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Theoretical electroencephalogram stationary spectrum for a white-noise-driven cortex: evidence for a general anesthetic-induced phase transition.
A model for the dynamics of a cerebral cortex in which inputs to neuronal assemblies are treated as random Gaussian fluctuations about a mean value is presented, suggesting the existence of phase transitions in the cortex. Expand
The Sleep Cycle Modelled as a Cortical Phase Transition
It is argued that the change from slow-wave sleep (SWS) to rapid-eye-movement (REM) sleep can be understood as a first-order phase transition from a low-firing, coherent state to a high-f firing, desychronized cortical state. Expand
Estimating leaf nitrogen concentration in ryegrass ( Lolium spp.) pasture using the chlorophyll red-edge: Theoretical modelling and experimental observations
Chlorophyll red-edge descriptors have been used to estimate leaf nitrogen concentration in ryegrass ( Lolium spp.) pasture. Two-layer model calculations have been used to predict the influence ofExpand
Cortical entropy changes with general anaesthesia: theory and experiment.
It is concluded that spectral entropy may be a sensitive monitor of the consciousness-unconsciousness transition, rather than a progressive indicator of anaesthetic drug effect. Expand
The bispectral index: a measure of depth of sleep?
The Bispectrals Index decreased during increasing depth of sleep in a fashion very similar to the decrease in Bispectral Index that occurs during general anesthesia. Expand
Modelling general anaesthesia as a first-order phase transition in the cortex.
The theory predicts that, as the critical point of phase change into unconsciousness is approached, the electrical fluctuations in cortical activity will grow strongly in amplitude while slowing in frequency, becoming more correlated both in time and in space. Expand
Toward a theory of the general-anesthetic-induced phase transition of the cerebral cortex. I. A thermodynamics analogy.
The significant result is the prediction that the entropy will decrease discontinuously at the moment of induction into unconsciousness, concomitant with a release of "latent heat" which should manifest as a divergence in the analogous heat capacity. Expand
General Anesthetic-induced Seizures Can Be Explained by a Mean-field Model of Cortical Dynamics
A mathematical model of cerebral cortical function is described, finding that subtle changes in the shape of the IPSP—induced by enflurane—are sufficient to cause the model of the cerebral cortex to undergo a sudden change in behavior from a general anesthetic state into a seizure-like state. Expand
Excitatory effects of gap junction blockers on cerebral cortex seizure‐like activity in rats and mice
The effect of gap junction blockade on seizure‐like activity in rat and mouse cerebral cortex slices is investigated, strengthening the case for a role for gap junctions in ictogenesis. Expand
Toward a theory of the general-anesthetic-induced phase transition of the cerebral cortex. II. Numerical simulations, spectral entropy, and correlation times.
Simulation work shows that there is an inverse relationship between spectral entropy H and correlation time T of the soma-voltage fluctuations: H inversely proportional to (ln T), and a theoretical analysis proves that this proportionality becomes exact for an ideal Lorentzian process. Expand