Freeman’S Review

Karl Pribram’s Book 1 Walter Freeman’s Review BOOK REVIEW Title: The Form Within: My Point of View Author: Karl H Pribram MD Publisher: Westport CT: Prospecta Press ISBN: 978-1935212-80-5 Date: 2013 Reviewer: Walter J Freeman MD Dept of Molecular & Cell Biology University of California at Berkeley Berkeley CA 94720 USA Phone 1-510-642-4220 [email protected] Length: 1,997 words, 4 pages 22 March 2014 Cognitive neuroscience is in disarray. The neural mechanisms of locomotion, navigation, and manipulation of objects are well in hand, as witnessed by advances in information technology, robotics and space exploration. What we lack is an understanding of the mechanisms of mind. The urgency of perceived need is attested by the massive funding allocated for brain research in programs in Europe, North America and Asia. The programs are modeled on the Manhattan Project and the Human Genome Project, despite the difference that while the theories of nuclear fission and of the double helix were well enough developed to support large-scale engineering applications, in contrast, neuroscientists cannot tell us how minds work. For examples, we do not understand how brains make and use symbols, or how natural languages work, or how to solve the framing problem, or how to illuminate the mysteries of consciousness. At best we can enhance our existing techniques to increase our rates of data collection and facilitate our large-scale storage and retrieval by data mining for analysis using existing theory. Karl Pribram believes there is a better way than megaprojects to learn how minds work. As a neurosurgeon he believes that the answers must come from studies of brain activities as and when the subjects are performing cognitive tasks with normal brains or brains that are modified by disease or by surgical intervention. At the age of 94 he has written in conversational style an amazingly clear, voluminously detailed, yet easily accessible description of his experiments over the past seven decades in neurocognition by man and animals. He insists that his book is not an autobiography; rather he has written an intellectual history in which he describes his thoughts and conjectures, and those of his students and colleagues, as they planned their experiments and analyzed their results. Thereby he enables his readers to experience what it is like to be in the laboratory as scientific facts emerge. He introduces personalities to match the legendary achievements of major actors in the growth of neuroscience in the 20th century. This is his valuable legacy, which will inform the next two or three generations in the on-going search for solutions to the mysteries of mind. When Karl came on the scene in the 1940s, brain-mind research worldwide was disorganized and in conflict or isolation. Earlier, in the second half of the nineteenth century, there had been enthusiastic unity in adoption of a thermodynamic model advanced by Hermann Helmholtz and colleagues, which was based on the thermodynamic concept of “nerve energy” and “nerve force”. This conceptual advance enabled scientists and clinicians of all persuasions to replace mystical “animal spirits” with something tangible and measureable and expel all vestiges of “vitalism” from science. However, during the scientific revolution at the end of the century, the consensus disintegrated, when biophysicists showed that “nerve energy” is not conserved and cannot be measured. Lacking a shared foundation in science, neurologists and psychiatrists on the whole stopped talking with each other Karl Pribram’s Book 2 Walter Freeman’s Review and formed diverse schools. Among these schools were the behaviorists who denied altogether that mind was subject to scientific investigation. On the other side, Sigmund Freud abandoned brain science and concentrated on the psychology of mind, as Karl discusses in his book. The importance of Karl’s illuminating recollections stems from his strong conviction of the necessity for studies simultaneously of the properties of brain and mind. As Karl relates in his book, after he completed his training in medicine and neurosurgery, he engaged in neurocognitive research on primates under Karl Lashley, the leading neuropsychologist of the era, who became famous for his ultimately failed search for the location of memories (“engrams”) in brains. He immersed himself in the rich heritage of neurological, psychiatric and bio-behavioral research accreting through the two world wars and the depression, most notably the theory of “central excitatory state (c.e.s.) of Sir Charles Sherrington (1929), the “Gestalt” theory of Wolfgang Köhler (1941), and the “mass action” theory of Karl Lashley (1952). Their data and concepts constituted the paradigm of “neural fields” that Karl has pursued now into the 21st century. With characteristic flair he often used holography to demonstrate the principle of distributed memory by simply removing the condenser from his slide projector and recovering the same image from all parts of the unfocused field. At this juncture Karl collaborated with Köhler by testing Köhler’s hypothesis that perception