Louis Jacobsohn-Lask was a German

Germans

The Germans are a Germanic ethnic group native to Central Europe. The English term Germans has referred to the German-speaking population of the Holy Roman Empire since the Late Middle Ages....

 neurologist

Neurologist

A neurologist is a physician who specializes in neurology, and is trained to investigate, or diagnose and treat neurological disorders.Neurology is the medical specialty related to the human nervous system. The nervous system encompasses the brain, spinal cord, and peripheral nerves. A specialist...

 and neuroanatomist. He studied medicine at the University of Berlin under Heinrich Wilhelm Waldeyer, Rudolf Virchow

Rudolf Virchow

Rudolph Carl Virchow was a German doctor, anthropologist, pathologist, prehistorian, biologist and politician, known for his advancement of public health...

, Emil du Bois-Reymond

Emil du Bois-Reymond

Emil du Bois-Reymond was a German physician and physiologist, the discoverer of nerve action potential, and the father of experimental electrophysiology.-Life:...

, Ernst Viktor von Leyden

Ernst Viktor von Leyden

Ernst Viktor von Leyden was a German internist from Danzig.Leyden studied medicine at the Friedrich-Wilhelms-Institut in Berlin, and was a pupil of Johann Lukas Schönlein and Ludwig Traube . He was a medical professor at several universities, including Königsberg, Strassburg and Berlin...

 and Robert Koch

Robert Koch

Heinrich Hermann Robert Koch was a German physician. He became famous for isolating Bacillus anthracis , the Tuberculosis bacillus and the Vibrio cholerae and for his development of Koch's postulates....

. In 1899 Jacobsohn and Edward Flatau

Edward Flatau

Edward Flatau was a Polish neurologist. His work greatly influenced the developing field of neurology. He established neurobiologic and neuropathological sciences in Poland...

 wrote Handbuch der Anatomie und vergleichenden Anatomie des Centralnervensystems der Säugetiere, which included one of first attempts to classify sulci and gyri of human brain cortex

Cerebral cortex

The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...

. In 1904 he wrote, together with Flatau and Lazar Minor

Lazar Salomowitch Minor

Lazar Salomowitch Minor was a Russian neurologist who was a native of Vilnius.Minor received his education at the University of Moscow, where he was a student of Aleksei Kozhevnikov . Afterwards he worked in Paris under Jean-Martin Charcot , and in Berlin with Carl Otto Westphal and Emanuel Mendel...

, another monograph, Handbuch der pathologischen Anatomie der Nervensystems. He described a finger flexion reflex called the Bekhterev-Jacobsohn reflex

Bekhterev-Jacobsohn reflex

The Bekhterev-Jacobsohn reflex, or Jacobsohn's finger flexion sign, is a clinical sign found in patients with pyramidal tract lesions of the upper limb...

 or Jacobsohn reflex. In 1936 he emigrated with his wife, Berta Jacobsohn-Lask (married in 1916), to Soviet Union

Soviet Union

The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

.