Fig. 6.

Threshold lines and frequency data for units in biceps. Best directions as found from the threshold line or the cosine fit are marked by arrows. Units 1 and 2 had significantly different preferred directions. Unit 3 showed more than one preferred direction. Action potential waveforms for unit 3 are shown for trials in the two lobes of activation. All data are from subject B. Bimodally tuned activity was seen in 29% of the biceps units pooled across all subjects.