Pigeons and MRI: Tesla vignettes.

N ikola Tesla's name is familiar to neuroradiologists, but few of us know why our profession and understanding of the brain are better because of him. His achievements were not universally recognized until 1960 (17 years after his death) when the Conference Generale des Poids et Mesures decided that the unit for measuring the magnetic field (B) should be called the " tesla. " The strength of the magnetic field of the earth at the equator is 31 microteslas, and it is worth remembering that magnets found even in small speakers are as powerful as those found in our MR imaging units (1–2.4T). 1 His research also involved supercon-ducting magnets cooled to a few degrees above absolute zero. Although Tesla was constantly on the verge of becoming rich, he died poor and alone at 86 years of age in a room at the Hotel New Yorker (still at 481 Eighth Avenue). After his death, unknown individuals and/or government forces removed his last inventions and papers from his apartment because they were thought to contain information regarding the " Death Ray, " in which the military was interested. 2 This ray, presumably a particle beam, could repel armies and bring down airplanes. The list of Tesla's inventions is long and incredible in its breadth. During his life, Mr Tesla struggled for recognition, and it mostly eluded him, the Nobel Prize being one example. In this Perspectives, I mention some colorful aspects of Mr Tesla's life rather than recounting his incredible accomplishments. Tesla came to America after living in France for 2 years, and Mr Edison hired him to work at the Edison Machine Works in New York City. Edison's electric power generators producing direct current (DC) worked well only when electricity requirements were small. The power and output of DC are relatively weak, making its transmission over long distances impractical. Tesla solved this issue by perfecting alternating current (AC). Transformers decrease or increase the power of AC as needed, so if long-distance transmission is required, power is amplified, making it more efficient (with DC current, a generator every 3– 4 km is needed). When Edison refused to pay him for his inventions, Tesla left and later sold them to Westinghouse. The War of Currents erupted, and Edison tried to instill fear in AC users by calling it extremely dangerous. He went as far as paying children to steal dogs, elec-trocute them …