Principles of Theoretical Neurophysiology

The present book has two origins, one very remote, the other nearer and more contingent. The first goes back to the time when I initiated my career as a neurophysiologist in Pisa, a small town with the advantage of a highly stimulating atmosphere created by two famous institutions, the University and the Scuola Normale Superiore. It came quite natur ally, then, while engaged in experimental work, to start brooding over the possible analogies between neurophysiological problems and those of the physical world. This slowly induced me to become less interested in the solution of the innumerable specific problems presented by the brain, and more in the general principles on which the brain function might be based. Certainly, for several years I had no clear idea of my purposes, or of the difficulties I could encounter in the task. However, it was clear enough that there ought to be a first, indispensable step: the search for methods of quantification of nervous activity, the sole way of allowing predictions about its behavior. At first, I somehow followed the fashion of the time, experiencing the impact of information theory on neurophysiology, but soon this was revealed as unsatisfactory, since it was only one aspect of the problem, and what I was interested in was not a way of describing the flow of information, but rather, the laws of the machinery.

At first, I somehow followed the fashion of the time, experiencing the impact of information theory on neurophysiology, but soon this was revealed as unsatisfactory, since it was only one aspect of the problem, and what I was interested in was not a way of describing the flow of information, but rather, the laws of the machinery.

I General Properties of the Brain.- 1.Introducing the Problem.- 1.1 Standpoints.- 1.2 Procedures and General Plan.- 1.3 The Beyond-the-Physics Problem.- 2. Structural and Functional Properties.- 2.1 The Brain Mass.- 2.2 Structures and Functions.- 2.2.1 Speech Characterizes Humans.- 2.3 Connectivity and Integration.- 2.3.1 Feedback.- 2.4 The Neurochemical Aspects of Brain Organization.- 2.5 Nerve Impulses and Signals.- 2.6 What Shall We Substitute for Structure?.- 3. The Key Property: Organization.- 3.1 Brain Functions Are Unitary Processes.- 3.1.1 Unity of Psyche.- 3.2 A Whole Is More Than the Sum of Its Parts.- 3.3 Maturation and Learning.- 3.4 "Human Whole" and "Brute Whole".- 4. Short Review of Approaches and Methods.- 4.1 The Standpoint "Structure = Function".- 4.2 Electrophysiological Methods.- 4.2.1 Analytical Neurophysiology.- 4.2.2 Microelectrodes.- 4.3 System Analysis.- 4.4 Brain Waves.- 4.5 Methods of Quantification of Nervous Activity.- 4.5.1 Quantification of Nerve Impulses.- 4.5.2 Quantification of Continuous Time Functions.- 4.5.2.1 Frequency Domain Methods.- 4.5.2.2 Time Domain Methods.- 4.5.2.3 Cortical "Evoked Response" Potentials.- 4.5.2.4 The Method of Correlation Between Brain Activities.- 5. Multidimensionality, Homogeneity and Fields.- 5.1 Multidimensionality Versus Unidimensionality.- 5.2 Can We Work with Simpler Systems?.- 5.3 The Problem of Homogeneity.- 5.4 The Hypothesis of the Continuum.- 5.5 Unstructured Activity and the Noise Problem.- 5.5.1 The Processing of the Activity by the Brain.- 5.5.2 Physiological Aspects of Mass Activity.- II Physics and the Brain.- 6. A First Approach: Statistics.- 6.1 Identification of a Framework of Laws.- 6.1.1 Chance and Determination.- 6.2 Statistics and Neuroscience.- 6.2.1 Statistical Mechanics and the Brain.- 6.2.2 Spontaneous and Ongoing Activity.- 6.2.3 Gibbs Ensembles and Steady State Motion.- 6.3 Thermodynamics and Brain Function: The Onsager Representation.- 6.3.1 The Problems of Entropy and Forces.- 7. States of the Brain.- 7.1 States and Stationarity.- 7.2 Identification of Brain States.- 7.2.1 Discrete Physiological States.- 7.2.2 Redefinition of the Concept of State.- 7.3 Quantum State Principles and the Brain.- 7.3.1 States and Vectors.- 8. Dynamic Laws and Transformations of Brain States.- 8.1 Statistical Laws and Deterministic Laws.- 8.2 Dynamic and Nervous Parameters.- 8.2.1 Generalized Coordinates and Energy.- 8.3 The Dynamic Forces in the Nervous System.- 8.3.1 Nervous Generalized Coordinates.- 8.4 States and Vector Relationships.- 8.4.1 Transformations in the Mechanics of States.- 8.4.2 Operators and Brain States.- 9. Reference Systems for Brain Function.- 9.1 Problems of the Brain Space.- 9.2 Properties of the Gaussian Coordinate System.- 9.3 Invariant Functions in the Central Nervous System.- 9.3.1 Which Functions Are Invariant?.- 9.3.2 Time and Space Measurements.- 9.4 Closing Comments.- 10. The Continuum in the Central Nervous System.- 10.1 A Few Basic Ideas.- 10.2 Factors Shaping the Fields of Force in the Nervous System.- 10.3 A Fundamental Concept: The Tensor.- 10.3.1 The Metric Tensor.- 10.3.2 The Metric Tensor in the Central Nervous System.- 10.4 Physiological Forces and Tensors in the Central Nervous System.- 11. Outlines of a Theory.- 11.1 The Physiological Fundaments.- 11.2 Steady States and Transformations.- 11.3 Methods.- 11.4 Perspectives.- 11.5 Gathering the Threads.- 12. On this Side of the Border: Relativistic Aspects.- 12.1 Is There a Brain Relativity?.- 12.2 Time.- 12.3 The Velocity "c" in the Nervous System.- 12.3.1 The Velocities "v" in the Nervous System.- 12.3.2 Mass, Velocity and Energy in the Central Nervous System.- 12.4 Inertial and Accelerated Systems in the Brain.- 12.4.1 The "Observers" in the Brain.- Appendix Beyond the Border: Metaphysics and the Brain A Sample of Problems.- A. 1 Introducing the Problems.- A. 2 Man and Animals.- A. 3 The Intellect.- A. 4 The Continuum.- A. 5 Theology and Neuroscience.- A. 6 Te