On the Lateralization of Emotion and Inter-Hemispheric Communication
1st Oct 2012Posted in: Blog 2
On the Lateralization of Emotion and Inter-Hemispheric Communication
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Recently, i was watching the World War II colour documentary series by Time. Having long been fascinated with pictures and stories from that period of our history, I have ploughed through dozens of documentaries about Hitler in utter amazement. The period interests me because fascism had never been seen on the scale the Nazis brought it to and i think we can learn a lot from how all that monstrous humanity came about. World War II is an historical event which I can come back to visually time after time, bewildered by the long tradition of human stupidity that is war. My consciousness seems to have an appetite for the horrible imagery because I can look with detachment as an observer who has not been personally traumatized by the events.  In what follows, i am going to present my experience of consuming this visual information and how this experience led me to do a little reading on the neurology of emotion.

As i continued to watch the 10 hour documentary series, i followed the Germans all across Europe and witnessed first hand accounts of the total insanity of war.  I watched over 4 or 5 nights in a row till i got to the end of the series on Netflix. With a clinical eye on dissecting the facts and putting them back together, i arrived at the same conclusion each time: ''all of this is just incomprehensible madness. It just confirms to me that the illusion of correctness and normalcy can persist in the face of all evidence to the contrary''. A form of addiction to that period in our history had already taken root in me and i was quite used to voluntarily subjecting my mind to the images and sounds and words from that time, all in the interest of gaining deeper knowledge about about who I am and where i come from. So with this clinical mindset and the objective of education in mind i consumed all of the re-coloured footage from the production in about 4 or 5 sittings. At some point, on day two i think, i began to feel depressed. Initially, I did not draw any connections between the depressed mood and the footage at all. Actually, i thought hormones, fluctuations in neurotransmitters, serotonin depletion, melatonin depletion possibly brought on by poor sleep, stress, nutritional deficits or lack of sunlight could be the culprits. By the third or fourth session i realized that the footage was itself making me sick. Even though i had seen the images in film dozens of times, i seemed to be a little more affected than usual and this sparked a curiosity as to why that might be. As with most of my posts, it is a sensed physiological change which prompts my investigation through words. Questions started to surface: ''Had my pupils come to rest on the images for longer periods than usual?  Had i been attending in different way to the information?'' Curiosity about my depressive state emerged for a number of reasons: First, I had only been paying half attention to the images because i was working on my laptop in a word processing capacity over the course of each exposure to the film. As i write this now, I am again facing a television program in the background.  (Not sure when this happened but at some point, one screen became not enough and i needed two...) I am watching t.v now as i write this... I was attending to a screen within a screen as i watched the documentary series just as i am now... Given that i was multitasking, i believed myself to be emotionally removed or shielded from the visceral impact of the images. The second reason why i was curious about about my feeling state is that it did not occur to me in real time that the images were making me feel unwell. Ordinarily, i am close enough to my sensations to realize in the present moment how and what i am feeling. I wondered if my brain had been taking things in on an emotional level which my analytically oriented left brain had not been aware of. My question was : ''how could stimuli evoke an emotional state in me without being observed by my consciousness?'' So far, i have arrived at the tentative conclusion that hemispheric differences might help to explain the question. At present, I believe, based on my reading that we enter modes of functioning which become dominant depending on context. A left brain mode tends to be more factually, verbally and analytically oriented. This is useful for all kinds of situations such as clinical analysis in an experiment, a lesson in mathematics and word processing.  A right brain mode is more emotionally attentive, more finely tuned to emotional cues such as facial expressions, non verbal signals, pitch and timber in a voice, empathy and social context. While in a dominant mode the sub mode remains active. The two hemispheres are working together all of the time so this is not an either/or proposition. One half is feeding the other and that process accounts for the hugely complex variation and richness in experience which we human beings are privileged with. Following a corpus callosotomy, the two hemispheres appear dichotic in that they are not only independent but somewhat dualistic or opposite in function. Interhemispheric communication through the corpus callosum explains why it is that we can put images into words or talk about music and touch or sing and play an instrument at the same time.  Think of the human brain in terms of a computer technology metaphor. A dual core processor is better and more efficient than a single core. When we sleep, right mode is most active, but left is not completely silent. When we awaken, left mode is in full effect and dominant throughout most of the day. For most people, left mode is dominant in day to day operations though there are some exceptions. Of course any time the social context becomes hugely important such as when danger is present, right mode kicks in and left shuts down somewhat though the left amygdala reportedly fires away with fervour as compared to the right when danger is close.  When i write a post, even though i am using the language centers in Broca's and Wernicke's i am usually drawing on autobiographical memory and emotional imagery of my right brain as the starting point. I think that creative journaling in art therapy is particularly popular and useful because it does produce trans hemispheric activity through the processing of emotional, non verbal content through words and images and two cores are better than one. There is some support for the idea that bilateral processing of difficult information is therapeutic. Getting people with PTSD to draw out their locked-in experiences in novel and non verbal ways is gaining greater recognition thanks to the work of some art therapists. Here are a couple of diagrams courtesy of the internet, which illustrate pathways through which emotional stimuli impact brain functioning.

