Emotions are a key part of making long-lasting memories. You probably don’t remember what you had for breakfast on this day last year, but chances are you remember where you were or what you were doing when 9/11 happened, or when someone you really cared about died, even if it was a decade ago.
From the perspective of the brain, and from an evolutionary standpoint, emotions are a useful barometer of things that it should ‘keep in mind.’ This is purely from a survival point of view. The intensity of the emotions is often correlated with how clear the memory is, even after many years.
Emotions are embodied, which means they are felt in the body to the extent that they are often visible to another person. Neuroscientists are not sure whether emotions trigger the body state or vice versa (do you smile because you’re happy or are you happy because you smile?) but what is clear is they have a very strong impact on each other and tend to operate simultaneously.
Our body has sensory neurons, whose job is to collect input and how we feel. Motorneurons, on the other hand, create an output, an action, which can be voluntary or not (sometimes you smile without realising it).
The link between our emotions and their embodiment happens through the enteric, sympathetic or parasympathetic nervous systems. The enteric system, as its name indicates, has to do with the guts but it also has an impact on and is impacted by things like our mood or stress levels. The sympathetic system is linked to our ‘flight or fight’ reflexes. This means it tends to increase our heart rate or dilate our pupils. It also controls our sweat glands, whether our hair gets erected, our blood pressure and our cortisol levels, among many other things. The parasympathetic system, finally, relates to ‘rest and digest’ functions. It lowers the heart rate and affects our bladder and colon.
Unsurprisingly, our age and lifestyle have an impact on whether we are more sympathetically or parasympathetically dominated. Children, whose bodies and brains are developing, as well as high-level athletes, tend to be sympathetically dominated. As we get older, on the other hand, we become increasingly parasympathetic and suffer from high blood pressure, hypertension etc.
Coming back to memories, there are mainly two types that our brains store. Broadly speaking, semantic memory is with regards to facts (like how much is 2+2, who is the president) and episodic memory refers to something that happened to us. Both types of memories are stored in the neocortex but while semantic memory can be accessed directly, episodic memories are recalled through the hippocampus. This means that every time we recall an episodic memory we experience it again, which is also referred to as consolidating a memory. This consolidation process is not perfect and can alter the memory over time but the emotional embodiment stays there.
This is why it is so difficult for our brains to overcome and let go of a traumatic episode - our brain considers it as a key piece of information for our survival. People or animals who suffer from Post Traumatic Stress Disorder, which is a mental problem caused by a traumatic event are a good example. One of our horses, for instance, went through something traumatic the first time someone put a saddle on her. We know this because the moment she sees a saddle, or a saddle pad for that matter, her body becomes stiff, she breathes heavily and her pupils dilate. She sweats between the ears and wants nothing to do with that saddle. This is an embodied emotional reaction to a bad memory which was triggered by something, such as the vision of a saddle, which recalled that past memory.
Scientists are trying to help people recover from PTSD by pharmaceutically blocking the embodied aspect of a traumatic memory. The idea is that if your body cannot react or feel what it used to when reliving that memory (through the use of drugs) that memory will gradually seize to be traumatic. On a more accessible level, this is also what happens when you try to get rid of an unpleasant feeling, like anger, by observing it and ‘letting it be.’ You are effectively dissociating the embodied part of that emotion. In other words, your body is trying to trick your mind into reclassifying something unpleasant into something that’s not.
At the same time, by studying paralysed people, and especially people suffering from the locked-in syndrome, neuroscientists have been able to conclude that the body acts both as a facilitator and as a release for our emotions. This is something that is often used in kind horsemanship training. Trainers will try to override the negative association of a bad memory by giving the horse relief, or pleasure (with a treat, for example) whilst going through a similar experience. It can take hundreds of times, however, before the new, positive memory can replace the negative one.
The mind is extremely powerful and evolved to keep us alive. It is crucial to understand the link between emotions, the body and memories for us, as well as our animals, to move forward and away from bad experiences.
This was written based on the Chicago curriculum ‘Neurobiology in everyday life’ which you can find here: https://www.coursera.org/learn/neurobiology/home/welcome