Single neurons generate action potentials that express their output in pulse frequencies, so that sensory stimuli can be microscopically expressed as spatial patterns of phase-locked firing of "feature detector" neurons. The visual, auditory, somatic, and olfactory cortices generate dendritic potentials that oscillate at frequencies from 1-100 Hz. These waves reveal macroscopic activity arising from synaptic interactions of millions of neurons. They share a spatially coherent oscillation as a "carrier", by which spatial patterns of amplitude modulation (AM) are transmitted in distinctive configurations, when subjects receive sensory stimuli they have learned to discriminate. These spatial AM patterns are unique to each subject, are not invariant with respect to stimuli, and cannot be derived from the stimuli by logical operations. The "carrier" is aperiodic, usually dispersed over a wide spectral range. Our simulations of the "carrier" indicate that its dynamics is chaotic, and that sequential patterns are freshly constructed during perception, because chaotic systems can create as well as destroy information. The entire experience of a subject, which is embedded in synaptic connections in cortex that were modified during learning, can be brought instantly to bear at each state transition by which a new construction is initiated. It is suggested that "feature binding" revealed by microscopic recording is related to the formation of a "chaotic construct" early in the process of perception.

To explain how stimuli cause consciousness, we have to explain causality. We can't trace linear causal chains from receptors after the first cortical synapse, so we use circular causality to explain neural pattern formation by self-organizing dynamics. But an aspect of intentional action is causality, which we extrapolate to material objects in the world. Thus causality is a property of mind, not matter.

The electrical activity of neurons in brains fluctuates erratically both in terms of pulse trains of single neurons and the dendritic currents of populations of neurons. Obviously the neurons interact with one another in the production of intelligent behavior, so it is reasonable to expect to find evidence for varying degrees of synchronization of their pulse trains and dendritic currents in relation to behavior. However, synaptic communication between neurons depends on propagation of action potentials between neurons, often with appreciable distances between them, and the transmission delays are not compatible with synchronization in any simple way. Evidence is on hand showing that the principal form of synchrony is by establishment of a low degree of covariance among very large numbers of otherwise autonomous neurons, which allows for rapid state transitions of neural populations between successive chaotic basins of attraction along itinerant trajectories. The small fraction of covariant activity is extracted by spatial integration upon axonal transmission over divergent-convergent pathways, through which a remarkable improvement in signal:noise ratio is achieved. The raw traces of local activity show little evidence for synchrony, other than zero-lag correlation, which appears to be largely a statistical artifact. Brains rely less on tight phase-locking of small numbers of repetitively firing neurons and more on low degrees of cooperativity achieved by order parameters influencing very large numbers of neurons. Brains appear to be indifferent to and undisturbed by widely varying time and phase relations between individual neurons and even large semi-autonomous areas of cortex comprising their cooperative neural masses.

Recent interest in consciousness and the mind-brain problem has been fueled by technological advances in brain imaging and computer modeling in artificial intelligence: Can machines be conscious? The machine metaphor originated in Cartesian "reflections" and culminated in 19th century reflexology modeled on Newtonian optics. It replaced the Aquinian view of mind, which was focused on the emergence of intentionality within the body, with control of output by input through brain dynamics. The state variables for neural activity were identified successively with animal spirits, lan vital, electricity, energy, information, and, most recently, Heisenbergian potentia. The source of dynamic structure in brains was conceived to lie outside brains in genetic and environmental determinism. An alternative view has grown in the 20th century from roots in American Pragmatists, particularly John Dewey, and European philosophers, particularly Heidegger and Piaget, by which brains are intrinsically unstable and continually create themselves. This view has new support from neurobiological studies in properties of self-organizing nonlinear dynamic systems. Intentional behavior can only be understood in relation to the chaotic patterns of neural activity that produce it. The machine metaphor remains, but the machine is seen as selfdetermining. 1.

