<i>From Being to Becoming: Time and Complexity in the Physical Sciences</i>

Prigogine, Ilya; Hiebert, Erwin N.

doi:10.1063/1.2890013

Cited by 662 publications

(762 citation statements)

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“…Each domain has a carrier wave of dendritic currents with a phase cone and amplitude fluctuations whose sum with the dendritic currents of other domains creates the background EEG. Most of these cooperative states are quenched [Prigogine, 1980], but some of them provide the seeds for growth of amplitude patterns that emerge in the plateaus of phase stability. The durations, recurrence intervals, and apparently the diameters had power-law distributions, which along with the 1/f PSD T and 1/f PSD X indicated scale-free dynamics with self-similarity of spatial conic patterns.…”

Section: Discussionmentioning

confidence: 99%

Dynamics of human neocortex that optimizes its stability and flexibility

Freeman¹,

Holmes²,

West³

et al. 2006

Int. J. Intell. Syst.

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The electroencephalogram (EEG) in normal resting subjects is robustly stable. In epileptic subjects it reveals instability. We investigated EEGs in states of a neurosurgical patient awake and at rest, in sleep, and in intractable partial complex seizures. We used a microgrid array of 64 electrodes in a 1x1 cm window fixed on the right inferior temporal gyrus. EEG signals were recorded during a week of neurosurgical evaluation for treatment. Comparisons with normal intracranial EEG were perforce made with data from animal studies. Analytic phase and amplitude were calculated with the Hilbert transform to get the temporal resolution needed to reveal spatiotemporal structure in the background EEG, The rest state revealed multiple overlapping patterns of local coherent oscillations in the beta range with conic phase gradients that had the appearance of bubbles in a pan of boiling water or droplets condensing and evaporating in fog. Cone diameters gave estimates of the distances across cortex over which the cortical oscillations were synchronized. Superimposed on shorter and smaller phase cones were larger and longer epochs of phase locking with briefly near-constant frequency and high amplitude. These coordinated analytic phase differences (CAPD) occurred between short periods of high spatial variance in phase differences. We interpreted the variance as evidence for phase transitions between transiently stable states, each demarcated by a stable phase cone. In sleep the phase cones and CAPD persisted with reduced amplitude, occasionally interrupted by long-lasting (~1 s) epochs with no spatial textures in phase and amplitude despite large increases in amplitude. A local seizure consisted of high amplitude 3/s waves with a steep spatial gradient of amplitude over the array. Seizure onset was seen after a pre-ictal period marked by reduction in cone diameters and related evidence for large-scale disintegration that appeared to accompany or lead to loss of cortical metastability.Stability and flexibility of human neocortex 3Freeman, Holmes, West, Vanhatalo

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Section: Discussionmentioning

confidence: 99%

Dynamics of human neocortex that optimizes its stability and flexibility

Freeman¹,

Holmes²,

West³

et al. 2006

Int. J. Intell. Syst.

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“…The emergence of order is symmetry breaking, and it carries the neocortex far from the pseudoequilibrium of its self-Walter J Freeman http://sulcus.berkeley.edu/wjf/EG_EEGPart1AnalyticAmplitude.pdf organized stable state, so that the order parameter can vary with time, which it cannot do in a system maintained at equilibrium. As shown by Prigogine (1980) and Haken (1983) the approach of a system far from equilibrium to a critical state transition is manifested by slowing of the rate of change in the order parameter and by increased amplitude of oscillations in the output. These are the changes that are revealed by R e , D e , and A(t).…”

Section: Implications Of the Hypothesismentioning

confidence: 99%

Origin, structure, and role of background EEG activity. Part 1. Analytic amplitude

Freeman

2004

Clinical Neurophysiology

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Objective: To explain the neural mechanisms of spontaneous EEG by measuring the spatiotemporal patterns of synchrony among beta-gamma oscillations during perception. Methods: EEGs were measured from 8x8 (5.6x5.6 mm) arrays fixed on the surfaces of primary sensory areas in rabbits that were trained to discriminate visual, auditory or tactile conditioned stimuli (CSs) eliciting conditioned responses (CRs). EEG preprocessing was by (i) band pass filtering to extract the beta-gamma range (deleting theta-alpha); (ii) low-pass spatial filtering (not high-pass Laplacians used for localization), (iii) spatial averaging (not time averaging used for evoked potentials), and (iv) close spacing of 64 electrodes for simultaneous recording in each area (not sampling single signals from several areas); (v) novel algorithms were devised to measure synchrony and spatial pattern stability by calculating variances among patterns in 64-space derived from the 8x8 arrays (not by fitting equivalent dipoles). These methodological differences are crucial for the proposed new perspective on EEG. Results: Spatial patterns of beta-gamma EEG emerged following sudden jumps in cortical activity called "state transitions". Each transition began with an abrupt phase re-setting to a new value on every channel, followed sequentially by re-synchronization, spatial pattern stabilization, and a dramatic increase in pattern amplitude. State transitions recurred at varying intervals in the theta range. A novel parameter was devised to estimate the perceptual information in the betagamma EEG, which disclosed 2 to 4 patterns with high information content in the CS-CR interval on each trial; each began with a state transition and lasted ~.1 s. Conclusions:The function of each primary sensory neocortex was discontinuous; discrete spatial patterns occurred in frames like those in cinema. The frames before and after the CS-CR interval had low content. Significance: Derivation and interpretation of unit data in studies of perception might benefit from using multichannel EEG recordings to define distinctive epochs that are demarcated by state transitions of neocortical dynamics in the CS-CR intervals, particularly in consideration of the possibility that EEG may reveal recurring episodes of exchange and sharing of perceptual information among multiple sensory cortices. Simultaneously recorded, multichannel betagamma EEG might assist in the interpretation of images derived by fMRI, since high betagamma EEG amplitudes imply high rates of energy utilization. The spatial pattern intermittency provides a tag to distinguish gamma bursts from contaminating EMG activity in scalp recording in order to establish beta-gamma recording as a standard clinical tool. Finally, EEG cannot fail to have a major impact on brain theory.Background EEG analytic amplitude 3Walter J Freeman http://sulcus.berkeley.edu/wjf/EG_EEGPart1AnalyticAmplitude.pdf Cover Figure Legend:The EEG shows that neocortex processes information in frames like a cinema. The perceptual content is foun...

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“…Ilya Prigogine (1980) has applied his theory of ''dissipative structures'', which feed on energy and evolve complex patterns in states that are far from equilibrium, to understand the nonlinear dynamics of brains. Hermann Haken (1983) has applied his theory of synergetics to comprehend the physical principles, by which masses of neurons can interact to generate spatiotemporal patterns of activity.…”

Section: Nonlinear Brain Dynamics and Neuroexistentialismmentioning

confidence: 99%