Table 2.

Estimated difference in arrival time of presynaptic and postsynaptic volleys at the corticospinal–motoneuronal synapses calculated from evoked responses in individual subjects (mean ± SD; 8 subjects for ISIs of −13, −3, +12, and +22 ms; 7 subjects for other intervals)

ISI	Planned interval at synapse	Calculated interval at synapse (ms)
−13 ms	−15 ms	−15.7 ± 0.28
−3 ms	−5 ms	−5.6 ± 0.97
+3 ms	1 ms	0.6 ± 0.78
+6 ms	4 ms	4.2 ± 1.00
+9 ms	7 ms	6.5 ± 1.16
+12 ms	10 ms	9.3 ± 0.95
+22 ms	20 ms	19.0 ± 1.22

Positive intervals indicate presynaptic volley before postsynaptic volley.