Change of brain magnetic field and cerebral blood flow accompaning voluntary movement revealed by functional imaging(Mind viewed through cognitive neuroscience: Neuroimaging, a window on the brain)

Abstract

Recent development of functional imaging has enabled us to approach brain function related to voluntary movement. Movement-related cortical field (MRCF) recorded by magnetoencephalography (MEG) has disclosed readiness field (RF), which starts 1 sec to the movement and distributes over the primary motor area contralateral to the moving side. RF culminates motor field (MF), whose generator source can be localized over the anatomical primary motor area. By comparing MRCF with previous EEG study, temporal profile of activation in the motor area can be well estimated. Recently, functional magnetic resonance imaging (fMRI) has become one of the powerful tools to delineate brain function. In addition to the high spatial resolution, event-related fMRI can obtain better temporal resolution. By this way, activated area related to muscle relaxation can be shown over the primary motor area and supplementary motor area. Combined functional imaging enables us to obtain better comprehension of brain mechanism related to voluntary movement.