was a Japanese-born American

biophysicist Biophysics is an interdisciplinary science that applies approaches and methods traditionally used in physics to study Biology, biological phenomena. Biophysics covers all scales of biological organization, from Molecule, molecular to organismic ...

and physician involved in research relating to the electrical impulses in the

nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes th ...

. Tasaki is credited with discovering the insulating function of the

myelin sheath Myelin is a lipid-rich material that surrounds nerve cell axons (the nervous system's "wires") to insulate them and increase the rate at which electrical impulses (called action potentials) are passed along the axon. The myelinated axon can be l ...

. His discoveries provided the foundation for a better understanding of diseases such as

multiple sclerosis Multiple (cerebral) sclerosis (MS), also known as encephalomyelitis disseminata or disseminated sclerosis, is the most common demyelinating disease, in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This d ...

, in which myelin is lost or damaged.

Early life and education

In 1910, Tasaki was born in Japan. Here and at the urging of his mother, he attended medical school, from which he received his M.D. in 1938. Rather than practising medicine, however, Tasaki decided to pursue his first love;

biophysics Biophysics is an interdisciplinary science that applies approaches and methods traditionally used in physics to study biological phenomena. Biophysics covers all scales of biological organization, from molecular to organismic and populations. ...

Career

While in Japan, he studied vertebrate

nerve fiber An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action po ...

s and discovered the insulating function of the

, a material that speeds the conduction of nerve impulses. He also was the first to show that electrical impulses traveling along myelinated nerve cells actually "jump" between the breaks in the myelin wrapping, called

nodes of Ranvier In neuroscience and anatomy, nodes of Ranvier ( ), also known as myelin-sheath gaps, occur along a myelinated axon where the axolemma is exposed to the extracellular space. Nodes of Ranvier are uninsulated and highly enriched in ion channels, al ...

. This process, termed

saltatory conduction In neuroscience, saltatory conduction () is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials. The uninsulated nodes of Ranvier are th ...

, is featured in a majority of physiology textbooks. After

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

, Tasaki's research took him to

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

and to

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

, where he further studied the properties of nerve fibers. In 1951, he came to the United States to work at

Washington University in St. Louis Washington University in St. Louis (WashU or WUSTL) is a private research university with its main campus in St. Louis County, and Clayton, Missouri. Founded in 1853, the university is named after George Washington. Washington University is r ...

. While there, Tasaki and his colleagues demonstrated how vibrations that occur in the

cochlea The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus. A core component of the cochlea is the Organ of Corti, the sensory org ...

in response to sound are translated into electrical signals that the brain can interpret. This effort led to the development of the field of

audiology Audiology (from Latin , "to hear"; and from Greek , ''-logia'') is a branch of science that studies hearing, balance, and related disorders. Audiologists treat those with hearing loss and proactively prevent related damage. By employing various ...

, indirectly providing the basis for diagnosing and treating many hearing disorders.

Research interests

Tasaki began his career at the

National Institutes of Health The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the late ...

in 1953, at

NINDS The National Institute of Neurological Disorders and Stroke (NINDS) is a part of the U.S. National Institutes of Health (NIH). It conducts and funds research on brain and nervous system disorders and has a budget of just over US$2.03 billion. The ...

, then called the National Institute of Neurological Disorders and Blindness. In 1957, he became a naturalized U.S. citizen. Later, he moved to the

NIMH NIMH may refer to: *Nickel–metal hydride battery (NiMH), a type of electrical battery *National Institute of Mental Health, an agency of the United States government *National Institute of Medical Herbalists, a professional organisation in the Un ...

, where he was a lab chief for 22 years. At the time of his death, he was on detail to the

Eunice Kennedy Shriver National Institute of Child Health and Human Development The ''Eunice Kennedy Shriver'' National Institute of Child Health and Human Development (NICHD) is one of the National Institutes of Health (NIH) in the United States Department of Health and Human Services. It supports and conducts research aime ...

. Since coming to NIH, Tasaki studied the physical and chemical processes that occur in nerve membranes.

Early life and education

Career

Research interests

References

Further reading