If you've never heard of Phineas Gage, it's time you did. He was a railroad construction supervisor. In 1848, at age 25, he was using a custom-made tamping rod to pack gunpowder in a drilled hole. He was very good at it, but this time he struck a spark. The rod was blasted upward: Entering at his right cheekbone, it went right through his head, exiting out the top where a baby's soft spot is, and landed about 25 yards away.Although the 16-pound rod performed a hemi-lobotomy, destroying his left frontal lobe, he never lost consciousness. He needed a lot of a doctor's care to recover, physically. His personality changed, but not so much as one might think. He was a neurological wonder for a couple of years, but moved to South America for a few more years, where he worked as a muleteer. Returning to the U.S. to his family in California, at age 34 he weakened and died. This Daguerreotype was made when he was about 28. He carried "his rod" with him at all times, and it was buried with him.
So little is known about him that apocryphal stories abound, based on no more than one or two statements by family members, that "he wasn't Phineas Gage any more." Yet in many ways he still really was Phineas Gage, a Phineas who had lost certain planning abilities, and a lot of "stick-to-it-iveness", but his memories were continuous. He had no amnesia, in contrast to many victims of traumatic brain injuries.
One might say that his mind was more intact than the body of a quadriplegic is. We don't say, after someone has lost the use of both arms and both legs, that "he isn't so-and-so any more." We actually expect a certain and significant change of personality due to the loss alone; at least some depression. Was Gage's loss any greater?
Let's go back to the beginning. At what level are we to look, in the brain, for the "seat of the mind"? In The Tale of the Dueling Neurosurgeons: The History of the Human Brain as Revealed by True Stories of Trauma, Madness, and Recovery, by Sam Kean, while he starts with a story a few centuries older than Gage's, he then takes us from the small to the large, in a search for what makes our minds tick. The opening chapter, the title chapter, tells the story of a horrible injury suffered by Henri II of France in 1559, during a joust. When his opponent's wooden lance splintered against his shield, a large piece entered below his eye, slammed to a stop at the back of his skull, and broke off.
During the eleven days until his death, the king was attended by the two best brain surgeons of the day, his own surgeon Ambroise Paré, and the famed anatomist Andreas Vesalius. The two doctors had different backgrounds, but they didn't really "duel". Each following his own experience and learning, they came to the same diagnosis, which agreed with the sketchy autopsy that was allowed after the king's death. Sam Kean begins with this story because its details foreshadow all of the significant developments in neuroscience over the following 450+ years.
I would love to dwell on the details brought out in all the twelve chapters of the book. But let us allow the author to tell his own tales. The chapters subsequent to the story of Henri II do indeed begin small, and advance to larger and larger structures and systems. The earliest debate was between those who believed the brain's signaling was entirely electrical (the "sparks") and those who believed it was primarily chemical (the "soups"). It turned out to be both, and the experiments that winkled out the various neurochemicals are worthy of a book or two of their own (I haven't looked, but I suspect that such books already exist).
Then, are the stringy things that make up so much of the brain a continuous network, or cells with long "wires" that connect them to other cells? The latter, but it took some silver nitrate solution spilled by Camillo Golgi to settle the matter. Although the consistency of the brain is about like ripe avocado, when one is extracted whole and toughened up chemically, to be more like well-set jello, various structures can be discerned, that have names like Thalamus, Hippocampus, Cerebellum, and the various lobes of the Cortex. It seems obvious to me that the physical structures indicate certain functions. Further, once the columns in the cortex were discerned microscopically, one would think they at least hint at a certain amount of specialization. But a debate raged for years between "functionalists" and those who insisted that the brain is a tabula rasa, a blank tablet, on which experience alone impresses its marks. The reality is a bit of both. Not just functions but proclivities of many sorts are with us from before birth, but there is lots of room for "writing" to be done; without the latter we'd have a hard time making memories.
Step by step, system by system, we traverse the realms of neuroscience, until the great question is asked: What of consciousness? It was once thought to be embodied in the Pituitary Gland. Later, in the frontal lobes. Most parts of the brain have had, and still have, their proponents. The author brings us this bit of clarity from V. S. Ramachandran, from his book Phantoms in the Brain: Consider any episode of a popular TV show such as Baywatch. Where is it located?
On the beach where the actors were filmed? In the camera that recorded the drama? In the cables pumping bits into your television? In the television itself? … in the storm of photons arriving at your eyes? Perhaps in your brain itself?
The best phrase of the book has the only answer we can discern:
Consciousness is not a thing in a place but a process in a population.
I once said in a sophomoric speech that "the mind is the program that runs in the brain." That's synonymous to the prior statement, just not as well put.
Here is a fact that surprised me when I first learned it, no more than a few years ago: We read in many places that the human brain contains about 100 billion neurons. I asked one day, of Google, for a breakdown of the brain's neuron count by brain structure or system. It wasn't easy to dig through the returns for something useful! This article (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2776484/) tells me this: the total brain contains about 86 billion neurons, including 14-16 billion in the cerebral cortex ("gray matter"), and most of the rest in the cerebellum, the "little brain" at the back, that controls our body. It seems about a billion neurons each are to be found in the brainstem and limbic system.
That means the vaunted "higher brain functions" that make us human use less than 20% of the neurons in the brain. Throw in the "reptile brain" and the "rat brain" in which our emotions and reflexes lie, and the total is very close to 20%. Nearly 70 billion neurons (~80%) take care of running the body. In all this, I don't know where the "subconscious" lies, and I don't think anyone else knows for sure.
Also, there is no singular brain location "for" any particular skill or function or even memory. SPECT and fMRI scans taken while a person is reading, playing music, adding 3-digit numbers, or whatever, display activity in widely spread regions throughout the cortex and underlying structures. Yes, you can touch someone's brain with an electrode and evoke, for example, the taste and smell of chocolate ice cream, as first experienced "that day on Coney Island". But ask the person to re-evoke that memory without the electrode while in a scanner, and not only does that spot light up, but so do several others. This holographic character of the brain, and memories in particular, must underlie the ability of Phineas Gage and others to lose big chunks of brain without necessarily losing any significant amount of memory.
On the other hand, an area such as the hippocampus, which is seen to be in use no matter what memory we evoke, seems to be a switching center. Lose it, and profound amnesia can result. Other regions are equally specialized. Some stuff is local, and some is not.
Stepping back, we seem to have produced something similar to the brain, at least as regards organization, in the Internet itself. It is not found in any one place; it is delocalized. Big chunks of it can be disabled (such as by a denial-of-service attack on a set of servers), but the rest just keeps ticking along. Can the Internet become conscious? I don't know. (Sam Kean doesn't go there). For those who think it already became conscious, the burden of proof is on them to show us the initiative we'd expect of a conscious entity.
Meanwhile, our brains are still the most complex items in the Universe. If all but one human were killed, and there were no aliens anywhere, that person's brain would contain more than half the complexity of the entire universe. We have a huge way to go towards understanding more than just a little. The "just a little" we know already is fascinating, and this book uncorks a lot of it for us.
The Rebus:
Limbic System
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