The Decision Reflex

        What are humans?  Certain religions would have us believe we are the center of the universe, however from a scientific and secular viewpoint, we are simply one of the myriad of products of a long and winding evolutionary 'road.'  We are the last surviving species of the genus 'homo,' however we are still organisms, as are house cats and fruit flies.  What makes us different is the long-held concept of consciousness, or a higher level of thinking than most of the animals with which we cohabitate the world.  Does this entail that there is something more in us, as homo sapiens, than there are in other organisms such as horses?  Or are we composed of the same six elements, and bound together by electricity and atomic bonds, just as every other organism that lives or has once lived?  Science has long ago proven the latter to be true, although the nature of consciousness itself has eluded our full comprehension.  In this post, I am going to broach my hypothesis as to how the 'mind' functions, as well as support it.
       What would happen if one's finger was placed on an source of immense heat? The body would react by immediately retracting the finger, or perhaps the entire arm.  However this is not voluntary.  In a situation such as this one, the nerves in the finger which sense the heat communicate that intense sensation to the spinal cord, which is a 'cord' of neural tissue (nerves and cell bodies of nerves), where it meets another nerve that will then send that communication back to the point of the sensation's origin, where muscles in that general area will react by contracting, thus pulling the finger backwards.  Only after this process, known as a reflex, will the individual become aware of it, because the spinal cord will also project this information to the brain, but by the time the individual might reach a state of awareness of the sensation of heat (in most cases, less than a second) the reflex will have already been completed. 
       Suppose the reflex described in the previous paragraph did not occur, and that in order for the finger to be pulled from the heat, the brain must make the decision to retract it.  The same nerves in the finger would sense the heat, and communicate it to the spinal cord.  The spinal cord would send the information to the brain, where it would pass through a number of systems until it reached a particular area of what is known as the cerebrum.  The cerebrum is the largest portion of the brain, and what most think of when they attempt to visualise it.  It is divided into two portions, which are known as the cerebral hemispheres. It is the topmost region of the brain, and its cortex ("bark" in Greek), or the external layer, has many grooves and fissures in it, and these are known as cortical folding.  The cortex of the cerebrum is called the cerebral cortex, and the frontal portion of the cerebrum is called the frontal lobe.  Each cerebral hemisphere has a frontal lobe, as well as one of each of the other three lobes (they are not to be referenced in this post), and the two hemispheres are connected by what is called the corpus callosum ("tough body" in Latin), which allows the two hemispheres to share information with one another (see the below figure).  The frontal lobe is responsible for planning movements, strategies, and things of that nature (all of which can be conscious processes),  and the information the aforementioned nerves received from the heat source would have to be processed by the frontal lobe, and then processed back to the point of the sensation's origin before the finger would be retracted.  But what exactly causes this process to become 'conscious?'

A visual of the cerebrum, its cortex, its hemispheres, and the corpus callosum. 

       According to Sam Harris, a neurologist as well as author of a number of books including Free Will, the decision making process of the brain is principally subconscious in nature: that is, the decision is made before the individual is aware of it.  The time it takes the individual to become aware of the decision is, as it was in the case of the reflex, much less than a second, although it has led myself to stipulate that perhaps the process of making a decision is akin to a reflex, and that the individual becomes aware of it due to the information being sent to a different region of the brain, as one might become conscious of a reflex due to the spinal cord sending the information concerning it to a different region of the nervous system: the brain.  Therein lies another question: which region?
       Neil R. Carlson's eleventh edition of his textbook The Physiology of Behaviour references a procedure known as the split-brain operation.  This operation is performed on those afflicted with epilepsy so severe that it cannot be controlled with drugs.  Epilepsy is a disorder in which the nerves of one of the cerebral hemispheres becomes overactive.  Those nerves then process through the corpus callosum, and cause nerves in the other hemisphere to become overactive, resulting in what's known as a seizure.  The purpose of the split-brain operation is to cut the corpus callosum, so that the overactive neurons cannot reach the other hemisphere.  This prevents the hemispheres from taking part in interhemispheric communication, or the sharing of information and perceptions between hemispheres, as well as causes rather interesting side effects.  In a case referenced by the same text, a post-op split-brain patient had been reading a book.  The book was in the patient's left hand, and the holding of the book therefore correlated to the right side of the brain (connections to the brain are inverted, i.e. left hand to right hemisphere, etc.). In the brain of this patient, the right hemisphere could not interpret individual components of something, such as words to a text.  Because the right cerebral hemisphere could not read what the book said, it became bored with it and caused the left hand to throw it away.  When it was later discussed, the patient was not aware that the right hemisphere had decided to do so, and simply witnessed his own hand "having a mind of its own."  In his textbook, Carlson has interpreted this as a region of the left cerebral hemisphere being involved in consciousness, and I would agree with this.  However, I would further stipulate that it is not the only region of the cerebrum so involved, so much as any region besides the one from whence the communication originated.
        For example, perhaps the frontal lobe is planning to contract the humerus, the long bone in the forearm.  The individual is at first not aware of this, however becomes so when the frontal lobe communicates with one of the regions of the cerebral hemisphere, either ipsilateral (on the same side) or contralateral (on the other side) to it, that is responsible for associating vision, audition, or other sensory information with memories.  At the point in which these two regions of the brain communicate, is the point at which the individual becomes aware of the frontal lobe's current activity.  An analogy which might be employed to conceptualise this process would be two individuals who are having a conversation, and a third who is listening in.  Equate one of the conversing individuals, individual A, to the frontal lobe, and the other individual, individual B, to the region to which the front lobe is communicating with.  The third person (individual C) is the individual whose brain this is occurring in.  Individual A is planning to buy a pizza to eat.  Individual C is not yet aware of this because individual A has not shared this plan.  When he shares it with individual B, individual B can help individual A figure out where to buy the pizza and how much it might cost.  Individual C is not aware of how each of the individual are forming these ideas, however he has now become aware of the plan to buy the pizza due to his listening to the communication between individuals A and B.  This is what I convict consciousness to be: the communication between different regions of the cerebrum, or perhaps between regions of the cerebrum and different areas of the brain in general.
       In the paragraph previous to my analogy, I stipulated that the region of the cerebrum that did not communicate with the right hemisphere (due to the split-brain op) in the patient was not the only one involved in consciousness.  Why?  The patient was not aware of the right hemisphere's boredom with the book, nor was he aware of its plan to throw the book away, which was due to the procedure performed to cure his severe epilepsy.  Would that then not mean that consciousness is isolated to only one hemisphere (left, in this case) of the brain?  Not necessarily, otherwise how would the individual have made the decision to read the book in the first place?  As I had mentioned previously, I convict the process of formulating plans and decisions is a subconscious one, and that this decision 'reflex' would cause the individual to become aware of it after the fact.  My hypothesis would entail the region of the brain that received the communication from the frontal lobe about its plan to pickup the book caused the individual to become aware of it, however the region of the brain that was supposed to receive information from the frontal lobe of the right cerebral hemisphere about its boredom of reading the book had been disconnected due to the split-brain operation, thus preventing the individual from becoming aware of it.
      This is but one of the many ideas I have concerning the brain and the nature of consciousness, and while I cannot yet ascertain whether or not there is truth in the concept of a 'decision reflex,' I deem it to be entirely plausible, and I look forward to being able to either prove or disprove myself in the future, when I have the means to.


References:

Carlson, Neil R. Physiology of Behavior. Boston: Allyn and Bacon, 2011. Print.

Harris, Sam. Free Will. New York: Free, 2012. Print.