Figure 7. Effects of DZP and BAC on the interaction LICI–SIHI.

Data are from eight subjects. A–C, SIHI in the absence of LICI was quantified as the ratio of MEP amplitudes in conditions K/I (‘SIHI_STIM’) and C/A (‘SIHI_MEP’). SIHI in the presence of LICI was quantified as the ratio of MEP amplitudes in conditions N/L (‘LICI–SIHI’). SIHI was significantly less in the presence of LICI than in the absence of LICI matched for TS intensity (SIHI_STIM) and test MEP amplitude (SIHI_MEP) in all three sessions (Student's paired two-tailed t tests; P < 0.0001). SIHI in the absence of LICI was significantly less in the TS intensity-matched condition (SIHI_STIM) as compared to the test MEP amplitude-matched condition (SIHI_MEP) (Student's paired two-tailed t test; P < 0.0001). PBO, DZP and BAC had no effect on the interaction between LICI and SIHI. Note that all data are derived from the Post₂ measurement where SIHI and LICI alone were readjusted to baseline after drug intake (see Methods and Fig. 1). Error bars, s.e.m.