[Movement-related cortical potential upon stepping forward].
We investigated movement-related cortical potentials (MRCPs) in 10 healthy subjects when they were stepping the right leg forward volitionally from the standing position, and compared with MRCPs associated with the foot dorsiflexion solely in sitting position. We recorded electroencephalogram (EEG), electrooculogram, surface electromyogram (EMG) on lower limb, and statokinesigram. We examined each EMG onset and several points on the statokinesigram as trigger points. MRCPs triggered by the right tibialis anterior, the left gastrocnemius, and the left soleus muscle had slow negative potentials containing slow phase and steeper phase. The potentials of both phases had the largest gradient at Cz. MRCPs triggered by the EMG onset of these three muscles resembled those associated with the foot dorsiflexion in their wave form, time course, and distribution pattern, but spread widely over the anterior recording sites. On the other hand, MRCPs triggered by the first deviation on the statokinesigram--by that first deviation assumed to take the first and foremost movement in this paradigm, were found to be delayed after the trigger point. The tibialis anterior muscle contributes to elevating a foot, and the contralateral gastrocnemius and soleus muscle to sustaining the weight. We were able to record apparent MRCPs when we adopted these EMG bursts, which play an important role in stepping forward, as trigger points. These records will be useful to analyze the mechanism of gait disturbance.
Saitou
K
K
Department of Neurology, Nagoya University, School of Medicine.
Washimi
Y
Y
Sakurai
N
N
Koike
Y
Y
D000200:Action Potentials; D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography; D004576:Electromyography; D005684:Gait; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D009068:Movement; D018482:Muscle, Skeletal / Q000502:physiology