Emotional Memory is Malleable

by Ram

Inhabited Painting by Helena Almeida*

The human brain consists of about one billion neurons. Each neuron connects to about 1,000 other neurons, totaling an unimaginable trillion connections. Neurons combine with each one and help lay down many memories at a time. Furthermore, emotions associated with a memory are stored in a different area of the brain than the content of the memory itself. While we do not know the storage capacity and the size of memory space in our brains, certain memories involve more details and take up more space. Other memories that are not worth remembering or that are forgotten are cleared up by the brain through a process called neuronal rewiring, thus freeing up more memory space.

A layman would define memory as objects, colors, sizes, and shapes or more complex emotional feelings like fear, worry, anxiety, joy, happiness, anger, and so on. While memories may seem a complex combination of objective information, neuroscientists see them as electrochemical signals that are exchanged between nerves; or simply put, information in the form of electrochemical signals that arise in a nerve from one specific area of the brain to another nerve in the same area or a different part of the brain which together encode everything that we associate with a memory.

Recently, we here at Yoga for Healthy Aging had some very stimulating exchanges on the topic of trauma, which triggered a lot of interesting discussion. Lives get severely disrupted following a traumatic experience and when, where and how the memory associated with the negative experience will surface depends on each individual. While most people recover from traumatic events, many do not, and they continue to experience constant fear, worry, anxiety and/or depression. Until recently, neuroscientists believed long-lasting traumatic events created non-pliable neuronal wiring that fired off these memory events randomly upon exposure to some stimulus. So the question that these scientists have been asking all along is: can traumatic memories be erased, wiped out, or overlaid with favorable events so that the person is free from periodic recurrences of traumatic experiences?

The answer is yes, and in a seminal paper recently published in the prestigious journal Nature Bidirectional switch of the valence associated with a hippocampal contextual memory engram, neuroscientists led by a noble laureate concluded that emotional/traumatic memories are malleable, meaning that they can be manipulated such that these unfavorable memories can be turned into more favorable ones. Using state-of-the-art techniques, these scientists were able to show in mice the areas of the brain that created both positive and negative memories and how these memories areas could be switched around. In addition to identifying the nerve cells that lit up after favorable or unfavorable experiences, these scientists also showed that the negative emotional memory got relived as though it was happening all over again. But when the mice that had been exposed to a shocking experience received a favorable experience, it stripped the painful and negative feelings associated with the previous traumatic memory, suggesting that new positive information attached to an unfavorable memory event may help to diffuse its negative impact.

According to these researchers, while negative and unfavorable memories may not fade away, they can be replaced, overlaid or changed by new and contrasting experiences. Emotional valence—which is a measure of good feelings (appetitive behavior) or bad feelings (aversive behavior)—is not rigid. And, based on the studies done on these mice, circumstances/events/places that were scary, unpleasant, or upsetting could become happy, safe, or warm. In the above mentioned study, as the mice got exposed to repeated favorable experiences, their neuronal connections involved with the negative events got overlaid by newer and positive connections, tilting the balance of emotional valence towards appetitive behavior. The hope was that in due course the neuronal connections responsible for firing off the negative events would shrink or be lost.

Although the neuroscientist’s work was with rodents, it may be possible to make an effective therapy for humans that focuses on positive feelings to overlay painful memories and transforms the negative experience (see Friday Q&A: Trauma Resurfacing, Crying in Class and Post Traumatic Stress Disorder: Yoga to the Rescue). What do I mean by “transforming negative experience”? Surely the traumatic memory does not go away—or does it? According to the authors of the above-mentioned study, transformation would mean using methods/ways to lessen the impact of the harrowing event and transform it to something less traumatic. So this “transformation” would make the memory less intense to help prevent those frequent flashbacks. Cognitive neuroscientists have also discovered that in response to the stress of recalling trauma, the brain also releases “feel good” chemicals, akin to a compensatory mechanism. These calming neurochemicals that help to deal with the stress and trauma may be the brain’s answer to fighting off the traumatic memory. So whenever we feel the traumatic memory arising, we could resort to methods that will stimulate the body to flood the brain with feel-good neurochemicals.

So what suitable remedial procedures exist for humans suffering from long-standing traumatic memories, such as those involved in PTSD? In addition to psychotherapy, group therapy, and neuro-medications, yoga practices, such as asanas, pranayama, meditation, self-inquiry and yoga nidra, may help to transform any negative experience. Through these methods it is hoped that the individual may come to terms with or accept the traumatic event, allowing him or her to build self-confidence and become stronger in both body and mind. This way, not only does the individual remain connected to his or her inner self, it also keeps the person in the present moment. 

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