I mentioned awhile back I am reading R. Joseph’s Neuroscience text to review and expand some old learnings. One thing I have not thought about for a long time are some particular lacunae in our consciousness such as phantom limbs, denial of disability, split brain and other disconnection effects, etc. Joseph highlights these in several places to illustrate the sequelae of neurological damage. In these cases the MEMBRAIN may retain its over all integrity surrounding our interiority while fractures hamper its functions of passing information in and out and keeping information in and out.
I talked about split brain phenomena earlier in discussing Jaynes’ book on the “Origin of Consciousness”, i.e., when the corpus callosum is surgically severed in the effort to control seizure activity by confining it to one hemisphere. Joseph relates further anecdotes from this research, such as a patient who was smoking with his left hand while the right kept trying to snatch the cigarette and throw it down and saying, “Stop that.” Here the right hemisphere wants to smoke but the left does not. Because the two are disconnected, they do not present with an integrated intent and instead present as if two minds were extant in one brain, fractured now into two MEMBRAINs containing two interiorities.
Consider the phenomena of a ‘phantom limb’ and its converse of sorts, a ‘neglected limb.’ When someone loses a limb that part of the brain’s connectome which served it retains the memory of that limb for a long time. Even though the person can see it is missing and certainly cannot use it, they feel it, they have impulses to use it, etc. Here the MEMBRAIN keeps in what has passed through and the new information now coming only slowly displaces the old. Even more remarkable in a way, Joseph cites many examples of neglect, which occurs when a perceptual area of the brain is damaged or its connections severed. We see this when a right handed person is asked to draw a clock and they crowd all the numbers into the right portion of the field because their right hemisphere is compromised, so the left portion is virtually (literally) unknown or unperceived. (Everybody remembers that right brain serves left side and vice versa, correct?) When the damage impairs the sensorimotor fields serving a limb, the rest of the brain does not receive innervation from it and so does not ‘know’ it exists. Sometimes the brain confabulates, i.e., makes up information, to fill in the void. A person whose arm has been neurologically disconnected in such a way, when asked about the arm, say to move it or if they can feel touch, will tell the doctor that that arm is not his. When asked whose it is, they will say, ‘It must be yours, doctor,’ and when the doctor holds up his or her two arms, then another story is concocted assigning the arm to someone else. We can more easily detect the neglect here because it involves the perceptual-motor system but other disconnections occur. A person may not show any emotions that they do feel because of the disconnect with areas serving empathic expression or they may not recognize familiar faces, even their own, because of damage to that area, a condition known as prosopagnosia. Some are virtually blind due to stroke damage and still maintain they can see even as they fumble and fall and bump into things.
My interest here arises from how these phenomena demonstrate so concretely the fact that our conscious reality is constructed at a very basic level. This only begins to approach the facts evinced when the construction somehow includes hallucinatory information of all types, e.g., psychiatric, normal, religious, dream states, inspirational, etc. The MEMBRAIN can be fractured in many ways and the interiority then loses some of its integrity as its tie to the sentient world is broken and then fills with information from other realms. Most times but not always a bad thing, that. Dream on.