title: Genetic and environmental influences on motor function: a magnetoencephalographic study of twins.
abstract: To investigate the effect of genetic and environmental influences on cerebral motor function, we determined similarities and differences of movement-related cortical fields (MRCFs) in middle-aged and elderly monozygotic (MZ) twins. MRCFs were measured using a 160-channel magnetoencephalogram system when MZ twins were instructed to repeat lifting of the right index finger. We compared latency, amplitude, dipole location, and dipole intensity of movement-evoked field 1 (MEF1) between 16 MZ twins and 16 pairs of genetically unrelated pairs. Differences in latency and dipole location between MZ twins were significantly less than those between unrelated age-matched pairs. However, amplitude and dipole intensity were not significantly different. These results suggest that the latency and dipole location of MEF1 are determined early in life by genetic and early common environmental factors, whereas amplitude and dipole intensity are influenced by long-term environmental factors. Improved understanding of genetic and environmental factors that influence cerebral motor function may contribute to evaluation and improvement for individual motor function.
authors.affiliation: Division of Functional Diagnostic Science, Osaka University Medical School , Suita , Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Araki
authors.affiliation: Division of Functional Diagnostic Science, Osaka University Medical School , Suita , Japan ; Department of Neurosurgery, Osaka University Medical School , Suita , Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hirata
authors.affiliation: Department of Neurosurgery, Osaka University Medical School , Suita , Japan.
authors.forename: Hisato
authors.initials: H
authors.lastname: Sugata
authors.affiliation: Division of Functional Diagnostic Science, Osaka University Medical School , Suita , Japan ; Department of Neurosurgery, Osaka University Medical School , Suita , Japan.
authors.forename: Takufumi
authors.initials: T
authors.lastname: Yanagisawa
authors.affiliation: Division of Functional Diagnostic Science, Osaka University Medical School , Suita , Japan.
authors.forename: Mai
authors.initials: M
authors.lastname: Onishi
authors.affiliation: Department of Diagnostic and Interventional Radiology, Osaka University Medical School , Suita , Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Watanabe
authors.affiliation: Center for Twin Research, Osaka University Medical School , Suita , Japan.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Omura
authors.affiliation: Center for Twin Research, Osaka University Medical School , Suita , Japan.
authors.forename: Chika
authors.initials: C
authors.lastname: Honda
authors.affiliation: Center for Twin Research, Osaka University Medical School , Suita , Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hayakawa
authors.affiliation: Division of Functional Diagnostic Science, Osaka University Medical School , Suita , Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Yorifuji
keywords: magnetoencephalography; motor function; movement-related cortical fields; twins