# Visual Demands of Walking Are Reflected in Eye-Blink-Evoked EEG-Activity
## 3 Results
### EEG Parameters
#### 3.2.2. ERPs
ing by topography was found (F(3,105) = 38.43, \(p<0.001\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.51\)), due to the fact that a difference between standing and walking in Alpha power level was observed at occipital sites only (frontal: F(1,35) = 0, \(p>0.1\); temporal: F(1,35) = 0.54, \(p>0.1\); parietal: F(1,35) = 3.59, \(p>0.1\); occipital: F(1,35) = 32.40, \(p<0.001\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.47\)). The Alpha level also increased with block (F(1,35) = 12.67, \(p=0.002\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.24\)), and this effect differed across electrode sites as well (interaction of block x topography: F(3,105) = 5.94, \(p=0.015\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.12\); frontal: F(1,35) = 27.05, \(p<0.001\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.42\); temporal: F(1,35) = 9.38, \(p=0.008\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.19\); parietal: F(1,35) = 13.94, \(p=0.001\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.26\); occipital: F(1,35) = 0.44, \(p>0.1\)). Finally, a triple interaction of walking condition by block by topography was observed (F(3,105) = 3.87, \(p=0.032\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.07\)). This modulation of the block effect across channel topography was observed only for walking on the meadow (F(3,105) = 9.83, \(p<0.001\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.18\)), but not for standing (F(1,35) = 1.62, \(p>0.1\)). Additionally, in the analysis across the two walking conditions, the Alpha base level further increased when traversing the obstacle course (F(1,35) = 14.12, \(p=0.001\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.27\)). This effect was, again, most pronounced at occipital sites (interaction of walking condition x topography: F(3,105) = 21.79, \(p<0.001\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.37\); frontal: F(1,35) = 3.63, \(p>0.1\); temporal: F(1,35) = 3.75, \(p>0.1\); parietal: F(1,35) = 0.93, \(p>0.1\); occipital: F(1,35) = 33.91, \(p<0.001\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.48\)). As in the comparison of walking on the meadow vs. standing, the Alpha level also increased with block (F(1,35) = 6.30, \(p=0.033\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.130\), which was least pronounced occipital (interaction of experimental block by topography: F(3,105) = 12.76, \(p<0.001\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.25\); frontal: F(1,35) = 8.79, \(p=0.011\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.18\); temporal: F(1,35) = 4.58, \(p=0.008\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.09\); parietal: F(1,35) = 23.05, \(p<0.001\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.38\); occipital: F(1,35) = 2.08, \(p>0.1\)). No main effect of walking was observed for Alpha perturbations when standing and walking on the meadow were compared (F(1,35) = 0.39, \(p>0.1\)). However, we found a significant interaction of walking conditions and topography (F(3,105) = 20.70, \(p<0.001\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.35\)). An effect of walking condition was only observed at the parietal electrode cluster (frontal: F(1,35) = 0.11, \(p>0.1\); temporal: F(1,35) = 0.03, \(p>0.1\); parietal: F(1,35) = 23.93, \(p<0.001\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.39\); occipital: F(1,35) = 5.43, \(p=0.051\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.11\)). Alpha perturbations marginally decreased with block (F(1,35) = 4.78, \(p=0.071\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.10\)). This effect differed between walking conditions (F(1,35) = 5.23, \(p<0.001\), \({}_{\text{adj}}\eta_{\text{p}}{}^{2}=0.18\)). Figure 6: Level of Alpha power and task-related perturbations (means and standard error of means) for the three walking conditions and separated for the two blocks. Alpha level increased with walking complexity at occipital sites. Alpha perturbations were increased for both walking conditions at parietal sites and decreased at occipital sites. Significant effects of walking condition are depicted for all pairwise comparisons (***: \(p<0.001\); \(+\): \(p<0.1\)). \(p=0.056\), \({\rm{adj}}{\rm{\eta_{p}}}^{2}=0.11\)).