Pain and the Brain

Pain and the Brain

Brain imaging studies show that pain can activate a wide network of brain regions. These brain regions may reflect activation of different networks all relating to separate aspects and consequences of pain. This could include not only the sensory processing of pain, but also attention-orientation, threat assessment and reaction to the painful stimuli.  Additionally, acute versus chronic pain affect neural circuits in different ways and therefore result in distinct symptoms.  When someone suffers from acute pain (such as hitting your finger with a hammer), the pain in short-lived and very responsive to common pain medications. However, someone suffering from neuropathic pain, which is defined as chronic pain that is caused by a damaged nervous system and nerve fibers, will experience persistent pain symptoms that are difficult to diagnose and do not respond to commonly used pain medications.

Pain and Neural Networks

Neurological information is carried through the brain by neural circuits. Defining these circuits with brain imaging in humans and animals lets us further understand how pain processing works.  Much of the information about pain neural circuits has come from marine and primate studies. However, with non-invasive brain imaging techniques, we have been able to define with great clarity the neurological systems involved in pain processing in healthy human participants. This has allowed us to create models of both acute and chronic pain circuits. The definition of these pain circuits allows us to visualize specific pain processing systems and better understand what is occurring in the brains of pain patients.

Pain and the Disease State

Understanding the dynamic neurological changes caused by a chronic disease is a big challenge. These changes in the brain involve the sensory experience (e.g., the development of a burning pain), along with the emotional experience (e.g., unpleasantness, depression, and suffering). With brain imaging techniques, we can both identify pain-activated areas in the human brain and follow the progression of the disease over time. From a clinical standpoint, information on disease progression is key. This data can improve pain diagnoses and create more targeted treatment strategies for chronic pain patients.  It can also allow for us to predict the development of chronic pain before it even happens – such as chronic pain following a surgery – and preemptively apply the appropriate treatment methods.

Pain and Biomarkers

Biomarkers for pain are needed in a number of clinical domains. They are necessary in properly defining pain in humans and animals. They are also key in creating models of altered function in chronic pain conditions. While researchers are starting to understand altered function in neurons, the specificities of these neural changes in chronic pain conditions are still unknown. Such neural changes are essential in understanding the underlying mechanisms of pain processing and how they influences cellular, molecular and physiological changes in chronic pain patients.  Defined pain biomarkers can be applied to clinical practices and aid in the development of more specified pain medications.

Pain and Analgesics

Analgesia is defined as the inability to feel pain. Analgesics are the drugs used to reach the analgesic state and provide pain relief to patients. Currently, we do not know exactly what is happening to a human’s nervous system when they are experiencing analgesia. However, brain imaging techniques can help us answer this question.  Analysis of brain images can allow for us to understand the relationship between nervous system circuits and analgesics. This can significantly contribute to drug development and provide further insight into how analgesic drugs affect specific nervous system circuits.  Additionally, brain imaging studies can help determine which analgesics are most effective for specific pain conditions and thus enhance future pain therapies.