Figure 7.

Neck motor units show nonlinear responses during complex motion, and responses at high frequencies differ markedly from previous model predictions. A, SPL motor unit responses to broadband (0-20 Hz white noise) vestibular stimulation in normal monkeys (N = 12 motor units). Dashed lines indicate 99% CIs for coherence between rotation velocity and motor unit spike times. Gain (normalized to maximum) and phase (deg) data are demonstrated at frequencies that exhibit significant coherence. Error bars indicate 95% CIs. For comparison, the superimposed dots represent gain for motor units in response to sinusoidal stimulation from Figure 2A. Black lines indicate the predicted VCR gain and phase from the neuromechanical model developed by Peng et al. (1996). B, SPL motor unit responses (N = 5 motor units) to the same broadband vestibular stimulation after BVL.