A, B: Non-rectified waveform averages of the FCR H-reflex and the FCR TEPs when a double pulse at an inter-stimulus interval of 40 ms was delivered to the cervicothoracic region or to the median nerve, respectively for two subjects. C: Overall average amplitude of the FCR H-reflex, FCR M-wave, and TEPs for subjects 1-12 evoked by a second pulse delivered to the median nerve or to the cervicothoracic region. D: Overall average amplitude of the FCR H-reflex, FCR M-wave, and TEPs evoked by a second pulse delivered to the median nerve or to the cervicothoracic region for subject 13. In both C and D graphs, the FCR H-reflex, FCR M-wave and TEPs were normalized to the associated potentials evoked by the first pulse. Asterisks indicate statistically significant differences from control values. Error bars indicate the SEM.