Interpreting magnetic fields of the brain: minimum norm estimates

1994 ◽  
Vol 32 (1) ◽  
pp. 35-42 ◽  
Author(s):  
M. S. Hämäläinen ◽  
R. J. Ilmoniemi
Keyword(s):  
Magnetic Fields ◽  
Minimum Norm ◽  
Norm Estimates ◽  
The Brain

The Weak Combined Magnetic Fields Reduce the Brain β-Amyloid in an Animal Model of Sporadic Alzheimer's Disease

PIERS Online ◽  
2009 ◽  
Vol 5 (4) ◽  
pp. 311-315 ◽  
Author(s):  
Natalia V. Bobkova ◽  
Vadim V. Novikov ◽  
Natalia I. Medvinskaya ◽  
Irina Yu. Aleksandrova ◽  
Eugenii E. Fesenko
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Animal Model ◽  
Magnetic Fields ◽  
Sporadic Alzheimer’S Disease ◽  
Combined Magnetic Fields ◽  
The Brain

scholarly journals Millimeter (MM) wave and microwave frequency radiation produce deeply penetrating effects: the biology and the physics

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Martin L. Pall
Keyword(s):  
Magnetic Fields ◽  
Electric Fields ◽  
Cardiac Activity ◽  
Maximum Level ◽  
Voltage Sensor ◽  
The Body ◽  
Time Varying ◽  
The Brain ◽  
Mm Waves

Abstract Millimeter wave (MM-wave) electromagnetic fields (EMFs) are predicted to not produce penetrating effects in the body. The electric but not magnetic part of MM-EMFs are almost completely absorbed within the outer 1 mm of the body. Rodents are reported to have penetrating MM-wave impacts on the brain, the myocardium, liver, kidney and bone marrow. MM-waves produce electromagnetic sensitivity-like changes in rodent, frog and skate tissues. In humans, MM-waves have penetrating effects including impacts on the brain, producing EEG changes and other neurological/neuropsychiatric changes, increases in apparent electromagnetic hypersensitivity and produce changes on ulcers and cardiac activity. This review focuses on several issues required to understand penetrating effects of MM-waves and microwaves: 1. Electronically generated EMFs are coherent, producing much higher electrical and magnetic forces then do natural incoherent EMFs. 2. The fixed relationship between electrical and magnetic fields found in EMFs in a vacuum or highly permeable medium such as air, predicted by Maxwell’s equations, breaks down in other materials. Specifically, MM-wave electrical fields are almost completely absorbed in the outer 1 mm of the body due to the high dielectric constant of biological aqueous phases. However, the magnetic fields are very highly penetrating. 3. Time-varying magnetic fields have central roles in producing highly penetrating effects. The primary mechanism of EMF action is voltage-gated calcium channel (VGCC) activation with the EMFs acting via their forces on the voltage sensor, rather than by depolarization of the plasma membrane. Two distinct mechanisms, an indirect and a direct mechanism, are consistent with and predicted by the physics, to explain penetrating MM-wave VGCC activation via the voltage sensor. Time-varying coherent magnetic fields, as predicted by the Maxwell–Faraday version of Faraday’s law of induction, can put forces on ions dissolved in aqueous phases deep within the body, regenerating coherent electric fields which activate the VGCC voltage sensor. In addition, time-varying magnetic fields can directly put forces on the 20 charges in the VGCC voltage sensor. There are three very important findings here which are rarely recognized in the EMF scientific literature: coherence of electronically generated EMFs; the key role of time-varying magnetic fields in generating highly penetrating effects; the key role of both modulating and pure EMF pulses in greatly increasing very short term high level time-variation of magnetic and electric fields. It is probable that genuine safety guidelines must keep nanosecond timescale-variation of coherent electric and magnetic fields below some maximum level in order to produce genuine safety. These findings have important implications with regard to 5G radiation.

scholarly journals Electric and magnetic fields of the brain accompanying internal simulation of movement

1996 ◽  
Vol 3 (2) ◽  
pp. 125-129 ◽  
Author(s):  
Wilfried Lang ◽  
Douglas Cheyne ◽  
Peter Höllinger ◽  
Willi Gerschlager ◽  
Gerald Lindinger
Keyword(s):  
Magnetic Fields ◽  
Electric And Magnetic Fields ◽  
The Brain

