Spatio-temporal characterization of intercostal activity during breathing in the cat.

It is envisaged that the motor control of the intercostal musculature--an assembly of mobile structures--can be characterized in terms of a conceptual spatially continuous control function, that underlies the discretely distributed muscular activity and reflects an inferred global dynamic control of the thoracic cage during breathing. The global control function is estimated by the spatio-temporal pattern obtained by averaging in time and space and interpolation of multichannel simultaneous intercostal EMG recording in the anaesthetized cat. Different examples of the experimental preparation in the presence of stimuli of different kinds are analysed. The resultant signal patterns are found to be self-consistent and capable of exhibiting systematically differing features in systematically differing experimental conditions, thus supporting the validity of the analysis and the choice of the estimator. It is concluded that a more detailed analysis of the requirements of this approach is then warranted. Such requirements are discussed, and, specifically, results that bear on the adequacy of spatial sampling rate are presented. It is suggested that such methods offer a promising approach in the study of motor control strategies of the respiratory apparatus.