BRAIN POTENTIALS AND VOLUNTARY MUSCLE ACTIVITY IN MAN

Abstract

In some normal subjects at rest the finger tremor frequencies at 10 and 25 per sec. correspond with the brain potential rhythms from over the precentral or frontal brain regions, even though no correspondence may be found with the occipital brain potential rhythms. Differential effects of stimulation on the tremor and brain potentials show that no necessary relationship exists between these 2 phenomena. Continuous abnormal tremor at 4 to 5 per sec. in paralysis agitans patients may show no correspondence with cortical potentials as recorded from any region of the head, but in some cases short bursts of large cortical potentials may appear at the tremor frequency when the patient is sufficiently relaxed. Each seizure wave in an epileptic attack may precede a clonic movement by about 100 msecs. or a burst of muscle potentials by about 50 to 60 msecs., although seizure waves may occur without clonic movements or may occur at frequencies independent of the movements in some attacks.