Brief thoughts about pain….
At this time, my research studies have led me to the issue of trying to understand the underlying cause of neuropathic pain. For the uninitiated, neuropathic pain is an abnormal chronic pain caused by injury or disease to the nervous system. Neuropathic pain is generally described by sufferers as electric like, burning, or experienced as intense crushing-like sensations. For some individuals, the pain can be so severe that they would prefer to commit suicide than to continue living with this type of pain.
At this time, there is no cure for neuropathic pain. In the best cases, clinicians are able to manage and reduce the severity of the pain to levels that are tolerable by patients. However, there are many issues with the treatments that we use to treat patients with neuropathic pain. The most obvious is that many of the drugs are incredibly strong painkillers and are vulnerable to abuse. Not to mention that many patients become desensitized to the use of these painkillers. They require increasing dosages in order to feel the pain alleviating effects.
There is a great need to discover new and more effective treatments for neuropathic pain. In my field of study of spinal cord injury, it is very common for injured patients to develop neuropathic pain symptoms.
I know many of you are not scientists, and from my point of view it would take many, many blog posts to teach anyone the basic foundations of our current knowledge about what causes neuropathic pain. This is not to say that you’re not smart, it’s just that pain at the neurological level can become incredibly complex and there are many exceptions to any rules we think we have that govern painful diseases.
Unlike cancer, where there are a set of definitions of the problem––i.e., a tumor grows and spreads leading to vital organ malfunction, and eventually death––pain is incredibly hard to define as a disease onto itself.
What is pain? This is a question for the ages. Philosophers and doctors have been asking this question for a long time.
For my purposes, I do not study pain in human subjects. I work with animal subjects. This already removes much of the complexity in studying pain diseases. There is an emotional component to pain that I believe is unique to human existence. Not to exclude the possibility that animals experience emotional pain, but as a scientist I am not able quantify emotion in a subject that cannot speak my language (that would be human).
Quantifying (i.e., quantification or whatever the proper verb might be) or really, deriving numerical data, is a key tool in the scientific method. All observations must be comparable to other observations. The only way we can do this as scientists is to turn everything into a number, and comparing those numbers against each other. For example, we see 10 rats flinching. Then we see 50 rats flinching after they receive a spinal cord injury. We’re able to compare the number 10, against the number 50. This is a very simplistic and fictional example, but you get the idea.
So how do we quantify pain?
In an animal model of pain, we have 2 tools that we can generally use.
First, is to examine observable behavior. An animal with abnormal pain will have certain behaviors, such as hunched posture, ruffled fur from poor grooming, a withdrawn or defensive stature, etc. Moreover, we can quantify (see definition above) these behaviors by touching the animal on the bottom of their feet and observing whether or not they remove their feet away from that stimulus. We call this a withdrawal reflex. As a human being you can imagine this as you removing your hand away from a hot surface. You don’t think about it, you just do it because it’s painful.
Second, we perform electrode implantation to study neuronal activity in pain centers within the brain and spinal cord. Neurons in animals that have abnormal pain also have abnormal electrical activity that we can quantify.
The electrical activity is likened to the electrical activity that you think of when someone tells you about a heart rate monitor. Or, if you recall the hospital monitors that show a person’s vital signs; these are electrical activities of different parts of the body.
I study the electrical activity of specific neurons involved in pain transmission in animal models of neuropathic pain. Neurons with abnormal pain will have much more electrical activity than those that are normal (i.e., no injury). The electrical activity in neuropathic pain (if put on an audio speaker) would actually sound like the static of a TV set on the wrong channel with the volume pumped all the way up.
I won’t go into detail into how we know this is related to neuropathic pain. But what I will say, and is clear to explain here, is that certain drugs can quiet the electrical activity associated with neuropathic pain.
The reductionist, simplistic approach of basic science research has provided the trustworthy tools we use in modern medicine.
One of my jobs in the lab is to determine how certain drugs work to reduce the underlying neurological problems associated with neuropathic pain. The electrical activity that we’re able to monitor in animals, which is associated with neuropathic pain, is the most quantifiable way (or the most objective) to determine if a treatment is effective or not.
Using both behavioral and electrical studies, we are able to further understand how pain works.
As a neuroscientist, what we do at the bench in terms of experimental projects may seem far removed in terms of applicability to people. However, my particular research has what we call strong translational potential, because the experiments are designed to mimic the SCI and pain diseases that are well characterized in humans. In other words, we aim to gather data that can be taken from the bench and applied, eventually, at the bedside.
- Spinal Cord Injury – Tonight’s Thoughts (neurovantage.wordpress.com)
- Neuropathic Pain and Memory (neurovantage.wordpress.com)