Spatial activation maps--bioelectric signals related to 3D recorded movements

The analysis of multidimensional neurophysiological data poses difficulties for the scientist in understanding the often complex inherent data relations. This is particularly the case when neuromuscular cell discharge parameters are to be related to body segment movement characteristics in freely behaving animals or humans. The understanding of such data is greatly simplified if the recorded data can be visualized in an adequate way, and relevant data relations are thus highlighted. This report describes a rationale for display and qualitative analyses of muscle discharge patterns in relation to three-dimensionally recorded limb or body movements. The method is illustrated by creating spatial activation plots and spatial activation maps of the electromyographic activity in the first interosseal muscle in the human hand, but this rationale for data presentation can be applied to most excitable tissues that are activated in relation to body or limb movements.