Assessing the psychophysics of posture control and its physiological correlates

Graphical visualization methods are described that enable psychophysical detection data to be quantitatively correlated with underlying physiological data in postural control studies. Stitched, raster and ensemble averaged time-series plots are graphical tools that can guide later quantitative analysis. The examples presented point out the role that early Tibialis Anterior and later Gastrocnemius EMG activation might play in the 2-Alternative Forced Choice psychophysical detection of 16 mm horizontal anterior perturbations of a sliding platform on which a subject stands, and their linkage to AP and ML Center of Pressure changes brought about by a perturbation. These methods also give a preliminary indication that differing or no response patterns were seen at 4 and 1 mm.