Table 2.
Dataset characteristics
| Monkey A |
Monkey X |
|||
|---|---|---|---|---|
| Low intensity | High intensity | Low intensity | High intensity | |
| Recording Characteristics | ||||
| Number of muscles recorded | 24 | 24 | 23 | 23 |
| Number of cortical sites tested | 139 | 140 | 108 | 107 |
| Number of recording sessions (days) | 55 | 46 | ||
| Preferred current intensity (μA) | 15 | 110 | 15 | 110 |
| Average actual current intensity (μA) | 15.5 ± 3.5 (15–50) | 107.6 ± 4.4 (100–120) | 15.0 ± 0.0 (15–15) | 109.6 ± 1.9 (100–110) |
| Percent of sites at preferred intensity | 97.8% | 75% | 100% | 96.3% |
| Frequency of stimulus pulses (Hz) | 10 | 10 | 10 | 10 |
| Number of epochs used+ | 1981 ± 122.5 | 1038 ± 138.9 | 2006 ± 85.2 | 1046 ± 61.4 |
| Result Characteristics | ||||
| Number of muscles with PStF in an StTA, averaged across all sites | 5.9 ± 4.0 (0–17) | 14.6 ± 5.7 (1–23) | 3.8 ± 2.8 (0–13) | 11.3 ± 5.0 (0–22) |
| % of sites with PStF: | ||||
| Shoulder muscles | 12 ± 5% | 37 ± 11% | 5 ± 3%# | 22 ± 10% |
| Elbow muscles | 15 ± 3% | 42 ± 8% | 8 ± 4% | 22 ± 7% |
| Wrist/Digits/Hand muscles | 18 ± 3% | 40 ± 5% | 10 ± 3%# | 27 ± 5% |
| One-way ANOVA results# | p = 0.047*, NPS | p = 0.621 | p = 0.022* | p = 0.200 |
| Minimum number of synergies needed | 10 | 5 | 11 | 4 |
Means are given ±1 SD, while the range is given in parentheses, when appropriate. A trial is a single average of hundreds of stimulation pulse responses.
+Epoch is analogous with stimulus pulse in this case, as each stimulus pulse was used to select the corresponding epoch of data. Thus, this is the average number of pulses used to calculate an StTA.
*Significant main effect seen for muscle group in a one-way ANOVA for each of the datasets.
NPS, Post hoc tests with Bonferonni corrections for multiple comparisons showed no significance in the A-LOW dataset.
#Results from a one-way ANOVA testing the effect of muscle group on percentage of sites with PStF are shown for each data set. Post hoc tests with Bonferonni corrections for multiple comparisons demonstrated that the average percentage of sites with PStF in the shoulder muscles was significantly less than those for the wrist/digits/hand muscle group (p = 0.022) for the X LOW StTA dataset.