“I think, therefore I am”: A look at memory, sensation, and experience

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After conversing about memory, senses, expectation generation and starting to read Jean-Dominique Bauby’s memoir on Locked-In Syndrome (The Diving Bell and the Butterfly), my previous perceptions about living and experiencing went essentially, out the window, or more precisely, out of my mind. Through these in-class conversations (including some with Bauby and I in my mind), something became clear: what we normally see as so essential to living, contact with the external world and our mind and body’s response to that contact, is in reality, minimal compared to the essentiality of thinking and memory in generating our experience of life. Through cases such as Bauby’s of Locked-In Syndrome, we know that expectation generation works: memory can trigger senses much in the same way physical stimuli do; challenging our idea of what it means to “experience” things. One can experience just as much through memory and the mind, and quite possibly more so as one can through solely movement and physical contact.

Before I begin, I must also clarify what I mean by “experience;” think of experience as when you touch an individual’s arm and ask them if they experienced that touch. Regardless of whether their nerves sensed the touch, if the individual says yes, they experienced the touch, and if they say no, they did not.  For example, take anosognosia, or “denial of illness;” occurring in about 58% of stroke victims who are left paralyzed on one side, patients report that they have movement in a paralyzed limb or side even when given demonstrable evidence in support of paralysis (1). This cannot be automatically attributed to mania either, as patients can have these symptoms without other deficits such as “sensory loss, inattention, or intellectual confusion (1).

To understand these concepts of experience furthermore, one can analyze Locked-In Syndrome and Quadriplegia. In Locked-In Syndrome and Quadriplegia, there is a dysfunctional connection between the I-function (what we recognize as the Self within the nervous system, that which “wills” and experiences) and central pattern generators of the caudal end of the nervous system, the caudal end including everything (spinal cord and nerves) under the brain stem. Central pattern generators are the connections between neurons that make action possible, i.e. there is a CPG for walking, eating, waving your arm, etc. In these cases, all central pattern generators are still intact but the I-function cannot reach them, unless a patient also had nerve damage in a limb or lost one, but this would not be a symptom of either syndrome.

Essentially, in these cases, the I-function no longer has a way of telling CPG’s to turn on, and thus no way of creating outputs within the nervous system. At the same time, the central pattern generators have no way of receiving input. This paradox makes it seem as if the CPG’s are not functioning, if neither is doing anything, but we know CPG’s are intact because of random muscle spasms, stretching (as Bauby reported every morning) and intact basic motor reflexes (such as a knee kick, or a finger moving when pinched). Even more ironically are Locked-In or Quadriplegic individuals reporting experiences, reporting that through memory, they could experience something again. Bauby said in Butterfly, that his “bottom hurt from sitting on it too long,” (2, p.75). The only way this was possible was that Bauby’s knowledge that his bottom would normally hurt after spending all day in a chair activated his memory and cause him to experience this soreness, even though he couldn’t experience this out of feedback from CPG’s.

            This ability to generate experience is limited however, similar to the way in which every time one recollects a dream, our detailed memory of the dream fades. Memories and sensations distort and fade.  The limited ability of memory and expectation generation however, challenges our previous idea that memory is enough to create experience.  Could this be similar to desensitization with smells and foggy vision when someone is tired? This phenomena makes it seem as if CPG’s action, although talked of as innate in class, are split equally between their basic innate nature and practice; so that some small details, or abilities are left intact without practice but are not as effective. This idea is of course, making parallels between CPG’s that control muscle action and CPG’s responsible for thought generation; which some would argue are not split in the same ways (concerning their functional nature).

A study in 2008 found that memory was in fact affected by active participation (3); TBI (traumatic brain injury) patients and patients with symptoms of Alzheimer’s were asked to remember pairs of words that were presented to them, they were presented a total of 3 times before testing for recollection. They were split randomly into two groups, both groups knowing they would be tested afterwards on memory. One group was simply shown one side of the card with one word and then the other side with the second word (words were typically paired by belonging to same category). The ‘generation’ group or active participation group however was shown the word (on either side) as well as the first letter of the other word, and were asked to say aloud if they could remember the second word. To conclude, the generation group recalled the words with much more accuracy, even though both groups were shown the same words. Thus, even though Bauby could remember and experience the touch of a hand whenever he wanted, without actively doing it, this ability would fade over time and eventually it would become much more difficult to generate this experience; because active participation is necessary to maintaining memory.

From this look at memory and experience, generation, sensation, etc. we essentially reach a simple conclusion: that “One can be, distinctively without the experience of being” (4). Although some evidence works to argue that without active participation, you are not “being” as much as is possible, all testimony and evidence does show that essential to “experience” is thinking, and not active physical experience.

1.      Haggard, Patrick. Lecture 8 Notes: “Some selected aspects of motor cortex damage in man.” C567B, Control of Human Action. Department of Psychology, UCL. 21 Mar 1996. http://www.psychol.ucl.ac.uk/patrick.haggard/c567/c5678.html

2.      Bauby, Jean-Dominique. The Diving Bell and the Butterfly. 1st ed. New York, NY: Vintage Books, Random House, Inc., 1998. Print.

3.      Schefft, Bruce K., Dulay, Mario F., and Fargo, Jamison D. "Use of a Self-Generation Memory Encoding Strategy to Improve Verbal Memory and Learning in Patients with Traumatic Brain Injury" Applied Neuropsychology 15 (2008): 61-68. http://works.bepress.com/cgi/viewcontent.cgi?article=1015&context=jfargo

4.   Grobstein, Paul. Lecture Notes 27 April 2010. /exchange/courses/bio202/s10/notes2