Fig. 3

USEA recordings were collected during a training session and used to train a decode (either a standard Kalman filter or a ReFIT Kalman filter). Subjects were then given online control of the virtual hand via real-time output from the trained decode. a Training data was collected by recording via USEAs while the subject imitated pre-programmed, single-DOF or multi-DOF virtual hand movements with their phantom hand. b Neuronal spiking was observed during intended movements (inset shows neuronal action potential waveforms). c For each trial, the firing rate on a given electrode was computed and compared to the movement cue position via correlation. d The correlation between firing-rate and movement cue was determined for each USEA electrode across many trials of a given movement, and electrodes with high correlations and independent activation for specific movements were selected as input for an online decode