随伴陰性変動

抄録

  Contingent negative variation (CNV) is a negative brain potential recorded by averaging electroencephalogram derived from scalp electrodes during a period between warning and response stimulus (foreperiod) to which subjects perform motor and/or mental response. Main generators of CNV are reportedly supplementary motor cortex, premotor cortex, primary motor cortex, frontal cingulate area, thalamus, and basal ganglia. CNV is considered to be a complex of early and late component (early and late CNV, respectively). The early reportedly reflects orienting response to warning stimulus and the latter motor preparation and anticipatory attention to response stimulus. CNV shows no effect of trial repetition and has high reproducibility. Therefore, CNV is probably a useful index of the brain functions mentioned above. Since 1970s, a number of studies reported that late CNV is equivalent to movement-related cortical potential. Recently, late CNV and movement-related cortical potential are considered to be different phenomenon, in that the former reflects a process of motor programming and the latter a process related to motor execution. Using CNV as an index of change in attention direction, researches in a field of postural control have started investigating a relationship between brain activity and the strategies of postural control.