(1910-1977), neurophysiologist William Grey Walter (also known as Grey Walter) was born in Kansas City, Missouri, on 19 February 1910 to journalist parents Karl Wilhelm Walter (1880-1965) and Minerva (Margaret) Lucrezia Hardy (1879-1953). The Walter family moved from the United States to Britain in 1915, where William remained for the rest of his life. He was educated at Westminster School (1922-1928), before taking the Natural Science Tripos at King’s College, Cambridge (1928-1931). He went on to pursue postgraduate research on nerve physiology and conditioned reflexes, gaining his MA in 1935. After completing his MA, Walter was invited to work at the Central Pathological Laboratory of the Maudsley Hospital, London, under neuropsychiatrist Frederick Lucien Golla (1877-1968). Since the late 1920s, Golla had become increasingly interested in the clinical applications of the burgeoning field of electroencephalography (EEG), the measurement of the electrical activity of the brain via electrodes placed on the scalp. Noting his skill in technical matters, Golla encouraged Walter to develop increasingly sophisticated EEG devices, and supported his application for a Rockefeller Travelling Fellowship to visit the Jena laboratory of German physiologist Hans Berger (1873-1941), widely credited as the founder of electroencephalography. Walter went on to achieve several key ‘firsts’ in electroencephalography, including the first detection of a cerebral tumour using the technique in 1936. Between 1936 and 1939, Walter expanded his research programme and took readings from hundreds of patients, focusing particularly on the electrical patterns of epilepsy. In 1939, Golla was invited to become director of the new Burden Neurological Institute, Bristol, an independent research unit specialising in the investigation and treatment of neurological, psychological, and psychiatric disorders, and invited Walter to become director of the Institute’s Physiology Department. At the Burden, Walter further developed his EEG apparatus, developing the automatic frequency analyser and the toposcope in 1943 and 1950 respectively. His research programme also became increasingly ambitious, with investigations into the cerebral effects of stroboscopic light beginning in 1947 and, later, the discovery of ‘contingent negative variation’ (CNV, or the ‘expectancy wave’) in the 1960s. Walter also played a key role in the professionalization of electroencephalography during this period, co-founding the journal Electroencephalography and Clinical Neurophysiology and organising meetings of the EEG Society (1943-1989). Outside of his clinical work, Walter became a key figure in early British cybernetics, the study of feedback, control, and communication systems in humans and machines that synthesised approaches from engineering, biology, and mathematics. He co-founded the Ratio Club, an informal dining and discussion group which provided a key social outlet for cybernetic enthusiasts, which met between 1949 and 1955. He also built several cybernetic devices in his spare time, the most famous of which were his robotic tortoises, or Machina Speculatrix, designed to function as simple models of the adaptable human brain. These received national attention when they were exhibited on television in 1950 and at the Festival of Britain in 1951. He also became a prolific public intellectual, writing 170 scientific publications, serving as an expert witness in court courses, appearing frequently on the BBC, and writing an immensely popular non-specialist text on his neuroscientific work, The Living Brain (1953). His work also gained a surprising popularity among counter-cultural artists during the 1950s and 1960s, including Beat writers William S. Burroughs and Allen Ginsberg, who saw Walter’s research as part of a broader investigation of human consciousness. Walter was married twice, first to Katharine Monica Ratcliffe in 1934 and then to Vivian Joan Dovey (1915-1980) in 1947, with whom he had one son, Timothy Walter (1949-1976). Walter and Dovey separated in 1960 and divorced in 1973. After their separation, Walter lived with Lorraine Josephine Aldridge (née Donn) until 1972. In 1970, Walter suffered severe brain damage following a road accident, forcing him to retire from full-time research work. He died of a heart attack in 1977.

(1906-1999), neurologist Herbert Henri Jasper was born in La Grande, Oregon on 27 July 1906. He was educated at Reed College, Portland before gaining his first Ph.D. at the University of Iowa in 1931. After graduating, Jasper obtained a Rockefeller Fellowship and studied neurology in Paris, before returning to work at the EEG Laboratory of Brown University, New York. In 1935, he published the first American paper on human electroencephalography (the measurement of the electrical activity of the brain) in the journal Science. After hearing about the experiments of neurosurgeon Wilder Penfield (1891-1976) at the Montreal Neurological Institute, which involved electrically stimulating the brains of conscious but anaesthetised patients to ‘map out’ the cerebral cortex, Jasper and his colleagues invited Penfield to lecture at the Psychology Department of Brown University and visit their EEG laboratory. This began a career-long collaboration between Jasper and Penfield, uniting their electroencephalographic and neurosurgical expertise in the treatment of temporal lobe epilepsy. Penfield later invited Jasper to join him in Montreal and establish the Institute’s EEG Department, which opened in January 1939. Later in 1939, Jasper enrolled as a medical student at McGill University, finishing the concentrated wartime curriculum in three years. In 1944, he was required to fulfil his military service in the Canadian Army (although he retained his American citizenship until deciding to stay in Canada permanently in 1950). After the war, Jasper’s EEG Laboratory in Montreal grew exponentially, with over 100 research fellows joining between 1945 and 1955, and a broadening programme of epilepsy investigations. In the late 1950s, Jasper played a key role in the creation of the International Brain Research Organisation (IBRO), and became its first Executive Secretary in 1960. During the Cold War, IBRO provided a platform for closer collaboration between Western and Soviet neuroscientists. In 1965, Jasper moved to the University of Montreal, broadening his research into areas such as the neurochemistry of sleep as well as continuing his work on epilepsy and seizure patterns. Jasper remained active in research up to a few months before his death. He died of a heart attack on 11 March 1999.

The Mayo Clinic is an American medical practice and research centre in Rochester, Minnesota. The Clinic evolved out of the late nineteenth-century surgical partnership of physicians William James Mayo (1861-1939) and Charles Horace Mayo (1865-1939), both of whom helped to found St Mary’s Hospital, Rochester in 1899 with their father, William Worrall Mayo (1819-1911). The Clinic’s educational and research activities expanded significantly in the early twentieth-century following the Mayo brothers’ establishment of the Mayo Foundation for Medical Education and Research at the University of Minnesota in 1915.