Tag Archives: neural imaging

Loving the Pain

The article “What Imaging Teaches Us About Pain” by Elizabeth Church was very informative to me.

First, it describes pain.  As much as we may hate pain and avoid it at all costs, pain is actually a good thing.  It is “an alarm system that protects individual organisms from potential or actual physical threats.”  It is a complex sensory and emotional experience that warns us if there is potential or actual damage to us, or if something is just wrong.  One type of pain described is nociception, which is the activation of nerve endings that respond differently to tissue-damaging stimuli.  The activation of these nerve endings may or may not be perceived as pain.  Pain is actually a very subjective experience.  Our experience of pain is completely dependent on our interpretation of it.  It is colored by our belief about the pain, our expectations, and our mood.  Our perceptions may or may not match with the nociceptive input.  Basically, our pain is fueled by our mind.

However, biology comes into play as well with genetic factors that influence the experience of pain.  There are even specific neurotransmitters in the forebrain that are involved with the reduction of the intensity of the pain experience.  The pain matrix is a large network that becomes activated during the nociceptive processing.  What is interesting is that individuals have different portions of the central nervous system that play different roles in pain processing in this pain network.  To get into some hard biology, there are common regions of the brain that are involved in pain processing.  These include the sensory-discriminatory areas of the central nervous system, which are the parietal lobe of the cerebral cortex, including the primary somatosensory (sense of touch), secondary somatosensory, thalamus (relays sensory information), and posterior portions of the insula (linked to regulation of emotion and homeostasis, perception, motor control, self awareness, and cognitive functioning).  Also, areas of the brain associated with cognition and affect (anterior portions of the insula, the anterior cingulated cortex, and the prefrontal cortex) help regulate pain.

As far as I can see, a lot of pain processing is located in the brain.  This means that neural imaging can be used to show pain intensity in an objective manner versus the normal participant evaluations that are subjective to their experiences.  While an fMRI would be nice to use to an imaging tool, it seems a little bulky for my experimental design, so I think DOT diffuse optical tomography might work better.  The participant wears a helmet with lights sources and detectors that absorb and respond to light, and by some scientific magic  this detects changes in cerebral blood flow, which show areas of brain activity.  I think that this method will be a nice addition to the subjective VAS scale I intend to include in my experimental design.

Another interesting point of this article was that the best alternative (non-medication) treatment of pain is meditation.  Meditation overall can improve attention, relieve anxiety and depression, reduce anger and cortisol levels, and strengthen immune responses and gray matter density.  While the benefits of meditation are numerous, I could never get past the boring part myself.  Also, meditators had a lower pain sensitivity than control subjects.  When faced with heat, it took higher temperatures before they felt any pain!  The strength of this pain regulation depends on the amount of meditation experience, and unfortunately 2000 plus hours are needed for significant control of pain.  Short term meditation does have some effect, though.  I would love to contrast a meditator with a drug addict, because in a way addicts adhere to their own inner mantra.