EEGs Disclose Significant Brain Activity Correlated with Synaptic Fickleness

We here study a network of synaptic relations mingling excitatory and inhibitory neuron nodes that displays oscillations quite similar to electroencephalogram (EEG) brain waves, and identify abrupt variations brought about by swift synaptic mediations. We thus conclude that corresponding changes in EEG series surely come from the slowdown of the activity in neuron populations due to synaptic restrictions. The latter happens to generate an imbalance between excitation and inhibition causing a quick explosive increase of excitatory activity, which turns out to be a (first-order) transition among dynamic mental phases. Moreover, near this phase transition, our model system exhibits waves with a strong component in the so-called delta-theta domain that coexist with fast oscillations. These findings provide a simple explanation for the observed delta-gamma and theta-gamma modulation in actual brains, and open a serious and versatile path to understand deeply large amounts of apparently erratic, easily accessible brain data.

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First-order transition features of the triangular Ising model with nearest- and next-nearest-neighbor antiferromagnetic interactions

Physica A Statistical Mechanics and its Applications ◽

10.1016/j.physa.2007.04.051 ◽

2007 ◽

Vol 383 (2) ◽

pp. 351-371 ◽

Cited By ~ 14

Author(s):

A. Malakis ◽

N.G. Fytas ◽

P. Kalozoumis

Keyword(s):

Ising Model ◽

Nearest Neighbor ◽

Order Transition ◽

First Order ◽

First Order Transition

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The relationship between fasting-induced torpor, sleep and waking in laboratory mice

SLEEP ◽

10.1093/sleep/zsab093 ◽

2021 ◽

Author(s):

Yi-Ge Huang ◽

Sarah J Flaherty ◽

Carina A Pothecary ◽

Russell G Foster ◽

Stuart N Peirson ◽

...

Keyword(s):

Body Temperature ◽

Rem Sleep ◽

Brain Activity ◽

Mammalian Species ◽

Nrem Sleep ◽

Laboratory Mice ◽

State Classification ◽

Metabolic Suppression ◽

The Relationship ◽

Electroencephalogram Eeg

Abstract Study objectives Torpor is a regulated and reversible state of metabolic suppression used by many mammalian species to conserve energy. Whereas the relationship between torpor and sleep has been well-studied in seasonal hibernators, less is known about the effects of fasting-induced torpor on states of vigilance and brain activity in laboratory mice. Methods Continuous monitoring of electroencephalogram (EEG), electromyogram (EMG) and surface body temperature was undertaken in adult, male C57BL/6 mice over consecutive days of scheduled restricted feeding. Results All animals showed bouts of hypothermia that became progressively deeper and longer as fasting progressed. EEG and EMG were markedly affected by hypothermia, although the typical electrophysiological signatures of NREM sleep, REM sleep and wakefulness enabled us to perform vigilance-state classification in all cases. Consistent with previous studies, hypothermic bouts were initiated from a state indistinguishable from NREM sleep, with EEG power decreasing gradually in parallel with decreasing surface body temperature. During deep hypothermia, REM sleep was largely abolished, and we observed shivering-associated intense bursts of muscle activity. Conclusions Our study highlights important similarities between EEG signatures of fasting-induced torpor in mice, daily torpor in Djungarian hamsters and hibernation in seasonally-hibernating species. Future studies are necessary to clarify the effects on fasting-induced torpor on subsequent sleep.

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The Effect of Topology on Phase Behavior under Confinement

Processes ◽

10.3390/pr9071220 ◽

2021 ◽

Vol 9 (7) ◽

pp. 1220

Author(s):

Arnout M. P. Boelens ◽

Hamdi A. Tchelepi

Keyword(s):

Phase Behavior ◽

Density Functional ◽

Capillary Condensation ◽

Good Description ◽

Functional Theory ◽

Minkowski Functionals ◽

First Order ◽

Lennard Jones ◽

And Topology ◽

First Order Transition

This work studies how morphology (i.e., the shape of a structure) and topology (i.e., how different structures are connected) influence wall adsorption and capillary condensation under tight confinement. Numerical simulations based on classical density functional theory (cDFT) are run for a wide variety of geometries using both hard-sphere and Lennard-Jones fluids. These cDFT computations are compared to results obtained using the Minkowski functionals. It is found that the Minkowski functionals can provide a good description of the behavior of Lennard-Jones fluids down to small system sizes. In addition, through decomposition of the free energy, the Minkowski functionals provide a good framework to better understand what are the dominant contributions to the phase behavior of a system. Lastly, while studying the phase envelope shift as a function of the Minkowski functionals it is found that topology has a different effect depending on whether the phase transition under consideration is a continuous or a discrete (first-order) transition.

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