Table 2.
Correlation of fMRI readouts with structural connectivity and vascular parameters.
| (a) | Interhemispheric interaction |
|||
|---|---|---|---|---|
| se-fMRI: ΔBOLDmax(il)/ΔBOLDmax(cl) |
rs-fMRI: FC (z-score aPc (S1)) |
|||
| Factor | Variance explained (%) | p-value | Variance explained (%) | p-value |
| FA (CC) (structural connectivity) | 0.27 | 0.47 | 62.51 | 0.003 (**) |
| CBVbsl (S1) | 0.06 | 0.21 | 0.01 | 0.98 |
| Slope ΔCBV/Δt (S1) (vascular reactivity) | 0.31 | 0.96 | 0.96 | 0.59 |
| ΔCBVmax (S1) (vascular reserve) | 6.69 | 0.19 | 0.57 | 0.67 |
| Body weight | 8.11 | 0.24 | 1.12 | 0.45 |
| Residuals | 84.54 | 34.81 | ||
| (b) | Local signal amplitude |
|||
| se-fMRI: ΔBOLDmax(cl) |
rs-fMRI: ALFF in aPc (S1) | |||
| Factor |
Variance explained (%) | p-value | Variance explained (%) | p-value |
| FA (CC) (structural connectivity) | 4.52 | 0.97 | 5.41 | 0.94 |
| CBVbsl (S1) | 7.87 | 0.98 | 4.53 | 0.63 |
| Slope ΔCBV/Δt (S1) (vascular reactivity) | 3.18 | 0.33 | 9.98 | 0.20 |
| ΔCBVmax (S1) (vascular reserve) | 27.23 | 0.02 (*) | 0.04 | 0.96 |
| Body weight | 0.14 | 0.84 | 2.6 | 0.46 |
| Residuals | 57.06 | 77.44 | ||
Statistical analysis with linear models for interhemispheric interactions and local amplitudes for both se-fMRI and rs-fMRI signals as a function of structural connectivity, vascular parameters, and body weight, measured under 1.1% isoflurane using a stimulus amplitude of 0.5 mA. (a) The ratio of the maximal amplitude of the BOLD response in the contra- and ipsilateral S1HL cortex (ΔBOLDmax(il)/ΔBOLDmax(cl)) following electrical hindpaw stimulation and FC in aPc were used as metrics to represent interhemispheric interactions for se-fMRI and rs-fMRI, respectively. (b) ΔBOLDmax(cl) following hindpaw stimulation in the se-fMRI experiment and resting-state ALFF values in (aPc) S1 were selected as metrics to representing local amplitude of the fMRI signal. The following factors were selected as explanatory variables: interhemispheric structural connectivity represented by FA of the CC, CBVbsl, vascular reactivity represented by the slope ΔCBV/Δt of the CBV response elicited by the injection of acetazolamide, vascular reserve represented by the ΔCBVmax of the acetazolamide response in S1, and the animal body weights. Structural connectivity (FA (CC)) was found to have a significant association with interhemispheric FC between the aPc regions, whereas vascular reserve was significantly associated with the BOLD response evoked by sensory paw stimulation. Variance explained of each factor in the model is expressed as percentage of the total sum of square. The p-values are obtained with likelihood-test ratio, *p ≤ 0.05, **p ≤ 0.01. Significant values are highlighted in bold case.