Modeling Pain Circuits: How Imaging May Modify Perception
Section snippets
What is pain?
During World War II, Henry Beecher observed that only one out of three soldiers wounded in battle complained of sufficient pain to receive morphine [9]. Most soldiers denied having any pain or claimed so little as to not require pain relief. A 1978 study of Israeli soldiers who had traumatic amputations after the Yom Kippur War replicated Beecher's report [10], and a 1982 study demonstrated similar findings in a civilian setting [11]. Approximately 40% of patients presenting to the emergency
Functional imaging during noxious stimulation
Many studies have examined the brain response to acute pain in healthy subjects using positron emission tomography, functional MRI, magnetoencephalography, and electroencephalography and are reviewed extensively elsewhere [20], [21], [22]. Similar techniques also have been extended to the study of chronic pain disorders, such as irritable bowel syndrome, fibromyalgia, atypical facial pain, and nonspecific low back pain. The persistence, intractability, and apparent absence of peripheral disease
Understanding functional pain
Overall, patients who have ongoing functional pain do not seem to activate areas of the brain that are not activated in normal control subjects. This suggests that if the brain is the source of functional pain, then it occurs as a consequence of an alteration in the intensity of activation within the usual pain neuromatrix rather than the consequence of a “functional pain center.” Although there are examples of brain activation being augmented in patients who have some functional pain disorders
Two pains
What the argument between Wall and Craig and the enduring presence of Cartesian dualism suggest is that there are two pains. It is obvious that pain is something brought about by external events. Patients in pain may be engulfed by their experience but they remain more than their pain. The pain is an internal feature of an external problem and is in the body not the mind. Alternatively, pain can be something that very much involves persons: their intentions, thoughts, likes, and hates and their
The application of social neuroscience to pain
Social neuroscience seeks to describe cognitions that are applied to social stimuli, cognitions that are specific to social stimuli, and the neural mechanisms that underlie those socially directed cognitions [55]. The social brain must, at least, read the mental state of other significant persons and, in so doing, alter future behavior and inner experience toward appropriate actions. What persons might feel, therefore, is dependent not only on events happening directly to them but also on their
Summary
Functional imaging with noxious stimuli has revealed that many regions of the brain are involved during the experience of pain, including the classical sensory pathways to S1 and S2 and pathways to areas associated with affect, such as the ACC, and cognition, such as the prefrontal cortex. In general, these findings have been integrated with a definition of pain that emphasizes the multidimensional nature of pain and with the biopsychosocial model that emphasizes the interplay of organic and
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