## 3 Results

Table 2: Differences of absolute power of electroencephalogram (EEG) with eyes open before and after watching a video. In addition, in the eyes open condition, the rmANOVA analysis of brain source activities showed significant main effects of time and brain region in alpha1 (\(F\) = 3.393, \(df\) = 5.355, \(p\) = 0.001) and alpha2 (\(F\) = 3.446, \(df\) = 5.207, \(p\) = 0.001) frequency bands. In the post hoc results, the following measurements were significantly increased after VR than before VR: alpha1 (342.635 \(\pm\) 236.021 vs. 515.076 \(\pm\) 423.659, \(p\) = 0.001) and alpha2 (590.988 \(\pm\) 462.924 vs. 795.884 \(\pm\) 683.322, \(p\) = 0.001) band activation in the cuneus, as well as alpha2 band activation in the posterior cingulate gyrus (PCG) (370.731 \(\pm\) 323.503 vs. 493.818 \(\pm\) 442.367, \(p\) = 0.001). This result is presented in Table 3 and Figure 1.  
In the eyes closed condition, the rmANOVA analysis of frequency band power showed no significant difference of main effect. However, in post hoc analysis, delta band power of the posterior region (12.301 \(\pm\) 5.067 vs. 13.434 \(\pm\) 6.234, \(p\) = 0.047) and beta2 band power of the global region (2.988 \(\pm\) 1.126 vs. 3.186 \(\pm\) 1.246, \(p\) = 0.047) were increased after VR. The rmANOVA analysis of brain source activities showed a significant main effect of time and brain region in beta1 frequency band. However, there was no significant result after post hoc analysis. Pearson correlation analysis was applied to the change of source activities (after-before) of the cuneus and PCG, as well as to the change of SSQ scores (after-before), to examine whether these factors were related to cyber sickness. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline  & \multicolumn{2}{c}{**Before VR**} & \multicolumn{2}{c}{**After VR**} & \multirow{2}{*}{\(\mathbf{t}\)} & \multirow{2}{*}{\(\mathbf{p}\)} \\ \cline{2-2} \cline{5-5}  & & \multicolumn{2}{c}{_Mean \(\pm\) SD_} & & \\ \hline
**Beta1** & & & & \\ Anterior & \(3.094\pm 1.358\) & \(3.158\pm 1.174\) & \(-0.400\) & 0.692 \\ Middle & \(2.819\pm 1.592\) & \(2.534\pm 1.089\) & 1.489 & 0.147 \\ Posterior & \(3.331\pm 1.751\) & \(3.676\pm 1.704\) & \(-2.441\) & 0.021 \\ Global & \(2.942\pm 1.263\) & \(3.063\pm 1.216\) & \(-1.191\) & 0.243 \\
**Beta2** & & & & \\ Anterior & \(4.944\pm 4.066\) & \(4.708\pm 2.811\) & 0.546 & 0.589 \\ Middle & \(3.394\pm 2.580\) & \(2.927\pm 1.721\) & 1.558 & 0.130 \\ Posterior & \(2.301\pm 1.480\) & \(2.562\pm 1.384\) & \(-1.732\) & 0.094 \\ Global & \(3.220\pm 1.754\) & \(3.181\pm 1.389\) & 0.240 & 0.812 \\
**Gamma** & & & & \\ Anterior & \(5.145\pm 4.356\) & \(4.824\pm 3.459\) & 0.517 & 0.609 \\ Middle & \(3.868\pm 3.569\) & \(3.214\pm 2.584\) & 1.432 & 0.163 \\ Posterior & \(1.414\pm 1.439\) & \(1.532\pm 1.308\) & \(-0.572\) & 0.572 \\ Global & \(3.058\pm 1.895\) & \(2.950\pm 1.614\) & 0.381 & 0.706 \\ \hline \hline \end{tabular}  
* \(p_{adj}\) \(<\) 0.0125 (Bonferroni correction adjusted \(p\)-value: 0.05/4 = 0.0125, where 4 refers to four brain sub-regions).  
\end{table} 
Table 2: _Cont._ \begin{table}
\begin{tabular}{l c c c c c} \hline \hline
**Frequency Band** & **MN Coordinate** & \multicolumn{2}{c}{**Before VR**} & \multirow{2}{*}{\(\mathbf{t}\)} & \multirow{2}{*}{\(\mathbf{p}\)} \\ \cline{3-3} \cline{5-6} \multicolumn{1}{c}{**and Brain Region**} & & & & \\ \cline{3-3} \cline{5-6} \multicolumn{1}{c}{} & & & & \\ \hline Alpha1 and Cuneus & \((-5,-80,35)\) & \(342.635\pm\) & \(515.076\pm\) & \(-3.631\) & \(<\)0.001 * \\  & \(236.021\) & \(423.659\) & \(-795.884\pm\) & & \\ Alpha2 and Cuneus & \((-5,-85,35)\) & \(462.924\) & \(683.322\) & \(-3.657\) & \(<\)0.001 * \\ Alpha2 and PCG & \((5,-70,15)\) & \(370.731\pm\) & \(493.818\pm\) & \(-3.633\) & \(<\)0.001 * \\  & \(323.503\) & \(442.367\) & \(-3.633\) & \(<\)0.001 * \\ \hline \hline \end{tabular}  
* \(p_{adj}\) \(<\) 0.00151 (Bonferroni correction adjusted \(p\)-value: 0.05/33 = 0.00151, where 33 refers to 33 brain sub-regions).  
\end{table}