2

Bioelectromagnetism

Einstein wrote in his letter, “It is thinkable that the investigation of the behavior of migratory birds

and carrier pigeons may someday lead to the understanding of some physical process which is not yet

known.” It is known that Einstein had attended a lecture by Karl von Frisch at Princeton University in

April 1949, a few months before he wrote his reply to Ghyn Davys. By attending this lecture, Einstein

had become acquainted with Karl von Frisch who had published very important fndings involving that

honeybees could communicate the location of rewarding fowers with conspecifcs via symbolic dance

(von Frisch, 1949). For this discovery, he won the Nobel Prize in Physiology or Medicine in 1973, along

with Nikolaas Tinbergen and Konrad Lorenz for their discoveries concerning organization and elicita­

tion of individual and social behavior patterns.

Te fusion of physics and biology predicted by Einstein has become a reality. A new research feld

was developed which combines physics (especially quantum mechanics) with biology, currently called

quantum biology. One of the attempts to clarify animal behavior by quantum biology is that migrating

birds may use geomagnetism to determine the direction of migration, and a radical pair model was pro­

posed. In 2000, Ritz et al. published a hypothesis showing that birds can sense magnetic felds with the

same strength as the geomagnetic feld and weaker by considering a radical pair system model, and pro­

posed that the blue-light photoreceptor protein, cryptochrome (CRY) found in the retina is the molecule

most likely to act as a radical pair (Schulten et al., 1976: Ritz et al., 2000: Timmel and Henbest, 2004).

Tis was constructed based on the concept of spin chemistry, in which the magnetic feld controls the

chemical reactions (Hayashi, 2004). CRY including favin adenine dinucleotide (FAD) is widely distrib­

uted in nature, i.e., animals, plants and bacteria. Te magnetic sensing ability is presumed to generate

the radical pair between FAD and amino acid residue as the intermediate by radical pair mechanism.

By having such magnetoreceptions in the retina, migratory birds are assumed to perceive visually in

which direction to migrate. Te possibility that cryptochromes serve as highly sensitive magnetorecep­

tions has been suggested. Currently, many other researchers are focusing on other mechanisms based

on quantum mechanics (Al-Khalili and McRadden, 2014).

In 1944, Erwin Schrödinger, who is the founder of quantum mechanics and a Nobel Laureate,

introduced the idea that living matter at the cellular level can be understood with the use of quantum

mechanics in his book (Schrödinger, 1944). Tis book was based on public lectures delivered at Trinity

College, Dublin, in February 1943. He wrote in his book:

Te living organism seems to be a macroscopic system which in part of its behavior approaches to

that purely mechanical (as contrasted with thermodynamical) conduct to which all systems tend,

as the temperature approaches the absolute zero and the molecular disorder is removed.

Schrödinger (1944, pp. 73–74)

Schrödinger claimed that life is a quantum-level phenomenon capable of fying in the air, walking on

two or four legs, swimming in the ocean, growing in the soil or, indeed, reading book (Al-Khalili and

McFadden, 2014). Quantum biology has gained attention in recent years as a result of many experimen­

tal observations. Now, it is a growing area of interdisciplinary research felds investigating non-trivial

quantum aspects of biological systems with the help of quantum physicists, chemists, biologists, bio­

chemists and engineers among others.

Forthwith, bioelectromagnetism which is the subject of this book also has a long research history.

Bioelectromagnetism can be regarded as a research feld that has developed through the integration of

classical physics and biology. Classical physics is a discipline based on the classical mechanics of Galileo

Galilei and Isaac Newton with the electromagnetic theory of James Clerk Maxwell. It can explain the

macroscopic phenomena found in our daily lives, and it is called classical physics. However, phenom­

ena at the microscopic level that could not be explained by classical physics were gradually reported.

Tus, a new physics to explain the phenomena at the microscopic level became necessary. Max Planck’s

discovery of the quantum of action in 1900 and Einstein’s theory of the photoelectric efect in 1905 and

theory of relativity led to the establishment of quantum mechanics as a new feld in physics in the early