Brain systems operate on many levels of organization, each with its own scales of time and space. Dynamics is applicable to every level, from the atomic to the molecular, and from macromolecular organelles to the neurons into which they are incorporated. In turn the neurons form populations; they form systems, and so on to an embodied brain interacting intentionally with its environment. Each level is "macroscopic" to the one below it and "microscopic" to the one above it. Among the most difficult tasks are those of conceiving and describing the exchanges between levels, seeing that the scales of time and distance are incommensurate, and that causal inference is far more ambiguous between than within levels. That holds for the relation of action potentials from microelectrodes to whole brain activity seen with new techniques for brain imaging: fMRI and PET. A new recourse is to conceive, identify and model an intervening "mesoscopic" level, which is a local selforganizing neural population. Its characteristic activities consist of 'spontaneous' action potentials and EEG dendritic activity. Mesoscopic neurodynamics gives a clear understanding of self-organized chaotic patterns of neural activity in primary sensory areas when significant stimuli arrive. These patterns are created with each sniff, glance, or movement of the head and hands. They are triggered by sensory input, but they are not the result of information processing, and they are not representations of stimuli. They are manifestations of the way in which brains make and test hypotheses. The patterns show that brains do not take information into themselves. They formulate expectations as hypotheses and test them by taking action into the environment. They are not data-driven; they are hypothesisdriven, and all ...

Perception is an intentional action through space in time by which the finite brain explores the infinite world. By acting, the brain thrusts its body into the future spacetime of the world while predicting the sensory consequences. Through perceiving its actions and their results, it remembers its predictions, its actions, and their consequences. To perform these operations the brain, through chaotic dynamics, constructs and uses finite perceptual matrices of spacetime and infers causation. Perceived time differs from world time in ways that are determined by the neural mechanisms of intentionality. In particular, perception of the self in action, through the mechanism of preafference, gives structure and content to the concepts of continuity, contiguity, duration, temporal order, cause, and effect. Perceptual scales are expanded beyond kinesthesia by conversion of time into space, such as by clocks and calendars. Remembered time differs from perceived time in being dependent on awareness, which makes it episodic, fragmentary, and subject to large variations in rates of time lapse in the flow of meanings. The attribution of causal agency to objects and events in the world results from anthropomorphization in accordance with the neural mechanisms of the internal perception of intentional action.

The essential task of brain function is to construct orderly patterns of neural activity from disorderly sensory inputs, so that effective actions can be mounted by the brain, a finite state system, to deal with the world's infinite complexity. Two schools of thought are described, that characterize distinctive sources of the order within brains, one passive, the other active. These schools have profoundly influenced ways two groups of contemporary neuroscientists design their experiments and process their data, so that they have very different perspectives on the roles of noise and chaos in brain function.

Perception is an intentional action by which the finite brain explores the infinite world. By acting, the brain thrusts its body into the future spacetime of the world while predicting the sensory consequences. By perceiving its actions and their results, it remembers its predictions. To perform these operations the brain, through chaotic dynamics, constructs and uses finite perceptual matrices of space, time and causation. Perceived time differs from world time in ways that are determined by the neural mechanisms of intentionality. In particular, perception of the self in action, through the mechanism of preafference, gives structure and content to the concepts of contiguity, duration, temporal order, cause, and effect. Remembered time differs from perceived time in being dependent on awareness, which makes it episodic, fragmentary, and subject to large variations in rates of time lapse in the flow of meanings.

Perception is an intentional action through space in time by which the finite brain explores the infinite world. By acting, the brain thrusts its body into the future spacetime of the world while predicting the sensory consequences. Through perceiving its actions and their results, it remembers its predictions, its actions, and their consequences. To perform these operations the brain, through chaotic dynamics, constructs and uses finite perceptual matrices of spacetime and infers causation. Perceived time differs from world time in ways that are determined by the neural mechanisms of intentionality. In particular, perception of the self in action, through the mechanism of preafference, gives structure and content to the concepts of continuity, contiguity, duration, temporal order, cause, and effect. Perceptual scales are expanded beyond kinesthesia by conversion of time into space, such as by clocks and calendars. Remembered time differs from perceived time in being dependent on awareness, which makes it episodic, fragmentary, and subject to large variations in rates of time lapse in the flow of meanings. The attribution of causal agency to objects and events in the world results from anthropomorphization in accordance with the neural mechanisms of the internal perception of intentional action. Time and Causation 2 Walter J Freeman

It is a major source of contention in brain dynamics as to whether the electrical rhythms of the brain show signs of chaos. Here we discuss evidence for the existence of chaos in a theory of brain electrical activity and provide unique depictions of the dynamics of this model.