Figure 2. Effects of SICI on IHI10 and IHI40 data from 10 subjects.

IHI_1mV represents IHI with a CCS of 1 mV (IHI10: condition 1B/1A, IHI40: condition 1G/1A). IHI_1mVCS2 represents IHI with intensity of the CCS adjusted to produce a 1 mV MEP in the left FDI muscle if preceded by a CS2 pulse (IHI10: condition 1E/1A, IHI40: condition 1J/1A). SICI-IHI_1mVCS2 is IHI in the presence of SICI (IHI10: condition 1F/1A, IHI40: condition 1K/1A). SICI significantly reduced both IHI10 and IHI40 when matched for stimulus intensity (IHI_1mVCS2 versus SICI-IHI_1mVCS2), but not when matched for MEP amplitude (IHI_1mV versus SICI-IHI_1mVCS2). Inhibition or facilitation is expressed as a ratio of the conditioned to unconditioned MEPs. Ratios above 1 represent facilitation and ratios below 1 represent inhibition. Error bars represent s.e.m. *Significant difference (P < 0.05).