10
6
10
3
1
10
−3
10
−6
10
−9
10
−12
10
−15
SQUID
sensitivity
DC
Mobile telephone
Brain stem
Brain (MEG)
Heart (MCG)
Lung (MPG)
Urban magnetic fields
Evoked fields
Hyperthermia
Magnetic storm
Earth
Magnetophosphene
Blood flow change by
magnetic stimulation
of sensory nerves
Magnetic stimulation
of the heart (τ = 1 ms)
Magnetic stimulation
of the brain (τ = 0.1 ms)
Ca
2+ Release
ELF
10 3
1
10
6
10
9
Parting of water
Magnetic orientation
MRI magnet
Consumer electronics
Frequency of magnetic field (Hz)
123
Static, Low-Frequency, and Pulsed Magnetic Fields
field strength to be 2 V/m, which is equal to the apparent threshold for peripheral
nerve stimulation in the frequency range from 10 Hz to 1 kHz (ICNIRP 1998). It
should be noted, however, that frequencies associated with body movements are
likely to be ≤10 Hz, the frequency below which more negative resting membrane
potential decreases the electrical excitability of neurons due to the slow inactivation of voltage-gated sodium ion channels (Bezanilla 2002). Head translational
and rotational frequencies during walking, for example, vary from 0.4 to 4.0 Hz
(Grossman et al. 1988; Pozzo et al. 1990; MacDougall and Moore 2005).
Biomagnetic phenomena for magnetic fields having different intensities and frequencies are shown in Figure 3.1 (Ueno and M. Iwasaka 1996b; Ueno and Shigemitsu 2007).
It is important to consider the intensities and frequencies of magnetic fields involved
in biomagnetic phenomena when discussing the relationship between magnetism and
living organisms. Regarding the effects of magnetism on living organisms, it should
Figure 3.1 Biomagnetic phenomena for medical and therapeutic applications. MPG, magnetopneumography; MCG, magnetocardiography; MEG, magnetoencephalography. (From
Ueno, S., and M. Iwasaka. 1996b. Magnetic nerve stimulation and effects of magnetic fields on
biological, phyisical, and chemical processes. Biological Effects of Magnetic and Electromagnetic
Fields, ed. S. Ueno, 1. New York: Springer; Ueno, S., and T. Shigemitsu. 2007. Biological effects and
static magnetic fields. Handbook of Biological Effects of Electromagnetic Fields: Bioengineering and
Biophysical Aspects of Electromagnetic Fields. 3rd ed. F. S. Barnes, and B. Greenebaum, 203. Boca
Raton, FL: CRC Press. With permission.)
Magnetic flux density (T)
6
10
3
1
10
−3
10
−6
10
−9
10
−12
10
−15
SQUID
sensitivity
DC
Mobile telephone
Brain stem
Brain (MEG)
Heart (MCG)
Lung (MPG)
Urban magnetic fields
Evoked fields
Hyperthermia
Magnetic storm
Earth
Magnetophosphene
Blood flow change by
magnetic stimulation
of sensory nerves
Magnetic stimulation
of the heart (τ = 1 ms)
Magnetic stimulation
of the brain (τ = 0.1 ms)
Ca
2+ Release
ELF
10 3
1
10
6
10
9
Parting of water
Magnetic orientation
MRI magnet
Consumer electronics
Frequency of magnetic field (Hz)
123
Static, Low-Frequency, and Pulsed Magnetic Fields
field strength to be 2 V/m, which is equal to the apparent threshold for peripheral
nerve stimulation in the frequency range from 10 Hz to 1 kHz (ICNIRP 1998). It
should be noted, however, that frequencies associated with body movements are
likely to be ≤10 Hz, the frequency below which more negative resting membrane
potential decreases the electrical excitability of neurons due to the slow inactivation of voltage-gated sodium ion channels (Bezanilla 2002). Head translational
and rotational frequencies during walking, for example, vary from 0.4 to 4.0 Hz
(Grossman et al. 1988; Pozzo et al. 1990; MacDougall and Moore 2005).
Biomagnetic phenomena for magnetic fields having different intensities and frequencies are shown in Figure 3.1 (Ueno and M. Iwasaka 1996b; Ueno and Shigemitsu 2007).
It is important to consider the intensities and frequencies of magnetic fields involved
in biomagnetic phenomena when discussing the relationship between magnetism and
living organisms. Regarding the effects of magnetism on living organisms, it should
Figure 3.1 Biomagnetic phenomena for medical and therapeutic applications. MPG, magnetopneumography; MCG, magnetocardiography; MEG, magnetoencephalography. (From
Ueno, S., and M. Iwasaka. 1996b. Magnetic nerve stimulation and effects of magnetic fields on
biological, phyisical, and chemical processes. Biological Effects of Magnetic and Electromagnetic
Fields, ed. S. Ueno, 1. New York: Springer; Ueno, S., and T. Shigemitsu. 2007. Biological effects and
static magnetic fields. Handbook of Biological Effects of Electromagnetic Fields: Bioengineering and
Biophysical Aspects of Electromagnetic Fields. 3rd ed. F. S. Barnes, and B. Greenebaum, 203. Boca
Raton, FL: CRC Press. With permission.)
Magnetic flux density (T)