["Time, place and person" and neurology].

The Department of Neurology, Hokkaido University, has been established since 1987, however the bases for neurology had been cultivated through psychiatry and neurosurgery in Hokkaido, especially under the pioneering work by Professor Mitsuo Tsuru. Hokkaido, the northernmost island of Japan, is located between 42 and 46 degrees, and the people have ancestors from various parts of Japan, since this island was reclaimed about 130 years ago. Three major neurological disorders, such as multiple sclerosis(MS), spinocerebellar degeneration(SCD) and Parkinson disease (PD), were discussed on the bases of Hokkaido island. We proved the existence of definite north-south gradient of MS, prevalence rate of 8.6 in Tokachi, Hokkaido, compared with 1-2 in the southern island. SCD, especially hereditary SCD, such as SCA1, SCA2 and SCA14 were reported from Hokkaido. The epidemiological studies of PD showed the prevalence rate of 104.6 at Iwamizawa, Hokkaido in 2000, and we proposed the prevalence rate of PD was close to those of Western countries under the collaborative works with Yonago, Kyoto, and Kagoshima by 2001. Neurology, and its specialization and training programs were also discussed to propose the importance of Neurology in Japan.