Bite-to-bite variation of muscular activity in cats.

Changes in electromyographic (EMG) activity between successive bites in the jaw-closing muscles of cats are described for the reduction of food with different textures. Plots of these data suggest, and statistics confirm, that one cannot predict the magnitude of EMG activity from one bite to the next, but that predicting the direction of change in EMG activity (i.e. increases or decreases) may be possible, given the relative magnitude of a bite. The patterns observed also show that the degree of variability between masticatory cycles differs among the jaw-closing muscles and with food texture. These patterns of muscle activity are related to the neural control of jaw movements.