Think for a second about what happens when the right brain gets bogged down with emotionally difficult experience. If there is no inter hemispheric treatment of that experience then there is simply nowhere for the experience to go to be relieved. Instead the trauma must sit there and be relived through the loop of autobiographical memory and non verbal experience. There is hardly any therapy possible in a situation like that. This is the basic premise of psychodynamic theory. When information gets locked into an unconscious emotional container through repression, it becomes noxious to the system just as undigested meat weights down digestion. When there is disequilibrium, there is unbalance and we feel unwell. This is why talk therapy works. Talk therapy works but so does art therapy because only art therapy has the tools to go into that non-verbal, sensory experience and treat it within the same parts of the brain where it was created. I am getting off topic but indulge me another minute or two and i will come back i promise...In talk therapy, we ask people to talk about what is bothersome and through this process alone, people find temporary relief in catharsis. Catharsis is an essential component of any insight driven psychotherapy and is sometimes in itself sufficient. Catharsis is why we ask young children to talk about their feelings and behaviours by saying to them: ''use your words''. The hope is that the frustration of a given child's difficulties could be alleviated if they could become able to process them in the other half of their brains. This is what is called insight in psychodynamic therapy. It is believed that a child or adult for that matter, can gain greater insight into the causes and consequences of difficult behaviour through the development of metacognitive abilities, otherwise known as ''use your words''. Metacognition is often defined as thinking about thinking but it might just as well be a form of thinking with words about feeling. Meta cognition is about using the rational mind to analyse one's thoughts, feelings and behaviour in order to better predict and control that behaviour. I am getting off the point of my post here aren't i? Let's get back to it: What i learned from my experience is what i already knew as an art therapist:  depressive ideation is insidious and can be acquired subliminally. It may be more true to say that depressive ideation is almost always acquired subliminally. After all, if we knew something was making us depressed, we would stop it at the outset wouldn't we? Based on this idea, it is believed by most people working in the profession of psychotherapy that depression has earlier roots in childhood experiences where young children have no natural defenses or understanding of how experiences are affecting them. By the time those children are adults, they only know that they are depressed but they do not necessarily know why. Actually, i clearly remember telling my mother around the age of 7 or so that i felt very sad but that i did not know why. My mother tried to get me to talk about it, but i could not for the life of me find any words. Part of a psychotherapists job, depending on therapeutic orientation and modality, might be to help clients understand where and when depressive ideation took root. When depression takes root unconsciously, the symptoms of that depression will also manifest on an unconscious level with patients not necessarily even realizing the depression is there at all. Given that there is no conscious cause attributed to the feeling in the conscious mind, there is no feeling to speak of. This is why the cognitive behaviourists say that :''Thoughts determine emotion''. If there are no thoughts tracing a feeling back to an origin then it is assumed by the mind that there is no feeling worth talking about. This is in part why most people do not get help for depression, choosing rather to believe that the inconvenience will pass. By the time many people seek professional help, depression has already got a firm hold on things.  There is only a feeling to be felt and that is not the same as a feeling to speak of. We can not use our words to talk about a feeling when we have no vocabulary to describe its origin or cause, when we are not conscious of what the feeling is or how it got there. This is why Narrative therapists ask: ''what is the depression doing to you?''. The idea is that externalizing the depression as an entity separate from the individual will help the afflicted individual to better observe what the depression is like. With some cognitive distance from the emotion, an individual is likely to gain greater perspective.  Something which has no explanation does not exist as far as consciousness is concerned.  If it has no etiology, no place of origin and no cause, the conscious mind can not be directly aware of it. So what happened as i was watching the documentary is that the gruesome images were entering into right brain perception through imagery, sound bites, explosions, music, the narrators monotonous tone. However, my left brain was completely oblivious to the effects because it was occupied with the word processing task being carried out on my laptop. Thus, my two brain halves had been split in an environmental corpus callosotomy. Through parallel processing in each half of my brain, the right hemisphere was recording the horror of the images in the documentary, the music and the tone of voice of the narrator but my left brain was working on this post. Unfortunately, the evidence on multitasking suggests that my post would only be half complete and that i would only be paying half attention to the program on the television because you can not spread your cognitive ressources too thinly. (Luckily, i have come back to this post in peace and quiet to make sure it is coherent!) Had i been consciously processing the documentary on an emotional level, i would have been immediately aware of the emotional effects through limbic system feedback such as decreased blood pressure, altered heart rate, nausea and serotonin drop, indicating the visceral reaction of disgust. Given that conscious information, i might have been able to go for a walk, take a break, do some exercise or engage in otherwise preventative behaviour. So my conclusion is that looking at information through a clinical lens with the intention of processing it analytically through words is no guarantee that another parallel emotional process is not taking place with its own set of parameters, causes and effects. Nothing too revolutionary about what i am proposing here but still kind of interesting when you consider the idea of two practically independent brains doing separate things for their own reasons. I think the age old conflict between the heart and the mind is really just a metaphor we use to help us understand the relationship between the right and left hemisphere respectively. The former serves as the functional location for most of those things we define as ''heart'' while the latter does most of the stuff we associate with mind of an intellectual. Let me ask you a question which has nothing to do with this post now: ''Which hemisphere has been dominant throughout history?''

I would be very happy if anyone responded to this post with some thoughts. If you are a neurologist, i will pay you (not what you usually charge) for your time and perspective on my conclusions. You can find my favourite youtube playlist on split brain experiments here:

2 Responses

  1. alex stein says:

    Hi, tomartist your site about art therapy and neuroscience looks very interesting and perhaps could be qualified as CEREBRART.

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