Chronic Pain May Be a Memory Problem

After an injury or pain-inducing experience, the body often heals itself, but a chronic pain may continue even after healing. National Institute of Medicine surveys suggest that some 116 million American adults are in chronic pain. Chronic pain is often accompanied by such emotions as anxiety, depression, and a significant reduction in quality of life. Drugs like opiates, steroids, and non-steroidal anti-inflammatories can be very effective in reducing acute pain, but may have little or no effect when post-healing chronic pain sets in.

How can pain persist when the original cause is gone? Clues have emerged from brain scans of chronic pain patients that show no sign of augmented activity in pain-mediated areas but do show increased activity in emotional and motivational areas of brain. The thought has now emerged in several research labs that chronic pain may actually be a memory. As if the chronic pain itself is not bad enough, the pain learning process may induce degenerative changes in emotional circuitry.

The idea dates back to the work of Pavlov over 100 years ago revealing that animals experiencing painful stimuli learn to associate that pain with other ongoing events, called conditioning stimuli, which include the associated emotional distress. The animals remember both the pain and the negative emotion, even when neither is any longer present. But until the last few years, nobody seems to have applied these findings to the issue of chronic pain in humans.

The idea is that a prolonged period of acute pain strengthens the emotional pathways that are activated during pain, and continuously reinforces the signals so that they do not go away even after the physical pain is gone. This process might even be thought of as a kind of addiction. Many theorists believe that the usual addictions, as to opiates, nicotine, etc. have a large learning and memory component.

We have known for a long time that pain can induce huge emotional distress. Numerous anecdotes establish that unpleasant emotional states are magnified by pain. But we also know that thoughts and emotions can regulate pain. For example, a mother's kiss may reduce a child's pain from a sudden injury better than any analgesic. In the heat of combat, a wounded soldier may feel no pain until after the attack is over. These pain-suppressing effects are not just psychological but even include inhibition of pain signals as they arise in the spinal cord.

Notably, one of the key brain areas involved in pain is the hippocampus, which is crucially involved in forming memories. But the hippocampus is a key linchpin in the neural circuitry that processes emotions and mediates stress.

You might think that this is a perverse feature of nature. But actually the process has its uses. Pain provides a teaching signal that makes one want to avoid such situations in the future. But in chronic pain the lesson becomes so well entrenched that the pain memory cannot be extinguished.

If this theory is correct, it means that the usual treatments for chronic pain need to focus on memory mechanisms. Minimizing the pain while healing is in progress should reduce the likelihood of developing chronic pain memories.

But of course, prevention is not always easy to accomplish. Today, physicians are more aware of the addictiveness of the most reliable pain killers: opiates. They tend to cut short use of opiates in order to prevent drug addiction.

One possible treatment may be akin to emerging treatments for post-traumatic stress syndrome (PTSD). Development of PTSD is reduced if morphine is given immediately after an acute trauma. A beta-blocking drug, propranolol, can have a similar preventing effect, presumably because it blocks memory reconsolidation. Whenever you recall a memory, it will be re-stored. While it is consciously "on-line," the memory is vulnerable to modification, and a new and perhaps less traumatic version of the memory can be saved in memory. In PTSD therapy, you might recall the memory and have its reconsolidation blocked by certain drugs that prevent memory consolidation.

Another possibility is to target the synaptic biochemistry involved in pain. Neuronal NMDA receptor molecules are involved in the emotional component of acute pain, and one drug that acts on these receptors, D-cycloserine, has been shown in animal studies to inhibit pain-related behavior for weeks afterward. There is also a protein kinase enzyme that mediates the emotional distress of pain. Animal studies show that there is a peptide that inhibits this enzyme and in the process reduces pain-related behavior. Work is underway in several laboratories trying to identify appropriate molecular targets in chronic-pain pathways so that appropriate drug therapies can be developed.

Sources:

Apkarian, A. V., Baliki, M. N., and Geha, P. Y. (2009). Towards a theory of chronic pain. Prog. Neurobiology. 87, 81-97.

