Behavior and TMS
| Experiment 1 (n = 18) | Experiment 2 | |||
|---|---|---|---|---|
| TMS task | fMRI task | Controls (n = 15) | PreHD (n = 14) | |
| Behavior (selective stop condition) | ||||
| Go accuracy (%) | 91.3 ± 5.1 | 87.2 ± 4.7 | 91.8 ± 5.0 | 86.2 ± 10.6 |
| Go RT (ms) | 611 ± 90 | 614 ± 81 | 863 ± 209 | 1100 ± 285* |
| Go decoupling rate (%) | 7.6 ± 4.8 | 3.9 ± 4.2 | 6.2 ± 3.3 | 11.5 ± 10.4 |
| Stop probability (%) | 50.3 ± 5.8 | 53.0 ± 11.8 | 57.0 ± 7.8 | 62.8 ± 8.1 |
| Stopping direction errors (%) | 3.5 ± 3.8 | 5.6 ± 7.6 | 2.0 ± 2.8 | 3.4 ± 3.5 |
| Continuing hand RT on stops (ms) | 755 ± 89 | 739 ± 81 | 1186 ± 360 | 1702 ± 55** |
| Stopping Interference Effect (ms) | 68 ± 63 | 60 ± 56 | 221 ± 183 | 467 ± 330* |
| Failed stopping RT (ms) | 559 ± 76 | 551 ± 71 | 720 ± 159 | 949 ± 498 |
| SSD (ms) | 310 ± 61 | 337 ± 60 | 543 ± 142 | 630 ± 143 |
| SSRT (ms) | 282 ± 61 | 251 ± 44 | 292 ± 94 | 405 ± 290 |
| TMS | ||||
| Resting motor threshold (% of max) | 46.2 ± 7.8 | N/A | 41.2 ± 6.9 | 47.3 ± 9.8 |
| Stimulation level (% of maximum) | 51.2 ± 8.1 | N/A | 45.5 ± 7.2 | 52.4 ± 9.8 |
| MSR MEP (mV) | 0.54 ± 0.36 | N/A | 0.77 ± 0.44 | 0.81 ± 0.37 |
| MSL MEP (mV) | 0.55 ± 0.33 | N/A | 0.86 ± 0.50 | 0.81 ± 0.40 |
| Null MEP (mV) | 0.53 ± 0.37 | N/A | 0.85 ± 0.47 | 0.78 ± 0.39 |
| MSR MEP modulation (%) | 4.4 ± 20.6 | N/A | −7.8 ± 11.9 | 6.5 ± 15.7** |
| MSL MEP modulation (%) | 16.9 ± 37.2 | N/A | 3.5 ± 24.3 | 6.5 ± 18.3 |
↵Values given as average ± SD. MEP, mean motor evoked potential amplitude (trimmed) for a given condition. MEP Modulation (percentage) is calculated as follows: (MSR or MSL MEP − Null MEP)/(Null MEP) × 100%. For Experiment 2, asterisks represent significant differences between preHD and controls at the *p < 0.05 and **p < 0.01 levels. See Materials and Methods for details regarding the calculation of the Stopping Interference Effect.