Table 3.
Stimulus intensities and MEP amplitudes under different stimulus conditions in Experiments 2 to 6
| S1–S2 ISI | Stimulus intensity (% of maximum stimulator output) |
MEP amplitude (mV) under different conditions |
||||||
|---|---|---|---|---|---|---|---|---|
| Threshold | CS | S1 | Adjusted S1 | S1 alone (A) | CS-S1 (E) | S1 alone (Acon) | ||
| Experiment 2 | 1.5 ms | 49.0 ± 6.6 | 0.8RMT | 54.8 ± 6.5 | 74.5 ± 13.4 | 0.50 ± 0.19 | 0.59 ± 0.18 | 0.48 ± 0.25 |
| (n= 8) | 2.9 ms | — | 0.8RMT | 54.8 ± 6.5 | 74.5 ± 13.4 | 0.57 ± 0.12 | 0.59 ± 0.22 | 0.57 ± 0.15 |
| 4.5 ms | — | 0.8RMT | 54.8 ± 6.5 | 74.5 ± 13.4 | 0.56 ± 0.13 | 0.47 ± 0.05 | 0.60 ± 0.17 | |
| Experiment 3 | 1.5 ms | 69.0 ± 9.0 (AP) | 0.8RMT (PA) | 75.2 ± 12.1 | 86.3 ± 13.2 | 0.56 ± 0.15 | 0.48 ± 0.28 | 0.49 ± 0.37 |
| (n= 7) | 48.3 ± 6.7 (PA) | |||||||
| Experiment 4 | 4.5 ms | 39.8 ± 7.7 (AMT) | 0.6AMT | 58.3 ± 12.4 | 60.8 ± 9.5 | 0.58 ± 0.17 | 0.54 ± 0.20 | NT |
| (n= 6) | — | 0.7AMT | 58.3 ± 12.4 | 65.2 ± 10.7 | 0.53 ± 0.13 | 0.48 ± 0.17 | NT | |
| — | 0.8AMT | 58.3 ± 12.4 | 70.8 ± 13.5 | 0.55 ± 0.20 | 0.58 ± 0.13 | NT | ||
| — | 0.9AMT | 58.3 ± 12.4 | 80.3 ± 11.8 | 0.59 ± 0.18 | 0.53 ± 0.22 | NT | ||
| — | 1.0AMT | 58.3 ± 12.4 | 74.8 ± 10.9 | 0.56 ± 0.20 | 0.55 ± 0.18 | NT | ||
| Experiment 5 | 4.0 ms | 47.5 ± 10.4 | 0.8RMT | 58.3 ± 12.4 | 76.8 ± 10.5 | 0.58 ± 0.25 | 0.49 ± 0.18 | NT |
| (n= 6) | 4.5 ms | — | 0.8RMT | 58.3 ± 12.4 | 76.8 ± 10.5 | 0.58 ± 0.25 | 0.49 ± 0.18 | NT |
| Experiment 6 | 1.5 ms | 48.3 ± 6.7 | 0.8RMT | 56.0 ± 7.2 | 52.0 ± 9.1 | 0.49 ± 0.16 | 0.50 ± 0.26 | 0.54 ± 0.22 |
| (n= 7) | 2.9 ms | — | 0.8RMT | 56.0 ± 7.2 | 52.0 ± 9.1 | 0.49 ± 0.19 | 0.53 ± 0.31 | 0.57 ± 0.24 |
| 4.5 ms | — | 0.8RMT | 56.0 ± 7.2 | 52.0 ± 9.1 | 0.63 ± 0.21 | 0.52 ± 0.23 | 0.64 ± 0.21 | |
AMT, active motor threshold; RMT, rest motor threshold; AP, anterior–posterior; PA, posterior–anterior; NT, not tested. AMT was used in Experiment 4. RMT was used in other experiments. RMT both in PA and AP current directions was tested in Experiment 3. For other experiments only RMT in PA current direction was tested. S1 intensity used in condition E was adjusted to produce 0.5 mV MEP in the presence of CS. Values are expressed as means ± standard deviation.