Mansour, A. R. et al. (2014). Chronic pain: the role of learning and brain plasticity. Restorative Neurology and Neuroscience. 32, 129-139.

Melazck, R., and Wall, P.D. (1965). Pain mechanisms: a new theory. Science. 150, 971-979.

Sandkühler, J., and Lee, J. (2013). How to erase memory traces of pain and fear. Trends in Neurosciences. 36(6), 343-352.

Readers of this column will be interested in "Memory Medic's" e-book,: "Improve Your Memory for a Healthy Brain. Memory Is the Canary in Your Brain's Coal Mine " (available in all formats from Smashwords.com). The book, devoted exclusively to memory issues in Seniors, includes review of many of the ideas in these columns over the last five years.

Memory Aggravates Relational Pain. There Is a Treatment

It’s that time of year for making New Year’s resolutions, and I am inspired to write this on January 1 because good resolutions can result. I never thought about the pain of broken relationships much in the context of learning experience and memory until I ran across a LinkedIn post from writer and speaker Carl Prude Jr. Here is what he posted:

“Resentment and unforgiveness are two of the wardens of relational pain. Whenever we employ them they only make sure that we are constantly reminded of the hurt and smallness we felt from hearing someone's negative remarks. They also make sure that we never see the incident in a forward-moving context - instead, keeping us chained to a low moment in our past. I try to look beyond the circumstances of their comment and evaluate the comment independently - to see if it has any constructive merit. If it was mean-spirited or intentional, I immediately dismiss it and forgive the person who said it.”

Usually when we think about memory we focus on how to strengthen it. But there are times when it is best to forget – as in the case of hurtful things we have endured from other people. Here is a case where nursing the hurt leads it to fester, not heal.

So, how do you teach yourself to forget things you should? This maybe especially hard if your focus has always been to enhance memory.

I have discussed some related ideas for erasing memories in earlier posts on new treatments for post-traumatic stress syndrome. In the next post, I will discuss some recent research on advertising where marketers work hard to erase the memories of counter-productive ads.

But here, I want to focus on erasing memories involving relational pain, like the kind you find among spouses in unhappy marriages, siblings clinging to memories of childhood conflicts, employees who are underappreciated or employers who resent lack of support and loyalty. Of course there are many kinds of broken relationships, but all have one thing in common:

The slights and insults are remembered

and etched in a heart of stone from frequent recall.

The pain will never go away as long as the memory is strengthened by recalling it. Typically, one has to learn to forget the pain, not necessarily what caused it. But how does one learn to forget pain?

In many cases, it is a matter of breaking the bad habit of rehearsing the memory and thus strengthening it. Humans react the same way as Pavlov’s dogs, in that repeating a stimulus, in this case the relational affront, conditions memory of it. Like Pavlov’s dogs, if you could repeat the stimulus without the associated pain, the affront would lose its association with the painful memory. Though our natural instinct is to disengage with people who have hurt us, the cure may require us to find ways to continue engagement under non-threatening circumstances. This is equivalent to repeating the conditioning harmful stimulus without the associated punishment – thus extinguishing memory of the original bad learning experience. This is not easy to do, and is sometimes unwise to attempt.

Nonetheless, the principle is sound. People can use the extra brain power that dogs do not have to review the memory more dispassionately. This demands a more objective analysis of the original painful events. It should begin by examining your own contribution to the event, as I explain in my book, “Blame Game, How To Win It.” People don’t usually say and do hurtful things without some kind of provocation, and it may have come from you. More objective analysis also usually reveals that the affront is not nearly as important as you have made it in order to nurture memory of the affront. Humans have a perverse need to remember and magnify affronts, for it validates their vanity. Saying to oneself, “I did not deserve this affront, my hands are clean” is salve to a wounded psyche. We feel better about ourselves, and superior to the perpetrator. Thus, we make sure we remember the events that bolster our vanity.

