathic Pain Pathways and Treatment Options
- Katya Bownas RN, PMH-BC
- Feb 5
- 3 min read
Chronic pain is a condition that involves dysfunction of the pain pathways leading to pain lasting beyond the typical healing process and can result in long-term disability. It is estimated that approximately 1 in 5 adults in the U.S. suffers from some form of chronic pain, and it is an incredibly difficult condition to treat due to the complex physiology of pain. In recent years, there has been increased effort to understand chronic pain and how to treat it in order to provide better quality of life to those who suffer from the condition. Several structural and functional changes in neurobiology as well as neurotransmitter dysfunction have been implicated in the development of chronic pain - we will review those findings and treatment modalities that may help alleviate this dysfunction in this week’s newsletter.
There are three primary pain classifications: neuropathic, nociceptive, and inflammatory. Today we will be focusing mainly on neuropathic pain, as it is caused by disease or damage to the central and/or peripheral nervous systems that persists after a primary injury or dysfunction. Neuropathic pain is a leading cause of chronic pain, and it is the subject of much of the research into neurobiological factors of chronic pain. Neuropathic pain is associated with conditions such as hyperalgesia (abnormally increased sensitivity to pain) and allodynia (pain response to typically non-painful stimuli). It is difficult to treat, as many patients who experience neuropathic pain will not respond adequately to traditional pain management techniques.
Pain pathways are complex and involve multiple structures in the brain, including the primary and secondary somatosensory cortices, the prefrontal cortex, the anterior cingulate cortex, amygdala, thalamus, hippocampus, and cerebellum. Peripheral injury activates glial cells (cells that support and protect neurons), which release neurotransmitters involved in pain pathways and communicate with neurons to facilitate pain transmission. In some cases, abnormal connections can be made within these pain networks following an injury, causing non-painful stimuli to activate pain receptors in the brain. In the case of chronic pain, things such as neural plasticity and BDNF, as discussed in our previous newsletter, may be harmful rather than helpful when impacting certain pathways, again increasing hypersensitivity to pain.
While studies exploring pain pathways, neurotransmitters, and the role of brain structures in chronic pain prove that it is a neurobiologically-impacted process, it is primarily considered to be a biopsychosocial illness due to its wide-ranging impacts on mental and social as well as physical wellbeing. For this reason, there are many treatments considered to be helpful in treating chronic pain, including a variety of pharmacological interventions as well as therapies such as CBT and traditional physical therapy. As with many complex conditions, a multi-pronged treatment approach has been shown to be the most effective - combining medical and therapeutic techniques to address the wide-ranging impacts of chronic pain.
Transcranial magnetic stimulation (TMS) has proven to be a promising therapeutic option for patients who struggle with chronic pain, and has been shown to have an analgesic effect which can last up to several weeks after the treatment. By impacting areas of the brain known to be involved in pain perception and transmission, cortical stimulation techniques such as TMS can help normalize these pathways. It also seems that TMS impacts both the emotional and physical impacts of pain in these patients - the relief of pain may be due to modulation to the somatosensory cortices and thalamic pathways, while the emotional elements of pain may be alleviated due to TMS’s impact on the limbic system, which plays an integral role in emotional regulation. While it is believed that stimulating the motor cortex is the preferred treatment location for chronic pain, some studies have shown (and we have seen firsthand in our clinic) that a traditional depression or anxiety protocol may also have analgesic benefit for patients with chronic pain.
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