In one sense Dr. Jill Bolte Taylor died the morning of her cerebral hemorrhage when the burst blood vessel flooded her left hemisphere and destroyed a large section. The neural connections that governed the language centers not only eliminated speech – both the ability to speak and comprehend the speech of others, but also her ability to create and comprehend her thoughts in the way she had known (Taylor, 2008, p. 66). The circuitry that allows one to think linearly and abstractly, to move, to recognize physical boundaries, to comprehend visual stimuli, as well as to make and comprehend speech were all affected by damage to the middle cerebral artery (pp. 18-19).
Having lost her left brain’s ability to process incoming sensory stimuli – to note, record, and categorize in a systematic way, she was assaulted by the sheer chaotic force of it all. For all intents and purposes, she became “an infant born into a woman’s body. And oh yes, the brain wasn’t working” (p. 65). Her limbic system now no longer had the “higher” functioning cerebral cortex to linearly process sensory input; in her earliest post-stroke days, information was processed in much the same way as it is for a newborn.
The limbic system, from the first, takes sensory input and processes it as emotion. The neural connections are based upon linking of these emotions. As the higher cortical cells mature, the connections are integrated into the existing emotionally based limbic processes. Thoughts are made in a more linear fashion as the new, more complex system takes any new input and compares it to and integrates it into the existing emotional landscape of the limbic “worldview”. In a safe and calm environment, the higher functioning “thinking” mind can override the reactive limbic mind and can choose a more rational, reasoning response (pp. 17-18).
Sleep becomes imperative for both the infant and the post-stroke patient. The brain needs to rest from all the physical work of creating new neural pathways. The post-stroke patient, like the newborn, feels assaulted, but is physically unable to move away from the stress. The only solution is to fall asleep! Here one can see that sleep performs two functions: that of restoration of the brain during slow-wave sleep (Himmanen, 2012) and as a means of controlling one’s environment. REM sleep allows the brain to sort out stimuli and to try and make sense of new input. Learning to think IS exhausting.
Psychologically, the ability to tune out overwhelming stimuli is quite important, I believe, to our wanting to grow and develop. Learning that one can have an impact on one’s surroundings is an extremely important developmental milestone in the development of consciousness. Tuning out serves to create a safe environment. A safe environment allows the amygdala to remain calm and to keep from triggering a hyper-vigilant. reactive response to possible danger. When the amygdala is calm, the hippocampus can learn and memorize new information – a vital task for the stroke patient as well as the newborn (Taylor, 2012, pp. 18-19).
Often, sleep does not come easily to the newborn nor to the stroke patient. In the newborn, the regulatory centers are still developing. In those who suffered a stroke, the regulatory centers have been compromised and must be rebuilt. Too much raw stimuli disrupts sleep and overloads the circuits. Sleep, which is necessary to break the stressed, wakeful cycle, is not easy for the overly stressed body to achieve. Having a loose schedule that has naps planned into it seems to help in learning to self-regulate.
The rhythm of an ordinary, low-key day has an ebb and flow that fits the needs of the individual and is probably good for all of us, but it is vital for the stroke patient as well as the newborn for healthy development of new neural pathways.
Himmanen, S. (2012). The function of sleep [Video lecture]. Retrieved from Psy 229: Introduction to Biological Psychology – Cedar Crest College: http://frameset.next.ecollege.com/%28NEXT%289bf3457d0f%29%29/Main/AllMode/FramesetHybrid/NavigateView.ed?courseItemType=CourseContentItem&subItemID=201109219&expandUnit=36866818
Taylor, J.B. (2008). My stroke of insight: A brain scientist’s personal journey. New York: Viking Penguin.