Entry #2: All I can think about are brains, or so it seems.

The brain interests me; no surprise there (mentioned it in the last two blogs already). Recently I was reading Plum and Posner's Diagnosis of Stupor and Coma by Jerome B. Posner, Clifford B. Saper, Nicholas D. Schiff and Fred Plum and have found the material very intriguing. In particular a section on consciousness and the difficulty in recognizing this level of brain function caught my attention.

On page 5 it talks about consciousness and it defines it as the ability/process of being cognizant of the self and the environment surrounding and the connection realized between the two. It goes on to describe the difficulties of determining consciousness by simple observation because some patients are conscious but not able to respond. Such as with locked-in syndrome where a patient has paralysis of all four extremities as a result of "de-efferented" nervous system signals. In simpler terms, the signals normally sent through the nervous system from the brain to the body, -efferent- are no longer making that journey and therefore whole body paralysis occurs. The mind remains intact and the patient is fully aware and conscious of the ongoing activity surrounding them, but is not able to easily respond (some individuals can learn to communicate through eye blinks - 1 blink for yes, 2 blinks for no, etc).  

Another possible reason consciousness is difficult to determine would be personal or psychological as a choice of the individual to not respond.

The text goes on to describe how consciousness could be mainly comprised of two parts, the content, as the overall grouping of activity of the brain and arousal of the brain system in function to create the awareness of self and environment. But the intriguingly, interesting part is that if a lesion happens to occur in a certain part of the brain, it could cause what is called functional loss of consciousness. What could happen is better described in direct quote (still from page 5):

"Such patients may have preserved awareness of most stimuli, but having suffered the loss of a critical population of neurons (e.g., for recognizing language symbol content, differences between colors or faces, or the presence of the left side of space), the patient literally becomes unconscious of that class of stimuli. Patients with these deficits are often characterized as "confused" by inexperienced examiners because they do not respond as expected to behavioral stimuli."

What this means is that, patients with certain lesions that affect, or loss of/at certain specialized neuron groups, such as recognizing colors, results in the individual not being able to comprehend the meaning of colors; literally they could have lost the ability to even have a definition of the concept of colors and therefore in relation or as a result, the ability for color identification is impaired. In other words, the content does not arouse the brain system to recognize the stimuli. Furthermore, to someone examining this brain function in the individual, it might erroneously seem as though the individual is merely confused and just needs some time to figure out/remember the colors for example. In actuality it could be that the individual doesn't have the brain function/neurons working properly to do so.

It's fascinating and thought provoking to think of how a small part of of consciousness works and the difficulty in recognizing it in others. But the real question is why am I always thinking about brains? Is it some Freudian subconscious Zombie tendency? I kid, the whole concept of zombies is silly anyways.






Source:
Posner, Jerome B., Clifford B. Saper, Nicholas D. Schiff, and Fred Plum. "Pathophysiology of Signs and Symptoms of Coma." Plum and Posner's Diagnosis of Stupor and Coma. 4th ed. Oxford: Oxford UP, 2007. 5. Print.

Photo credit:
Plum and Posner's Diagnosis of Stupor and Coma.


Updated November 3, 2015 at 9:27 AM