Control and training of individual motor units.

Experiments clearly demonstrate that with the help of auditory and visual cues man can single out motor units and control their isolated contractions. Experiments on the training of this control, interpreted as the training of descending pathways to single anterior horn cells, provide a new glimpse of the fineness of conscious motor controls. After training, subjects can recall into activity different single motor units by an effort of will while inhibiting the activity of neighbors. Some learn such exquisite control that they soon can produce rhythms of contraction in one unit, imitating drum rolls, etc. The quality of control over individual anterior horn cells may determine rates of learning.