The advances in neuroscience in the past two decades have been as spectacular as the advances in artificial intelligence. A great deal of symbiosis has also developed between the two sciences. A galaxy of the world's most brilliant scientists has contributed to this. Their achievements, however, remind us of what Newton said: "I have seen further because I have stood on the shoulders of giants."
In the high noon of behaviorism in the first half of the twentieth century the search for consciousness had become unfashionable and the very term had become taboo among respectable philosophers. The neuroscientists, thanks to the "two-cultures" syndrome, were fortunately not aware of what was happening on the other side of the fence and they continued their search for the seat of human consciousness. The question of how consciousness is instantiated is central to the study of brain-mind. The man who set them on their search did not have the resources of magnetic resonance imaging or positron emission technology. He had something more powerful, the mind of a genius, and he took the first great step in a sheer leap of scientific observation. His name was Hippocrates.
Hippocrates, who is regarded as the father of scientific medicine taught in the fifth century BC in the Greek island of Kos. His study of epileptics and brain damage cases led him to firmly dispel the notion that the seat of consciousness lay in the diaphragm and the heart even though emotions manifested themselves by sensations in these areas. His observations led him to conclude that the seat of mental life lay in the brain and he said authoritatively—
"Some people say that the heart is the organ with which we think and that it feels pain and anxiety. But it is not so. Men ought to know that from the brain and from the brain only arise our pleasures, joys, laughter and tears. Through it, in particular, we think, see, hear and distinguish the ugly from the beautiful, the bad from the good, the pleasant from the unpleasant... I hold that the brain is the most powerful organ of the human body... Eyes, ears and tongue act in accordance with the discernment of the brain.... To consciousness the brain is messenger...Wherefore I assert that the brain is the interpreter of consciousness. The diaphragm has a name due merely to chance and custom, not to reality and nature."
Aristotle called Hippocrates "The Great Physician." In modern times the great neurosurgeon Wilder Penlleld was so fascinated by his teaching that he wrote a fictional biography called The Torch about "the man as he must have been". Penfield regarded Hippocrates' treatise as the landmark work on the brain-mind studies till the discovery of electric discharges in the brain twenty three centuries later. He focused his studies on the brain incapacitated to perform particular functions because of disease or accidental damage. This set the methodological frame for research on localization of brain functions and the "mapping of the mind" for future generations of neuroscientists.
Hippocrates' conception of the brain as the messenger and interpreter of consciousness has, in the last two decades of the twentieth century, become unbelievably complex and sophisticated. It has become a search for a neural code. Neuroscience as Young says, has become an exercise in showing "how the organization of the brain can be considered as the written script of the program of our lives." He goes on to say that the brain is "an agent issuing instructions after it has decoded (understood) the signals it receives about what is going on around it." How the brain encodes the signals it gets into its own language was explained by the Nobel prize winning neuroscientists David Hubel and Torstein Wessel who worked out the correlations between groups of cells in the visual cortex and images in the visual field. The brain has a language of its own for mapping visual images just as the computer has digital language into which it translates and processes human language and symbols.
The mapping of the brain in the early part of the twentieth century was in fairly simple contour map cartographic terms with various areas delineated to which functions were assigned. Some of the pioneers of brain research, like Broca, Wernicke, Sylvius, Roland and Langerhans are remembered in the names given to different areas, fissures, ducts and glands in the brain. The mapping of the brain is no more like Mercator's projections. It is done in multilayered holograms showing the wired circuitry of the brain—the complex neural pathways between the transducers and the sensory areas.
Hippocrates confidently planted the flag of consciousness on the continent of the brain and there it remains. The precise seat of consciousness, however, continues to be elusive. The pineal gland, the thalamus, the reticular formation, the hippocampus, Broca's and Wernicke's areas have all been put forward at different times as likely candidates. Two thousand five hundred years after Hippocrates set them on their quest the neuroscientists are still searching.
Last Frontier of the Mind - Challenges of the Digital Age, Mohandas Moses, Chapter 3