269,893 research outputs found
Plasma Brain Dynamics (PBD): A Mechanism for EEG Waves Under Human Consciousness
EEG signals are records of nonlinear solitary waves in human brains. The waves have several types (e.g., α, β, γ, θ, δ) in response to different levels of consciousness. They are classified into two groups: Group-1 consists of complex storm-like waves (α, β, and γ); Group-2 is composed of simple quasilinear waves (θ and δ). In order to elucidate the mechanism of EEG wave formation and propagation, this paper extends the Vlasov-Maxwell equations of Plasma Brain Dynamics (PBD) to a set of two-fluid, self-similar, nonlinear solitary wave equations. Numerical simulations are performed for different EEG signals. Main results include: (1) The excitation and propagation of the EEG wave packets are dependent of electric and magnetic fields, brain aqua-ions, electron and ion temperatures, masses, and their initial fluid speeds; (2) Group-1 complex waves contain three ingredients: the high-frequency ion-acoustic (IA) mode, the intermediate-frequency lower-hybrid (LH) mode, and, the low-frequency ion-cyclotron (IC) mode; (3) Group-2 simple waves fall within the IA band, featured by one or a combination of the three envelopes: sinusoidal, sawtooth, and spiky/bipolar. The study proposes an alternative model to Quantum Brain Dynamics (QBD) by suggesting that the formation and propagation of the nonlinear solitary EEG waves in the brain have the same mechanism as that of the waves in space plasmas
Discrete structure of the brain rhythms
Neuronal activity in the brain generates synchronous oscillations of the
Local Field Potential (LFP). The traditional analyses of the LFPs are based on
decomposing the signal into simpler components, such as sinusoidal harmonics.
However, a common drawback of such methods is that the decomposition primitives
are usually presumed from the onset, which may bias our understanding of the
signal's structure. Here, we introduce an alternative approach that allows an
impartial, high resolution, hands-off decomposition of the brain waves into a
small number of discrete, frequency-modulated oscillatory processes, which we
call oscillons. In particular, we demonstrate that mouse hippocampal LFP
contain a single oscillon that occupies the -frequency band and a
couple of -oscillons that correspond, respectively, to slow and fast
-waves. Since the oscillons were identified empirically, they may
represent the actual, physical structure of synchronous oscillations in
neuronal ensembles, whereas Fourier-defined "brain waves" are nothing but
poorly resolved oscillons.Comment: 17 pages, 9 figure
How the stomach and the brain work together at rest
Low-frequency electrical waves in the stomach seem to be synchronised with the activity of a newly discovered resting-state network in the human brain
Raising argument strength using negative evidence: A constraint on models of induction
Both intuitively, and according to similarity-based theories of induction, relevant evidence raises argument strength when it is positive and lowers it when it is negative. In three experiments, we tested the hypothesis that argument strength can actually increase when negative evidence is introduced. Two kinds of argument were compared through forced choice or sequential evaluation: single positive arguments (e.g., “Shostakovich’s music causes alpha waves in the brain; therefore, Bach’s music causes alpha waves in the brain”) and double mixed arguments (e.g., “Shostakovich’s music causes alpha waves in the brain, X’s music DOES NOT; therefore, Bach’s music causes alpha waves in the brain”). Negative evidence in the second premise lowered credence when it applied to an item X from the same subcategory (e.g., Haydn) and raised it when it applied to a different subcategory (e.g., AC/DC). The results constitute a new constraint on models of induction
Links between traumatic brain injury and ballistic pressure waves originating in the thoracic cavity and extremities
Identifying patients at risk of traumatic brain injury (TBI) is important
because research suggests prophylactic treatments to reduce risk of long-term
sequelae. Blast pressure waves can cause TBI without penetrating wounds or
blunt force trauma. Similarly, bullet impacts distant from the brain can
produce pressure waves sufficient to cause mild to moderate TBI. The fluid
percussion model of TBI shows that pressure impulses of 15-30 psi cause mild to
moderate TBI in laboratory animals. In pigs and dogs, bullet impacts to the
thigh produce pressure waves in the brain of 18-45 psi and measurable injury to
neurons and neuroglia. Analyses of research in goats and epidemiological data
from shooting events involving humans show high correlations (r > 0.9) between
rapid incapacitation and pressure wave magnitude in the thoracic cavity. A case
study has documented epilepsy resulting from a pressure wave without the bullet
directly hitting the brain. Taken together, these results support the
hypothesis that bullet impacts distant from the brain produce pressure waves
that travel to the brain and can retain sufficient magnitude to induce brain
injury. The link to long-term sequelae could be investigated via
epidemiological studies of patients who were gunshot in the chest to determine
whether they experience elevated rates of epilepsy and other neurological
sequelae
Fractal Fluctuations and Quantum-Like Chaos in the Brain by Analysis of Variability of Brain Waves: A New Method Based on a Fractal Variance Function and Random Matrix Theory
We developed a new method for analysis of fundamental brain waves as recorded
by EEG. To this purpose we introduce a Fractal Variance Function that is based
on the calculation of the variogram. The method is completed by using Random
Matrix Theory. Some examples are given
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