operates by cortex constructing representations of stimuli by making images of them in “geometric isomorphism”. Köhler made a fatal category error when he identified the perceptual vector fields of the Gestalts with the scalar DC electric fields of the EEG, and replaced “nerve energy” of thermodynamics with “electric energy” of the EEG. Karl reports in his book that he and Roger Sperry among others quickly disproved the hypothesis that the EEG extracellular electric fields of ionic current played any causal role in Gestalt formation. More recently Karl has explored other aspects of the use of EEG and ECoG, but in the 1950s the damage was done. The EEG was relegated to the status of noise far removed from the primacy of action potentials, and was treated as “the roar of a crowd at a football team.” Field theory was banished from mainstream neuroscience. The isolation was compounded by the historical fact, which was described by Thomas Kuhn in his path-finding analysis, “The Structure of Scientific Revolutions” (1962), that work in one paradigm cannot disprove another, because paradigms differ in axioms, methods, classic experiments, rules of evidence, and heroes. One replaces another when the other becomes paralyzed with paradoxes and intractable failures that the one resolves. The process requires a generation to die and be replaced. I know this history because I lived through a significant part of it. Karl was my teacher in the Yale School of Medicine in 1950 and read my thesis. He has been my mentor ever since. I am grateful for his leadership and friendship. Hence conflict within neuroscience persists. Beginning in the 1950s mainstream neuroengineers and systems analysts modified the 19th century thermodynamic model by replacing “nerve energy” with “information” (Freeman, 2007). Thereby they created a new paradigm of “neural pulses”. Every textbook of neurophysiology in that era stated that action potentials were the sole means of communication between neurons in the brain. With a single chop, engineers and neuroscientists alike discarded half the electrical activity of the brain. With great confidence they revised the “nerve energy” paradigm by replacing it with it with “information”. They located information sources and sinks in the body and the environment. They conceived the sensory receptors as transducing energy from the environment and coding it as “ information” in trains of pulses. They replaced the “channels” of nerve tracts that carried “nerve energy” with single axons and dendrites like wires, which they represented with drawings of Golgi stains done by neuroanatomists Ramon y Cajal and his last graduate student Rafael Lorente de Nó. They modeled “information processing” by treating action potentials as binary digits that served as symbols in symbolic dynamics. They adopted Claude Shannon’s information theory despite Shannon’s vociferous opposition to application of his theory to problems in semantics. These diverse developments in brain theory in the 1950s coincided with the perfection of engineering techniques for recording action potentials from the brains of animals and humans who were fully alert and engaged in cognitive tasks. Neuroscientists flocked to the new Karl Pribram’s Book 3 Walter Freeman’s Review paradigm of “neural pulses”, much as they had to the doctrine of “nerve energy” a century before, while the paradigm of “neural fields” fell into relative obscurity. Disunity prevails because a strict interpretation of the Neuron Doctrine excludes field effects and insists that the pulse is the sole carrier of neural information, despite numerous discoveries of spikeless neurons, gap junctions, ephapsis, etc. in the past six decades. The action potential persists as the gold standard for observation and interpretation of neural activity. What is at issue may seem to resemble the wave-particle duality in quantum theory, but the disagreement is epistemological, not ontological, theoretical and not experimental. For the pulse paradigm the firing of a neuron is conceived as a “representation” of an action, object, person or “concept” according to Rodgrico Quian Quiroga (2013). The sensory information from the environment is combined with information stored in memory and condensed into a point in space- time. The pulse is treated as a symbol of what it represents. The length of a train of pulses represents the degree of certainty of the retrieved information. Information processing is by symbolic dynamics. For the field paradigm the firing of a neuron is seen as a random instantiation of a pulse in a time- space window over an interactive neural population. The population is creating a wave function that is carried by all of the neurons by time-sharing. The firing looks random in the recording of individual pulse trains, but it is seen as synchronized in multiple pulse trains recorded simultaneously or by correlation with the local field potential. The wave function is defined by integration over time-space of the impact of the transmitted pulse on all neurons to which the axon carries the pulse.

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