Abstract
The present study applied spectral analysis of finger photoelectric plethysmogram (PTG) to describe the emotional factor involved in baseline deflection of PTG. Using 23 normal male students as subjects, PTG was measured under rest, verbal instruction, and electric shock conditions. PTG spectral analysis via fast Fourier transform was carried out on the consecutive 10×9ms×1024 points×4 (398.64s) samples in each condition with frequency resolution at 0.0109Hz. In the analysis of power spectra, two distinct power peaks were observed in all conditions; below 0.3Hz and around 1.0Hz. It was confirmed that the former was baseline deflection and the latter was heart beat component. There were no differences in each peak frequency among conditions. Whereas peak power below 0.3Hz tended to increase all through verbal instruction and electric shock conditions as compared to rest one. These results were discussed in relation to anxiety involved in emotion.
