Table 2.
Functional MRI (fMRI) BOLD scaling during scaled voluntary muscle activation.
|
A. ANCOVA results in Group B, during scaled GMM voluntary activation
Testing for scaling in averaged BOLD signal extracted from three pre-defined ROIs from Group A | |||
| β 1 comparing BOLD strength during L to strength during H | SMA | M1-L | M1-R |
| Estimated Mean Difference (L-H) | −79.8394 | −61.0844 | −71.5869 |
| standard error (SE) | 15.1499 | 8.8635 | 14.4091 |
| p-value | p < 0.0001 | p < 0.0001 | p < 0.0001 |
| 95% confidence interval | −109.91, −49.711 | −78.6760, −43.4929 | −100.1800, −42.9889 |
| β 2 comparing BOLD strength during M to strength during H | |||
| Estimated Mean Difference (M-H) | −49.8340 | −42.1037 | −49.3905 |
| standard error (SE) | 14.3108 | 8.1451 | 13.3617 |
| p-value | p = 0.0007 | p < 0.0001 | p = 0.0004 |
| 95% confidence interval | −78.2371, −21.4310 | −58.2695, −25.9378 | −75.9097, −22.8713 |
|
B. ANCOVA results in Group B, during scaled PFM voluntary activation
Testing for scaling in averaged BOLD signal extracted from three pre-defined ROIs from Group A | |||
| β 1 comparing BOLD strength during L to strength during H | SMA | M1-L | M1-R |
| Estimated Mean Difference (L-H) | −29.4630 | −38.1871 | −39.1023 |
| standard error (SE) | 4.8281 | 5.2601 | 5.8865 |
| p-value | p < 0.0001 | p < 0.0001 | p < 0.0001 |
| 95% confidence interval | −39.0455, −19.8805 | −48.6270, −27.7473 | −50.7854, −27.4192 |
| β 2 comparing BOLD strength during M to strength during H | |||
| Estimated Mean Difference (M-H) | −28.9518 | −34.9262 | −33.9300 |
| standard error (SE) | 4.7456 | 5.2520 | 5.9434 |
| p-value | p < 0.0001 | p < 0.0001 | p < 0.0001 |
| 95% confidence interval | −38.3705, −19.5330 | −45.3499, −24.5024 | −45.7259, −22.1340 |
Scaling in BOLD signal strength during three distinct levels of voluntary activation, low (L), medium (M), and high (H), is investigated using an ANCOVA model. See MEHODS section. Aij = Intercept + β1 * L + β2 * M + 0 * (H) + β3 * Rij + Ui + Eij Aij is the 75 percentile of the pre-assumed Active period, while Rij is the 50 percentile of the preceding pre-assumed Rest period. L is identifier of low activation, M is identifier of medium activation, and H is identifier of high activation.
Each participant is assumed to have a unique intercept [Intercept + Ui].
SMA (supplementary motor area); M1-L (primary motor cortex, left hemisphere); M1-R (primary motor cortex, right hemisphere).