The man with two brains?

When a new year begins, we spontaneously review the highlights of the year that has just ended. Well, here in this blog, the review didn’t happen in January… because I decided to enjoy holidays and take a little break. I admit it. However, in terms of neuroscience, one of the best meetings I had last year took place in November. I met the brilliant Michael Gazzaniga, who was for the first time in Argentina –in the auditorium of the Argentinean Scientific Society (Sociedad Científica Argentina)- thanks to INECO foundation (which stands for Cognitive Neurology Institute in Spanish). I wouldn’t have learned that event would take place if it hadn’t been for a student of mine (thanks, Silvia!).

Michael Gazzaniga is considered “the father of cognitive neuroscience”. Professor of Psychology in the University of California, Santa Barbara, Michael is important because he has been providing -already for several decades- fundamental answers about how our mind works based on the neural processes of the brain. And, as a consequence, about the principles of some of our emotions as well. So that you get an idea of how relevant his work is, you should only learn that he carried out his Ph.D. dissertation on psychobiology under the guidance of Roger Sperry, a guy who deserved the Nobel prize (precisely because of the research together with Michael!).

Back in the ‘60s, Sperry and Gazzaniga studied the behaviors of epileptic patients who had undergone the same kind of surgery several years before. The intervention had attempted to alleviate the massive fits of epilepsy, and had consisted in “disconnecting” both brain hemispheres. The procedure itself consisted in severing an area of the brain –called corpus callosum- which transfers signals between the right and left hemispheres. Thus, patients could keep up with a relatively normal life, without fits as before. They were called “split brain” patients. Sperry basically showed that each brain hemisphere works as an independent conscious processing unit, and he also contributed to the understanding of the lateralization of brain functions.

In the subsequent studies that Gazzaniga performed along his career, he kept providing new findings about that lateralization and about how the hemispheres connect to each other. Lateralization means that the cortex of one brain hemisphere does not bear the same functions as the cortex in the other. Nevertheless, we must be careful with the arbitrary generalizations made in popular psychology… such as the left hemisphere being the ‘logical’ one while the right hemisphere stands for the ‘creative brain’. It is undeniable that differences in processing can be measured between one side and the other, but these differences are truly subtle and not exaggerated. In fact, for instance, logic and creativity are processed in both sides, despite there is a slight bias in each one.

Anyway, one of the most remarkable things that Gazzaniga discovered is a way of processing the information, of working, which he calls “the left hemisphere interpreter”. After loads of research, Gazzaniga realized that the left hemisphere remarkably contributes to our explanations for finding out the meaning of the circumstances surrounding us, and our role within them. The “interpreter” tries to rationalize and generalize the information that we receive, so as to link the past with the present. How did Gazzaniga discover that? In the initial experiments, he showed his split brain patients an image which was only visible though their right eyes. (For those of you who don’t know, what our right eye sees is processed in the left hemisphere… Yes, indeed, we are all cross-wired in our inside…). In these cases, the patients could provide an explanation of what they had seen. However, if Gazzaniga showed the image only to their left eyes (that is, if the image was processed by the right hemisphere), subjects claimed to see nothing.


Gazzaniga presenting at the Argentinean Scientific Society

Emotionally speaking, “the interpreter” being lateralized as a function means that processing-the-meaning-of-things is mostly performed in our left side. This isn’t just a mere cognitive issue; it is an emotional issue. Because whenever we don’t figure out what’s going on, whenever we don’t find cohesion to the episodes of our lives, we are invaded by a huge feeling of unease. We feel uncomfortable. Let’s imagine for a moment that we don’t understand what’s going on right now. Let’s imagine we don’t know why we are feeling  what we feel, or why we’ve just done something, or that we don’t realize who we are. We’d be clearly drawn into a massive feeling of uncertainty. We’d become vulnerable, experiencing ourselves insecure.

The feeling of certainty and safety derived from being able to understand what’s going on is an essential emotion. So it is the confusion and dislocation that come up when we cannot build up a model of how reality works. We are constantly trying to understand what happens to us and to make sense of what surrounds us. The matter is sometimes deeper and, occasionally, we attempt to find the meaning of our life. Even of life itself (as Viktor Frankl explained). Let’s notice how much this has to do with what contemporary cognitive scientists call “beliefs”: the model of reality that each one of us has built (the way we interpret the world and ourselves in it). And let’s notice, therefore, how entangled emotions are with cognitive processes of our mind/brain -that is, those processes that allow us to know the world, to perceive it, and also the operations of learning, memory and attention.

I strongly recommend you to read the interview that the wise scientific journalist of La Nación newspaper, Mrs. Nora Bär, made to Michael by clicking here. It is really interesting –though in Spanish. You can also look for some of Michael’s books in the web, such as Social  Brain, The Ethical Brain, and the recently launched Who’s in Charge?: Free Will and the Science of the Brain.


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