Applying Independent Component Analysis to the Artifact Detection Problem in Magnetoencephalogram Background Recordings

2008 ◽  
pp. 84-92
Author(s):  
Javier Escudero ◽  
Roberto Hornero ◽  
Daniel Abásolo ◽  
Jesús Poza ◽  
Alberto Fernández
Keyword(s):  
Magnetic Fields ◽  
Quantum Interference ◽  
Brain Activity ◽  
External Noise ◽  
Low Noise ◽  
High Temporal Resolution ◽  
Artifact Detection ◽  
Mental Diseases ◽  
Electroencephalogram Eeg ◽  
The Brain

The analysis of the electromagnetic brain activity can provide important information to help in the diagnosis of several mental diseases. Both electroencephalogram (EEG) and magnetoencephalogram (MEG) record the neural activity with high temporal resolution (Hämäläinen, Hari, Ilmoniemi, Knuutila, & Lounasmaa, 1993). Nevertheless, MEG offers some advantages over EEG. For example, in contrast to EEG, MEG does not depend on any reference point. Moreover, the magnetic fields are less distorted than the electric ones by the skull and the scalp (Hämäläinen et al., 1993). Despite these advantages, the use of MEG data involves some problems. One of the most important difficulties is that MEG recordings may be severely contaminated by additive external noise due to the intrinsic weakness of the brain magnetic fields. Hence, MEG must be recorded in magnetically shielded rooms with low-noise SQUID (Superconducting QUantum Interference Devices) gradiometers (Hämäläinen et al., 1993).

Introduction

2017 ◽  
pp. 3-12
Author(s):  
Riitta Hari ◽  
Aina Puce
Keyword(s):  
Magnetic Fields ◽  
Human Brain ◽  
Brain Dynamics ◽  
Electric Currents ◽  
Electrical Currents ◽  
Activation Patterns ◽  
Neuronal Communication ◽  
Electrical Potentials ◽  
Electric And Magnetic Fields ◽  
The Brain

Neuronal communication in the brain is associated with minute electrical currents that give rise to both electrical potentials on the scalp (measurable by means of electroencephalography [EEG]) and magnetic fields outside the head (measurable by magnetoencephalography [MEG]). Both MEG and EEG are noninvasive neurophysiological methods used to study brain dynamics, that is temporal changes in the activation patterns, and sequences in signal progression. Differences between MEG and EEG mainly reflect differences in the spread of electric and magnetic fields generated by the same electric currents in the human brain. This chapter provides an overall description of the main principles of MEG and EEG and provides background for the following chapters in this and subsequent sections.

Alternate magnetic fields potentiate monoamine oxidase activity in the brain

2000 ◽  
Vol 7 (2) ◽  
pp. 121-125 ◽  
Author(s):  
Isao Yokoi ◽  
Hideaki Kabuto ◽  
Yukiko Nanba ◽  
Nihei Yamamoto ◽  
Norio Ogawa ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Monoamine Oxidase ◽  
Oxidase Activity ◽  
Monoamine Oxidase Activity ◽  
The Brain

scholarly journals Comparison of noise-normalized minimum norm estimates for MEG analysis using multiple resolution metrics

NeuroImage ◽  
2011 ◽  
Vol 54 (3) ◽  
pp. 1966-1974 ◽  
Author(s):  
Olaf Hauk ◽  
Daniel G. Wakeman ◽  
Richard Henson
Keyword(s):  
Minimum Norm ◽  
Norm Estimates

Potentiation of Immune Responsiveness in Aging by Static Magnetic Fields Applied to the Brain.

1994 ◽  
Vol 719 (1 The Aging Clo) ◽  
pp. 410-418 ◽  
Author(s):  
BRANISLAV D. JANKOVIĆ ◽  
PREDRAG NIKOLIĆ ◽  
VITOMIR ĆUPIĆ ◽  
KATARINA HLADNI
Keyword(s):  
Magnetic Fields ◽  
Immune Responsiveness ◽  
Static Magnetic Fields ◽  
The Brain
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