Three Mini-reviews: Focus on the Brain
In Search of Memory: The Emergence of a New Science of Mind
By Eric R. Kandel. Norton, 2006.
|Norton & Co. page for the book|
If signs are more than mere theoretical fallacies, they are bound to correspond to brain states and processes. In particular, it is difficult to conceive of signs independently from the capacity of brains to structure and preserve information, and to use this information as needed in new situations with varied degrees of flexibility. This is why memory research should be of prime interest to Semioticians. A pleasurable way to get acquainted with cutting edge research in this field is to peruse Nobel Prize winner Eric Kandel’s In Search of Memory: The Emergence of a New Science of Mind (2006). This book skillfully blends autobiography with scientific explanations of how memory works. It also offers glimpses of how laboratory research proceeds under complex economic and sociological constraints. An Austrian Jew whose family fled Nazi persecutions and settled in the United States when he was nine years old, Kandel recounts his early fascination with history and Freud’s ideas, and his own determination to provide neuro-physiological evidence for the tenets of psychoanalysis. He soon abandoned this goal when it became obvious that the theoretical simplicity of the model could not be mapped in any realistic way on the complexity of the human brain. He engaged instead in a scientific search for the neuro-chemical processes that explain how experience becomes inscribed in the brain to the point of modifying behavior in a permanent manner and, often, vividly accesses consciousness in remembering. For the sake of convenience, he started his experiments with an organism endowed with comparatively large neurons, a giant sea marine snail called Aplysia californica. This organism has a relatively simple brain in comparison with the primate brain but evolution is very conservative and some basic processes in the treatment of information show remarkable continuity. The brain of Aplysia has only 20,000 neurons grouped into nine separate clusters, or ganglia. Since each ganglion has a small number of cells, researchers can isolate simple behaviors that are controlled by specific groups of neurons. They can then study changes in particular cells as a behavior is altered by learning (p. 147). Kandel retraces the painstaking efforts by successive teams of researchers in various disciplines to understand how memories are formed in the brain, achieving on the way medical advances that have improved the treatment of memory impairments in humans. The book leads us to the last frontier, the quest for an explanation of memory as the richly textured vicarious experience of the past that can be at times actualized in consciousness and prompts us to act in certain specific ways. Such an understanding cannot be disconnected from the processes that have been identified through the research that Kandel and others have reported, and which continues to be intensively investigated, notably in the context of research on Alzheimer’s Disease, the progressive degradation and eventual collapse of human semiotic competence.
Brain Arousal and Information Theory: Neural and Genetic Mechanisms
|Harvard University Press page for the book|
By Donald Pfaff. Harvard University Press, 2006.
Central nervous system arousal is fundamental to all cognitive and emotional functions. When Semioticians refer to semiosis in a human context or with respect to inter-specific communication, they must assume a degree of brain arousal and a range of sensitivities to various kinds of information that have been selected in the course of evolution. Endo- and exosemiotics necessarily involve sensory and proprioceptive alertness, motor activity, and emotional response. Donald Pfaff, a Professor of Neurobiology and Behavior at The Rockefeller University, first endeavors in this provocative book to formulate a universal definition of arousal that is both elementary and fundamental, primitive and undifferentiated. He relies on contemporary neural and genetic techniques to measure with precision the physical variables of what could be broadly called the primal semiotic function of the brain. What modifications from whatever sources in the environment command attention, and how the brain becomes alive to, and makes sense of such information form the main focus of this book. Pfaff uses Shannon’s theory of information (information is an event that is in inverse proportion to its probability) as a basis for the interpretation of neurological and behavioral data. His comprehensive explanations are drawn from the tenets of evolutionary biology. Many questions are raised in the course of the book as his approach is not dogmatic but heuristic. His theory is nevertheless formulated in view of state of the art research in the many disciplines from which he draws the data supporting his argument. Special attention is paid to olfaction and vision but the whole range of sensory inputs is covered in this daring synthesis. The substantial chapter concerning fear and sexual arousal (p. 99-125) is particularly engaging.
Rhythms of the Brain
By György Buzsáki. Oxford University Press, 2006.
|Oxford University Press page for the book|
Time is one of the blind spots of semiotics. Saussure repeatedly asserts in his manuscripts that in language, and presumably in all other semiological domains, time is of essence. This undoubtedly accounts for the intractability of the problem which prevented him from publishing any work in general linguistics. The Course is a posthumous (and questionable) reconstruction that glosses over this fundamental issue. Peirce famously brought time into semiotics with the notion of (infinite) semiosis. In later thinkers influenced by Marxist dialectics the temporality of signs became conceptualized as dialogical. But what is the use of time for understanding the temporal dimension of signs if it is not measured and remains a vague, Heraclitean philosophical notion embedded in Euclidean geometry? A fascinating book by Hungarian neuroscientist György Buzsáki, who teaches at Rutgers University, sheds some light on some fundamental aspects of the ticking brain. The author encapsulates the gist of his work as follows: “Brains are foretelling devices and their predictive powers emerge from the various rhythms they perpetually generate. At the same time, brain activity can be tuned to become an ideal observer of the environment, due to an organized system of rhythms.” What most Semioticians categorize as signs are ultimately elements or nodes in anticipatory structures or processes. But as long as their psychological horizon remains bounded by William James’s or James J. Gibson’s works, whatever the respective merits of these works were in their own time, they will hardly be able to advance beyond the type of folk semiotics that may fascinate undergraduate students but sounds totally irrelevant to the great majority of researchers in the cognitive neurosciences who address the very same questions which were at the origin of early semiotic thinkers’ speculations. Buzsáki’s book is written with clarity with a view to communicate numerous results of experiments to a wide constituency of researchers and to discuss their significance in terms of the larger picture. Its highly informative 400 pages require sustained attention and efforts but are not intimidating. It is rooted in a rich humanist tradition as the interpretations of the technical data are often related to, or framed within philosophical, literary and musical experience. In addition to being based in part on the author’s own research, Rhythms of the Brain can be characterized as an up-to-date encyclopedia of contemporary research as it offers a meta-analysis of over a thousand scientific works bearing on the ways in which the brain deals with, and generates temporal information. While the text itself is highly reader-friendly for a non-specialist, the numerous footnotes provide references and details intended for neuroscientists. Interested readers would benefit from also perusing Sync: The Emerging Science of Spontaneous Order (2003), an inspiring book by Steven Strogatz, a Professor of Applied Mathematics at Cornell University.