BARRY: While an infant brain rewires itself in response to many strong stimuli, an adult brain changes largely in response to stimuli that are behaviorally relevant. These ideas became clear to me when I underwent optometric vision therapy.
I did not use my eyes in the way that people with normal vision do. Since my former way of seeing - looking with one eye and turning in the other - allowed me to move about with reasonable accuracy, my visual habits became entrenched. Optometric vision therapy made me aware of how I used my two eyes and then provided me with tasks that could be completed only if I consciously changed my viewing habits. Only then did I learn to aim the two eyes simultaneously at the same point in space. This new ability then promoted changes in brain circuitry which led to the ability to see in 3D. Since this new way of looking provided me with a more efficient and more informative way of seeing, these changes became automatic.
My experience, as well as that of several others also described in my book, have taught me that you cannot understand brain plasticity by studying brain circuits in isolation from the whole person. To rewire your adult brain, to rehabilitate yourself, you need to understand how you interact and cope with the world, and then put yourself in situations which teach you to perform differently. If you can learn a better way of negotiating the world, you can change the circuitry in your brain.
LEHRER: In Fixing My Gaze, you describe what happens at a cellular level when we learn something new, be it seeing in 3-D or learning how to read. What can educators and teachers learn from this new science of learning?
BARRY: Science is revealing what every good teacher already knows. We can change the synapses and wiring in our brain and thus learn new things if we are exposed to and pay attention to novel situations, if we stay motivated, and if we practice. Novel experiences, as well as the anticipation of a reward, stimulate ancient areas of our brain, such as the brainstem and basal forebrain. Activation of these areas liberate powerful neuromodulators, including dopamine and serotonin, onto our cortical neurons and circuits, and these neuromodulators facilitate and strengthen synaptic changes which underlie learning. Practice and repetition are necessary to make these changes long-lasting. Optometric vision therapy provided me with the novel and rewarding experiences that triggered synaptic rewiring in my brain. In fact, I wonder if an infant's brain is so malleable in part because everything is new to them; their neuromodulatory areas must be continually active.