Abstract

Walter Freeman established a unique approach for interpreting brain processes, perception, cognition, and intentionality. Freeman's neurodynamics approach evokes the concepts of mass action and synchrony in neural populations, and even today is far ahead of the field of dynamical systems in hierarchical brain models. He summarized the essence of his views on the physiology of perception in a landmark paper on the pages of Scientific American in 1991. He spelled out the main components of his neurodynamics theory in that essay, which became a classic in brain theory and cognition. His approach has been hailed by many and attracted a large number of scientists all over the world. At the same time there were fellow scientists who objected to Freeman's approach and dismissed its basic tenets. This love or hate relationship followed Freeman until his death in his home in Berkeley, on 24 April 2016. In the present contribution we review the progress of Freeman's theory of neurodynamics over the past 25 years. We describe his work in light of new developments in experimental and theoretical approaches to brain dynamics, establishing new directions in computational neuroscience, cognitive monitoring, computational and mathematical modelling, field theories of cognition and intelligence, and his quest towards inventing novel engineering applications.