• This study was supported in part by Grant MH 14439, National Institute of Mental Health.

Address requests for reprints to: Elmer E. Green, Research Department, The Menninger Foundation, Topeka, Kansas 66601.


Zero firing or single-motor-unit firing in large forearm muscle bundles was achieved in less than twenty minutes, in seven out of twenty-one subjects, through the use of a feedback meter which showed the subject his own electromyographic tension level. Five of these seven subjects reported body-image illusions.

The behavior of single motor units under these conditions indicates the existence of a reflex-type neural oscillator in the striate neuromuscular domain, whose operation is gated or controlled from the central nervous system.

The electronic system needed to operate the feedback meter can be assembled from standard amplifiers but standard EMG Integrator (rectifier) couplers usually must be modified in order to detect single motor unit firing. The final system is considerably more sensitive than those commercially available.