Table 2.
Mean differences between patients and healthy subjects in effective connectivity among motor areas in the context of affected hand movements (right-hand movements for healthy subjects) (DCM B-matrix) (follow-up tests for significant interaction effects from a 2 (group)×30 (connection) ANOVA corrected for multiple comparisons, Dunn et al., 1961).
| Connection modulated by affected/right-hand movements | Mean (SD) coupling strength for controls a | Mean (SD) coupling strength for patients a | Mean Δ in coupling strength (SEM) (patients–controls) | Correlation with composite motor performance score b |
|---|---|---|---|---|
| Session 1 (≤72 hours post-stroke, n=12) | ||||
| IL PMC–IL M1 | +0.1717 (0.0346) | +0.0749 (0.0728) n.s.c | Δ−0.097 (0.023) | r=0.64 (p=0.013) |
| IL PMC–IL M1 | +0.1392 (0.0667) | +0.0667 (0.0432) | Δ −0.072 (0.023) | r=0.71 (p=0.005) |
| CL PMC–IL M1 | +0.1075 (0.0443) | +0.0488 (0.0720) n.s.c | Δ−0.059 (0.024) | n.s. |
| IL SMA–CL M1 | −0.0783 (0.0565) | −0.0385 (0.0325) n.s.c | Δ +0.040d (0.019) | n.s. |
| IL PMC–CL M1 | −0.0600 (0.0426) | −0.0258 (0.0135) | Δ +0.034d (0.013) | n.s. |
| IL M1–CL M1 | −0.0592 (0.0332) | −0.0176 (0.0243) n.s.c | Δ +0.042d (0.012) | r=−0.50 (p=0.048) |
| Session 2 (10–14 days post-stroke, n=12) | ||||
| IL SMA–IL M1 | +0.1717 (0.0346) | +0.1260 (0.0514) | Δ−0.046 (0.018) | n.s. |
| CL M1–IL M1 | −0.0142 (0.0326) n.s.c | 0.0187 (0.0199) | Δ +0.033d (0.011) | r=−0.51 (p=0.045) |
| IL SMA–CL M1 | −0.0783 (0.0565) | −0.0367 (0.0335) | Δ +0.042d (0.019) | n.s. |
| IL M1–CL M1 | −0.0592 (0.0332) | −0.0299 (0.0253) | Δ +0.029d (0.012) | n.s. |
| IL PMC–CL M1 | −0.0600 (0.0426) | −0.0237 (0.0215) | Δ +0.036d (0.014) | n.s. |
CL, contralesional; IL, ipsilesional; M1, primary motor cortex; n.s., not significant, i.e., p>0.05 corrected; PMC, ventral premotor cortex; SEM, standard error of the mean; SMA, supplementary motor area.
Positive coupling parameters indicate promoting influences, negative coupling parameters indicate inhibitory influences.
Composite motor scores represent the factor values of the first principal component resulting from a PCA of the ARAT score for the affected hand and the grip force index at the respective session.
Coupling parameter was not different from zero in a one-sample t-test within the respective group (p<0.05 FDR-corrected).
Positive differences in inhibitory connections indicate a reduction in inhibition (i.e., “disinhibition”).