Also basic to rational analysis is the recognition that all people make mistakes. We have to put ourselves in this category too, but focusing on the misdeeds of others reduces the perceived need to admit our own flaws. Learning to accept and live with human nature is a hallmark of maturity, and it is no wonder that many of our remembered grievances occurred in childhood when we had not yet learned to understand and accept the weaknesses of others.

Nursing grudges creates the habit of nursing grudges. The cure is to have more self-discipline in breaking of bad habits. I explore this in the above-referenced book. But one example comes from a racial bias experiment I described in which racially biased people were trained to be more accepting by having more emotionally neutral social interactions with members of the opposite race. Humans are hard-wired to be more comfortable in a like social group. That’s why tribalism persists even in most cultures even today.

How does one acquire more self-discipline, which of course is needed to break habits? Well, we could join the military and go to boot camp.  In boot camp, you learn to do things you don’t really want to do. In everyday life, forcing yourself to do what is needed and though not appealing, creates character and self-control. Self-induced practice can include making yourself do such things as:

·         Self-train in small steps. “Life by the inch is a cinch. Life by the yard is hard.”

·         Act as if you already are as you wish to be.

·         Get your act together (pay attention, get off your butt, organize your life, dress and groom well).

·         Always be on time.

·         Do things you know you should, even though you don’t want to.

·         Do the hard things first.

·         Increase, rather than decrease, dealing with people you don’t like.

Finally, it is essential to be more introspective about one’s self-esteem. As I explain in the book, self-esteem has two components, self-confidence and self-worth. The fully actualized person has both. Neither component alone is sufficient to neutralize the false gratification we feel from perverse remembering and magnification of affronts. Generating self-confidence is relatively easy, because it can be earned. So get out and earn it, emphasizing things that seem to work for you and learn what you have to do to build small successes into big ones.

Sense of self-worth is harder to have. At one time or another, all of us have endured neglect, slights, and insults. We may have been used, perhaps even abused. How does one cure a broken spirit? First, I recommended believing in a God who created you, loves you, and values you. Accept that love, pray intently with thanks for it, and ask that it give you strength to be a better person. Second, be more socially active and engage with more different kinds of people one on one. Seek friendship, remembering the axiom that to have a friend one needs to be a friend.

Actualization begins with realizing the importance of caring for yourself. The commandment, “Love your neighbor as you love yourself,” needs to be thought of more in terms of the italicized words. Ability to love others or forgive affronts depends on one’s self-esteem. Each of us should examine our every thought and action with the question, “Is this really helping me, or is it good for me?”

As I said at the outset, nursing the hurt makes it fester, not heal.

Blame Game, How To Win It is endorsed by media celebrities Dr. Laura Schlessinger and Reverend Robert Schuller. The book is available through Amazon.

Remembering the Bad Along With the Good

In my Sept. 15, blog I surveyed an experiment that showed people learning more from their successes than from their failures. In so doing, I raised the possibility that the learning gain was promoted by the release of the "reward transmitter," dopamine. Now I find a new research report on the effect of dopamine on the long-term storage of bad memories. The process studied was the long-term memory of fear and pain. Rats were trained to remember a strong foot shock, which lasted at least 14 days. Injecting a dopamine blocker into the hippocampus erased the long-term memory if given 12 hours after the original foot-shock experience. This suggests that the normal release of dopamine can promote memory, which is not surprising since dopamine promotes the formation of proteins used in synaptic junctions of neurons.

However, foot shock is certainly not rewarding and probably does not release dopamine. But the end of the foot shock pain is a rewarding relief. Also, rewarding things do happen even to rats after a nasty foot shock (like sex with mates, eating, drinking, sleeping, etc.). The ongoing release of dopamine in the course of just living may help rats form lasting memories, regardless of the nature of memory. This raises questions that scientists have not studied yet. But it may be that dopamine helps us remember both the good and the bad. And maybe is one reason why bad memories are hard to erase.

Source: Rossato, J. et al. 2009. Dopamine controls persistence of long-term memory storage. Science. 325: 1017-1020.