| 1 | Name: | Dr. Vernon B. Mountcastle | |
| Institution: | Johns Hopkins University | ||
| Year Elected: | 1976 | ||
| Class: | 2. Biological Sciences | ||
| Subdivision: | 209. Neurobiology | ||
| Residency: | Resident | ||
| Living? : | Deceased | ||
| Birth Date: | 1918 | ||
| Death Date: | January 11, 2015 | ||
Vernon B. Mountcastle was born in Shelbyville, Kentucky, educated in the public schools of Roanoke, Virginia and attended Roanoke College, Salem, Virginia, from which he graduated in 1938 with honors in chemistry. He then attended Johns Hopkins University School of Medicine in Baltimore, Maryland. He received his MD in 1942 and interned in Surgery at the Johns Hopkins Hospital, July 1942-43. He then served in the U.S. Naval Amphibious Forces for three years, with two major campaigns in the European Theater of War: Anzio, Italy and Normandy, France. Following demobilization, he had the intent to follow a career in Neurosurgery, and in preparation went to spend a year in the research laboratories in Neurophysiology with Professor Philip Bard, then director of the Department of Physiology. He never left, and spent his entire career in research on the function of the brain, and at Johns Hopkins. Mountcastle was director of the Department of Physiology from 1964-80, and then became for nine years Director of the Philip Bard Laboratories of Neurophysiology. He retired from active laboratory work and in that time established the Mind-Brain Institute, located on the arts and sciences campus of Johns Hopkins University. He spent his retirement years in writing monographs, including Perceptual Neuroscience. The Cerebral Cortex and The Sensory Hand. Neural Mechanisms in Somatice Sensation. Dr. Mountcastle married Miss Nancy Clayton Pierpont of Salem, Virginia in 1945. They have two surviving children and six grandchildren. His hobbies were English literature and history. He had also been an avid sailor, tennis player and horseman most of his life. Vernon Mountcastle contributed to understanding brain functions in four areas: (a) the functional organization of the somatic afferent system and cerebral cortex; (b) the dynamic mechanisms of signal processing in the somatic afferent system; © the correlation between sensory performance and central neural events in waking, non-human primates and the general laws governing those relations; and (d) the neural mechanisms of the parietal lobe system in spatial perception and directed visual attention. He showed by electrophysiological methods the precise representation of the body form in the somatic afferent system at levels of thalamus and cortex, and demonstrated the specificity of sets of columns, modular units composed of chains of neurons powerfully connected in the vertical, trans-laminar directions. This was confirmed in anesthetized and waking cats and monkeys, in both the sensory and association areas of the cortex. It is now generally accepted as a principle of organization of the cerebral cortex, and is incorporated into present concepts of cortical distributed systems. Mountcastle then used the method of single neuron analysis to explore the dynamic neuronal operations in the somatic afferent system, and how they relate to somatic sensory performance. He conceived that this could be done by direct, simultaneous application of the methods and concepts of Psychophysics and Neurophysiology, together with new methods for studying the higher functions of the brain in performing, non-human primates. This general method is now a widely used and productive method in CNS physiology. The general principle evolving from this series of investigations is that the relation of the observer (monkey or human) to events in the external world varied along quantitative continua set by the transducing properties of the receptors and first-order fibers engaged by the stimuli. Thereafter, the relation of performance to central neural events along a linear continuum. This generality has been confirmed for a number of somesthetic submodalities. An extensive series of experiments was carried out on the sense of vibration, which provides a signature of the temporal order of the impulses discharges evoked by the vibrating stimuli. Studies were made from the level of the first-order input in monkeys to that of sensory performance measured in psychophysical experiments in monkeys and humans: the functional properties of neural elements are identical in the two primates. This included direct studies of cortical activity during detections and discriminations. A major finding was that the neural code in the postcentral somatic sensory cortex upon which discrimination depends is the temporal order of impulse discharge. This was later pursued to define the code transformations that intervene between the input portal in the somatic sensory cortex of the postcentral gyrus to the output from the motor cortex leading to overt discrimination. A major change was a shift of emphasis from study of sensory systems to that of higher functions, particularly of the parietal lobe system. This required new methods and new concepts to deal with the conditionality of higher functions. It was discovered that sets of parietal lobe neurons were embedded in distributed systems that control the projection of the arm towards a target, the shaping of a hand to grasp the target, and sets differentially active during directed visual attention. It was then found that the visual world is represented in the parietal lobe system in a manner completely different from that of the striate system. It provides a halo surrounding the head of extreme sensitivity to visual events in the immediate behavioral surround, of the flow of the visual world during movements of the eyes, head and body. These neural mechanisms are inferred to serve the illusions of vection. This work opened for direct electrophysiological study the higher functions of the brain, a research program now actively pursued in many laboratories. It has led to a deeper understanding of the disorders of attentions and of consciousness that follows parietal lobe lesions in man. Vernon Mountcastle died January 11, 2015, at age 96, at his home in Baltimore, Maryland. He had been awarded the American Philosophical Society's Karl Spencer Lashley Award in 1974 and was elected to its membership in 1976. | |||