Muscles express motor patterns of non-innervating neural networks by filtering broad-band input

We describe three slow muscles that responded to low-frequency modulation o f a high-frequency neuronal input and, consequently, could express the moto r patterns of neural networks whose neurons did not directly innervate the muscles. Two of these muscles responded to different frequency components p resent in the same input, and as a result each muscle expressed the motor p attern of a different, non-innervating, neural network. In an analogous man ner, the distinct dynamics of the multiple intracellular processes that mos t cells possess may allow each process to respond to, and hence differentia te among, specific frequency ranges present in broad-band input.