## 3 Results
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**EEG Indices** & **Site** & **Before Inhalation (\(\mu\)V\({}^{2}\))** & **During Inhalation (\(\mu\)V\({}^{2}\))** & \(t\)**-Test** & \(p\)**Value \({}^{*}\) \\ \hline AFA & Cp6 & 4.1374 \(\pm\) 1.5095 & 1.6438 \(\pm\) 1.0255 & 2.102 & 0.049 \\ \hline AB & Cp6 & 14.7287 \(\pm\) 8.7909 & 10.4411 \(\pm\) 8.8256 & 2.243 & 0.037 \\ \hline AHB & Cp6 & 7.6548 \(\pm\) 4.9757 & 5.3986 \(\pm\) 4.7224 & 2.565 & 0.019 \\ \hline ALB & Cp6 & 3.2775 \(\pm\) 1.7220 & 2.1519 \(\pm\) 1.5705 & 2.596 & 0.018 \\ \hline AG & Cp6 & 9.4893 \(\pm\) 7.0053 & 7.2170 \(\pm\) 6.6503 & 2.183 & 0.042 \\ \hline RST & Cp6 & 0.3243 \(\pm\) 0.0671 & 0.2172 \(\pm\) 0.0506 & 2.171 & 0.043 \\ \hline RMT & F3 & 0.3474 \(\pm\) 0.0930 & 0.2264 \(\pm\) 0.0630 & 2.229 & 0.038 \\ \cline{2-6}  & Cp6 & 0.4220 \(\pm\) 0.0957 & 0.2730 \(\pm\) 0.0833 & 2.111 & 0.048 \\ \hline RSMT & F3 & 0.7462 \(\pm\) 0.1598 & 0.4902 \(\pm\) 0.1312 & 2.219 & 0.039 \\ \cline{2-6}  & Cp6 & 0.5872 \(\pm\) 0.1481 & 0.3999 \(\pm\) 0.1026 & 2.159 & 0.044 \\ \hline SEF50 & T8 & 12.3871 \(\pm\) 1.2176 & 10.1593 \(\pm\) 0.8395 & 2.374 & 0.028 \\ \hline \hline \end{tabular}  
* AFA, absolute fast alpha; AIB, absolute low beta; AHB, absolute high beta; AB, absolute beta; AG, absolute gamma; RST, ratio of SMR to theta; RMT, ratio of mid beta to theta; RSMT, ratio of SMR mid beta to theta; SEF50, spectral edge frequency 50%; The results are significant changes of absolute and ratio values before and during the inhalation of geosmin with the exclusion of relative values (Out of 25 EEG indices). Values are expressed as the mean \(\pm\) standard deviation.
* Significant difference (\(p\)\(<\) 0.05), Number of subjects—20.  
\end{table} 
Table 1: Significant changes of EEG power spectra during the inhalation of geosmin in both genders. In the present study, the effect of inhalation of geosmin and 2-methylisoborneol on EEG activity according to gender variation was also analyzed. In men, there was no significant change in absolute and relative values during the exposure of geosmin. On the other hand, a significant increase of absolute alpha (3.5391-4.6670 uV\({}^{2}\) at F8) and fast alpha (0.4061-0.7929 uV\({}^{2}\) at F8 and 0.3116-0.6550 uV\({}^{2}\) at T8) activity was observed during the inhalation of 2-methylisoborneol (Table 3). The \(t\)-mapping of brain wave changes clearly expressed the modification of EEG waves due to the exposure of 2-methylisoborneol in men (Figure 3). In addition to absolute waves, relative alpha, relative slow alpha, and RAHB (3.7485-5.4337 uV\({}^{2}\) at Fc6) significantly increased in men during the inhalation of 2-methylisoborneol. In the case of women, significant changes were observed in 18 indices during the inhalation of geosmin and 10 indices during the inhalation of 2-methylisoborneol. The absolute waves, high beta (14.0263-10.5390 uV\({}^{2}\)), and low beta (5.6537-3.9980 uV\({}^{2}\)) significantly decreased at the Cp6 region during the inhalation of geosmin (Table 2; Figure 3). The relative values of alpha, beta, gamma, fast alpha, slow alpha, low beta, mid beta, and high beta significantly decreased during the inhalation of geosmin. Additionally, a significant decrease of RST, RMT, RSMT, SEF50, SEF90, and ASEF was observed in women (Table 2). With regards to SEF50 and SEF50 activity, significant changes were